Life Cycle Analysis of Hemp Textile Yarn

INRA – Institut National de la Recherche Agronomique French National Institute for Agronomy Research Unité Mixte de Recherche INRA-AGROCAMPUS Sol, Ag...
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INRA – Institut National de la Recherche Agronomique French National Institute for Agronomy Research

Unité Mixte de Recherche INRA-AGROCAMPUS Sol, Agronomie, Spatialisation 65, rue de Saint Brieuc – CS 84215 35042 Rennes Cedex, FRANCE

Life Cycle Analysis of Hemp Textile Yarn Comparison of three hemp fibre processing scenarios and a flax scenario Lea Turunen Hayo van der Werf

This report is a result of the European Union project HEMP-SYS - Design, Development and Up-Scaling of a Sustainable Production System for HEMP Textiles: an Integrated Quality SYStems Approach; Contract No QLK5-CT-2002-01363.

Version of 31 May 2006

Abstract In the recent past, there has been a revived interest in natural textile fibres other than cotton. Within the framework of the project HEMP-SYS - Design, Development and Up-Scaling of a Sustainable Production System for HEMP Textiles: an Integrated Quality SYStems Approach, the present study aimed to quantify major impacts associated with the production of hemp yarn using a Life Cycle Analysis (LCA) methodology and to compare the impacts of hemp yarn to those of flax and cotton yarn. For the evaluation of the impacts of hemp crop production, a generic Central-European scenario was sketched, based on hemp production practices in Hungary and France. The flax crop scenario was based on production practices in France, Belgium and the Netherlands. For hemp fibre processing, traditional warm water-retting according to current production practices in Hungary was treated as a reference. Three scenarios were compared to the reference: 1) Bio-retting: hemp green scutching followed by water-retting using selected bacteria, 2) BabyHemp, based on desiccation and stand-retting of pre-mature hemp, 3) dew-retting of flax. The yarn production stage, employing the wet ring spinning technology, was largely same for all four scenarios. Overall, neither of the alternative scenarios was unambiguously better than the reference. The environmental impacts of the hemp reference scenario and the flax scenario were very similar, except for pesticide use (higher for flax) and direct water use (higher for hemp). Bio-retting had higher impacts than the reference scenario for climate change and energy use, due to higher energy input in the fibre processing stage. BabyHemp had higher impacts than the reference scenario for eutrophication, land occupation (both due to its low yield) and pesticide use. Comparison with cotton was difficult due to lack of comparable data, but for the crop production stage hemp performs clearly better than cotton with respect to pesticide use and water use. However, during the fibre processing and yarn production stages hemp requires more energy, resulting in higher impacts. In general, a reduction of the environmental impacts associated with the production of hemp yarn should give priority to a reduction of eutrophication in the crop production phase and of energy use in the fibre processing and yarn production stages. Finally, technological development, in particular aiming at the reduction of labour requirements, seems essential for the successful production of hemp textiles in Europe. Key words: environmental impact, fibre processing, flax, hemp, Life Cycle Assessment, yarn production

“LCA of Hemp Textile Yarn”

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INTRODUCTION .................................................................................................4

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HEMP TEXTILE CHAIN ......................................................................................5 2.1 HEMP ESSENTIALS .......................................................................................5 2.2 LIFE CYCLE OF HEMP TEXTILES.................................................................6

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METHODOLOGY ..............................................................................................11 3.1 3.2 3.3 3.4

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METHODOLOGY IN GENERAL....................................................................11 SCOPE OF STUDY .......................................................................................11 SYSTEM BOUNDARIES AND ALLOCATION PRINCIPLES ........................12 CHARACTERISATION FACTORS................................................................14

LIFE CYCLE INVENTORY – PROCESS DESCRIPTIONS AND DATA ..........16 4.1 CROP PRODUCTION AND HARVEST.........................................................16 4.1.1 Crop production .....................................................................................16

4.1.1.1 Processes and data ...................................................................................... 16 4.1.1.2 Emissions associated with crop production .................................................. 17

4.1.2 Harvest ..................................................................................................18 4.1.3 BabyHemp .............................................................................................18 4.2 FIBRE PROCESSING ...................................................................................19 4.2.1 Overview of fibre processing .................................................................19 4.2.2 Traditional warm water-retting scenario.................................................20

4.2.2.1 Processes and data ...................................................................................... 20 4.2.2.2 Emissions from retting .................................................................................. 24

4.2.3

Bio-retting scenario................................................................................25

4.2.3.1 Processes and data ...................................................................................... 25 4.2.3.2 Emissions from bio-retting ............................................................................ 28

4.2.4 BabyHemp scenario ..............................................................................28 4.3 YARN PRODUCTION....................................................................................28 4.3.1 Processes and data ...............................................................................28 4.3.2 Emissions from bleaching and spinning ................................................30 5

FLAX .................................................................................................................31 5.1 IN GENERAL .................................................................................................31 5.2 CROP PRODUCTION AND HARVEST.........................................................31 5.3 FIBRE PROCESSING AND YARN PRODUCTION ......................................32

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COTTON ...........................................................................................................34 6.1 6.2 6.3 6.4

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IN GENERAL .................................................................................................34 CULTIVATION AND HARVESTING ..............................................................34 FIBRE PROCESSING AND YARN PRODUCTION ......................................35 LCA STUDIES ON COTTON.........................................................................36

RESULTS OF THE IMPACT ASSESSMENT ...................................................37 7.1 IMPACTS FOR HEMP AND FLAX SCENARIOS ..........................................37 7.1.1 Eutrophication........................................................................................37 7.1.2 Climate change......................................................................................39 7.1.3 Acidification............................................................................................39 7.1.4 Energy use.............................................................................................40

“LCA of Hemp Textile Yarn” 7.1.5 Land, pesticide and direct water use .....................................................42 7.2 SCENARIO VARIATIONS .............................................................................42 8

DISCUSSION ....................................................................................................45 8.1 COMPARISON OF THE SCENARIOS FOR IMPACTS AND YIELD ............45 8.1.1 Bio-retting relative to warm water-retting scenario.................................45 8.1.2 BabyHemp relative to warm water-retting scenario ...............................46 8.1.3 Bio-retting scenario relative to BabyHemp.............................................46 8.1.4 Hemp versus flax ...................................................................................46 8.1.5 Hemp versus cotton...............................................................................47 8.2 ENVIRONMENTAL “HOT SPOTS” OF THE HEMP SCENARIOS................49 8.2.1 In general...............................................................................................49 8.2.2 Warm water-retting ................................................................................50 8.2.3 Bio-retting ..............................................................................................51 8.2.4 BabyHemp .............................................................................................52

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CONCLUSIONS AND OUTLOOK ....................................................................53

REFERENCES ..........................................................................................................55 PERSONAL COMMUNICATIONS............................................................................61

APPENDIX A: DETAILED HEMP CROP PRODUCTION INVENTORY APPENDIX B: DETAILS OF THE FLAX SCENARIO APPENDIX C: DETAILED FLAX CROP PRODUCTION INVENTORY APPENDIX D: ADDITIONAL DATA CONCERNING PROCESS INPUTS APPENDIX E: INVENTORY – CROP PRODUCTION APPENDIX F: INVENTORY – FIBRE PROCESSING APPENDIX G: INVENTORY – YARN PRODUCTION APPENDIX H: COMPARISON OF TRANSFORMATION EFFICIENCIES AND YARN YIELDS

“LCA of Hemp Textile Yarn”

1 INTRODUCTION Ever since Eve ate the apple, clothing and textiles in general have been indispensable parts of our human existence. These days, textile manufacture and retail are a big business, as the lifetime of a product is determined not so much by its wearability than by ever changing fashion trends. Cotton and synthetic fibres, 48% and 45%, meet most of the worldwide textile demand (WWF, 1999). Both are associated with considerable environmental problems: Synthetic fibres deplete non-renewable fossil resources, while contemporary cotton cultivation is characterised by high water requirements and use of substantial amounts of fertilisers and pesticides. Furthermore, cotton cultivation is restricted to sub-tropical climates (Pimentel et al., 1991; WWF, 1999). Under the paradigm of sustainable development, alternatives are looked for. There is an increasing recognition that a shift towards non-cotton natural fibres could contribute greatly to the sustainability of the textile industry. In the European context, alternative fibre crops such as hemp and flax are also interesting because they grow well Europe wide, while cotton thrives only on the most southern edge of the continent. Furthermore, fibre crop cultivation is compatible with the recent EU agricultural policy promoting a switch from food to non-food crops. In November 2002, a comprehensive EU-funded 3-year study called HEMP-SYS was launched under the thematic programme: Quality of life and management of living resources of the 5th Framework (Amaducci, 2003). One of the main objectives of the project is to “promote the development of a competitive, innovative and sustainable hemp textile industry in the EU by developing an improved, ecologically sustainable production chain for high quality hemp fibre textiles…” (HEMP-SYS, 2002). Within the framework of the project, the present study aimed to quantify major impacts associated with the production of hemp textiles using the life cycle analysis (LCA) method, in order to generate propositions for modifications of the production chain, leading to reduced impacts. The study compared the impacts of hemp to those of flax and cotton. In practice, the analysis was carried out up to and including the production of yarn; the functional unit was 100 kg of bleached yarn, which is also used as a unit of comparison between the alternative fibres.

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“LCA of Hemp Textile Yarn”

2 HEMP TEXTILE CHAIN 2.1 HEMP ESSENTIALS Hemp (Cannabis sativa L.) is an annual plant, with a rigid, woody stem, which varies from 150 to 550 cm in height. The leaves are characteristically palmate with 7 to 9 leaflets (Sankari, 2000). The fibre of commercial interest is derived from the stem. Hemp (as well as flax) is a bast fibre plant, which means that the fibres are extracted from the outer part of the plant stem, called bast (Ebskamp, 2002). The inner part of the stem consists of woody core. A single bast fibre cell (fibril) is 2-100 mm in length (Sankari, 2000). Fibres are tightly joined together by hemicelluloses, pectins and lignins and thus form fibre bundles, whose theoretical length may extend to the entire plant height (Sankari, 2000). The hemp industry uses these fibre bundles, called “technical fibres”, as a raw material. Normally, for simplicity, the term “hemp fibre” refers to technical fibres, not to individual fibre cells. Isolation of the technical fibres from the plant stem requires several steps and yields three valuable fractions: long fibres (the product of interest for this study), short fibres and shives (broken woody core). Use of hemp for textiles is not a new invention, but rather a rediscovery. Hemp (along with flax) was an important source for textile yarns until the 18th century. It is often mentioned that Levi Strauss made his first jeans from hemp cloth. European hemp production, especially for textile applications, declined to close to zero after World War II for several reasons: large scale production of cotton, high labour costs compared to the developing countries, the appearance of synthetic fibres, and drug policies. The last few decades have shown a revived interest in hemp as a renewable resource. Hemp has been praised by some as a true wonder crop. The potential of hemp as an attractive crop for sustainable fibre production was pointed out in the early 1980’s (Hanson, 1980). A study by van der Werf et al. (1995), among others, proved most claims of early hemp advocates to be true and concluded that hemp is indeed an agronomically attractive crop. Hemp can supply high fibre yields, requires little or no pesticide and suppresses weeds and some major soil-borne diseases. Thus, it has been concluded that hemp manifestly fits into organic/sustainable farming systems (van der Werf et al., 1996). Hemp can be easily incorporated into current cropping systems. It is commonly grown in rotation with winter wheat. Gorchs and Lloveras (2003) report that farmers consider it an excellent break crop for wheat for several reasons. Hemp is effective in suppressing weeds, thus leading to reduced herbicide costs for the following crop. Hemp leaves the soil in excellent condition, allowing direct drilling for the subsequent winter wheat. They also report a significant yield increase in a wheat crop grown after hemp in comparison to wheat grown in monoculture. In the EU, a marked increase in hemp cultivation has taken place during the past few years, but the total area planted to hemp is still modest: 15300 ha in 2003 (EU-15) (Eurostat, 2004). Several bast fibre based industries are operating in the European Union: hemp is used in speciality papers (e.g. cigarette papers), technical textiles (e.g. twine, rope, geotextiles), car parts (e.g. dashboards), and building materials (insulation materials) (Sankari, 2000). However, fibre production in the European context, with high labour costs, can only be truly profitable if the

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“LCA of Hemp Textile Yarn” raw material can be transformed into high added-value products. Textiles are a good example of such an application.

2.2 LIFE CYCLE OF HEMP TEXTILES A “cradle to grave” life cycle of hemp (or another natural fibre) textiles in “coarse resolution” is depicted in Figure 1.

CROP PRODUCTION

Production and supply of energy carriers (e.g. electricity, diesel)

FIBRE PROCESSING

YARN PRODUCTION Waste water treatment FABRIC PRODUCTION Production of fertilisers, pesticides, chemicals, machines etc.

FINISHING

TEXTILE MANUFACTURE Solid waste management Transport

RETAIL

USE RECYCLING DISPOSAL

Figure 1. The main stages of the life cycle of (hemp) textiles. The white boxes are within the scope of this study (the life cycle stages following yarn production, and solid waste management were not included).

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“LCA of Hemp Textile Yarn” This study focussed on the first three main stages of the life cycle, i.e. on the yarn production chain. The first stage in this chain is crop production. In the fibre processing stage the fibres are extracted from the stem and transformed to raw material for yarn and subsequently fabric production. Each of the main production stages comprises many smaller, successive operations, i.e. each sub-system contains a chain of unit processes. There are many alternative production techniques and methods and, if sketched in more detail, a standardised textile production chain does not exist. Hemp is grown in several parts of Europe. At the other end of the yarn production chain, techniques and know-how exist to spin hemp long fibre into yarn. The stage in between, the fibre processing, is for the moment the bottleneck of the hemp textile production chain. At present traditional fibre processing of hemp is at the same technological stage as 50 years ago. As this technology is labour intensive, it is only viable for low labour-cost countries (e.g. Hungary, Romania, China). For the Western-European context, an optimum processing method is still to be found. Garment production from yarn onwards might seem a straightforward sequence of weaving, cutting of fabric and sewing the pieces together. In the modern world, however, the story is much more complicated, even for a basic garment like a T-shirt. A wide variety of treatments exists to modify the qualities and/or appearance of the textiles. The resources of this study did not allow us to delve into the complexity of textile finishing, and therefore the LCA was carried out up to and including the yarn (see Chapter 4). Nevertheless, below, the main processes of the garment production and the rest of the life cycle, as well as their environmental significance are outlined. This hopefully helps a reader to get a more complete picture over the life cycle. The quantitative contribution of the individual life cycle stages (Figure 1) to most of the environmental impacts is poorly documented. For energy consumption, a provisional estimation is that the consumption in the first three stages (crop production, fibre processing, yarn production) is of the same order of magnitude as the consumption in the subsequent three stages (fabric production, finishing, textile production) (Pulli, 1997). However, the energy consumption in the “Use” phase is estimated to be approximately three times higher (Pulli, 1997; Blackburn and Payne, 2004). Fabric production There are two main methods for creating apparel fabric from yarn: weaving and knitting. Weaving involves the interlacing of yarns at right angles (e.g. denim jeans, blouses). Knitting involves looping the yarn or yarns around and through one another (e.g. T-shirt, pull-over) (Seagull and Alspaugh, 2001). Energy consumption plays a significant role in both operations, as they are mechanical processes. The figures can differ significantly from one mill to another (Table 1), amongst others because energy consumption per kg of cotton increases strongly with the fineness of the yarn. Alternative techniques and weaving machines also differ greatly in their energy requirement (Weber, 1998). Needless to say, knitting has its own energy requirements. Apart from energy use, weaving involves another environmental concern: prior to the actual weaving, the warp1 is sized, i.e. sizing agents are applied to the warp in order to lubricate and protect it during weaving. The main sizing agents are either based on native polysaccharides or fully synthetic polymers. The type of sizing agent applied varies according to the fibres processed, the weaving technique etc. Furthermore, sizing agent formulations are usually 1

The warp are the threads which are held along a loom while other threads are passed across them.

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“LCA of Hemp Textile Yarn” mixtures of various substances; additional auxiliaries may also be present in the sizing mixtures. The sizing agents are later removed by the finisher in a desizing process, which results in a high chemical oxygen demand (COD) load in the wastewater (EC, 2003). Table 1. The variability of energy consumption for three phases of the (cotton) textile chain (modified from Weber, 1998). Production phase

Energy consumption (MJ/kg cotton)

Spinning (yarn production) Weaving Finishing

15-47 15-57 58-125

Finishing “Finishing” is a term used to refer to all the different treatments that aim to modify the aspect of the yarn or fabric, bringing added comfort, style and functionality. The term is somewhat misleading, since the finishing processes are not necessarily the last steps in cloth manufacture. They can indeed be positioned at different stages of the production process (Figure 2).

FINISHING PROCESSES pretreatment, dyeing, printing, functional finishing, washing, drying, etc.

FIBRE PROCESSING

Loose fibres

YARN PRODUCTION

Yarn

FABRIC PRODUCTION

Fabric

Figure 2. Finishing processes in relation to the textile chain (modified from EC, 2003).

The finishing processes include pre-treatment, dyeing, printing, functional finishing and coating; washings and dryings are also involved. “Textile finishing” cannot be defined as a standard sequence of treatments, but rather is a combination of unit processes that are chosen, depending on the requirements of the final user. The details of all the finishing options are not given here, but the following description of cotton pre-treatment serves to illustrate the complexity of the issue. The purpose of the pre-treatments is to prepare the fibre/fabric for dyeing. For example, cotton pre-treatment includes normally various, mostly wet, operations: singeing = removing the protruding surface fibres by passing the fabric through a gas flame desizing = removing sizing compounds from woven fabric previously applied to the warp scouring (also known as boiling-off or kier boiling) = extraction of impurities present on the raw fibre or picked up at a later stage mercerising (with tension/caustification/ammonia mercerising) = different techniques/ methods, carried out to improve tensile strength, dimensional stability and lustre of cotton bleaching = an obligatory step when the fibre has to be dyed in light colours

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“LCA of Hemp Textile Yarn” Some of these operations are obligatory only for certain make-ups; some treatments can be combined in a single step (EC, 2003). Potentially, all the above-mentioned steps are employed just in preparation for dyeing; various dyes and dying techniques would require a study of their own. Finishing processes cover also more special treatments such as fireproof, antibacterial etc. finishing. The IPPC BREF (EC, 2003) is a good reference to contemporary textile finishing. The energy consumption and emission levels associated with finishing depend on the type of fibre, the choice of processes, the techniques and the machinery employed. The main environmental issues arising from finishing are emissions to water and energy consumption (Table 1). Emissions to water are of concern, as water is used as the principal medium for removing impurities, applying dyes and finishing agents. The input of chemicals and auxiliaries added at the finishing mills can amount to up to 1 kg per kg of processed textile. Residues in the product are negligible; therefore the bulk is discharged as aqueous effluent. The range of these substances is very extensive: more than 7000 auxiliaries have been listed. Among the products applied during the process, the highest environmental loads arise from salts, detergents and organic acids (in that order). Typical COD loads are in the order of 40-80 g/kg fibre (EC, 2003). Energy is consumed primarily in raising the temperature of the baths and in drying and curing2 operations. To this aim steam is normally produced on-site. Electrical energy is required for driving the machinery. The total specific energy consumption is in the range of 29-72 MJ/kg of finished textile, where the consumption of electricity is about 1.8-5.4 MJ/kg (EC, 2003). Textile manufacture The manufacture of textiles (garments, home textiles etc.) mostly involves cutting the fabric and sewing the pieces. These processes do not involve environmental concerns beyond the use of electricity for the machines. Some textile waste is also produced at the cutting step, but this has been minimised by modern computerised cutting systems. One LCA relevant aspect is the transport of cloth to developing countries, where the labour intensive manufacturing is frequently carried out, and the transport of the ready products back to industrialised countries. Use Use of a garment itself does not affect the environment, but the impacts of maintenance on the life cycle of apparels and textiles are major (Pulli, 1997; Blackburn and Payne, 2004). Domestic laundering is a very frequent task in households and involves use of water and detergents as well as energy for the washing machine and, more and more frequently, also for drying. Blackburn and Payne (2004) calculate that the consumer use accounts for 76% of the energy consumption of a cotton towel over its lifetime. Recycling and disposal Some form of recycling is an important part of the life cycle of textiles. Nearly half of the household textiles are recycled either in their original form or e.g. as cleaning rags before their final disposal (Figure 3). The application of carefully controlled heat to a fabric or garment to cause a reaction in the finishing agents thus fixing it. Finishing agents that require curing include some pigments, easy-care finishing agents, etc. They are applied on the fabric prior to curing, normally by padding. For example, curing permanently sets previously pressed creases in certain wash and wear garments.

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“LCA of Hemp Textile Yarn”

Loss 8%

Landfill 40%

Second hand 10% Cleaning rags 5%

Old clothes, exported 20% Combustion 12%

Old clothes, domestic 5%

Figure 3. Fate of old household textiles in 1990 (from Weber, 1998).

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“LCA of Hemp Textile Yarn”

3 METHODOLOGY 3.1 METHODOLOGY IN GENERAL Environmental impacts associated with hemp yarn production were evaluated using a method called Life Cycle Assessment (LCA). LCA involves quantifying and evaluating the resources consumed and the emissions to the environment at all stages of the life cycle of a product – it encompasses extraction of resources; production of materials, product parts and the product itself; use of the product and its reuse, recycling or disposal (Guinée et al., 2002). After defining the goal and scope of the assessment, the first step is to compile an inventory of the relevant inputs and outputs of a system (the result of this phase is called the Life Cycle Inventory, LCI). In the subsequent Impact Assessment phase, the potential environmental impacts associated with those inputs and outputs are evaluated (ISO,1997). The calculations were elaborated by means of the computer software SimaPro 5.1 (PRé Consultants, Amersfoort, The Netherlands). A normalisation was carried out, i.e. the impact score for each environmental theme was divided by the annual per capita impact score in Europe. Normalisation helps to “better understand the relative magnitude for each indicator result of the product system under study” (ISO, 2000).

3.2 SCOPE OF STUDY Rather than carrying out a complete LCA over the entire life cycle of hemp textiles, as outlined in chapter 2.2, this study analysed the environmental impacts of the production of bleached, 100% hemp yarn of approximately 26 Nm3. The functional unit of the study was defined as 100 kg of this yarn. Production of the functional unit was studied from “cradle to gate”, i.e. emissions and use of resources from agricultural crop production, through fibre processing until the end product were taken into account. Further use of the yarn (for textile manufacture) or its disposal was excluded from the analysis, as sufficient time was not available. Environmental impacts of textile production processes have been studied by Laursen et al. (1997), Pulli (1997) and Blackburn and Payne (2004). The consumer use phase is included in the two latter publications on LCA of a cotton t-shirt and cotton towels, respectively. For the evaluation of the impacts of the crop production phase, a generic Central-European crop production scenario was sketched, based mainly on information on hemp production in Hungary and France. Environmentally relevant parameters did not seem to differ significantly between Hungary and France. Traditional, water-retting based hemp fibre processing (see Chapter 4.2), which has completely disappeared from Western Europe, is still exercised in Eastern Europe, most importantly in Hungary and Romania. The production volumes have greatly diminished in the last decades. Such traditional processing is not directly applicable in Western Europe due to many labour intensive steps, but in Europe it is still the only operational technology used at a large scale for 3

The metric count number (Nm) specifies the yarn thickness/count. The count number in Nm indicates the length in meters of one gram of yarn. Hence a gram of 26 yarn is 26 meters long. The yarn of this count is typically used for example for denim fabric, i.e. jeans.

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“LCA of Hemp Textile Yarn” the production of hemp fibre for textiles. So, a reference scenario was defined based on traditional hemp fibre processing in Hungary. The reader should note that in this report the term “water-retting” is used interchangeably with “warm water-retting”. For Western European high labour cost conditions, less labour intensive and thus economically more viable fibre processing methods are searched for. At the moment various approaches are being developed side by side. In this study we constructed two alternative scenarios to be compared with the reference scenario. These scenarios are elaborated on in chapter 4.2. Here it is important to mention that, whereas the reference scenario is based on an old, proven technology, the two other scenarios describe technologies/methods that are still at a development stage. The data for these scenarios is based on small-scale pilot production and is therefore provisional, and more uncertain than the data the reference scenario is based on. The yarn production was assumed to employ wet spinning technology, which is commonly used in the production of fine bast fibre yarns. Light bleaching of rove (an intermediary product in yarn production) was included in the analysis. The impacts of yarn production were estimated based on production parameters from the Linificio e Canapificio Nazionale Company, Italy, which is one of the most important bast fibre wet spinning mills in the world. It is not only interesting to compare the environmental impacts of the three different hemp scenarios, but also to see how the impacts of hemp yarn production compare to those of its alternatives. Flax shares many characteristics with hemp (fibre meta-structure and the resulting processing, fibre properties etc.). It is produced in Europe and also advertised as an environmentally friendly crop (low fertiliser and pesticide inputs etc.) (among others Sharma and Van Sumere, 1992; Sankari, 2000; ITL, 2004). We are not aware of any LCA study comparing hemp and flax fibres for textile application or of a study on flax, comparable to our assessment. So, a scenario was defined for fibre flax production and processing. The scenario is based on flax cultivation in France/Belgium/Netherlands, which is at the leading edge of European flax production, and on the common flax long fibre processing methods employed in Europe. There was also a desire to compare hemp with cotton, the most common textile fibre (WWF, 1999). However, available time was not sufficient to construct a cotton production scenario for this study. Thus the comparison will be based on published cotton LCA studies. The comparison will be qualitative rather than quantitative, because the direct comparison of LCA studies is hardly possible, due to different basic assumptions, scope of study and so on. In general, the life cycle stages that are within the scope of this assessment lend themselves well for the comparison of hemp textiles with the flax or cotton equivalents. From yarn onwards the production processes are in principle similar for all the three fibres. As mentioned above, further processing does not depend so much on the fibre (as hemp, flax and cotton are all natural cellulose fibres) as on the desired end product and its qualities.

3.3 SYSTEM BOUNDARIES AND ALLOCATION PRINCIPLES System boundaries differentiate the system under analysis from its environment. General boundaries of the study are given below. Process specific system boundaries, data sources and assumptions are discussed in more detail in the following chapters.

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“LCA of Hemp Textile Yarn” Capital equipment: Construction, transport from the factory and maintenance of machinery that is directly employed in the production processes were included, with a few exceptions when data was not available (contribution of those machines was estimated to be not very significant). Buildings, however, were not included in the analysis due to lack of data. Possible impacts of storage between various production stages were not taken into account. The machinery used for crop production, fibre processing and yarn production was assigned to three categories, with different production and delivery emissions. The categories are listed in Table 2. The emissions associated with the production, delivery, repair and maintenance of the machines were taken into account based on Gaillard et al. (1997). The impacts were allocated to the relevant processes according to the hours of use compared to the total hours of use over the service life of the machine. Table 2. Machinery classification (modified from Gaillard et al., 1997). Category

Description

Energy requirement (in MJ/kg) for Manufacture

Repair/Maintenance

A

Tractors (95 % steel, 5 % rubber)

14.6

26

B

Harvesters (95 % steel, 5 % rubber)

12.9

23

C

Other machines (100 % steel)

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28

Land occupation: Agricultural land occupation was included within the system boundaries, whereas land occupation owing to industrial infrastructure was not. Human labour: The impacts of human labour were excluded. It should be kept in mind, however, that the different production scenarios do require significantly different inputs of human labour. For any socio-economic evaluation or overall decision-making process such differences are highly relevant. Chemicals: The production of chemicals (pesticides, bleaching agents etc.) was taken into account whenever sufficient data was available. However, the effects of pesticides used in crop production on the environment were not assessed. Transport of raw materials and intermediate products were included in the study. On the contrary, the short transports within one processing site (e.g. moving bales around with a forklift) were neglected. Also, intermediate baling of fibres (except baling at field) and other packaging for storage or transport were not considered.

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“LCA of Hemp Textile Yarn” Allocation principles The allocation of environmental impacts, in the case of co-products4, was based on the economic value, which represents a measure of the incentive for production (Audsley et al., 1997). Economic allocation is not without problems, as the prices of natural fibres fluctuate according to the supply-demand situation, which is affected by many factors ranging from agricultural yield to fashion trends. Nevertheless, economic allocation was chosen over massbased allocation, because long (and short) fibres represent only a small fraction of the stem mass, but they are the major reason for hemp cultivation. For flax it is even more so: 85% of the economic value of a fibre flax crop is generated by the long fibres, that, by weight, represent only 10-20% of the yield (Mallet, pers. comm., 2004). Thus, in our opinion, it only makes sense to allocate the environmental effects to the co-products based on economic value. Published price statistics, which would be the preferred source for price data, were unfortunately not available for hemp. We consulted a number of producers and experts in order to obtain a reliable estimation of the prices for the purpose of this analysis. The prices reflect the situation in 2003-2004. It is important for the reader to realise that for the purpose of an economic allocation it is the relative values of the co-products rather than their absolute prices that really matter. Furthermore, the prices of similar products in different scenarios need not be identical, as long as within one allocation step the prices reflect the relative value of the co-products. Data sources At the inventory step the production system under study must be defined in terms of the flows of energy and material entering the system (inputs) and the polluting substances emitted to the environment outside the system boundaries (outputs). This requires appropriate data sources. Project partners provided process- and site-specific data, which was complemented by literature sources. Personal communication with project partners, producers and experts was an irreplaceable source of data for this study. The list of informants is included at the end of the report.

3.4 CHARACTERISATION FACTORS In the Life Cycle Impact Assessment phase, it is first determined which impact categories (environmental themes) will be considered. The impact categories considered in this study are: eutrophication, climate change, acidification, energy use and land occupation. Next, the indicator result for each impact category is determined. This is done by multiplying the aggregated resources used and the aggregated emissions (from the life cycle inventory) of each individual substance with a characterisation factor for each impact category to which it may potentially contribute (Heijungs et al., 1992). Characterisation factors are substance specific, quantitative representations of the additional environmental pressure per unit emission of a substance (Huijbregts et al. 2000). The characterisation factors used in this study are given below for each impact category.

4

A co-product is any of two or more products from the same unit process (ISO, 1998).

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“LCA of Hemp Textile Yarn” Eutrophication covers all potential impacts of high environmental levels of macronutrients, in particular N and P. Eutrophication potential (EP) was calculated using the generic EP factors by Guinée et al. (2002) in kg PO4-eq., NH3: 0.35, NO3: 0.1, NO2: 0.13, NOx: 0.13, PO4: 1, N: 0.42, P: 3.06 and chemical oxygen demand (COD): 0.022. Climate change was defined here as the impact of emissions on the heat radiation absorption of the atmosphere. As recommended by Guinée et al. (2002) Global Warming Potential for a 100year time horizon (GWP100) was calculated according to the GWP100 factors by IPCC (Houghton et al., 1996) in kg CO2-eq., CO2: 1, N2O: 310, CH4: 21. Acidifying pollutants have a wide variety of impacts on soil, groundwater, surface waters, biological organisms, ecosystems and materials (buildings). As recommended by Guinée et al. (2002) Acidification Potential (AP) was calculated using the average European AP factors by Huijbregts (1999) in kg SO2-eq., NH3: 1.6, NO2: 0.5, NOx: 0.5, SO2: 1.25. Energy use refers to the depletion of energetic resources. Energy use was calculated using the Lower Heating Values proposed in the SimaPro 1.1 method (PRé Consultants, 1997), crude oil: 42,6 MJ/kg, natural gas: 35 MJ/m3, uranium (in ore): 451000 MJ/kg, coal: 18 MJ/kg, lignite: 8 MJ/kg, gas from oil production 40.9 MJ/m3, wood pellets 17 MJ/kg. Land occupation refers to the use of land as a resource, in the sense of being temporarily unavailable for other purposes due to the growing of crops. This is a quantitative assessment, which does not distinguish quality of land use. In addition to these impact categories that are commonly considered in an LCA study, the use of pesticides was assessed. However, the impacts of pesticides and their metabolites were not taken into account in this study, as appropriate characterisation factors are lacking for many of these substances. The direct water use in processing was also calculated. No characterisation was involved, as we did not intend to transfer this production input into a larger impact category.

Average European AP factors take into account regional sensitivity to acidification. The indicator result is expressed in “kg SO2 emitted in Switzerland equivalent”, with the AP factor for Switzerland being 1.0. The value of the average European AP factor for SO2 (1.2) indicates that, on average, Europe is more sensitive to acidifying pollutants than Switzerland.

15

“LCA of Hemp Textile Yarn”

4 LIFE CYCLE INVENTORY – PROCESS DESCRIPTIONS AND DATA 4.1 CROP PRODUCTION AND HARVEST 4.1.1 Crop production 4.1.1.1

Processes and data

For the evaluation of the impacts of the crop production phase, a generic Central-European crop production scenario was sketched, based mainly on information on hemp production in Hungary supplied by Iványi, I. (pers. comm., 2004). Additional data sources were van der Werf (2002) and a discussion with French hemp producers (Quinton, S. et al., pers. comm., 2004). There was insufficient data to construct regional or national production scenarios and, in fact, environmentally relevant parameters, such as the amounts of fertiliser and fuel used due to field operations, do not seem to vary significantly across Europe. The hemp crop is assumed to be grown for the stem/fibre only. The investigated crop production scenario is described below. The detailed production inventory is given in Appendix A (see also Appendix E). The field operations preceding hemp production depend on the previous crop, which is commonly winter wheat. Wheat stubble breaking is regarded as part of the wheat production process and thus outside the system boundaries of this study; the first operation included in the analysis is the ploughing of the field, 26-32 cm deep. Lime application is assumed to take place once every three years. Amounts of fertiliser applied are: 68 kg N, 30 kg P2O5 and 114 kg K2O per hectare. According to Good Agricultural Practice, the amount of fertilisation was calculated based on the anticipated crop needs (van der Werf, 2002). Two passes by tractor were assigned for the fertiliser application, i.e. nitrogen is applied separately, while phosphate and potassium applications are coupled. See Appendix D for further details on process input data (energy carriers, fertilisers etc.). Subsequently, the seedbed is harrowed and 55 kg of seed per hectare is sown. The production of the seed for sowing was taken into account, assuming similar inputs to those of the fibre crop, with a few exceptions: amount of seed (25 kg/ha), need for mechanical weed control, harvest of seed with a combine harvester, and a seed yield of 1000 kg/ha (Quinton et al., pers. comm., 2004). Road transport of the seed to the farm over a distance of 300 km was included. Until the harvest there are no further operations. No pesticides are used on hemp. The use of common contemporary agricultural machines is assumed for field operations, despite the fact that the current state of the machinery in some hemp production regions, e.g. Hungary, is not as modern as in Western Europe. Details of machinery are presented in Table 3. The duration of different operations and the fuel use (Appendix A) was based on unpublished data from van der Werf (2004).

16

“LCA of Hemp Textile Yarn” Table 3. Details of agricultural machinery.

Machine

Category *

Weight (kg)

Tractor: 4WD, 50 kW

A

3900

7200

Audsley et al., 1997

Tractor: 4WD, 75 kW

A

4700

4200

Audsley et al., 1997

Plough: 4-furrow

C

1300

1200

Audsley et al., 1997

Lime spreader

C

1000

3000

Unpublished data, van der Werf, 2004

Disc broadcaster: >450 l, 15 m

C

280

3000

Audsley et al., 1997

Roller: 5 m

C

1100

500

Unpublished data, van der Werf, 2004

Seed drill: 3m

C

550

525

Audsley et al., 1997

Rotary harrow: 3m

C

1000

540

Audsley et al., 1997

Mounted crop sprayer: 1000 L, 15 m

C

800

4200

Audsley et al., 1997

Cultivator: 2.2 m

C

700

480

Audsley et al., 1997

Blade mower/ Combine harvester: 95 kW

B

7550

1500

Flake et al., 2000

Pulling machine: 55 kW

A

3500

1500

Flake et al., 2000

* See Table 2

4.1.1.2

Service life (hours) (ha)

Reference

Emissions associated with crop production

Ammonia emissions due to the application of ammonium nitrate fertiliser were estimated according to ECETOC (1994): emission factor (EF) was 0.02 kg of NH3-N per kg N applied. The loss of nitrate nitrogen (NO3-N) to groundwater was estimated to be 40 kg/ha, which corresponds to a moderate nitrate loss (van der Werf, 2004). Unpublished data from Hungary (Iványi, pers. comm., 2004) strongly suggests that for regions with low summer and autumn rainfall (such as the Hungarian hemp production regions) 20 kg/ha would be a more likely figure. Emissions of nitrous oxide nitrogen (N2O-N) were estimated according to Mosier et al. (1998). For direct emissions from soils EF was 0.0125 kg of N2O-N per kg N input after the volatilisation of ammonium. For indirectly induced emissions EF was 0.01 kg of N2O-N per kg of NH3-N emitted and 0.025 kg of N2O-N per kg of NO3-N emitted. Emissions of nitric oxide nitrogen (NOXN) were estimated according to Rossier (1998) at 10% of emissions of N2O-N. Run-off of PO4-P to surface water was estimated according to Rossier (1998): an EF of 0.01 kg of PO4-P per kg of P input from fertilisers was used. Emissions of Cd, Cu, Ni, Pb and Zn to the soil were calculated according to a balance approach, considering input by fertilisers and output via harvested produce. Heavy metal content of fertilisers was based on Rossier (1998). Data on heavy metal uptake of crops is rare. Reference uptake was based on a wheat crop yielding 6800 kg/ha of grain containing 0.12 mg/kg of Cd, 5.9 mg/kg of Cu, 0.22 mg/kg of Ni, 0.2 mg/kg of Pb and 31 mg/kg of Zn (contents based on Audsley et al., 1997 and Baize, pers. comm., 2001).

17

“LCA of Hemp Textile Yarn”

4.1.2 Harvest The word “harvest” refers to the gathering of a crop and usually it is understood to include the operations from mowing the crop to collecting it from the field (if not carried out simultaneously). In this report, however, “harvest” refers only to the operation of mowing, which leaves the stems on the field. The subsequent operations depend on the chosen fibre processing method, and are thus discussed as part of the Fibre processing sub-system (chapter 4.2). Fibre hemp is harvested just before the end of flowering, normally in August. The crop is mown and laid down on the ground in swaths. For the long fibre production it is important to keep the hemp stems oriented, i.e. parallel, throughout the harvest and further processing. Hemp harvesting in Hungary is actually carried out by a mower that, in addition to cutting, also binds the stems in sheaves (20-30 cm in diameter). We did not have detailed information on this machine and it is expected to be replaced by a newer technology, because at present the harvest requires a significant amount of human labour. A modern harvester that would accommodate the need for stem orientation is still to be developed. Nevertheless, our scenarios assume such a harvester and we will estimate the LCArelevant parameters, e.g. fuel use, emissions, etc., based on a contemporary blade mower (Table 3). More information on different harvesting technologies can be found in Bassetti et al. (1998) and Müssig and Martens (2003), among others. A stem yield of 8 t/ha was assumed (among others, Meijer et al., 1995; Kozłowski et al., 1998). This weight corresponds to dry stems; dry in this context means 14% humidity. The same principle applies to all the stem and fibre weights given in this report.

4.1.3 BabyHemp The sheer length of the hemp plant explains some of the difficulties concerning its harvest and subsequent handling. In addition, its strong fibres call for a robust cutting equipment at harvest. Most existing bast fibre processing facilities are ill suited for hemp, as they mostly process flax, which is a significantly shorter and more delicate plant. Instead of developing the machinery and processing facilities for hemp, some people have started modifying hemp to suit the existing equipment. In Italy this approach has resulted in a dawning commercial production of “BabyHemp” (Amaducci, 2005). BabyHemp is grown at high plant density. For the purpose of the analysis, BabyHemp crop production is according to the generic European scenario, with the following exceptions: 100 kg seed is sown per hectare (Amaducci, pers. comm., 2004), and the fertilisation was reduced in proportion to the stem yield. Emissions associated with crop production were calculated as explained in 4.1.1.2. The NO3-N loss to groundwater was assumed to be 40 kg/ha, as in the general scenario. The growth of the BabyHemp crop is terminated by herbicide spraying when it is 120-140 cm tall: 4 kg/ha of both the herbicide Glyphosate and the auxiliary substance ammonium sulphate are used (Amaducci, 2005). The resulting stems are similar in length to flax and thus can be further handled and processed with existing flax machinery. After desiccation BabyHemp stems are pulled, instead of cut. This operation is identical to flax pulling, and a number of firms offer machines for flax harvest. We assume the use of a Depoortere self-propelled machine that pulls

18

“LCA of Hemp Textile Yarn” one swath at a time (Flake et al., 2000) (Table 3; Appendix B, Table B2). The machine lays the stems parallel in swaths on the ground.

4.2 FIBRE PROCESSING 4.2.1 Overview of fibre processing I) Traditional warm water retting scenario

II) Bio-retting scenario

HARVEST

HARVEST

DRYING ON THE FIELD

DRYING ON THE FIELD

B

WARM WATERRETTING

DRYING ON THE FIELD

III) BabyHemp scenario

DESICCATION/ STAND-RETTING

HARVEST (Pulling)

B

GREEN SCUTCHING

DEW-RETTING

BIORETTING

DRYING ON THE FIELD

B

DRYING

SOFTENING

SCUTCHING B

SCUTCHING B

B

= Material flow = Transport HACKLING B

= Baling

B

= Baling, excluded from the analysis

Figure 4. Alternative fibre processing scenarios and their unit processes. Unit processes with the same colour have comparable functions. The unit-processes in perforated boxes are discussed within other subsystems.

19

“LCA of Hemp Textile Yarn” Three fibre-processing scenarios were analysed in this study (Figure 4). Boxes with the same colour present operations with a comparable function. The general purpose of the operations (such as retting and scutching) is explained for the traditional warm water-retting scenario, which is considered as the reference scenario. Scenario specific peculiarities are elaborated on in the description of the respective scenario. The process inventories are included in Appendix F.

4.2.2 Traditional warm water-retting scenario 4.2.2.1

Processes and data

Traditionally (and contemporarily in Hungary and Romania) hemp stems are bound as sheaves of 20-30 cm diameter at harvest. In order to facilitate drying, the sheaves are lifted into tepee-like formations (Figure 5), each containing about forty sheaves. After about a week, when the water content of the stems has fallen below 15%, the sheaves are assembled into big, loose, rectangular bales for transport from the field. All this is done manually (Iványi, pers. comm., 2004), so we associate no resource use or polluting emissions to it. The baled hemp is assumed to be loaded by a tractor equipped with a front loader into a truck and transported directly to a fibre-processing site over an average distance of 60 km. Longer stem transport distances are not economically viable (Homonyik, pers. comm., 2004; Pfeiffer, pers. comm., 2004; Tofani, pers. comm., 2004).

Figure 5. Hemp sheaves drying in tepee-like formation at Hungarohemp. (Photo by Turunen, L., 2004)

20

“LCA of Hemp Textile Yarn” Retting The first process at the fibre processing facility is retting. The purpose of retting (the blue boxes in Figure 4) in general is the decomposition of the pectic substances by which the fibre bundles are attached to the surrounding bark matrix and the woody core. This will facilitate the subsequent mechanical separation of the fibre bundles from the rest of the stem. The warm water-retting process relies on the natural micro-organisms (anaerobic bacteria being the most important), that are present on the plant during the growing season. Warm water-retting provides these organisms with good growth conditions (mainly temperature), in which they multiply rapidly and the retting process functions well. More detailed information on retting can be found e.g. in Sharma and van Sumere, 1992. The following description of warm water-retting is based on the actual operational sequence at Hungarohemp Kenderipari és Logisztikai Rt (Hungarohemp, for short), Nagylak, in southeastern Hungary. It is one of the two remaining hemp-processing factories in Hungary; some 30 years ago there used to be around 36 of such factories in the country! (Homonyik, pers. comm., 2004). Unless otherwise mentioned, data is based on a visit to the processing site in August 2004, as well as on personal communication with Attila Homonyik (2004). For retting, loose bales of hemp sheaves are loaded into open concrete retting pools and secured in place with metal bars (Figure 6). Pools are filled with water of about 28 °C, which is a mixture of thermal water (47 °C) and ordinary well water. The reader should note, that no artificial heating is involved and thus the input of non-renewable energy for heating the retting water is zero. The stem-water mass ratio is 1:14. The stems ret for 5 days. During retting the stem mass loss is about 10%. The fate of the retting liquor and associated emissions will be discussed below. The stems need to be dried after retting, in order to prevent spoilage during intermediary storage. The subsequent scutching process requires the raw material to be dry, too. In the warm water-retting scenario the use of a traditional drying method is assumed, in accordance with the Hungarohemp practice. The retted hemp sheaves are assembled again into tepee stacks on a field next to the retting pools. The operation does not cause significant environmental impact. The drying and moving of the bound sheaves requires a great deal of manpower, though. Thus this drying method is not economically feasible in Western Europe and it is likely to be replaced by other methods in the long run in Hungary too. Hemp is retted either right away after harvest in the autumn, if time/weather allows, or in the following spring/summer. In winter, the air temperature is too low for retting, which takes place in outdoor pools. Before and after retting the stems are stored outdoors in big barn-shaped stacks, called “pyramids”. During this storage about 10% of the stems are lost due to spoiling.

21

“LCA of Hemp Textile Yarn” a)

b)

c)

Figure 6. a) A concrete retting pool at Hungarohemp, Hungary. b) Loose bales of hemp sheaves are loaded in the retting pool and secured in place with metal bars. c) Retting in process: the stems are let to ret for 5 days, submerged in water. (Photos by Turunen, L., 2004)

Scutching Retting is followed by a mechanical operation called scutching (purple boxes in Figure 4), which separates the fibres from the rest of the bark and the woody core. Scutching comprises, in fact, two operations: breaking (or crushing) and the actual scutching (or beating, or swingling). The first operation aims at breaking the woody core of the stem into small pieces, called shives, without damaging the fibres. This is done by passing the stems between pairs of fluted rollers. During the actual scutching the broken stems are beaten by rotating blades, so that the shives fall away and short tow fibres are separated from long fibres (Sultana, 1992).

22

“LCA of Hemp Textile Yarn” a)

b)

c)

Figure 7. a) Dry, retted hemp stems are being fed to the scutching machine at Hungarohemp, Hungary. b) Scutching drums. c) At the output end of the scutching machine long fibres are retrieved. (Photos by Turunen, L., 2004)

We took the production parameters according to the process at Hungarohemp (Figure 7). They use a 30-35–year old Italian scutching machine, some parts of which have been recently replaced. The scutching capacity is 1 ton of stems per hour; this consumes 120 kWh of

23

“LCA of Hemp Textile Yarn” electricity from the public grid (Homonyik, pers. comm., 2004). The process data is congruent with data from an Austrian scutching facility (Pfeiffer, pers. comm., 2004). Ayuso (1996) gives a similar consumption of electricity, but a much lower throughput. Apart from electricity, no further inputs are used in this step, but manpower requirements are substantial. At Hungarohemp, the operation of the scutching line involves about 10 people. Apart from the main product, i.e. the scutched long fibre (called “scutched hemp” in hemp industry jargon), scutching produces “scutching tow” (short fibres) and shives, which both have an economic value. The short fibres can be used to make twines or coarse yarns; shives are an excellent material for, amongst others, animal bedding. The co-products call for allocation, which is based on the yields and prices presented in Table 4. Table 4. Co-products resulting from the hemp scutching process, their yield and economic value, both according to Homonyik (pers. comm., 2004), and resulting allocation factors. Co-product Scutched long fibre Scutching tow Shives

Yield (% of the input mass)

Economic value (€/kg)

Allocation factor (%)

9 23 40

1.75 0.75 0.20

38.42 42.07 19.51

Coarse plant residues and dust make up the remaining mass fraction (28%). In most European countries, contemporary regulation concerning safety at work requires the dust to be filtered from air. At Hungarohemp, this waste is burned at the site in a boiler along with other fuels, to provide heating for the factory. We did not consider the benefits of this use as a fuel. Baling and packing of the scutched hemp for the subsequent transport were also omitted from the analysis.

4.2.2.2

Emissions from retting

Water-retting starts with an aerobic phase, in which the bacteria decompose the stems’ pectic materials, releasing CO2 as the main by-product of decomposition. Under oxygen-rich conditions 40-50% of the original carbon content of the stems would be converted into bacterial cell wall carbon. However, without additional aeration, which is the case in both the Warm water-retting and Bio-retting scenarios, the oxygen of the retting liquor is soon depleted. Under anaerobic conditions only about 15 % of carbon is completely metabolised by bacteria; the rest ends up in the retting liquor in the form of fatty acids and other decomposition intermediates (Kozłowski, 1992). Apart from CO2, methane and H2S may sometimes be produced during the anaerobic phase. Accumulating volatile fatty acids, especially butyric acid, are responsible for the characteristic, unpleasant smell arising from water-retting (Ayuso, 1996). The direct air emissions from retting were not taken into account in this study, due to a lack of emission data. Moreover, wastewater is assumed to be much more important an issue than emissions to air, as water-retting results in a large volume of wastewater. Retting liquor is characterised by a high oxygen demand, owing to the high concentration of incompletely degraded organic compounds (Table 5). Thus it should not be released directly into natural waters. The retting liquor can either be spread on agricultural land (Ayuso, 1996; Tofani, pers. comm., 2004) or treated biologically

24

“LCA of Hemp Textile Yarn” (Ayuso, 1996). At Hungarohemp, the wastewater is pumped into a system of 6 settling ponds, where a natural biological cleaning process takes place. Currently the wastewater volume is a small fraction of the volume for which the facility was dimensioned. As a result, the water has a very long retention time in the system. Due to significant evaporation, there is practically no water outflow from the settling ponds to the nearby open channel that eventually discharges into a river. However, considering a hoped-for future increase in the production, there are plans to replace the pond system with a proper water treatment plant. The plant is also foreseen to treat the sewage from the nearby town. Table 5. Average parameters of the retting liquor at the Hungarohemp facility (Homonyik, pers. comm., 2004). The parameters marked with a star (*) were used as inputs in calculations to estimate the emissions from waste water treatment. Parameter pH Chemical oxygen demand, COD * Biological oxygen demand, BOD5 Ammonium * Total P * Suspended matter Soluble substances, total Soluble substances, organic Soluble substances, inorganic Soluble oxygen

Unit

Average value

mg/l mg/l mg/l mg/l mg/l mg/l % of total soluble subst. % of total soluble subst. mg/l

7.5 1827 932 41.8 15.5 106.7 4021 68 32 0

For our analysis we assumed that the retting liquor was treated in a municipal wastewater treatment plant. Wastewater treatment inputs (electricity, chemicals) and emissions were calculated using the Calculation Tool for Municipal Wastewater Treatment Plant (Ecoinvent Centre, 2004). Resource use and emissions due to the construction of the sewage system and the treatment plant infrastructure were not included in the analysis. Raw wastewater parameters from Hungarohemp (Table 5) were used as inputs for the calculation tool. The impacts of sludge disposal were not considered.

4.2.3 Bio-retting scenario 4.2.3.1

Processes and data

A fibre processing strategy based on “green scutching”, followed by “bio-retting” (short for biotechnological retting) is being developed by Gruppo Fibranova, Perignano, Italy, within the HEMP-SYS project. In this scenario, after harvest, the stems are left lying on the field disposed into a parallel swath. The stems dry without additional inputs in 4-8 days to below 15% humidity, which is a prerequisite for successful baling (van der Werf, 2002). A round baler that can pick up and press stems without altering their parallel orientation exists, but we had no specific data on it. Thus the 25

“LCA of Hemp Textile Yarn” impacts of baling were based on a flax round bale press (Appendix B, Table B2). The baled hemp is loaded by a tractor equipped with a front loader onto a truck and transported to a fibreprocessing site over an average distance of 60 km as in the reference scenario. In this scenario we assume that there are no losses due to spoiling, as hemp is stored indoors. Green scutching As the dry stems are brought from the field to the processing site, they are first scutched green6, i.e. the stems are scutched before retting. The advantage of green scutching is that removing the woody core before retting significantly reduces the amount of material to be retted. Thus the water consumption is potentially reduced compared to traditional water-retting. Green scutching is carried out by standard scutching machines. We used the process parameters according to the scutching process at the Waldviertler Flachshaus in Austria (Pfeiffer, pers. comm., 2004). This is one of the places where green scutching for Gruppo Fibranova has been carried out at the pilot stage. A 15-year-old UNION NV (Beveren-Leie, Belgium) flax scutching line is employed. This means that the hemp stems have to be cut into portions of approximately 1 meter. A harvester that would do this is being developed (Amaducci, 2005), but this is not expected to greatly alter the environmentally relevant parameters of the harvesting process. The long fibre scutching line comprises a bale-opener, a breaker as well as 8 scutching turbines. The capacity of the scutching line is approximately 1 ton of stem per hour. The nominal power of the whole line is approximately 150 kW (bale-opener 3 kW, breaker 30 kW, scutching turbines 105 kW, dust extraction and evacuation of shives 12 kW). The normal driving power of the equipment is estimated at 75% of the nominal value. Thus the electricity consumption per ton of stem is estimated at about 112 kWh. Electricity is supplied by the public grid. The process yields green scutched long fibre as well as two other co-products: scutching tow (short fibres) and shives. The allocation factors are presented in Table 6. The remaining mass fraction (30%) is made up by coarse plant residues and dust. The electricity for dust extraction was included in the overall energy consumption, but otherwise the impacts of the treatment and disposal of these wastes were not accounted for. It is actually not known how they are disposed of. Baling and packing of the scutched hemp for the subsequent transport were also omitted from the analysis. Table 6. Co-products resulting from the hemp green scutching process, their yield and economic value, both according to Tofani (pers. comm., 2004), and resulting allocation factors. Co-product Green scutched long fibre Green scutched short fibre Shives

6

Yield (% of the input mass) 12.5

Economic value (€/kg) 1.00

Allocation factor (%) 45.05

12.5

0.50

22.52

45

0.20

32.43

“Green hemp” is a common term applied to unretted stems.

26

“LCA of Hemp Textile Yarn” Bio-retting The green decortication is followed by bio-retting. The principle is the same as in warm waterretting: the hemp fibre is loaded into open tanks that are then filled with heated water. The difference is that, instead of relying on natural bacteria, an inoculum of selected pectinolytic bacteria is added to the water to improve retting. The production of the inoculum was not included in the analysis. For the purpose of the analysis the fibre-water mass ratio was defined as 1:20, based on current practice at Gruppo Fibranova. Wood pellets are used to heat and maintain the retting water at 35 °C for the 72 hours of retting. 60 kg pellets (heating value 17 MJ/kg) are required per 100 kg of green scotched long fibre (Tofani, pers. comm., 2004). After retting, the fibre bundles are chemically separated, but still physically “glued” together by a kind of biofilm (Amaducci, pers. comm., 2004). This can be removed chemically, but this is not in line with the aim of environmentally sound production practices. In place of chemicals Fibranova uses rinsing and mechanical softening after bio-retting, which have shown to yield good results (Amaducci, pers. comm., 2004). Thus, the retted fibre is first rinsed with cold, pressurised water. At present water consumption is 80 l/kg fibre, but it is hoped to be reduced to 50 l/kg and finally, with appropriate filtering devices in place, to 10 l/kg (Tofani, pers. comm., 2004). For the analysis, we assumed a consumption of 50 l/kg of fibre. After retting, the fibres are dried by a hot air dryer. Data on process specific energy demand was not available, so we estimated the impacts based on yarn drying at Linificio (see chapter 4.3): a hot air dryer using steam as a heating media. The steam generator is fuelled by natural gas. The dried fibre needs still to be softened in order to yield fibre of sufficient quality for yarn production. The softening is in principle a mechanical shaking process. Softening removes remaining shives (ca 5%); some of the long fibres may be broken and thus become short fibre. First, the latter part of a scutching line at Waldland was tested for softening, but long fibre loss was very high (ca 40% ended up as short fibres). Fibranova is now changing to a new softening device based on the principle of “counter posed fluted rollers”. It has been assessed that the loss is dramatically reduced to 0.5-1% (Tofani, pers. comm., 2004). We presumed this loss to be 1%, obviously in addition to the above-mentioned 5% of shives. The operation was estimated to require 25% of the engine power of the scutching drums, i.e. 25 kW (Amaducci, pers. comm, 2004). Heuser (1927) happens to give a very similar value for a hemp softening machine of the 1920’s. A second allocation (Table 7) was carried out, although at this step the yields of other coproducts are low. Prices were adopted from the prices of comparable products of the warm water-retting scenario (Table 4). Table 7. Co-products resulting from the hemp bio-retting procedure, including the mechanical softening, their yield and the economic value, both according to Tofani (pers. comm., 2004), and resulting allocation factors. Co-product Yield (% of the Economic value Allocation factor input mass) (€/kg) (%) Long fibre 94 1.75 98.95 Short fibre 1 0.75 0.45 Shives 5 0.20 0.60

27

“LCA of Hemp Textile Yarn”

4.2.3.2

Emissions from bio-retting

No data was available on the emissions to air or the contents of the bio-retting wastewater. Thus we assumed the amount of substances originating from the material to be retted, expressed per dry matter entering the retting tank, to be the same as in the warm water-retting scenario. Due to a lower plant material-water ratio and rinsing, the water volume per unit dry matter input is greater and consequently the wastewater on the whole is more diluted than in warm waterretting scenario. A wastewater treatment was assumed and the resulting emissions were calculated as explained in 4.2.2.2.

4.2.4 BabyHemp scenario The rationale behind the BabyHemp scenario was explained in 4.1.3, as the BabyHemp cultivation technique differs from the “standard” hemp crop production. In this scenario the fibre processing stage overlaps with crop production. Desiccation, which is part of the BabyHemp harvest technique, does not only terminate the crop growth, but it encourages “stand-retting”. After desiccation, the crop is left standing in the field for 30-50 days depending on weather conditions (Amaducci, 2004). Due to fungal colonists, the stems start retting in situ (Sharma and Van Sumere, 1992; Amaducci, pers. comm., 2004). After pulling (see 4.1.3) the stems are left lying on the field until they are dry. If the stems are still not well retted, they may be left on the field for a longer time to stimulate further (dew) retting. We assume that the stems are turned once during drying/dew-retting (Amaducci, pers. comm., 2004). Finally the dry stems are baled with round baling machines. We assume the use of machinery (developed for flax) according to Flake et al. (2000): a Union self-propelled turner and a John Deere pulled baling press (Appendix B, Table B2). Estimations of the stem yield of retted stem vary between 2.5 and 4 ton per hectare (Amaducci, pers. comm., 2004; Amaducci, 2005). An average value of 3.25 t/ha was used in the analysis. Further processing of BabyHemp is like processing of flax and, in essence, like warm waterretted hemp (Figure 4), i.e. the BabyHemp is scutched. The processing parameters were assumed to be same as for warm water-retted hemp (Amaducci, pers. comm., 2004).

4.3 YARN PRODUCTION 4.3.1 Processes and data The impacts of yarn production are estimated based on the long fibre spinning line in a bast fibre spinning mill of Linificio e Canapificio Nazionale, Villa d’Almè, Italy. The scutched or softened hemp is assumed to be transported by road over a distance of 400 km from the fibre-processing site to the yarn production facility. The electricity consumption figures include both lighting and air conditioning, which make up a fair share of the total consumption.

28

“LCA of Hemp Textile Yarn” Hackling In the fibre processing stage the fibres have been separated from the woody core of the plant stems and they have been somewhat refined. The fibres that are used as raw material for yarn production are still in the form of rather coarse fibre strands, i.e. bundles of many fibres held together by hemicelluloses and residual pectins. The material also contains some woody particles (shives) and other impurities. Thus, at the onset of yarn processing, the fibre bundles are further refined in a process called hackling which yields a product called sliver, as well as hackling tow as a co-product. During hackling the fibres are combed with pinned elements (hackles). The action of the pins straightens the fibre, splits the fibre bundles into finer ones and cleans the fibres from adhering shives. The pinning density of the machine increases from the entry end, so as to gradually achieve finer fibre. In the process some fibre bundles unavoidably break down into shorter fibres. The separated short fibres are used in short fibre spinning, which is outside the system boundaries of this study (Ross, 1992; Pavoni, pers. comm., 2004). At the delivery end of the hackling machine the hackled long fibres are overlapped and converted into a continuous length to form a sliver. The yield of sliver was defined as 50% for water-retted hemp and BabyHemp (Pavoni, pers. comm., 2004) and 40% for bio-retted hemp (Tofani, pers. comm., 2004). The allocation factors are presented in Table 8 and Table 9, respectively. The economic value was based on the price information from Linificio (Pavoni, pers. comm., 2004). It was assumed that 10% of the input mass is lost as dust, which is collected by the air filtration system. We didn’t have information on the treatment of the collected dust and it is not taken into account. Table 8. Co-products resulting from the hackling of water-retted hemp and BabyHemp, their yield and economic value (both according to Pavoni, pers. comm., 2004) and resulting allocation factors. Co-product Sliver Hackling tow

Yield (% of the input mass)

Economic value (€/kg)

Allocation factor (%)

50 40

2.15 1.30

67.40 32.60

Table 9. Co-products resulting from the hackling of bio-retted hemp, their yield and economic value (both according to Tofani, pers. comm., 2004) and resulting allocation factors. Co-product Sliver Hackling tow

Yield (% of the input mass)

Economic value (€/kg)

Allocation factor (%)

40 50

2.15 1.30

56.95 43.05

From sliver to rove: the preparation system After hackling, sliver is further processed in a preparation system consisting of a series of six drawing frames and a roving frame. The operating principles of the various “frames” can be somewhat difficult to comprehend. Here it will suffice to say that the preparing system on the one hand gradually draws out the sliver making it longer and thinner. On the other hand, at each frame several slivers are brought together into one in order to improve the regularity and homogeneity of the sliver. In the end, the sliver is given a twist to obtain rove, which is wound on

29

“LCA of Hemp Textile Yarn” big pierced bobbins for the following bleaching phase (Ross, 1992; Pavoni, pers. comm., 2004). Material loss over the preparing system is 5%. Bleaching Bleaching, apart from its whitening action, removes the residual pectins and hemicelluloses. This allows finer and stronger yarns to be spun, compared to untreated rove (Ross, 1992). It is thus an essential operation in the production of fine textile yarns. An alkali treatment replaces bleaching if the natural colour of the fibre is to be retained. Bleaching is, in fact, a sequence of two to four different, subsequent treatments. Rinsing is necessary between the treatments as well as at the end of bleaching, in order to eliminate dirt and chemical products. Bleaching requires elevated temperatures (90 °C) and thus consumes a lot of energy. We took the main chemicals into account according to a peroxide bleaching recipe (Appendix G). No data was obtainable on stabilisers and other auxiliaries (surfactants with emulsifying, dispersing and wetting properties) that are known to be an indispensable part of such treatments (EC, 2003; Pavoni, pers. comm., 2004). On the other hand, most probably it would have been difficult to analyse the environmental aspects associated with these commercial products (EC, 2003). Spinning, drying and winding Eventually hemp is spun into yarn via wet ring spinning. It is a slower and more expensive method than the two other common spinning techniques (open end rotor spinning and vortex spinning). However, to date ring spinning seems to be the only technique that yields pure bast fibre yarns of sufficient quality for apparel textile applications. Wet spun yarn must be dried after spinning. This is carried out in a hot air dryer. Steam, produced by a natural gas fuelled generator is used as a heat carrier. Finally the yarn from small “cops” (spinning bobbins) is wound on bigger cones for retailing in a winding process. The winding machine also checks and removes the defects of the yarn. Apart from spinning technique, the total environmental impacts of yarn production depend greatly on the fineness of the yarn (Weber, 1998). This could not be taken into account, as only average input-output figures were available for the spinning process at Linificio. The data obtained from Linificio corresponds to bast long fibre wet ring spinning, producing pure flax/hemp yarns of 10 to 39 Nm. The fineness of our functional unit, 26 Nm (the finest metric count attainable from hemp at the moment), is in the middle of the production range, but it is not know how the production of different yarn counts is distributed.

4.3.2 Emissions from bleaching and spinning The repeated rinses during bleaching result in a large volume of waste water. At Linificio the bleaching wastewater is treated at a private biological wastewater treatment plant. The wastewater from wet spinning is first treated physico-chemically due to its mineral oil content. Emissions to natural waters were derived from the environmental authorities’ report concerning the effluent water quality at Linificio (Boffelli, pers. comm., 2004). The energy consumption and the inputs for the treatment process were calculated using the Calculation Tool for Municipal Wastewater Treatment Plant (Ecoinvent Centre, 2004). Resource use and emissions due to the construction of the sewage system and the treatment plant infrastructure were not included in the analysis.

30

“LCA of Hemp Textile Yarn”

5 FLAX 5.1 IN GENERAL Flax (Linum usitatissimum L.) is an 80-120 cm tall annual plant with a straight and cylindrical single stem; its diameter at the base varies between 1-2 mm. Like hemp, flax is a bast fibre plant, i.e. its fibres are derived from the outer part of the stem. Different varieties have been developed to be grown either for fibre or for seed. Seed flax is often called linseed. Dual-purpose varieties exist. Not surprisingly, for textile applications, fibre flax varieties are preferred owing to their superior fibre length and quality. Linen is the term normally used to refer to yarns and fabrics made from flax fibre. Flax seed yields oil for industrial uses (paints, soaps etc.); the seedcake or whole seeds are also used as animal feed (ITL, 2004). Generally flax is cultivated in areas where the daily temperature remains below 30 °C. Flax generally requires about 700 mm of annual rainfall; preferably well distributed throughout the year. This accounts for the success of this crop in temperate and maritime areas e.g. in coastal Western Europe (Sultana, 1992). After the Second World War, flax lost its status as an important raw material, but its cultivation and processing never ceased completely, as was the case with hemp. As a consequence, the European flax industry recovered relatively rapidly, once the interest in natural fibres revived. Presently, within the EU (15 countries) 124200 ha were under fibre flax cultivation in 2003 (Eurostat, 2004).

5.2 CROP PRODUCTION AND HARVEST Flax generally follows a cereal crop, frequently wheat, in the crop rotation. As for hemp, a good soil structure is an essential requirement and careful soil preparation is important (Sultana, 1992). Thus, for our production scenario soil preparation was assumed equal to the operations of the generic hemp scenario. Fertilisation was assumed to be 40 kg N, 30 kg P2O5 and 60 kg K2O per hectare, based on fertilisation recommendations and other data sources (among others, Sultana, 1992; Flake et al. 2000; Hanfaes Research Centre, 2004). It is difficult to make a generalisation concerning the fertiliser use, as this depends on the soil nutrient status. To yield good quality fibre and to avoid lodging, excess nitrogen fertilisation should be avoided. In some cases this might mean no nitrogen fertilisation (Sultana, 1992). Emissions associated with crop production were calculated as explained in 4.1.1.2. The NO3-N loss to groundwater was supposed to be 40 kg/ha, as in the general hemp scenario. Dense stands are desirable for fibre flax production in order to encourage the growth of long, slender and unbranched stems. The objective is 1800-2000 plants/m2 (Sultana, 1992). The sowing rate varies according to the variety and its seed size (Sultana, 1992). We assumed the use of 115 kg of sowing seed per hectare.

31

“LCA of Hemp Textile Yarn”

Flax is susceptible to competition by weeds in its early growth phase and good weed control is essential (de Jong and Wood, 1997). Herbicides can be sprayed before and just after sowing or after emergence, when the flax plants are 5-12 cm tall. Once the crop reaches the height of 1215 cm, the high plant density normally provides a good soil cover and, as a result, weeds have difficulty in establishing themselves (Sultana, 1992). A plant protection scenario was constructed, based on the information that, on average, flax is treated three times with plant protection agents, principally with herbicides (ITL, 2004). Data on the most common weeds in flax crops (Sultana, 1992), the principle European flax pests (various sources agreed on (flax) flea beetle and thrips) and recommended treatment doses (Demeestere, 1999) were also used. (Appendix B, Table B1). We assumed that the sowing seeds are treated with a fungicide, as this seems to be recommended and somewhat routinely done (Demeestere, 1999; Hanfaes Research Centre, 2004). Fibre flax is harvested by a pulling machine as described for BabyHemp (chapter 4.1.3), but without desiccation. Yields can vary considerably from one year to another. There is also a large variation between countries. We assumed a yield of 6 ton of dry (14% humidity) stems per ha (Meijer et al., 1995; Kozłowski et al., 1998). In contrast to hemp, a fibre flax crop produces also seed, which is firstly used for sowing the next crop, but the surplus can be sold for other uses (oil extraction, animal feed, etc.). In the fibre production, the decapsuling (i.e. the rippling of the seed capsules from the straw) is often coupled with turning during dew-retting, which will be described below (Sultana, 1992). One ton of fibre flax yields about 100 kg of seed (ITL, 2004). Linseed can yield over 4000 kg seed per hectare; this as a side note. The prices of both flax stem and seed are 0.2-0.3 €/kg (Mallet, pers. comm., 2004), so here the economic allocation is reduced to a mass allocation, which was used to allocate impacts to the two co-products. The inventory of flax crop production in detail is included in Appendix C (see also Appendix E).

5.3 FIBRE PROCESSING AND YARN PRODUCTION Retting Since the 1950’s dew-retting has replaced water-retting for flax in Western Europe, due to its lower labour and capital requirements. A complete mechanisation of the dew-retting method was crucial for the development of the flax sector (Sharma and Van Sumere, 1992). The method involves leaving the pulled stems on the field, exposed to rain, dew and sunshine for several weeks. In Western Europe, dew-retting normally takes about 3 weeks. However, the process is extremely weather dependent and can extend to up to 3 months (Flake et al., 2000; ITL, 2004). During that time the stems are turned at least once, possibly several times, to facilitate even retting. We assumed two turnings in the scenario. The use of a Union self-propelled turner was assumed (Flake et al., 2000) (Appendix B, Table B2). We found no reference for the loss of dry weight during dew-retting and a 10% loss was assumed, as in warm water-retting of hemp. As for hemp, the moisture content should be below 15% at baling. This ensures that the retted flax can be preserved for several years (Sharma and Van Sumere, 1992). Flax is normally

32

“LCA of Hemp Textile Yarn” collected by pressing it into large bales by coiling. The machinery was taken according to Flake et al. (2000): a John Deere pulled baling press. Scutching The flax fibre processing is as described for the Baby Hemp scenario (Figure 4). The allocation factors are given in Table 10. As for hemp, some of the input mass (16%, in this case) ends up as waste, either as coarse plant residues or dust. Their further treatments or disposal methods were not known and they were not taken into account. Table 10. Co-products resulting from the flax scutching process, their yield (based on Flake et al. 2000; A.G.P.L., 2004; Hanson, pers. comm., 2004), economic value (Mallet, pers. comm., 2004) and resulting allocation factors. Co-product Scutched long fibre Scutching tow Shives

Yield (% of the input mass)

Economic value (€/kg)

Allocation factor (%)

18 11 55

1.80 0.35 0.02

86.75 10.31 2.95

Yarn production Hackling parameters are identical to those of hemp, except the relative yields of sliver (long fibre) and hackling tow (short fibre) (Table 11). The remaining operations of yarn production are as described for hemp. The amounts of chemicals used for bleaching are different, though, according to the actual practice at Linificio (Pavoni, pers. comm., 2004). Table 11. Co-products resulting from the flax hackling process, their yield and economic value (both according to Pavoni, pers. comm., 2004) and resulting allocation factors. Co-product Sliver Hackling tow

Yield (% of input mass)

Economic value (€/kg)

Allocation factor (%)

65 25

2.15 1.30

81.13 18.87

33

“LCA of Hemp Textile Yarn”

6 COTTON 6.1 IN GENERAL Cotton is an annual, herbaceous shrub, which is normally cultivated to the height of 1.2 m (the average natural height is 4.5-6.0 m). “Cotton” actually refers to several species, included in the genus Gossypium (three species are commercially important). Cotton is one of the most important non-food crops in the world, and economically the most important vegetable fibre. The cotton fibre, either in its pure form or in blends, is the principal clothing fibre of the world. Botanically, cotton fibres are elongated epidermal cells of the cotton seed coat (Proto et al., 2000). Cotton is cultivated on around 30 million hectares, in over 70 countries in tropical and subtropical regions. However, the “great 6” (India, USA, China, Pakistan, Uzbekistan, and Turkey) produce 75 % of global yield (KATALYSE, 1998). Cotton produces not only fibre but also oil-rich seed. Cottonseed oil is used for cooking, margarine, soap and other chemical and pharmaceutical uses. The residue of seed milling, the cottonseed cake, is used as an animal feed (Proto et al., 2000).

6.2 CULTIVATION AND HARVESTING Intensive monoculture is contemporarily the most common production mode for cotton, less than 1% of the crop is produced organically (Weber, 1998). 73% of the global cotton acreage is irrigated, since irrigation strongly increases yield: an average fibre (lint7) yield of 854 kg/ha is given for irrigated cotton in contrast to 391 kg/ha for rain-fed cotton (WWF, 1999). Rain-fed cotton (high value varieties) requires 800-1000 mm of annual precipitation. Irrigation consumes between 7 (Israel) to 29 (Lake Aral area) cubic meters of water per kilogram of lint, depending on the irrigation technique (WWF, 1999). “The extensive irrigation of cotton has a severe impact on regional freshwater resources, considering that the irrigated cotton is grown mainly in dry climates where water scarcity is a natural phenomenon…Cotton production uses agricultural chemicals heavily and therefore offers a significant risk of pollution of freshwater ecosystems with nutrients, salts and pesticides… ” (WWF, 1999) Besides water, other inputs used in cotton production vary considerably from one region to another. This is reflected in yield figures: whereas Israel produced 1700 kg of lint per hectare in 1996/97 (the highest yield per area in that period), the yields in Uganda reached only 50 kg/ha (KATALYSE, 1998). Global averages (e.g. the yield of 565 kg/ha) are clearly not the right data to be compared with European bast fibre production. We decided to use the data from the United States as a reference for the comparison, because, of the major cotton producers, it corresponds best to European production conditions (level of technology, economic situation etc.). Average USA seed cotton yield for the period 2000-2004 is 2021 kg/ha (FAO, 2005). Using 7

Lint (or “raw fibre”) is the fibres that surround unprocessed cotton seeds. The lint and seed combined, the primary product of harvesting, is called “seed cotton”.

34

“LCA of Hemp Textile Yarn” data on processing efficiencies according to Pulli (1997), after drying and ginning this would yield 708 kg/ha of lint (35%), and 580 kg/ha of yarn (82%). The available literature sources did not give a detailed description of the soil preparation, which presumably involves tillage, base fertilisation and seedbed preparation. In the U.S. in 2000, the amount of synthetic fertiliser applied per hectare of cotton was 159 kg, on average (Organic Trade Association, 2001). According to Spaar (1997) water consumption due to irrigation is 7.8 m3/kg of lint in Texas and 12.2 m3/kg in California. The monoculture production mode makes cotton very vulnerable to weeds, pests and diseases. As a result, approximately 10% of the worldwide pesticide production is applied on cotton. Of this, 66% is insecticides, 19% herbicides, 3% fungicides and 12% harvest aid chemicals (Weber, 1998). Cotton production uses only 2.4% of the total cultivated surface, so pesticide use per unit area is high (WWF, 1999). In the U.S. in 2000, 6.56 kg of pesticides were applied per hectare, on average (Organic Trade Association, 2001). The growth period of cotton is 140-200 days. Once the fibre containing cotton bolls are matured, they are removed by hand or mechanically. In the USA the entire crop is machine picked (Laursen et al., 1997). Cotton harvesters are self-propelled machines that remove the seed cotton8 from the stalk. The seed cotton is then packed on the field into bale modules and transported to the gin for the next operation (Seagull and Alspaugh, 2001). Proto et al. (2000) mention that hand picked cotton “must be picked at weekly intervals to prevent discoloration of the lint (the fibres) in the field. Thus the picking is a very laborious task.” Conventional growers often use growth regulators and defoliants to control boll maturation. Defoliation also facilitates mechanical harvesting and decreases the trash in seed cotton (Laursen et al., 1997).

6.3 FIBRE PROCESSING AND YARN PRODUCTION Due to differences in the morphology of the fibre, cotton fibre processing is less complicated than that of bast fibres. Cotton fibres are elongated epidermal cells of the cotton seed coat. After the harvest a single operation, called ginning, suffices to convert the seed cotton into usable fibres for textile applications. The mature fibres are simply dried and mechanically separated from short fibres and seed. Ginning is the bridge between agricultural cotton production and textile manufacturing, and in this sense it is comparable to bast fibre scutching (Seagull and Alspaugh, 2001). At the spinning mill, machines called openers first open the cotton bales and then clean the fibres, blending the fibres from different bales. Next the fibres are aligned, paralleled, further cleaned and condensed into sliver in a carding process. Then individual slivers are blended in the drawing process, which also continues the paralleling and cleaning of the fibres. Cotton is compatible with the three most common spinning techniques (ring spinning, open end (OE) rotor spinning and vortex spinning) (Steffes, 2004). In general the efficiency of cotton spinning is higher than the efficiency of bast fibre spinning, due to differences in fibre characteristics (Cierpucha et al., 2002). In OE rotor spinning and vortex spinning the drawn sliver is directly spun i.e. roving and winding operations are not required. Thus these techniques are faster and more productive than ring spinning and therefore increasingly favoured. Literature reveals a wide range of values for energy consumption of cotton spinning (Table 12). Laursen et al. (1997) 8

See the previous footnote.

35

“LCA of Hemp Textile Yarn” mention yet another source that puts the total consumption of energy for the same process sequence at 15-45 MJ/kg of textile. Table 12. Literature values for the energy consumption of yarn production in the cotton spinning system.

Preparation

Energy consumption (MJ/ kg) Blackburn and Payne, 2004 Laursen et al., 1997 /kg* /kg yarn

Spinning

Opening and cleaning Carding Blending and combing Drawing Roving Spinning

2.1

0.72-0.92

2.6 -

0.58-0.96 0.48

3.1 0.8

0.21-0.32 0.86-1.16 (only for ring spinning) 2.16-10.2

18.7 (ring spinning) 5.8 ?

Winding Air conditioning and lighting

0.76-2.00 0.53-2.36

TOTAL 33.1 6.33-18.36 *It is not clear from the publication whether the energy consumption is expressed in terms of the output of each process or of the ultimate output of the (towel) production.

6.4 LCA STUDIES ON COTTON Since, within this project, it was not feasible to construct a scenario for cotton, the comparison relies on the cotton LCA results found in the literature. They are not many and due to differences in assumptions, methodology, boundaries of the study etc. direct comparisons are difficult to make. A study by nova-Institut (1996) gives some LCA relevant information on the environmental impacts of the “cultivation and harvest” life cycle stage for cotton, as well as for hemp (Table 13). Weber (1998) cites two studies that estimate the energy consumption in the crop production phase at 10-40 and 39-52 GJ/ton of cotton. Table 13. Primary energy input (PE) and emissions for the life cycle stage “cultivation and harvest” for cotton and hemp (per 1 ton of fibre) (modified from nova-Institut, 1996).

Cotton Hemp

PE GJ

CO2 kg

N2O kg

CO2-Eq. kg

SO2 kg

NO2 kg

SO2-Eq. kg

25.2 8.2

1680 544

3.03 1.26

2650 947

2.49 1.21

14.8 4.52

12.9 4.37

36

“LCA of Hemp Textile Yarn”

7 RESULTS OF THE IMPACT ASSESSMENT 7.1 IMPACTS FOR HEMP AND FLAX SCENARIOS 7.1.1 Eutrophication The eutrophication potential was lowest for the flax scenario (2.6 kg PO4-eq), followed by bioretting and water-retting scenarios (3.0), and highest for the BabyHemp (4.9) (Table 14). The contribution of the crop production stage ranged from 75 to 93%, depending on the scenario (Figure 8). Emissions originating from the soil (N and P) made up about 90% of this. The remainder resulted e.g. from the diesel combustion in the field operations. The retting effluent contributed 13% of the total impact in the hemp water-retting scenario (Figure 8). The role of the effluents in bio-retting scenario was minimal. Yarn production contributed to eutrophication through the emissions of electricity production. The relative contribution of the production of 100 kg of yarn to per capita eutrophication in Europe ranged from 6.8 to 12.9% (Table 15).

kg PO4-eq. / 100 kg yarn

6 5 4

Yarn production

3

Fibre processing: Others

2

Fibre processing: Retting effluents

1

Crop production: Others Crop production: Soil emissions

0 Wa

Bio

BH

Flax

Figure 8. Contribution (in kg PO4-eq.) of the different production stages of the production of 100 kg of yarn to eutrophication, according to the scenarios: hemp water-retting (Wa), hemp bio-retting (Bio), BabyHemp (BH) and flax. Unit processes are shown separately if they contribute 10% or more to the total impact for one or several of the scenarios. “Others” (for crop production and fibre processing) refers, for the specific production stage, to the impacts from unit processes, other than those mentioned separately.

37

“LCA of Hemp Textile Yarn” Table 14. The environmental impacts of yarn production expressed per 100 kg kg of yarn for the investigated scenarios: hemp water-retting, hemp bio-retting, BabyHemp and flax. Impact category Eutrophication Climate change Acidification Energy use Land occupation Pesticide use (active substance) Water use (direct)

Unit

Hemp waterretting

Hemp bioretting

BabyHemp

Flax

kg PO4-eq. kg CO2-eq. kg SO2-eq. MJ 2 m ·year kg

3.04 1350 7.38 25500 1160 0

3.02 1810 9.01 35800 1260 0

4.94 1460 8.02 26500 2410 0.874

2.61 1360 8.16 26100 1150 0.296

m3

19.9

22.1

7.63

7.23

Table 15. Normalised impacts, i.e. the contribution of the production of 100 kg of yarn according to the investigated scenarios (hemp water-retting (Wa), hemp bio-retting (Bio), BabyHemp (BH) and flax (F)) to per capita environmental impacts in Western Europe for five impact categories. Contributions are calculated by dividing the impacts of the production of 100 kg yarn (Table 14) by annual per capita impacts for Western Europe in 1995 (normalisation value). Impact category Eutrophication Climate change Acidification Energy use Land occupation

Unit kg PO4-eq. kg CO2-eq. kg SO2-eq. MJ m2·year

Normalization value

Reference for normalization value

38.4 14600 84.2 154000 10100

Huijbregts et al., 2001 Huijbregts et al., 2001 Huijbregts et al., 2001 Pré Consultants, 1997 Huijbregts et al., 2001

38

Contribution (%) Wa

Bio

BH

F

7.9 9.2 8.8 16.6 11.5

7.9 12.4 10.7 23.2 12.5

12.9 10.0 9.5 17.2 23.9

6.8 9.3 9.7 16.9 11.4

“LCA of Hemp Textile Yarn”

7.1.2 Climate change For this impact, the hemp water-retting and the flax scenarios had the lowest values (1350 and 1360 kg CO2-eq, respectively), followed by the BabyHemp scenario (1460). Hemp bio-retting had the highest impact (1810) (Table 14). For the flax and for two of the hemp scenarios, the crop production stage represented 15-24% of the impacts, fibre processing 6-7% and yarn production 69-78% (Figure 9). For bio-retting the fibre processing stage made up 28% of the total impact, which reduced the relative contribution of yarn production to 56%. The large contribution of the fibre processing stage in this scenario was due to fibre drying.

kg CO2-eq. / 100 kg yarn

The relative contribution of the production of 100 kg of yarn to per capita climate change in Europe ranged from 9.2 to 12.4% (Table 15). 2000

Yarn production: Others

1800

Yarn production: Winding

1600

Yarn production: Drying

1400 1200

Yarn production: Spinning

1000 800

Yarn production: Rove bleaching

600

Fibre processing: Others

400

Fibre processing: Fibre drying

200

Crop production

0

Wa

Bio

BH

Flax

Figure 9. Contribution (in kg CO2-eq.) of different production stages of the production of 100 kg of yarn to climate change, according to the scenarios: hemp water-retting (Wa), hemp bio-retting (Bio), BabyHemp (BH) and flax. Unit processes are shown separately if they contribute 10% or more to the total impact for one or several of the scenarios. “Others” (for fibre processing and yarn production) refers, for the specific production stage, to the impacts from unit processes, other than those mentioned separately.

7.1.3 Acidification Acidification potential was lowest for the hemp water-retting scenario (7.4 kg SO2-eq), followed closely by the BabyHemp (8.0) and the flax (8.2) scenarios. It was highest for hemp bio-retting (9.0) (Table 14). Acidification was largely (62-79%) due to yarn production in all scenarios (Figure 10). Fibre processing was responsible for 8.5-9.7% of the impact in all scenarios, except bio-retting. Drying increased the contribution of fibre processing to 24% in this case. The contribution of crop production was highest for BabyHemp (19%) and lowest for flax (10%). The relative contribution of the production of 100 kg of yarn to per capita acidification in Europe ranged from 8.8 to 10.7% (Table 15). 39

“LCA of Hemp Textile Yarn”

10 Yarn production: Others

kg SO2-eq. / 100 kg yarn

9 8

Yarn production: Winding

7 6

Yarn production: Spinning

5

Fibre processing: Others

4 3

Fibre processing: Fibre drying

2

Crop production

1 0 Wa

Bio

BH

Flax

Figure 10. Contribution (in kg SO2-eq.) of different production stages of the production of 100 kg of yarn to acidification, according to the scenarios: hemp water-retting (Wa), hemp bio-retting (Bio), BabyHemp (BH) and flax. Unit processes are shown separately if they contribute 10% or more to the total impact for one or several of the scenarios. “Others” (for fibre processing and yarn production) refers, for the specific production stage, to impacts from unit processes, other than those mentioned separately.

7.1.4 Energy use Energy use was highest in the hemp bio-retting scenario (35800 MJ) and similar for the other three scenarios (around 26000 MJ) (Table 14). Energy use resulted dominantly from yarn production: 85-88% in all scenarios, except for bio-retting, where it was 63%. The importance of yarn production was diminished in the bio-retting scenario by the greater energy use in the fibre processing stage (33% of the total), largely due to drying (Figure 11). In the other scenarios the contribution of fibre processing was 6-7%, while in all the scenarios energy use in crop production made up only 4-8%. The yarn production stage, which contributed, by far, most to energy use (as well on the climate change and acidification impact categories that are linked to it), was essentially the same for all four scenarios. Its large contribution overshadowed the differences in the previous stages of the production chain. Figure 12, where the impacts of the yarn production stage were excluded, allows a better examination of the significance of the various other sub-processes. It is observed that apart from fibre drying, the retting in tanks (essentially the heating of retting water) raises the energy consumption in the bio-retting scenario. The effect of softening is negligible. In all scenarios the 400-km transport of long fibre from the fibre processing to the yarn-processing site generates very little energy use in comparison with the rest of the processes. The relative contribution of the production of 100 kg of yarn to per capita energy use in Europe ranged from 16.6 to 23.2% (Table 15).

40

“LCA of Hemp Textile Yarn”

40000

Yarn production: Others

MJ / 100 kg yarn

35000

Yarn production: Winding

30000 25000

Yarn production: Drying

20000

Yarn production: Spinning

15000

Fibre processing: Others

10000

Fibre processing: Fibre drying

5000

Crop production

0 Wa

Bio

BH

Flax

MJ / 100 kg yarn

Figure 11. Contribution (in MJ) of different production stages of the production of 100 kg of yarn to energy use, according to the scenarios: hemp water-retting (Wa), hemp bio-retting (Bio), BabyHemp (BH) and flax. Unit processes are shown separately if they contribute 10% or more to the total impact for one or several of the scenarios. “Others” (for fibre processing and yarn production) refers, for the specific production stage, to the impacts from unit processes, other than those mentioned separately.

14000

Transp. of long fibre (400 km)

12000

Softening

10000

Retting in tank

8000

Scutching

6000

Green scutching

4000

Baling/retting on field Fibre drying

2000

Crop production

0 Wa

Bio

BH

Flax

Figure 12. Contribution (in MJ) of unit processes of the crop production and fibre processing stages of the production of 100 kg of yarn to energy use, according to the scenarios: hemp water-retting (Wa), hemp bio-retting (Bio), BabyHemp (BH) and flax.

41

“LCA of Hemp Textile Yarn”

7.1.5 Land occupation, pesticide use and direct water use The flax and the hemp warm water-retting scenarios had the smallest land occupation (1150 and 1160 m2·year, respectively), followed closely by hemp bio-retting (1260) (Table 14). Land occupation for BabyHemp was more than double (2410). The relative contribution of the production of 100 kg of yarn to per capita land occupation in Europe ranged from 11.4 to 23.9% (Table 15). Pesticide use was zero for both hemp warm water-retting and hemp bio-retting, 0.296 kg of pesticide active substance were used in the flax scenario and 0.874 kg in the BabyHemp scenario (Table 14). Expressed per hectare this made 2.58 kg for flax and 4 kg for BabyHemp. It should be stressed that the absence of any pesticide use is a major environmental asset for hemp, which it shares with virtually no other annual crop. Direct water use was similar on the one hand for the flax and the BabyHemp scenarios (7.2 and 7.6 m3, respectively), and for the hemp water-retting and the hemp bio-retting scenarios, on the other hand (19.1 and 22.1 m3, respectively) (Table 14). Rove bleaching accounts for all the direct water use in the BabyHemp and the flax scenario. In the two other hemp scenarios the rove bleaching uses the same volume (i.e. 7.63 m3), while the rest is consumed in the retting. In bio-retting, water use in retting is divided between water for retting (36%) and water for rinsing (64%) (data not shown).

7.2 SCENARIO VARIATIONS A lack of knowledge about the true value of a quantity leads to an uncertainty of the results based on that quantity. Besides the lack of available data, the natural variability of certain parameters (e.g. crop yield per ha) results in an uncertainty. The sensitivity of the results to changes in some key parameters was explored through a limited sensitivity analysis. To this effect, variations of warm water-retting and bio-retting scenarios were compared to their respective original scenarios. Table 16. Results of the hemp warm water-retting scenario variants per 100 kg yarn. Pesticide use and water use are not shown, as the scenario alterations did not affect them. Eutrophication

Climate change

Acidification

Energy use

kg PO4-eq.

kg CO2-eq.

kg SO2-eq.

MJ

Land occupation m2·year

25500

1160

25200 (-1.2%) 25900 (+1.6%) = 30100 (+18.0%)

927 (-20.1%) 1540 (+32.8%) = =

Warm water-retting 3.04 1350 7.38 scenario (W1) Crop yield +25% 2.58 (-15.1%) 1300 (-3.7%) 7.18 (-2.7%) (W2) Crop yield –25% 3.80 (+25.0%) 1440 (+6.7%) 7.72 (+4.6%) (W3) NO3 emissions –50% 2.07 (-31.9%) 1330 (-1.5%) = (W4) + Gas heating for 3.07 (+1.0%) 1620 (+20.0%) 7.73 (+4.7%) retting water “=” means that the value is equal to that of the reference scenario.

For the hemp warm water-retting scenario the effect of a 25% change in the assumed crop yield of 8 ton/ha had a major effect on eutrophication and land occupation, while the effect on other impact categories was small (W1 and W2, Table 16).

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“LCA of Hemp Textile Yarn”

The effect of halving the nitrate field emissions was investigated, as there is reason to believe that in certain pedo-climatic conditions (e.g. in Hungary) nitrate leaching is significantly lower than the assumed 40 kg/ha, which is based on the French climate and soil conditions. Eutrophication is observed to be very sensitive to the value of nitrate emissions, whereas the other impacts are barely affected (W3, Table 16). The last modification to the reference scenario concerns the use of fossil energy for heating the retting water, since hot thermal water is not available in most places. This would cause a major increase in both climate change (+20%) and energy use (+18%), but would hardly affect eutrophication or acidification (W4, Table 16). For the bio-retting scenario, some modifications to fibre processing were explored, in order to evaluate possibilities for improving its environmental profile. First, the substitution of the renewable energy source (wood pellets) by natural gas for heating the retting water had a modest negative effect on climate change (B1, Table 17). This is mainly caused by the fact that the non-fossil CO2 emissions resulting from the use of wood pellets do not contribute to the climate change impact, whereas the fossil CO2 resulting from natural gas does contribute. If no energy was used in fibre drying, the energy use and climate change would be reduced by over 20%, i.e. the unit operation of drying counts for 20% of the total impact for these categories over the whole yarn production chain (B2, Table 17). Effect on acidification is lower. A combination of the two previous modifications would not yield impacts much different from those of the no-energy variant (B3, Table 17). Substitution of gas by a renewable energy source in fibre drying would significantly reduce climate change, but would hardly affect the other impact categories (B4, Table 17). Table 17. Results of the hemp bio-retting scenario variants per 100 kg yarn. The pesticide and water use are not shown, as the scenario alterations had no effect on them.

Bio-retting scenario

Eutrophication

Climate change

Acidification

Energy use

kg PO4-eq.

kg CO2-eq.

kg SO2-eq.

MJ

Land occupation m2·year

3.02

1810

9.01

35800

1260

(B1) Wood substituted by 2.99 (-1.0%) 1920 (+6.1%)* 8.94 (-0.8%) = = gas in heating the baths (B2) No energy input for 2.95 (-2.3%) 1400 (-22.7%) 7.91 (-12.2%) 28000 (-21.5%) = drying (B3) = (B1)+(B2) 2.92 (-3.3%) 1520 (-16.0%) 7.85 (-12.9%) 28100 (-21.5%) = (B4) Gas substituted by 3.10 (+2.6%) 1510 (-16.6%) 9.18 (+1.9%) 35600 (-0.6%) = wood in drying * The increase in CO2 emissions corresponds to the biogenic emissions from wood pellets that are not included in the calculation of GWP. “=” means that the value is equal to that of the reference scenario.

Economic allocation of impacts is often debated on the grounds that market prices fluctuate and thus introduce uncertainty. The effect of different prices of scutching co-products was tested, as the relative prices of flax co-products differed significantly of those of hemp. As can be observed in the Table 18, with hemp prices the results of the flax scenario would decrease for all the impacts. The effect of scutching prices was major on eutrophication, land occupation and pesticide use, whereas climate change, acidification and energy use changed only very little.

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“LCA of Hemp Textile Yarn”

Table 18. The effect of changed prices of flax scutching products on the LCA results (per 100 kg yarn). Water use is not shown, as the price alterations did not affect it. Eutrophication

Flax scenario

Acidification

Energy use

kg PO4-eq.

Climate change kg CO2-eq.

MJ

Land occupation 2 m ·year

Pesticide use kg act. subst.

kg SO2-eq.

2.61

1360

8.16

26100

1150

0.296

(F1) Hemp prices 1.99 (-24%) 1280 (-6%) 7.72 (-5%) 25300 (-3%) 833 (-28%) 0.215 (-27%) at scutching (F2) Hemp prices 2.36 (-10%) 1330 (-2%) 7.99 (-2%) 25800 (-1%) 1020 (-11%) 0.263 (-11%) at scutching, except shives Prices (per kg) used in the flax scenario & resulting allocation factors: long fibre 1.80€ (86.8%), short fibre 0.35€ (10.3%), shives 0.02€ (3.0%). F1 prices & allocation factors: long fibre 1.75€ (62.1%), short fibre 0.75€ (16.2%), shives 0.20€ (21.7%). F2 prices & allocation factors: long fibre 1.75€ (77.1%), short fibre 0.75€ (20.2%), shives 0.02€ (2.7%).

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“LCA of Hemp Textile Yarn”

8 DISCUSSION 8.1 COMPARISON OF THE SCENARIOS FOR IMPACTS AND YIELD 8.1.1 Bio-retting relative to warm water-retting scenario The bio-retting scenario had higher impacts than the warm water-retting scenario for all impact categories except eutrophication and pesticide use, where there was no difference between the two scenarios. The higher impacts of bio-retting for climate change and acidification are related to the higher energy use in the fibre processing stage. The higher energy use, in turn, is mostly the consequence of a more energy intensive retting process (Figure 12). Bio-retting involves heating the retting water and drying of the retted fibre, whereas in the warm water-retting scenario naturally warm water is exploited and stems dry on the field without inputs. It has to be noted, that for climate change, the scenarios differed due to the fibre drying process only (Figure 9). Retting water heating did not contribute to this impact, due to the renewable energy source (wood chips) used. If a non-renewable source, such as gas, had been used the climate change would have further increased by 6%. The yield percentages of long fibre were slightly lower in the bio-retting scenario than in the warm water-retting scenario: the yarn yield in the bio-retting scenario was 90% of that of the warm water-retting scenario (Appendix H). As a consequence, even with identical inputs, the impacts (expressed in terms of the final product, yarn) would be higher for the bio-retting scenario. This is illustrated by the results in the land occupation category, in which bio-retting has a slightly higher impact, although the crop production stage, which alone is responsible for the land occupation, was exactly the same for the two scenarios. The crop production stage and in particular nitrate leaching were identified as the greatest contributor to the eutrophication impact. Identical results in this category for the two scenarios are a logical consequence of the shared crop production stage. The above-mentioned effect of differences in yield is counterbalanced by the somewhat higher emissions due to the retting liquor in the warm water-retting scenario (Figure 8). It has to be added, that the emissions due to the retting liquor are quite uncertain. We have confidence in the effluent quality measurements made at Hungarohemp. For bio-retting the emissions per kg matter to be retted were assumed equal to those in Hungarohemp. It is impossible to say whether this is a valid assumption. We believe that it might be an underestimation, because rinsing is likely to extract substances more effectively from the retted fibre. The slightly higher direct water use in the bio-retting scenario goes against one of the leading ideas of the method: to reduce the water consumption by first green decorticating the stems, thus minimising the bulk of retted material. At the moment, however, the rinsing step in the bioretting scenario increases water consumption threefold compared to retting itself. If rinsing were omitted, water consumption would come down to 13 m3 per 100 kg of yarn, which is significantly lower than the 20 m3 of the warm water-retting.

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“LCA of Hemp Textile Yarn”

8.1.2 BabyHemp relative to warm water-retting scenario BabyHemp had higher values than warm water-retting for all impacts except direct water use. The significantly higher values for eutrophication and land occupation are due to the lower stem yield per ha for BabyHemp: 3.25 ton/ha of retted stem versus 6.5 ton/ha of retted stem for the warm water-retting scenario (Appendix H). The slightly higher values in climate change, acidification and energy use categories for BabyHemp are to be attributed to the difference in yield at the crop production stage. The subsequent stages of yarn processing and yarn manufacture were namely assumed to be the same for the two scenarios. The use of Glyphosate for desiccation of BabyHemp results in the pesticide use of 0.9 kg active substance per 100 kg of yarn, compared to zero for warm water-retting. Direct water use, on the contrary, is only 38% of that of warm water-retting, since no water is used in retting, but only in bleaching.

8.1.3 Bio-retting scenario relative to BabyHemp The bio-retting scenario had higher values for energy use, climate change, acidification and water use. The main reason is the more energy intensive fibre processing stage in the bio-retting scenario (see 8.1.1). BabyHemp had higher impacts for eutrophication and land occupation due to the lower yield of stems per ha (discussed above). Pesticide use was also unfavourable for BabyHemp.

8.1.4 Hemp versus flax Flax had impacts similar to those of the hemp water-retting scenario for all impacts except eutrophication, water use and pesticide use. The eutrophication value was slightly lower because flax retting does not involve any effluents. In addition, higher yield of long fibre (discussed below) has an effect. Flax water use was similar to BabyHemp water use, since both involve water use only in rove bleaching. Pesticide use for flax (0.296 kg) was higher than for water-retting or bio-retting, where no pesticides were used. However, it was only 34% of the pesticide use in the BabyHemp scenario. For flax, yarn yield per hectare was double compared to that of the hemp warm water-retting scenario, which has the best per-ha-yield of the three hemp scenarios (Appendix H). This was surprising, since higher yield is often given as one of the major advantages of hemp over flax. In explaining this result, it is important to look at the proportional yields of the long fibre (Figure H-1, Appendix H), which are higher for both fibre processing (18% vs. 9 % of water-retted hemp) and yarn production (53% vs. 40.5% of water-retted hemp). The higher long fibre extraction rates largely compensate the 25% lower green stem yield of flax. The flax yield of 6 ton/ha can be debated, but so can the hemp yield of 8 ton/ha. Of the many yield levels found in the literature, we tried to find realistic comparable values for the two crops. For hemp, the sensitivity of the results to yield level was explored (Table 16). The results of impact categories dominated by the crop production stage, such as eutrophication and land

46

“LCA of Hemp Textile Yarn” occupation, were almost proportionally affected by changes in per ha yield. Other impact categories were less sensitive to changes in yield. The alteration of prices of flax scutching co-products (Table 18) illustrates the fact that with the current prices economic returns are largely generated by the flax long fibre and, as a result, the environmental impacts are allocated mostly to it. For hemp, economic value of the co-products and, consequently, the environmental impacts are more evenly distributed. The hemp prices applied to flax allocated a greater share of the impacts to the other co-products and decreased the impacts for flax long fibre. The scutching price alteration affected mainly the impacts dominated by the crop production stage, i.e. eutrophication, land occupation and pesticide use, because the impacts caused by post-scutching processes are not affected by this allocation.

8.1.5 Hemp versus cotton The comparison with cotton was limited to a cautious qualitative discussion. The few LCA studies on cotton textiles that we found were hardly comparable to our study. The study by nova-Institut (1996) indicated that in the crop production and harvest phase the primary energy requirement and the resulting emissions from cotton are approximately three times higher than from hemp (Table 13), but that this advantage is counterbalanced by the fibre and yarn processing stages of the life cycle. Fibre processing is more complicated for bast fibres than for cotton. So far, ring spinning is considered the only technology suitable for the production of fine bast fibre yarns. It happens to be both the slowest and most (energy) expensive of the three major spinning technologies (Seagull and Alspaugh, 2001). Any of the three can be used to spin cotton, yielding yarns of sufficient quality for most applications. So, cotton spinning in general can be expected to use less energy and thus lead to lower impact values for energy use, climate change and acidification. Irrigation is a topical issue related to cotton production. Irrigation water use amounts to around 10 m3 water per kilogram of lint in the USA (average of Texas and California) (Spaar, 1997). This would correspond to 12.2 m3 per kg of yarn (Appendix H). Hemp or flax in the European context do not normally require irrigation. However, the two fibre processing options (warm water and bio-retting) involve significant water use. The water consumption due to retting in these two scenarios amounts to about 13 m3 per 100 kilogram of yarn and thus to only 1% of the water used in cotton irrigation. Contemporarily no plant protection agents are used on hemp and many claim that hemp is completely problem-free when it comes to pests. This contrasts with the high pesticide application rates on cotton. On average 6.56 kg of pesticide active substance per hectare is applied on cotton in the USA (Organic Trade Association, 2001). The BabyHemp scenario, with its 4 kg of active substance per hectare, is not very much behind. Kilograms of pesticide are, of course, only a quantitative aspect. WWF (1999) claims that according to the recommendation of WHO, most pesticides used for cotton are hazardous. As far as we know, the glyphosate used for desiccation of BabyHemp does not belong to this category. It is very difficult to quantify the environmental impacts of pesticides, as a vast array of different compounds each with their unique environmental fate and effects exists. Jödicke (2001) assessed the ecotoxicity of textile production using a complex fate model for chemicals. Yet, she concludes that in her study the supply and use of energy dominated the environmental effects of the product.

47

“LCA of Hemp Textile Yarn” It is good to acknowledge, that, contrary to popular belief, nearly 300 insects have been described on hemp but very few cause appreciable crop losses. Thus, hemp is rather pesttolerant than pest-free (McPartland, 1999).

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“LCA of Hemp Textile Yarn”

8.2

ENVIRONMENTAL “HOT SPOTS” OF THE HEMP SCENARIOS

8.2.1 In general A normalisation of the results indicates the areas that need most attention. The normalisation (Table 15) revealed that the production of hemp and flax yarn contributed more to energy use than to other impact categories. Energy use, in turn, is dominated by the yarn production stage, mainly due to electricity consumption. The impact categories energy use, climate change and acidification are very much interrelated, as currently energy demand is largely met by fossil fuels. Their combustion results in the emissions of carbon dioxide and sulphur oxides. The former is the most well known greenhouse gas, while the latter contributes to acidification. Consequently the yarn production stage is the most important contributor to climate change and acidification, too. For the four scenarios, the total energy consumption of the yarn production stage (230 MJ/kg of yarn, Figure 11) seems high in comparison to literature values for yarn production in a cotton spinning system (6-33 MJ/kg of yarn, Table 12). It has to be remembered, however, that our final results concerning energy use, are calculated with the total efficiency of 31% between the primary energy source and the point of electricity consumption. We have reason to believe that the literature values refer to the energy consumption at the point of consumption. A comparable value for the yarn production at Linificio is only three times higher than the value given for cotton spinning by Blackburn and Payne (2004) (Table 19). The cited literature values refer to cotton spinning, as we are not aware of published studies on the energy consumption or other environmental impacts of bast fibre spinning. The threefold difference in energy use can thus be largely attributed to differences in the spinning technology between cotton and bast fibres. Even seemingly similar processes, e.g. sliver preparation, are likely to be more complicated for bast fibres than for cotton. For “comparable” unit processes our values were 23% (rove preparation) and 28% (ring spinning) higher than those given by Blackburn and Payne (2004) (Table 19). Several reasons for this difference can be proposed. First of all, due to the different fibre properties bast fibre spinning is less efficient than cotton spinning (Cierpucha et al., 2002). In addition, cotton is spun dry, while bast fibre requires a wet spinning method, which seems to require more energy. In addition, wet spinning implies an additional operation of yarn drying, which consumes a significant amount of energy (Table 19). Furthermore, yarn production from bast fibres includes bleaching, which is not part of the cotton yarn production sequence (cotton is commonly bleached too, but at the later stage of textile production). Our data includes air conditioning and lighting, while Blackburn and Payne do not specify whether these are included. According to Weber (1998), about 40% of the energy consumption in a weaving mill is caused by air conditioning, lighting and general heating. In our results, air conditioning and lighting make up 19% of the total energy consumption. The only exception to the good correlation of our results with the above mentioned publication is our energy consumption for winding, which is 3.4 times that given by Blackburn and Payne (2004) (Table 19). It is almost as high as the consumption due to spinning, although in other sources (Weber, 1998; Blackburn and Payne, 2004) it represents only 15-30% of the spinning consumption.

49

“LCA of Hemp Textile Yarn” Table 19. Comparison of energy consumption for cotton spinning (literature values) and for bast fibre yarn production at Linificio. Unit processes of cotton yarn production

Energy consumption (MJ/ kg) Blackburn and Payne, 2004 Linificio, our input values /kg1

Opening and cleaning Carding Drawing & Roving

2.1 2.6 3.9

Spinning (ring spinning, dry)

18.7

Winding Air conditioning and lighting TOTAL

/kg of yarn

Unit processes of bast fibre yarn production

2.3

Hackling2

4.8 16.3 23.9

Rove preparation Bleaching Spinning (ring spinning, wet) Yarn drying Winding

5.8 ?3

31.3 20.0 Included in the values above

33.1

98.6

1

It is not clear from the publication whether the energy consumption is expressed in terms of the output of each process or of the ultimate output of the (towel) production. 2 Allocation due to co-products was taken into account. 3 It is not known whether the given values include air conditioning and lighting. In any case, it is not mentioned separately.

For eutrophication, the crop production phase is the biggest contributor. The eutrophying emissions resulting from hemp and flax growing are, however, by no means exceptional. In fact, hemp has been identified as a low-impact crop relative to other common annual crops (van der Werf, 2004). Some emissions via leaching from agricultural land seem inevitable. But to minimise the impact, any measures leading to a reduction in nitrate leaching are highly interesting, as a 50% reduction of the amount of NO3 leached reduced eutrophication by 32% over the yarn production chain (Table 16). For the crop production phase alone, a reduction of eutrophication of 43% was reported (van der Werf, 2004). In general, the optimisation of nitrogen fertilisation and the reduction of the period between harvest and the establishment of the next (catch) crop are the principal measures recommended to reduce NO3 leaching (Gustafson et al., 2000). However, fertilisation was optimised in our scenarios, therefore a rapid establishment of the next crop or of a catch crop seems the most promising measure to reduce nitrate emissions and eutrophication. The assumption concerning nitrate leaching from the field under hemp/flax cultivation strongly affects eutrophication results, since crop production corresponds to a large share of the eutrophication impact.

8.2.2 Warm water-retting Warm water-retting did better or similar than the other scenarios for all impact categories, except eutrophication and water use. Contrary to the working hypothesis proposed by Fibranova, a combination of green decortication and bio-retting is not a water saving option with its present operating parameters.

50

“LCA of Hemp Textile Yarn” In the literature, water-retting is often considered to be “bad” for the environment, above all, due to the emissions carried by the retting water effluent. However, in this study the contribution of the retting liquor (after wastewater treatment) to eutrophication was small compared to the impact of the crop production stage (mainly nitrate leaching from the field). The situation would be different without a waste water treatment process. It should be also remembered, that LCA is a global analysis and while globally the emissions of eutrophying substances from retting may not be significant, they might, however, have a considerable local impact at the recipient water body. Apart from treatment of the wastewater, there is the possibility to spread it on agricultural land, too (Ayuso, 1996; Tofani, pers. comm., 2004). According to Kempa and Bartoszewski (1992), the effluent can stimulate crop growth, but it should be enriched with nitrogen compounds to balance its nutrient content. For agricultural uses they recommend the retting effluents to be either treated with lime or diluted with potable/surface water due to their acidity. Of course free thermal water is not a common, abundant resource. If retting water was heated by gas, for example, the energy use and climate change would augment by around 20%, so thermal water is a real advantage in this scenario. It is interesting to note, that the effect of 400 km transport (of long fibre) had a negligible impact on energy use in comparison with the impacts of water heating in the bio-retting scenario (Figure 12). So, it seems that from the environmental point of view even fairly long transport distances are justified, if “free” warm water can be exploited. Economical constraints might of course be different. Thermal water is not available in many places, but waste heat of process cooling waters might be available.

8.2.3 Bio-retting High energy input in the fibre processing stage is the most critical issue of the bio-retting scenario (high impacts due to yarn production are common to all scenarios). Especially drying of the fibre after retting stands out as an energy intensive unit process. It should be kept in mind, that the absolute impacts and the subsequent large contribution of the fibre drying process are accompanied by a great uncertainty. The process parameters were taken from the yarn drying process at Linificio, and it is known that the yarn is first dried to 0% moisture and water is then added to re-establish the desired moisture content of around 10%. This is certainly not done for fibre drying, so there is reason to believe that the impacts based on the Linificio system are somewhat overestimated. Nevertheless, more energy efficient options for drying are worth exploring. At the moment a solely thermal process is used, i.e. water is evaporated by heat, which always requires a lot of energy. Pre-drying by mechanical means and a search for the most efficient evaporative drying equipment could help to curb the energy use and other associated environmental impacts. Using a renewable energy source for drying could reduce climate change. In the fibre processing stage, the heating of retting water also adds to the environmental impacts. Use of a renewable energy source (wood pellets) is an appropriate choice with regards to climate change. The possibility of reducing the retting time from 72 hours down to, for example, 48 hours is worth checking, as it would reduce energy use for maintaining the water temperature and would subsequently lead to less acidification. A reduced water-fibre ratio at retting would also diminish the energy use in retting. The rinsing water is not heated, but possibilities for cutting down water use in this process should be investigated, as lower water consumption is an aim in itself.

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“LCA of Hemp Textile Yarn”

Banik et al. (2002) report that a similar approach for jute (they call it ribbon retting), i.e. first green scutching and then retting, reduced the water requirement to almost half and environmental pollution level to one-fourth in comparison with conventional stem retting. So, the bio-retting method has the potential to improve the traditional warm water-retting. However, its operating parameters require optimisation.

8.2.4 BabyHemp The major “hot spot” of the BabyHemp scenario is its low stem yield. This increases the environmental impacts of cultivation in terms of the output. Another important hot spot is the pesticide use at harvest, which is not exactly compatible with the idea of environmentally sound production. The BabyHemp scenario performed fairly well for climate change, acidification, energy use and water use due to low energy input and water use in fibre processing, and it would seem to be a good alternative to the traditional warm water-retting. However, due to plant immaturity at harvest and to the stand/dew-retting process, it can be questioned whether, in reality, the fibre meets the quality requirements for the production of fine textile yarn. In fact, the basic dewretting of hemp (i.e. the BabyHemp scenario with desiccation omitted) is commonly described as unfeasible for the production of apparel textile fibres, due to unevenness of retting and resulting unsatisfactory fibre quality. This was confirmed in a discussion with French hemp producers (Quinton et al., pers. comm., 2004). Desiccation should help in achieving a good retting result, but uniform desiccation of standing hemp might pose problems. Uneven desiccation might arise because the density of the crop canopy and the high number of individual plants make it difficult to apply sufficient active ingredient on to every stem (Easson and Long, 1992). Non-uniform desiccation, on the other hand, results in uneven and thus unsatisfactory stand-retting. BabyHemp is harvested a lot earlier than normal hemp and so the often quoted problems of basic dew-retting, namely low autumn temperatures and possibly extensive rain, should not hamper the retting process. On the contrary, especially in Italy where the BabyHemp production has started, the weather at the time of harvest (July) may be much too dry for good retting. Due to the poor controllability of the retting process, not only the absolute fibre quality can be doubted, but also large variability can be expected. This is problematic for industrial uses, which require uniform raw material (Müssig and Martens, 2003).

52

“LCA of Hemp Textile Yarn”

9 CONCLUSIONS AND OUTLOOK LCA methodology was used to evaluate the environmental impacts of three hemp yarn production scenarios and a flax yarn production scenario. The comparison of traditional warm water-retting based hemp processing (reference scenario) with its two newly proposed alternatives and with flax revealed that, overall, neither of the alternatives was unambiguously better than the reference. The environmental impacts of the hemp reference scenario and the flax scenario were very similar, except for pesticide use (higher for flax) and direct water use (higher for hemp). Comparison with cotton was difficult, due to lack of comparable data, but for the crop production stage hemp performs clearly better than cotton with respect to pesticide use and water use. However, during the fibre processing and yarn production stages hemp requires more energy, resulting in higher impacts. A reduction of the environmental impacts associated with the production of hemp yarn should give priority to reduction of eutrophication in the crop production phase and reduction of energy use in the fibre processing and yarn production stages. A self-evident fact is that if yields can be improved, not only in agriculture, but in every processing step without increasing inputs, impacts per kilogram of final product will decline and profit (environmental and financial) will increase. Hemp breeders have been concentrating on developing varieties with increased fibre content. It seems, however, that less than half of the total amount of fibre is recovered as long fibre. Apart from aiming at ever-higher fibre content, an additional goal should perhaps be to maximise the yield of long fibre. The optimisation of fibre processing should also be an important goal. The West-European flax sector has worked intensively for the last 20 years to maximise the yield of long fibre and they now “harvest the fruits” of this development. Under the sustainability paradigm, it is necessary not only to increase the yield of long fibre, but also to exploit the full potential of the other co-products to produce additional profits. Short fibre (from scutching and hackling), is a valuable raw material, which can for example be spun to coarser yarns with a technique a bit different from that used for the long fibre. Shives are valued as an excellent animal bedding material. Technological developments seem crucial for the development of the hemp textile industry in Europe. Contemporarily significant amounts of hemp long fibres are only produced in the Eastern countries, mainly Hungary and Romania, where the labour costs are low. The level of mechanisation of the current production methods is low in these countries and the technology is not directly transferable to Western Europe. In the long run it will probably encounter problems in the Eastern countries, too. Therefore, technological development, in particular aiming at the reduction of labour requirements, is essential for the successful production of hemp textiles in Europe. The development of suitable equipment can make a significant difference, as illustrated by this example: due to mechanisation in flax harvesting, only 5 man hours are required to carry out the same amount of work that, 20 years ago, required 50 man hours (Sultana, 1992). In order to diminish the uncertainty of the results, better data (differentiated by regions, field conditions etc.) on nitrate leaching from the field under hemp/flax cultivation would be needed. In addition, quality of data regarding emissions associated with retting leaves room for improvement. Firstly, no quantitative information on the air emissions of retting was available. Secondly, the information on the contents of the retting effluent at Hungarohemp is expected to be fairly certain, but due to the natural variability of the stem material, the microbial process etc.

53

“LCA of Hemp Textile Yarn” these figures are prone to a great variability. For bio-retting the emissions per kg of to-be-retted material were assumed to be equal to those at Hungarohemp, but we do not know whether this is a valid assumption. It might be an underestimation, because the rinsing is likely to extract substances more effectively from the retted fibre. Each investigated production scenario is associated with an “environmental profile”, which were assessed in this study. What has not been done is to consider the actual fibre/yarn quality along with the environmental impacts. Besides the environmental sustainability of an agro-industrial production system, the quality of fibres is indeed an important aspect, since proper fibre quality is the foundation of any successful spinning operation. Throughout this study we have assumed that the different scenarios yield long fibre of similar quality, but this can be questioned. Fibre quality is a focal issue within the HEMP-SYS project and it would be very interesting and “enlightening” to combine the LCA results with the analysis of fibre quality obtained from different scenarios. It would bring us one step closer to finding the most sustainable fibre scenario remembering that the concept of sustainability has three dimensions: environmental, social and economical.

54

“LCA of Hemp Textile Yarn”

References A.G.P.L., 2004. Le lin en France. Association Générale des Producteurs de Lin, Paris, France. Amaducci, S., 2003. HEMP-SYS: Design, Development and Up-Scaling of a Sustainable Production System for Hemp Textiles – An Integrated Quality Systems Approach. Journal of Industrial Hemp 8 (2): 79-83. Amaducci, S., 2005. Hemp production in Italy. Journal of Industrial Hemp 10(1): 109-115. Audsley, E., Alber, S., Clift, R., Cowell, S., Crettaz, P., Gaillard, G., Hausheer, J., Jolliet, O., Kleijn, R., Mortensen, B., Pearce, D., Roger, E., Teulon, H., Weidema, B., van Zeijts, H., 1997. Harmonisation of environmental life cycle assessment for agriculture. Final Report Concerted Action AIR3-CT94-2028. Silsoe Research Institute, Silsoe, United Kingdom. Ayuso, S., 1996. Faseraufschluss bei Hanf. Ansätze für einen ökologischen Vergleich verschiedener Aufschlussverfahren für die textile Nutzung, 1. Auflage, 11/96. Nova-Institut, Hürth, Germany. Banik, S., Basak, M.K., Paul, D., Nayak, P., Sardar, D., Sil, S.C., Sanpui, B.C., Ghosh, A., 2003. Ribbon retting of jute – a prospective and eco-friendly method for improvement of fibre quality. Industrial Crops and Products 17: 183-190. Bassetti P., Mediavilla, V., Spiess, E., Ammann, H., Strasser, H., Mosimann, E., 1998. Hanfbau in der Schweiz – Geschichte, aktuelle Situation, Sorten, Anbau- und Erntetechnik, wirtschaftliche Aspekte und Perspektiven. FAT-Berichte 1998 No. 516. Ed.: Eidg. Forschungsanstalt für Agrarwirtschaft und Landtechnik (FAT), Tänikon, Switzerland. Blackburn, R., Payne, J., 2004. Life cycle analysis of cotton towels: impact of domestic laundering and recommendations for extending periods between washing. Green Chemistry 6: G59-G61. BUWAL, 1996. Ökoinventare für Verpackungen. Schriftenreihe Umwelt Nr. 250/1+2, Bundesamt für Umwelt, Wald un Landschaft, Bern, Switzerland. Cierpucha, W., Ma kowski, J., Wa ko, J., Ma kowski, T., Zar ba, S., Szporek, J., 2002. Application of Flax and Hemp Cottonised Fibres Obtained by Mechanical Method in Cotton Rotor Spinning. Fibres & Textiles in Eastern Europe 10: 32-34. Davis, J., Haglund, C., 1999. Life Cycle Inventory (LCI) of fertiliser production. Fertiliser products used in Sweden and Western Europe. SIK Report no. 945. The Swedish Institute for Food and Biotechnology, Göteborg, Sweden. de Jong, S., Wood, I.M., 1997. Plant fibre crops. In: Hyde, K. (Ed.) The New Rural Industries – A handbook for Farmers and Investors. Rural Industries Research & Development Corporation (RIRDC), Australia. pp. 453-463. Demeestere, G., 1999. Handleiding – kwaliteitszorg in de vlassector. Vormingsinstituut voor K.M.O, Centrum Kortrijk, Kortrijk, Belgium

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Easson, D.L., Long, E.N.J., 1992. Pre-harvest Retting of Flax with Glyphosate. In: Sharma, H.S.S., Van Sumere, C.F., 1992. The Biology and Processing of Flax. M Publications, Belfast, Northern Ireland. pp 213-228. Ebskamp, M.J.M., 2002. Engineering flax and hemp for an alternative to cotton. TRENDS in Biotechnology 20 (6): 229-230. EC (European Commission), 2003. Reference Document on Best Available Techniques for the Textiles Industry, Integrated Pollution Prevention and Control (IPPC). Downloaded from the site of the European IPPC Bureau (http://eippcb.jrc.es/pages/Fabout.htm). ECETOC, 1994. Ammonia emissions to air in Western Europe. Technical report no. 62. European Chemical Industry Ecology & Toxicology Centre, Brussels, Belgium. Ecoinvent Centre, 2004. Ecoinvent data v1.1. Final reports ecoinvent 2000 No. 1-15. Swiss Centre for Life Cycle Inventories, Dübendorf, Switzerland, 2004, CD-ROM. Eurostat, 2004. Eurostat on-line database. Statistical Office of the European Communities, Luxembourg. (http://epp.eurostat.cec.eu.int/portal/page?_pageid=1090,1&_dad=portal&_schema=PORTAL) FAO, 2005. FAOSTAT Agriculture Data. Available at: http://faostat.fao.org/. Flake, M., Fleissner, T., Hansen, A., 2000. Ökologische Bewertung des Einsatzes nachwachsender Rohstoffe für Verkleidungskomponenten in Automobilbau – Lebensweganalyse verschiedener Faserverbundwerkstoffe. Institut für Geographie und Geoökologie der Technischen Universität Braunschweig, Braunschweig, Germany. Gaillard, G., Crettaz, P., Hausheer, J., 1997. Inventaire des intrants agricoles en production végétale. Base de données pour l’établissement de bilans énergétiques et écologiques en agriculture. Compte rendu de la station fédérale de recherches en économie et technologie agricoles no. 46. FAT, Taenikon, Switzerland. Gorchs, G., Lloveras, J., 2003. Current Status of Hemp Production and Transformation in Spain. Journal of Industrial Hemp 8 (1): 45-64. Guinée, J.B., Gorrée, M., Heijungs, R., Huppes, G., Kleijn, R., de Koning, A., van Oers, L., Wegener Sleeswijk, A., Suh, S., Udo de Haes, H.A., de Bruijn, H. van Duin, R., Huijbregts, M.A.J., 2002. Handbook on Life Cycle Assessment. An Operational Guide to the ISO standards. Kluwer Academic Publishers, Dordrecht, The Netherlands. Gustafson, A., Fleischer, S., Joelsson, A., 2000. A catchment-oriented and cost-effective policy for water protection. Ecological Engineering 14: 419-427. Hanfaes Research Centre, 2004. Guidelines for growing Flax. Flax and Hemp Project, University of Wales, Bangor, Gwynedd, UK. Downloaded from www.flaxandhemp.bangor.ac.uk/pdfs/GuidelinesForGrowingFlax.pdf (15.11.2004) Hanson, J., 1980. An outline for a U.K. hemp strategy. The Ecologist 10: 260-263.

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“LCA of Hemp Textile Yarn” HEMP-SYS, 2002. HEMP-SYS project – Technical Annex, March 2002. Provided by S. Amaducci, Instituto di Agronomia, Università Cattolica di Milano Sede di Piacenza, Piacenza, Italy. Heijungs, R., Guinée, J.B., Huppes, G., Lankreijer, R.M., Udo de Haes, H.A., Wegener Sleeswijk, A., Ansems, A.M.M., Eggels, P.G., van Duin, R., Goede, H.P., 1992. Environmental Life Cycle Assessment of products, I Guide, II Backgrounds. Centre of Environmental Science, Leiden, The Netherlands. Heuser, O., 1927. Hanf und Hartfasern. Verlag von Julius Springer, Berlin, Germany. p.120. Houghton, J.T., Meira Filho, L.G., Callander, B.A., Harris, N., Kattenberg, A., Maskell, K., 1996. Climate change 1995: the science of climate change. Cambridge University Press, Cambridge, United Kingdom. Huijbregts, M.A.J., 1999. Life-cycle impact assessment of acidifying and eutrophying air pollutants. Calculation of characterisation factors with RAINS-LCA. Interfaculty Department of Environmental Science, Faculty of Environmental Science, University of Amsterdam, Amsterdam, The Netherlands. Huijbregts M.A.J., Schöpp, W., Verkuijlen, E., Heijungs, R., Reijnders, L., 2000. Spatially explicit characterisation of acidifying and eutrophying air pollution in life-cycle assessment. Journal of Industrial Ecology 4 (3): 125-142. Huijbregts, M.A.J, Huppes, G., de Koning, A., van Oers, L., Suh, S., 2001. LCA normalisation factors for the Netherlands, Europe and the World. Centre of Environmental Sciece, Leiden University, Leiden, The Netherlands. ISO, 1997. International Standard 14040. Environmental management – Life cycle assessment – Principles and framework. International Organisation for Standardisation, Geneva, Switzerland. ISO, 1998. International Standard 14041. Environmental management – Life cycle assessmnet – Goal and scope definition and inventory analysis. International Organisation for Standardisation, Geneva, Switzerland. ISO, 2000. International Standard 14042. Environmental management – Life cycle assessment – Life cycle impact assessment. International Organisation for Standardisation, Geneva, Switzerland. ITL, 2004. Institut Technique du Lin, Paris, France. www.lin-itl.com/html/default.htm. Jödicke, A., 2001. Möglichkeiten und Grenzen der Ökobilanz bei Chemikalienintensiven Prozessen: Veredlung und Gebrauch eines Baumwoll-T-Shirts. DISS. ETH Nr. 14 005. Die Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland. KATALYSE - Institut für angewandte Umweltforschung, 1998. Leitfaden Nachwachsende Rohstoffe. 1. Aufl., Müller, Heidelberg, Germany. pp 106-113, 225.

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“LCA of Hemp Textile Yarn” Proto, M., Supino, S., Malandrino, O., 2000. Cotton: a flow cycle to exploit. Industrial Crops and Products 11: 173-178. Pulli, R., 1997. Ökobilanz eines Baumwoll-T-shirts mit Schwerpunkt auf den verwendeten Chemikalien. Diplomarbeit an der Abteilung für Umweltnaturwissenschaften. Die Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland. Ross, T., 1992. Preparation and Spinning of Flax Fibre. In: Sharma, H.S.S. and Van Sumere, C.F., 1992. The Biology and Processing of Flax. M Publications, Belfast, Northern Ireland. pp 275-296. Rossier, D., 1998. Ecobilan. Adaptation de la méthode écobilan pour la gestion environnementale de l’exploitation agricole. Service Romand de Vulgarisation Agricole, Lausanne, Switzerland. Sankari, H., 2000. Towards bast fibre production in Finland: stem and fibre yields and mechanical fibre properties of selected fibre hemp and linseed genotypes. Academic dissertation. Agricultural Research Centre of Finland, Jokioinen, Finland. Seagull, R., Alspaugh, P., 2001. Cotton fibre development and processing – an illustrated overview. International Textile Center, Texas Tech University, Lubbock, Texas, USA. pp 72-81. Sharma, H.S.S., Van Sumere, C.F., 1992. The Biology and Processing of Flax. M Publications, Belfast, Northern Ireland. Spaar, T., 1997. Environmental Balance of Cotton Production in the High Plains Texas and the San Joaquin Valley California. Diplomarbeit an der Abteilung für Umweltnaturwissenschaften. Die Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland. Steffes, E., 2004. Die Renaissance der europäischen Bastfaserspinnerei durch Verspinnung von Hanffasern auf Autocoro Rotorspinnmaschinen. Schlafhorst Autocoro GmbH, Mönchengladbach, Germany. Downloaded from www.nova-institut.de/nr/ (2.7.2004) Sultana, C., 1992. Growing and Harvesting of Flax. In: Sharma, H.S.S. and Van Sumere, C.F., 1992. The Biology and Processing of Flax. M Publications, Belfast, Northern Ireland. pp 83-109. Tobler, M.I., Schaerer, S., 2002. Environmental impacts of different cotton growing regimes. Seminar on sustainability and textile technology 9.-10.7.2002, Klippeneck, Germany. Available in: www.texma.org/tobler_LCA.pdf van der Werf, H.M.G., van Geel, W.C.A., Wijlhuizen, M., 1995. Agronomic research on hemp (Cannabis sativa L.) in the Netherlands, 1987-1993. Journal of the International Hemp Association 2: 14-17. van der Werf, H.M.G., Mathijssen, E.W.J.M., Haverkort, A.J., 1996. The potential of hemp (Cannabis sativa L.) for sustainable fibre production: a crop physiological appraisal. Annals of Applied Biology 129: 109-123. van der Werf, H.M.G., 2002. Hemp production in France. Journal of Industrial Hemp 7 (2): 105109.

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“LCA of Hemp Textile Yarn” van der Werf, H.M.G., 2004. Life Cycle Analysis of field production of fibre hemp, the effect of production practices on environmental impacts. Euphytica 140: 13-23. Weber, A., 1998. Umweltaspekte der Baumwolle. Neujahrsblatt aus dem Institut für Textilmaschinenbau und Textilindustrie der Eidgenössischen Hochschule Zürich, Zürich, Switzerland. pp 12-21. WWF, 1999. The impact of cotton on fresh water resources and ecosystems. A preliminary synthesis. Background paper. World Wide Fund for Nature, Gland, Switzerland.

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Personal communications Amaducci, S., Istituto di Agronomia Universitatà Cattolica di Milano Sed di Piacenza, Piacenza, Italy. (project partner) Boffelli, F., Linificio e Canapificio Nazionale, Villa d’Almè, Italy. (project partner) Hanson, M., Brille A. NV, Wevelgem, Belgium. (flax scutcher) Homonyik, A., Hungarohemp Kenderipari és Logisztikai Rt, Nagylak, Hungary. (project partner) Iványi, I., Tessedik Sámuel College, Faculty of Water and Environmental Management, Szarvas, Hungary. (project partner) Mallet, C., Association Général des Producteurs de Lin, Paris, France. Pavoni, M., Linificio e Canapificio Nazionale, Villa d’Almè, Italy. (project partner) Pfeiffer, G., Waldland Vermarktungsges.m.b.H, Friedersbach, Austria. (project partner) Quinton, S. (INRA, chair of the meeting), Beherec, O. (FNPC), Delanoe, J.L. (PDM Industrie), Gagnaire, N. (INRA), Grosjean, Y. (Eurochanvre), Legendre, G. (Ministère de l’Agriculture), Maillard, D. (La Chanvière de l’Aube), Ravachol, A. (Plasticana). The first meeting of a working group “Etude environnementale de la partie agricole de la filière chanvre” of the project “Etude de caractéristiques environnementales du chanvre par l’analyse de son cycle de vie”, 08.10.2004, Paris, France. Tofani, C., Gruppo Fibranova, Livorno, Italy. (project partner)

61

APPENDIX A-1

APPENDIX A: Detailed hemp crop production inventory System: Hemp crop production, 1 hectare.

Sub-system: Generic European production scenario 1 Code

A 1.1

Description

Unit

3

4

5

6

7

8

Machine Service Service Technical No. of Work/ Kg of tractor weight life life coefficient units or machine / other (kg) (h) (ha) runs hours machine

INPUTS Soil preparation

1.1.1 Principal soil preparation = ploughing Machinery Plough: 4-furrow plough Tractor (4WD, 75 kW) Fuel Diesel (16 l/h)

1300 4700

Fuel Diesel (15 l/h)

1 1

4200

1.25

1.08 1.40

0.2

2.20 0.22

0.75

1.85 0.84

20

1100 4700

500

1 1

4200

l

1.1.3 Stubble ploughing Machinery Cultivator (3 m) (1x) Tractor (4WD, 75 kW) Fuel Diesel (15 l/h)

1200

l

1.1.2 Seed bed preparation Machinery Roller (5 m) Tractor (4WD, 75 kW)

1.2

2

3

1000 4700

540

1 1

4200

l

11.25

Base fertilisation Machinery Lime spreader (0.33x) Tractor (4WD, 50 kW) Disc broadcaster Tractor (4WD, 50 kW) Fuel Diesel (15 l/h, 7 l/h)

1400 3900 280 3900

l

3000

0.33 0.33 2 2

7200 3000 7200

5.48

0.13 0.5

0.15 0.07 0.19 0.27

APPENDIX A-2

Mineral fertilisers Lime Ammonitrate 33/0/0 Triple superphosphate 0/46/0/0 Potassium chloride 0/0/60/0

1.3

kg kg kg

666 206 65.8

kg

189

Sowing Machinery Rotary harrow (3 m) Seed drill (3 m) Tractor (4WD, 75 kW) Fuel Diesel (15 l/h) Seed Cultivar X

1.4

1000 550 4700

540 525 4200

l

15

kg

55

1 1 1

1

1.85 1.05 1.20

1

2.0

5.03

Harvest: mowing & laying in swaths Machinery Blade mower Fuel Diesel (5 l/h)

7550

l

1500

10

Input summary Ammonium nitrate 33/0/0

kg

206.4

Triple superphosphate 0/46/0/0

kg

65.81

Potassium chloride 0/0/60/0

kg

189.2

Lime

kg

666

Seed

kg

55

l

64.7

Fuel: diesel Kg of tractor (cat. A)

kg

3.92

Kg of harvester (cat. B)

kg

5.03

Kg of other machines (cat. C)

kg

8.38

B

OUTPUT

B.1

Harvest Dry, green hemp stems (14% humidity)

kg

8000

APPENDIX B-1

APPENDIX B: Details of the flax scenario Table B1. Plant protection scenario for the flax production scenario. Pesticide category

Active substance

Herbicide

Triallate

Dose (kg/ha)

Treatment frequency * (times/growing season)

1.4

1

Purpose

Pre-sowing treatment against the most common flax weeds Linuron 0.4 0.5 Post-sowing treatment against the most common flax weeds Bentazon 1.2 0.5 Treatment at 5-20 cm growth stage against the most common flax weeds Insecticide Phosalone 0.6 0.333 Against flea beetle and thrips Lambda-Cyhalothrin 0.007 0.333 Against flea beetle and thrips Parathion 0.4 0.333 Against flea beetle and thrips * The treatment frequencies are hypothetical, based on the assumption that flax is treated three times per growing season and principally with herbicides (ITL, 2004). It was assumed that a pre-sowing herbicide treatment is used every year. The second herbicide treatment depends on the development of the weeds and we assumed a equal distribution (frequency 0.5) between the two alternative treatment times (right after sowing or at 5-20 cm stage). Our scenario includes one treatment with an insecticide. The three active substances are the most common against the main flax pests. Their use is assumed to be equally common.

Table B2. Technical data on special machines developed for flax harvest (according to Flake et al., 2000). The machinery is also employed in the BabyHemp scenario.

Power Fuel consumption Speed Optimum speed Weight Working width Brand name * bale width

kW l/h km/h km/h kg m

Pulling machine, self propelled 55 4 0-25 8 3500 1.40 1 swath/run Depoortere

Turner, self-propelled 25 3 0-30 8 2300 n.a. 1 swath/run Union

Baler, pulled from 44 6-8 1773 1.17* John Deere

APPENDIX C-1

APPENDIX C: Detailed flax crop production inventory System: Flax crop production, 1 hectare.

Sub-system: France/Belgium/Netherlands production scenario 1 Code

A 1.1

Description

Unit

3

4

5

6

7

8

Machine Service Service Technical No. of Work/ Kg of tractor weight life life coefficient units or machine / other (kg) (h) (ha) runs hours machine

INPUTS Soil preparation

1.1.1 Principal soil preparation = ploughing Machinery Plough: 4-furrow plough Tractor (4WD, 75 kW) Fuel Diesel (16 l/h)

1300 4700

Fuel Diesel (15 l/h)

1 1

4200

1.25

1.08 1.40

1 1

0.2

2.20 0.22

1 1

0.75

1.85 0.84

20

1100 4700

500 4200

l

1.1.3 Stubble ploughing Machinery Cultivator (3 m) (1x) Tractor (4WD, 75 kW) Fuel Diesel (15 l/h)

1200

l

1.1.2 Seed bed preparation Machinery Roller (5 m) Tractor (4WD, 75 kW)

1.2

2

3

1000 4700

540 4200

l

11.25

Base fertilisation Machinery Lime spreader (0.33x) Tractor (4WD, 50 kW) Disc broadcaster Tractor (4WD, 50 kW) Fuel Diesel (15 l/h, 7 l/h)

1400 3900 280 3900

l

3000

0.33 0.33 2 2

7200 3000 7200

5.48

0.13 0.5

0.15 0.07 0.19 0.27

APPENDIX C-2

Mineral fertilisers Lime Ammonitrate 33/0/0 Triple superphosphate 0/46/0/0 Potassium chloride 0/0/60/0

1.3

kg kg kg

666 121 65.0

kg

100

Sowing Machinery Rotary harrow (3 m) Seed drill (3 m) Tractor (4WD, 75 kW) Fuel Diesel (15 l/h) Seed Cultivar X Fungicide: Prochloraz

1.4

1000 550 4700

540 525

1 1 1

4200

l

15

kg kg

115 0.046

1

1.85 1.05 1.20

Plant protection Machinery Mounted crop sprayer (1000l, 15 m) Tractor (4WD, 50 kW) Disc broadcaster (> 450 l, 12 m) Tractor (4WD, 50 kW) Fuel Diesel (7l/h) Products Herbicide: Triallate x 1 Herbicide: Linuron x 0.5 Herbicide: Bentazon x 0.5 Insecticide: Phosalone x 0.33 Insecticide: Lambda-C. x0.33 Insecticide: Parathion x 0.33

800 3900 280

7200

3900

7200

4200

2 0.5

3000

2 1

0.27 0.09

1

0.25

0.14

l

5.25

kg kg kg kg kg kg

1.4 0.2 0.6 0.20 0.00023 0.13

0.38

APPENDIX C-3

1.5

Harvest: pulling & laying in swaths Machinery Pulling machine (55 kW) Fuel Diesel (4 l/h)

3500

1500

1

l

8

Ammonium nitrate 33/0/0

kg

121

Triple superphosphate 0/46/0/0

kg

65

2.0

2.33

Input summary

Potassium chloride 0/0/60/0

kg

100

Lime

kg

666

Seed

kg

115

l

68.0

Fuel: diesel Kg of tractor (cat. A)

kg

6.66

Kg of other machines (cat. C)

kg

8.85

B

OUTPUT

B.1

Harvest Dry, green flax stems (14% humidity) Seed (9% humidity)

kg

6000

kg

600

APPENDIX D-1

APPENDIX D: Additional data concerning process inputs General Energy carriers and road transport

Data from BUWAL 250 database (BUWAL, 1996) in SimaPro.

Electricity

UCPTE (represents the electricity production of 17 Western European countries) energy mix data from BUWAL 250 database (BUWAL, 1996) in SimaPro. This data assumes a total efficiency of 31% (including power line losses) between primary energy source and the point of electricity consumption.

Crop production N fertiliser

Impacts of production based on ammonium nitrate (35% N) West European average data (Davis and Haglund, 1999).

P2O5

Impacts of production based on triplesuperphosphate (48% P2O5) West European average data (Davis and Haglund, 1999).

K2O

Impacts of production based on KCl in Germany (Patyk and Reinhardt,1997). Modification: For energy carriers (heavy oil, diesel, natural gas and electricity) Buwal 250 process sheets available in SimaPro were used instead of data proposed by Patyk and Reinhardt. This was done for consistency as Buwal energy carriers are used in other processes.

CaO

Based on CaO from limestone (Kalkstein, 54.3% CaO) and burnt lime (Branntkalk 97.0% CaO) in Germany (Patyk and Reinhardt, 1997). Modification as in the case of K2O.

Heavy metals from fertilisers

Heavy metal content of fertilisers was based on Rossier (1998).

Transport of fertilisers to the farm

Based on Nemecek and Heil (2001).

Generic pesticide

Data from Gaillard et al., 1997. Average of production data for 37 active ingredients.

Ammonium sulphate

Ammonium sulphate used in fertilisers (or in our case as desiccation auxiliary) is produced as a by-product from caprolactam production, coke oven operations or gas scrubbing. Therefore, use of resources and emissions from its production were neglected (Davis and Haglund, 1999).

APPENDIX D-2

Yarn manufacture H2O2

Impacts of production based on confidential data from a producer (KEMIRA, Finland).

Other bleaching chemicals

Data available in SimaPro was used.

APPENDIX E-1

APPENDIX E: Inventory – Crop production Generic Central-European hemp production scenario Input/Output

Category

Substance

Output Input Input

Product Supply material Supply material

Input

Supply material

Input

Supply material

Input Input Input Input Input Input Output Output Output Output Output Output Output Output Output

Supply material Supply material Supply material Supply material Supply material Resource Emission Emission Emission Emission Emission Emission Emission Emission Emission

Dry, green hemp stems Lime Ammonium nitrate (33/0/0) Triple superphosphate (0/46/0/0) Potassium chloride (0/0/60/0) Seed for sowing Machinery, cat. A * Machinery, cat. B * Machinery, cat. C * Diesel Agricultural land NH3 N2O NOX Nitrate Phosphate Cd Cr Ni Pb

* see Table 2 in the report.

Quantity Unit

Impact media

1000 kg 83.2 kg 25.8 kg 8.22 kg 23.7 kg 6.88 490 629 1.05 309 1250 207 363 76.0 22.2 50.6 333 2410 710 546

kg g g kg MJ m2·year g g g kg g mg mg mg mg

Air Air Air Water Water Soil Soil Soil Soil

APPENDIX E-2

BabyHemp production scenario (desiccation included in the fibre processing, Appendix F) Input/Output

Category

Substance

Output

Product

Input Input

Supply material Supply material

Input

Supply material

Input

Supply material

Input Input Input Input Input Output Output Output Output Output Output Output Output Output

Supply material Supply material Supply material Supply material Resource Emission Emission Emission Emission Emission Emission Emission Emission Emission

Dry, green hemp stems corresponding to 1000 kg dry, retted stems Lime Ammonium nitrate (33/0/0) Triple superphosphate (0/46/0/0) Potassium chloride (0/0/60/0) Seed for sowing Machinery, cat. A * Machinery, cat. C * Diesel Agricultural land NH3 N2O NOX Nitrate Phosphate Cd Cr Ni Pb

* see Table 2 in the report.

Quantity Unit

Impact media

kg 83.2 kg 25.8 kg 8.22 kg 23.7 kg 30.8 1.90 2.58 758 3077 207 650 136 54.5 50.7 184 2340 437 297

kg kg kg MJ m2·year g g g kg g mg mg mg mg

Air Air Air Water Water Soil Soil Soil Soil

APPENDIX E-3

Flax production scenario Input/Output

Category

Substance

Output

Dry, green flax stems

1000 kg

Output Input Input

Principal co-product Co-product Supply material Supply material

100 kg 111 kg 20.2 kg

Input

Supply material

Input

Supply material

Input Input Input Input Input Input Output Output Output Output Output Output Output Output Output

Supply material Supply material Supply material Supply material Supply material Resource Emission Emission Emission Emission Emission Emission Emission Emission Emission

Seed Lime Ammonium nitrate (33/0/0) Triple superphosphate (0/46/0/0) Potassium chloride (0/0/60/0) Seed for sowing Pesticides (act. ingred.) Machinery, cat. A * Machinery, cat. C * Diesel Agricultural land NH3 N2O NOX Nitrate Phosphate Cd Cr Ni Pb

* see Table 2 in the report.

Quantity Unit

Impact media

10.8 kg 16.7 kg 19.2 430 1.11 1.48 432 1667 162 392 82 29.5 67.0 438 3110 726 619

kg g kg kg MJ m2·year g g g kg g mg mg mg mg

Air Air Air Water Water Soil Soil Soil Soil

APPENDIX F-1

APPENDIX F: Inventory - Fibre Processing Figures replaced by an X in the following tables are confidential, and are thus omitted. Machinery categories are explained in Table 2 in the report.

Warm water-retting scenario Post-harvest field operations, warm water-retting and storage Input/Output

Category

Substance

Output

Product

Input

Supply material

Input Input Input Input Output

Supply material Supply material Supply material Resource Waste

Dry, retted hemp stems (after storage) Dry, green hemp stems Machinery, cat. A Machinery, cat. C Diesel Water Retting liquor

Quantity Unit

Impact media

1000 kg 1240 kg 0.242 0.0360 33.0 17.3 16.3

kg kg MJ m3 m3

To WWT*

* WWT = waste water treatment

Scutching Input/Output

Category

Substance

Quantity Unit

Output

Scutched long fibre

1000 kg

Output

Principal co-product Co-product

2560 kg

Output Input Input Input Output Output

Co-product Supply material Supply material Supply material Waste Waste

Scutching tow (short fibre) Shives Dry, retted hemp stems Machines Electricity Dust Coarse plant residues

4440 11100 34.9 5868 1670 1440

kg kg kg MJ kg kg

Impact media

---

APPENDIX F-2

WWT - Waste water treatment Input/Output

Category

Substance

Output Input Input Input Input Input Input Input Output Output Output Output Output Output Output Output Output Output Output Output Output Output

Waste Waste Supply material Supply material Supply material Supply material Supply material Supply material Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission

Treated waste water Retting liquor Iron sulphate Aluminium sulphate Iron (III) chloride 1 Electricity, low voltage Transport by train Transport by 28 t truck VOC CO CO2, non-fossil 2 CH4 NH3 N2O NOX COD NH4+ N Nitrate Phosphate Sulphate Chlorides

Quantity Unit 1.00 1.00 70.3 19.0 96.1 1.97 0.111 0.135 0.0273 1.83 1.70 6.02 0.671 0.158 0.547 354 13.4 0.917 60.6 16.6 60.4 63.0

m3 m3 g g g MJ tkm tkm g g kg g g g g g g g g g g g

Impact media Water

Air Air Air Air Air Air Air Water Water Water Water Water Water Water

1

Impacts of production not taken into account due to lack of data. This CO2 is not taken into account in the calculation of the Global Warming Potential, since it is part of the short (i.e. biogenic) carbon cycle

2

Bio-retting scenario Post-harvest field operations and green scutching Input/Output

Category

Substance

Quantity Unit

Output

Green scutched long fibre

1000 kg

Output

Principal co-product Co-product

1000 kg

Output Input Input Input Input Input Output Output

Co-product Supply material Supply material Supply material Supply material Supply material Waste Waste

Green scutching tow (short fibre) Shives Dry, green hemp stems Tractor Other machines Diesel Electricity Dust Coarse plant residues

3600 8000 4.36 27.1 595 3240 960 1440

kg kg kg kg MJ MJ kg kg

Impact media

---

APPENDIX F-3

Bio-retting, rinsing, drying and mechanical softening Input/Output

Category

Substance

Output

Principal co-product Co-product Co-product Supply material Resource Supply material Supply material Supply material Supply material Waste

Hemp long fibre

1000 kg

Hemp short fibre Shives Green scutched hemp fibre Water Machines Electricity Energy from wood pellets Natural gas Retting liquor and rinsing water

11.0 53.0 1520 84.0 2.50 5.04 10.9 28.5 82.0

Output Output Input Input Input Input Input Input Output

Quantity Unit

kg kg kg m3 kg GJ GJ GJ m3

Impact media

To WWT

BabyHemp scenario Desiccation and post-harvest field operations (stand-/dew-retting) Input/Output

Category

Substance

Output

Product

Input Input Input Input Input

Supply material Supply material Supply material Supply material Supply material

Dry, retted BabyHemp stems Dry, green hemp stems Tractor Other machines Diesel Herbicide (act. substance)

Quantity Unit

Impact media

1000 kg * 1.24 0.640 205 1.54

kg kg kg MJ kg

* The exact amount of green hemp stems is not known, because the crop is only weighed after retting. In our calculations the input corresponding to 1000 kg of dry, retted BabyHemp stems was produced on 3080 m2 of agricultural land.

APPENDIX G-1

APPENDIX G: Inventory - Yarn Production All processes described in this appendix, except hackling, are identical for the three hemp scenarios and the flax scenario. Figures replaced by an X in the following tables are confidential and are thus omitted. Hackling (Water-retted hemp & BabyHemp) Input/Output

Category

Substance

Output

Sliver

Output

Principal co-product Co-product

Input Input Input Output

Supply material Supply material Supply material Waste

Hackling tow (short fibre) Scutched hemp Machines Electricity Dust

Quantity Unit

Impact media

1000 kg 800 kg 2000 1.56 2780 200

kg kg MJ kg

--

Hackling (Bio-retted hemp) Input/Output

Category

Substance

Quantity Unit

Output

Sliver

1000 kg

Output

Principal co-product Co-product

1250 kg

Input Input Input Output

Supply material Supply material Supply material Waste

Hackling tow (short fibre) Scutched hemp Machines Electricity Dust

Input/Output

Category

Substance

Output

Sliver

Output

Principal co-product Co-product

Input Input Input Output

Supply material Supply material Supply material Waste

2500 1.95 3480 250

kg kg MJ kg

Impact media

--

Hackling (Flax)

Hackling tow (short fibre) Scutched flax Machines Electricity Dust

Quantity Unit

Impact media

1000 kg 385 kg 1538 1.20 2140 154

kg kg MJ kg

--

APPENDIX G-2

Preparation system Input/Output

Category

Substance

Output Input Input Input Output

Product Supply material Supply material Supply material Waste

Rove Sliver Machines Electricity Dust/Fibre waste

Input/Output

Category

Substance

Output Input Input Input Input Input Input Input Input Output

Product Supply material Supply material Supply material Supply material Supply material Supply material Supply material Resource Waste

Bleached rove Rove Electricity Natural gas NaOH Na2CO3 Na4O2SiO2 H2O2 Water, demineralised Waste water

Quantity Unit 1000 1050 0.599 4140 50.0

kg kg kg MJ kg

Impact media

--

Bleaching Quantity Unit 1000 1120 760 14.9 X X X X 55.6 55.6

kg kg MJ GJ kg kg kg kg m3 m3

Impact media

To WWT*

* WWT = waste water treatment

Spinning Input/Output

Category

Substance

Output Input Input Input Input Input Output

Product Supply material Supply material Supply material Supply material Resource Waste

Yarn Bleached rove Machines Electricity Mineral oil Water, demineralised Waste water

* WWT = waste water treatment

Quantity Unit 1000 1040 0.844 23.9 53.3 13.3 13.3

kg kg kg GJ kg m3 m3

Impact media

To WWT*

APPENDIX G-3

Yarn winding Input/Output

Category

Substance

Output Input Input Input

Product Supply material Supply material Supply material

Yarn (on cones) Yarn (on cops) Machines Electricity

Quantity Unit 1000 1000 2.22 20.0

Impact media

kg kg kg GJ

WWT - Waste water treatment Input/Output

Category

“Substance”

Output Input

Waste Waste

Input Input Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output Output

Supply material Supply material Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission Emission

Treated waste water Waste water (bleaching and spinning) Electricity, low voltage Transport by 28 t truck VOC CO CO2, biogenic * CH4 COD NH4+ Nitrite Nitrate Sulphates Chlorides Cr Fe Ni Pb Cu Zn

Quantity Unit 1 m3 1 m3 0.508 0.0370 0.00969 0.649 0.603 2.13 97.0 1.00 4.43 0.0885 710 570 0.0500 0.400 0.200 0.0500 0.0500 0.150

MJ tkm g g kg g g g g g g g g g g g g g

Impact media Water

Air Air Air Air Water Water Water Water Water Water Water Water Water Water Water Water

* This CO2 is not taken into account in the calculation of the Global Warming Potential, since it is part of the short (i.e. biogenic) carbon cycle

APPENDIX H-1

APPENDIX H: Comparison of transformation efficiencies and yarn yields Hemp, water-retting

Hemp, bio-retting

BabyHemp

1 ha

1 ha

1 ha

8000 kg dry, green stem

8000 kg dry, green stem

3250 kg dry, retted stem

81%

12.5%

6480 kg dry, retted stem 9%

1000 kg green scutched long fibre

236 kg yarn

9%

23% s.f.

66%

23% s.f.

583 kg scutched long fibre 40.5%

12.5% s.f.

658 kg scutched long fibre 32%

40% s.f. 1724 kg s.f.

293 kg scutched long fibre 40.5%

50% s.f. 1329 kg s.f.

213 kg yarn

119 kg yarn

Flax

Cotton

1 ha

1 ha

6000 kg dry, green stem

2021 kg seed cotton

40% s.f. 865 kg s.f.

90%

5400 kg retted stem 18%

35%

11% s.f.

972 kg scutched long fibre 53%

512 kg yarn

708 kg lint

25% s.f. 837 kg s.f.

82%

580 kg yarn

Figure H-1. Comparison of the yields of yarn per ha of cultivation for the three hemp scenarios and the flax scenario as well as for cotton (cotton based on Pulli, 1997 and FAO, 2005). s.f. = short fibre.

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