COGENchallenge - European Campaign for the Development and Documentation of 1000 Small-scale Cogeneration Projects in European Cities and Towns
Pick the right cogeneration technology
A technology checklist of small-scale cogeneration July 2006
Table of contents
Choose your technology ....................... 2 Gas turbine............................................ 3 Gas engine............................................ 4 Heating oil engine ................................. 5 Biogas engine ....................................... 6 Steam turbine........................................ 7 Stirling engine ....................................... 8 Fuel cell................................................. 9 COGENchallenge Facilitators ............. 10 Who we are ......................................... 11
1
Choose your technology You can produce heat and electricity together with different technologies: you just recover heat from the traditional electricity production unit. As the heat must be used close to the consumer, the cogeneration units needs to be approximately sized to the size of the consumer. The range of the available technologies is quite wide. You will choose your cogeneration technology according some criteria, specific to your activity and your heat demand. The table below lists the technologies: "++" means the technology is very suitable to produce the heat you need, and "+" means less suitable. No quotation means the technology can not produce the type of heat you need, such as the Stirling engine or the fuel cell which cannot (yet) produce steam.
Cogeneration
Fuels (not exhaustive)
technologies Gas turbine
Natural gas, biogas, heating oil
You need
You need
You need
hot water?
steam?
hot air?
++
++
++
++
+
+
++
+
+
++
+
Natural gas, biogas, heating oil, Gas Engine
vegetable oil, wood
Heating oil
Natural gas, biogas, heating oil,
Engine
vegetable oil, wood Natural gas, biogas, heating oil,
Steam turbine
vegetable oil, wood, etc.
++
Stirling engine
Natural gas, biogas, heating oil, wood
++
Hydrogen or, via reforming, all others Fuel cell
fuels
++
2
Gas turbine Gas turbines have become the most widely used prime mover for large-scale cogeneration in recent years. Gas turbines are not only used in large-scale applications. Smaller units, starting at around 400 kWe are available on the market. Since the late 1990s microturbines have become available. They are derived from automotive turbochargers and are available from 30 kWe. Microturbines use less space than conventional engines and maintenance costs are lower. Moreover, the emission of pollutant gases is reduced, especially those gases that cause acid rain and ozone layer depletion. Electrical efficiencies are typically lower than in internal combustion engines. Smallest unit
Typical small-scale unit
28 kWe
250 kWe
26%
30%
52 kWth
330 kWth
47%
40%
NOx emission:
< 9 ppmV
< 9 ppmV
CO emission:
< 10 ppmV
< 9 ppmV
1.3 x 0.7 x 1.9 m
4 x 2.2 x 2.3 m
0.5 tons
235 tons
2 500 € /kWe
1 500 € /kWe
Electrical power: Electrical efficiency: Thermal power: Thermal efficiency:
Size (L x W x H): Weight: Investment:
Exhaust gas Water feeding Heat recovery boiler Steam
Post-combustion (eventualy)
Natural gas
Steam consumption
Natural gas
Burning Air
Filter
Generator
Gas turbine Gas turbine
3
Gas engine Most small-scale cogeneration units are internal combustion engines operating on the same familiar principles as their petrol and diesel automotive counterparts. Engines run with liquid or gaseous fuels, such as heating oil, natural gas or biogas, and are available from 5 kWe to more than 1,000 kWe. Internal combustion engines have a higher electrical efficiency than turbines, but the thermal energy they produce is generally at lower temperatures and so they are highly suited to buildings applications. The usable heat to power ratio is normally in the range 1:1 to 2:1. Smallest unit
Typical small-scale unit
5 kWe
250 kWe
26%
36%
12 kWth
368 kWth
62%
53%
NOx emission:
350 mg/Nm3
250 mg/Nm3
CO emission:
300 mg/Nm3
300 mg/Nm3
Size (L x W x H):
1 x 0.7 x 1 m
3.5 x 1.8 x 2.2 m
0.5 tons
5 tons
3 000 € /kWe
800 € /kWe
Electrical power: Electrical efficiency: Thermal power: Thermal efficiency:
Weight: Investment:
Exhaust gas
Heat recovery boiler
Hot water and/or steam consumption
Exhaust gas Cooling water Generator
Engine
Gas or heating oil or biogas engine Heat exchanger
Fuel
Water feeding
4
Heating oil engine When natural gas or biogas is not available, you can choose an heating oil engine.
Smallest unit
Typical small-scale unit
5.3 kWe
250 kWe
30%
37%
10.5 kWth
314 kWth
59%
47%
NOx emission:
2 150 mg/Nm3
250 mg/Nm3
CO emission:
300 mg/Nm3
300 mg/Nm3
Size (L x W x H):
1 x 0.7 x 1 m
3.2 x 1.5 x 2.2 m
0.5 tons
4 tons
3 000 € /kWe
800 € /kWe
Electrical power: Electrical efficiency: Thermal power: Thermal efficiency:
Weight: Investment:
Source: 5 kWé heating oil engine in a Municipality house (Amel - Belgium)
5
Biogas engine When biogas is available, you can choose a biogas engine.
Smallest unit
Typical small-scale unit
20 kWe
250 kWe
31%
37%
34 kWth
340 kWth
53%
50%
NOx emission:
250 mg/Nm3
500 mg/Nm3
CO emission:
1 000 mg/Nm3
650 mg/Nm3
Size (L x W x H):
1.8 x 0.8 x 1 m
3.5 x 1.6 x 2.3 m
0.8 tons
5 tons
4 700 € /kWe
700 € /kWe
Electrical power: Electrical efficiency: Thermal power: Thermal efficiency:
Weight: Investment:
Source: 1.25 MWé biogas engine in a Food Industry Lutosa (Electrabel – Belgium)
Source: 102 kWé biogas engine in a small village (La Surizée - Belgium)
6
Steam turbine Steam turbines have been used as prime movers for large-scale cogeneration systems for many years. Typically, steam turbines are associated with larger power stations but also smaller units starting with 200 kWe are frequently used. The overall efficiency generally is very high, achieving up to 84%. Steam turbines run with solid, liquid or gaseous fuels, both fossil and renewable. The typical heat to power ratio of steam turbines is around 6:1. Typical small-scale unit Electrical power:
500 kWe
Electrical efficiency:
10%
Thermal power:
3,000 kWth
Thermal efficiency:
70%
NOx emission: CO emission: depending on the boiler
Size (L x W x H): Weight: Investment: Exhaust gas
Water feeding High pressure boiler
Steam turbine
High pressure steam Generator
Fuel Low pressure steam
Steam turbine
Steam consumption
7
Stirling engine For very small-scale applications with a capacity between 0.2 kWe and 9 kWe, Stirling engines can be used. These engines are external combustion devices and therefore differ substantially from the conventional models. The Stirling engine has fewer moving parts than conventional engines, and no valves, tappets, fuel injectors or spark ignition systems. It is therefore quieter than normal engines. Stirling engines also require little maintenance and the emission of pollutants is low. Smallest unit
Typical small-scale unit
1 kWe
7.5 kWe
11%
24%
7 kWth
22 kWth
79%
70%
NOx emission:
80 mg/Nm3
80 mg/Nm3
CO emission:
50 mg/Nm3
50 mg/Nm3
0.5 x 0.6 x 0.85 m
1.3 x 0.7 x 1 m
0.15 tons
0.46 tons
6 000 € /kWe
2 600 € /kWe
Electrical power: Electrical efficiency: Thermal power: Thermal efficiency:
Size (L x W x H): Weight: Investment: Heater
Regenerator Cooling water
Expansion cylinder
Cooler
Expansion piston
Compression cylinder
Generator
Compression piston
SOLO 161
Note this is new technology as the investment costs are still falling.
8
Fuel cell A new development is the use of fuel cells for cogeneration. It needs to be said, however, that fuel cells are not yet commercially available. Fuel cells convert the chemical energy of hydrogen and oxygen directly into electricity without combustion and mechanical work such as in turbines or engines. The hydrogen is usually produced from natural gas by a process known as reforming. The total efficiencies of cogeneration systems reach 85 to 90%, while the heat to power ratio is in the range 5:4 and tends towards 1:1. Fuel cells with a capacity of 1 kWe provide heat and power to single family houses, whereas bigger applications of around 200 kWe can be used in hospitals for example. Smallest unit
Typical small-scale unit
1 kWe
200 kWe
38%
36%
1.2 kWth
217 kWth
47%
39%
NOx emission:
< 2 ppmV (if natural gas)
< 1 ppmV (if natural gas)
CO emission:
< 2 ppmV (if natural gas)
< 2 ppmV (if natural gas)
0.9 x 0.9 x 1.8 m
5.4 x 3 x 3 m
0.5 tons
19 tons
up to 100 000 € /kWe
up to 5 000 € /kWe
Electrical power range: Electrical efficiency: Thermal power range: Thermal efficiency:
Size (L x W x H): Weight: Investment:
ELECTRO LYTE
EXH AU ST
Source: Fuel Cell Hand
Note this is new technology as the investment costs are still falling.
9
COGENchallenge Facilitators
GERMANY:
AUSTRIA:
Paul Fay
Jan Bleyl
Stadt Frankfurt am Main - Energiereferat
Grazer Energieagentur
Galvanistraße 28
Kaiserfeldgasse 13/I
D- 60486 Frankfurt am Main (Germany)
A-8010 Graz (Austria)
Tel: +49 69 212 39199
Tel: +43 316 811 848-20
Fax: +49 69 212 39472
Fax: +43 316 811 848-9
Email:
[email protected]
Email:
[email protected]
FRANCE:
SPAIN:
Reinhard Six Rhônalpénergie Environnement (RAEE) 10 rue des Archers FR-69002 Lyon (France) Tel: +33 4 78 37 29 14 Fax: +33 4 78 37 64 91 Email:
[email protected]
Carlos García Fundación Asturiana de la Energía (FAEN) Área de Relaciones Externas C/ Fray Paulino, s/n E-33600 Mieres (Spain) Tel: +34 985 46 71 80 Fax: +34 985 45 38 88
BELGIUM:
Email:
[email protected]
Ismaël Daoud
SLOVENIA:
Cogeneration Facilitator for Wallonie COGENSUD asbl Bd Frère Orsban, 4 B-5000 Namur (Belgium) Tel: +32 81 250 480 Fax: +32 81 250 490 Email:
[email protected]
Stane Merse "Jozef Stefan" Institute - Energy Efficiency Centre Jamova 39 SI - 1000 Ljubljana (Slovenia) Tel: +386 1 5885 250 or 210 Fax: +386 1 5885 377 Email:
[email protected]
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Who we are
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