World Geothermal Power Generation

International Geothermal Development World Geothermal Power Generation 2001 – 2005 By Ruggero Bertani – Enel, Generation and Energy Management -Renew...
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International Geothermal Development

World Geothermal Power Generation 2001 – 2005 By Ruggero Bertani – Enel, Generation and Energy Management -Renewable Energy - Geothermal Production

Editor's Note: The following article is published in the GRC Bulletin by special permission of Geothermics, the International Journal of Geothermal Research and its Applications (Elsevier), Vol. 34, No. 6, December 2005, pp. 651-690. This rendition of the article underwent minor editing to GRC Bulletin style.


review has been made of all the country update papers submitted to the World Geothermal Congress 2005 (WGC2005) from countries in which geothermal electricity is currently being generated. The most significant data to emerge from these papers, and from followup contacts with representatives of these countries, are: • A total of 24 countries now generate electricity from geothermal resources; • Total installed capacity worldwide is approximately 8,930 megawatts-electric (MWe), corresponding to about

8,030 MWe running capacity and electric energy production of nearly 57,000 gigawatt-hours (GWh) (early 2005 data); Costa Rica, France (Guadeloupe), Iceland, Indonesia, Italy, Kenya, Mexico, Nicaragua, Russia, and the United States have increased the capacity of their geothermal power plant installations by more than 10 percent with respect to the year 2000; New members of the geothermal electricity generating community include Austria, Germany and Papua New Guinea; Installed capacity in Argentina and Greece is now null since their geothermal power plants have been dismantled; and 19 countries have carried out significant geothermal drilling operations since 2000, with 307 new wells.

Figure 1. Installed geothermal capacity and electricity generation 1995-2005.

MAY / JUNE 2006

Introduction This paper discusses the latest developments in geothermal electricity generation worldwide. It focuses on changes with respect to previous similar reports (Huttrer 1995, 2000, 2001). For each country producing electricity from geothermal resources, information from relevant Country Update Reports presented at the World Geothermal Congress 2005 (WGC2005, convened on April 24-29, 2005 in Antalya, Turkey) has been integrated with first-hand data provided by members of the International Geothermal Association (IGA). Detailed information is not provided here, but can be readily obtained from papers listed under References. The primary objective of this paper is to identify geothermal fields currently under exploitation to generate electricity, their characteristics (e.g. reservoir depth, and fluid temperatures and pressures), and the status of operating geothermal power plants. Limited emphasis is given to data on geothermal field potential. A summary of data is provided in Table 1, including geothermal capacities in early 2005; annual energy production; number of geothermal units installed; percentage of national power capacity that is contributed by geothermal; and the percentage of energy produced nationally from geothermal resources. Changes in installed geothermal power generating capacity worldwide over the last 10 years are presented in Table 2. Before proceeding further, two terms frequently used in this paper should be defined. Installed capacity (in MWe) is the reference value for power plants, set by the manufacturer as its target output when the facility is operating under design conditions. Possible reserve units should not 89

International Geothermal Development Table 1. Worldwide geothermal power generation in early 2005


Installed Capacity (MWe)

Running Annual Energy Capacity Produced (MWe) (GWh/y)1

Number of Units

Australia 0.2 Austria 1.2 China 28 Costa Rica 163 El Salvador 151 Ethiopia 7.3 France (Guadeloupe) 15 Germany 0.2 Guatemala 33 Iceland 202 Indonesia 797 Italy 791 Japan 535 Kenya 129 Mexico 953 New Zealand 435 Nicaragua 77 Papua New Guinea (Lihir island) 6 Philippines 1,930 Portugal (Sao Miguel island) 16 Russia 79 Thailand 0.3 Turkey 20 United States 2,564

0.1 1.1 19 163 119 7.3 15 0.2 29 202 838 699 530 129 953 403 38 6 1,838 13 79 0.3 18 1,935

0.5 3.2 96 1,145 967 0 102 1.5 212 14,838 6,085 5,340 3,467 1,088 6,282 2,774 271 17 9,253 90 85 1.8 105 17,917

1 2 13 5 5 2 2 1 8 19 15 32 19 9 36 33 3 1 57 5 11 1 1 209






be considered as part of installed capacity, but may be accounted for separately. Running capacity (in MWe) is the highest average value over a one-hour period of output from a power plant, measured at the generator transformer supply voltage terminals, while operating at stated design conditions or corrected to design point conditions (Spielberg-Planer et al., 2001). Running capacity can be correlated directly with energy produced and with relevant reservoir characteristics (Table 3). The main characteristics of geothermal fields worldwide are presented in Table 3. The table includes only fields providing at least a few MW running capacity and fields for which at least some relevant data were available. It is worth recalling the final part of the message delivered during the World Geothermal Congress 2000 by Dr. Phillip 90

Wright, IGA President at that time: “At the 1975 United Nations Conference on Geothermal Energy, held in San Francisco, California, Dr. Patrick Muffler (USGS, retired) reported that some 1300 MW of geothermal electrical power generation capacity were installed in 10 countries. At this meeting, WGC2000, Mr. Gerry Huttrer (Geothermal Mgmt. Co., Inc. – Frisco, CO) reported that installed geothermal generation capacity has reached 7,974 MW in 21 countries. In 25 years, we have added 6,700 MW of installed capacity around the world. This amounts to an average of only 270 MW of new geothermal generating capacity per year since Dr. Muffler’s report in 1975, and an average of only 240 MW of new geothermal generation capacity per year since WGC1995 in Florence, Italy. Mr. Huttrer also reported that the worldwide electrical energy production from geothermal power plants has

Percent of National Capacity

Percent of National Energy

Source of Data

negligible negligible 30% of Tibet 8.4 14 1 9 negligible 1.7 13.7 2.2 1.0 0.2 11.2 2.2 5.5 11.2 10.9 12.7 25 negligible negligible negligible 0.3

negligible negligible 30% of Tibet 15 22 n/a 9 negligible 3 17.2 6.7 1.9 0.3 19.2 3.1 7.1 9.8 n/a 19.1 n/a negligible negligible negligible 0.5


reached 49,000 GWh per year. Energy production is a much better measure of our contribution than installed capacity, because geothermal power plants usually operate at a higher capacity factor than other types of power plants. But how are we to understand this figure of 49,000 GWh/y of energy production? To help form a perspective, let us note that the International Energy Agency reports that total electricity consumed worldwide in 1996 was 13,700,000 GWh. In other words, geothermal energy accounts for less than 0.4 percent of the world’s total electricity consumption.” The trend has not improved since 2000. Installed geothermal capacity has increased by approximately 960 MWe (Fig. 1 and Table 2), or only about 190 MWe per year added during the 2000-2005 period. Worldwide, the contribution of geothermal to total electricity generated is less than half of one GRC BULLETIN

International Geothermal Development Figure 2. Geothermoelectric installed capacity worldwide in early 2005.

percent. World net electricity generation for 2003 was 15.8 million GWh/y (U.S. Department of Energy, pub/international/iealf/table63.xls), while geothermal generation was only 0.057 million GWh per year. Figure 2 is a world map showing countries that generate electricity using geothermal resources, and their installed capacity in early 2005. Changes in installed capacity during the last 30 years, as well as changes in electricity generation between 1995 and 2005, are reported in Table 4. Recent increases in oil prices and predicted decline in oil reserves during the coming years could lead to a boost in the amount of geothermal electricity produced. However, this will be affordable only with appropriate government policies and regulations, and with some sort of incentives to attract investors. The acceptance of the Kyoto Climate Change Protocol by many countries might also help the geothermal electricity market achieve a one-percent share in world electricity production by 2010. This is still a long way from fulfilling the world’s renewable energy target, but for the next five years it is a reasonable objective with geothermal technologies currently available. MAY / JUNE 2006

Table 2. Variation in installed geothermal generating capacity worldwide between 1995 and early 2005.


1995 (MWe)

2000 Early 2005 (MWe) (MWe)

2000-2005 Increase (MWe)

Australia 0.2 Austria 0 China 29 Costa Rica 55 El Salvador 105 Ethiopia 0 France 4.2 Germany 0 Guatemala 0 Iceland 50 Indonesia 310 Italy 632 Japan 414 Kenya 45 Mexico 753 New Zealand 286 Nicaragua 70 Papua New Guinea 0 Philippines 1,227 Portugal 5 Russia 11 Thailand 0.3 Turkey 20 United States 2,817

0.2 0 29 143 161 7.3 4.2 0 33 170 589 785 547 45 755 437 70 0 1,909 16 23 0.3 20 2,228

0.2 1.2 28 163 151 7.3 15 0.2 33 202 797 791 535 129 953 435 77 6 1,930 16 79 0.3 20 2,564

0 1.2 -1 20 -10 0 10.8 0.2 0 32 208 6 -12 84 198 -2 7 6 21 0 56 0 0 336






Percent Increase unchanged new plant unchanged 14% -6% unchanged 250% new plant unchanged 19% 35% 1% -2% 186% 26% unchanged 11% new plant 1% unchanged 243% unchanged unchanged 15% 13% 91

International Geothermal Development Table 3. Main characteristics of geothermal fields worldwide (early 2005).



China Costa Rica El Salvador El Salvador France Guatemala Guatemala Guatemala Iceland

Yangbajain Miravalles Ahuachapán Berlín Guadeloupe Amatitlán Zunil I Zunil II Krafla

4 30-35 3-4 2-3 4 6-9 4 8-10 5-6

Iceland Iceland Indonesia Indonesia Indonesia Indonesia Indonesia Indonesia Italy Italy

Nesjavellir Svartsengi Darajat Dieng Kamojang Lahendong Salak Wayang Windu Bagnore Larderello

6-8 6-8 10 12 15-20 4 20-25 30 5 250

Italy Italy

25 50


Piancastagnaio Travale Radicondoli Kakkonda

Japan Japan

Matsukawa Mori

Japan Japan Japan

Kenya Kenya Kenya Mexico Mexico Mexico

Ogiri Onikobe Otake Hatchobaru Sumikawa Takigami Uenotai Yanauzu Nishiyama Olkaria E Olkaria NE Olkaria W Cerro Prieto Las Tres Vírgenes Los Azufres

Mexico New Zealand New Zealand New Zealand New Zealand New Zealand

Los Humeros Kawerau Mokai Ngawha Ohaaki Rotokawa

Japan Japan Japan Japan


Drilled Area (km2)

Type of Reservoir

Reservoir Depth (m)

Liquid Liquid Liquid /Steam Liquid Liquid Liquid /Steam Liquid Liquid /Steam Liquid 1000-2000 Liquid Liquid /Steam Steam Liquid Steam Liquid Liquid Liquid Liquid Steam

200 1000-2000 600-1500 2000-2500 300-1100 1000-2000 1500-2300 800-1200 300-1200 240-340 1000-2000 1000-2000 2000 1000-2000 1400-1600 1000-2000 1000-2000 1000-2000 1000-3000 1000-4000

Liquid Steam

Reservoir Production Temperature (°C) Wells

Reinjection Wells

Capacity (MWe)

140-160 240 230-240 300 250 300 300 240 190-210

12 32 19 9 6 4 6 2 20

6 20 5 15 n/a n/a 2 n/a 2

15 163 63 56 15 5 24 5 60

270-320 240 245 280-330 245 260-330 240-310 250-270 200-330 150-270 350 200-300 190-250

15 10 17 25 29 15 30 18 7 180

n/a 1 n/a n/a n/a n/a 15 n/a 4 23

90 46 135 60 140 20 371 110 19 473

19 22

11 0

60 147

230-260 350-360 260 230-250




10 10

1 9

24 50

260 250 240-300

11 7 20

6 7 13

30 12 122



4 6

Steam Liquid

8 8 8-10

Liquid Liquid Liquid

1000-3000 1000-4000 350 500 1000 2500-3000 1000-1500 500-1500 2000-2500 1000-2000 500 1000 1000-2500

5 5 9-10 10

Liquid Liquid Liquid Liquid

1500-2500 2000 1000-2000 1000-2600

250 160-260 300-320 270-320

8 5 9 19

12 9 3 2

50 25 29 65

Liquid Liquid Liquid Liquid Liquid Liquid/Steam

500-2000 1800-2700 1000-2000 2800 2100 1600 2000-3000 1000-2000 1000-2000 2000 600-2800 1500-2500 2000-2500

250-300 250-300 250-300 300-340 280 150-200 280-300 290-320 240-300 270-320 220-240 230-280 270-330

26 9 1 149 4 29

0 n/a n/a 9 2 6

45 12 70 720 10 188

17 6 4 2 24 2

2 2 3 2 n/a 3

35 14 51 9 96 29

5 9 12 150-200 30 35 20 2 12 25 5-8 25

Liquid Liquid Liquid Liquid Liquid Liquid


International Geothermal Development Country


New Zealand Nicaragua

Wairakei Momotombo

Papua New Guinea Philippines Philippines

Lihir Bac-Man Mak-Ban


Mt. Apo

Philippines Philippines

Drilled Area (km2)

Type of Reservoir

15 4

Liquid/Steam Liquid

3-5 25-30 14

Liquid/Steam Liquid Liquid



Palinpinon Tiwi

15-20 13

Liquid Liquid






Mutnovsky Pahuzhetka Kizildere Casa Diablo Coso East Mesa Heber Salton Sea The Geysers Puna Brady Beowawe Dixie Valley Soda Lake Steamboat Stillwater Roosevelt

12-15 1-2 4 12 20 24 5 16 100 1-2 10 3 5 8 5 16 3

Liquid/Steam Steam Liquid Liquid Liquid Liquid Liquid Liquid Steam Liquid Liquid Liquid Liquid Liquid Liquid Liquid Liquid

Reservoir Depth (m) 1000-2000 300-800 800-1700 1700-3000 300-1000 1000-2000 900 3400 500 1500 2000-3000 900 2800 1000-2000 2000-3000 700-2500 300-800 500-1000 200 500-3500 1500-2500 1200-1800 1000- 2500 600-3000 2000 300-700 1000-2500 1800-2500 500-1500 200-800 1000-1500 500-2000

Reservoir Production Temperature (°C) Wells

Reinjection Wells

Capacity (MWe)

160-260 180-200 200-240 240-300 250-300 260-280 345

60 12

n/a 4

204 38

3 24 72

n/a 12 21

6 150 402





280-320 320

43 43

26 16

192 263

260-300 300-320 240-300 180-210 240 160 200-330 150-190 160-180 290-310 300 200-300 180 215 230 180 160 160 240-270




17 7 15 8 90 35 21 31 424 3 6 3 7 5 11 4 4

4 n/a 2 5 20 44 23 26 43 4 9 1 10 5 5 3 3

62 11 17 27 230 98 65 336 888 27 21 16 68 17 66 13 20

n/a: data not available; this table includes only fields providing at least a few MW running capacity and for which some relevant data were available.

Geothermal Power Generation Activities During 2001-2005 This section highlights new geothermal projects worldwide that were initiated and completed between 2000 and 2005. Power plants that started up after the year 2000, but related to activities that began earlier, have not been included. New installed capacities are reported in Table 5. Facilities currently under construction, for a total of 551 MWe, are listed in Table 6. It is also possible to estimate shortterm prospects for additional installed capacity, as there are some geothermal projects needing only financing and final approval for plant construction. It is realMAY / JUNE 2006

istic to expect an increase of at least 1,300 MWe in installed capacity worldwide before 2010. These projects (or areas) are: Deep Yangbajain field (China); Miravalles, Rincón de la Vieja, Las Pailas, Borinquen (Costa Rica); San Vincente, Chinameca, Obrajuelo, Cuyanausul (El Salvador); Langano (Ethiopia); Bouillante III (France, Guadeloupe); Amatitlán, Zunil (Guatemala); Hellisheidi, Reykjanes (Iceland); Darajat, Lahendong, Kamojang (Indonesia); Larderello, Travale, Bagnore (Italy); Olkaria (Kenya); Los Humeros, La Primavera (Mexico); Wairakei (New Zealand); San Jacinto-Tizate (Nicaragua); Northern Negros (Philippines); Terceira (Azores,

Portugal); Kamchatka-Mutnovsky, Kuril Islands (Russia); Glass Mountain, Salton Sea (California), Steamboat, Desert Peak (Nevada), and Cove Fort-Sulphurdale (Utah). Considering these short-term prospects (at least 1,300 MWe more) and power plants already under construction or likely to be installed (additional 551 MWe), the forecast for world installed capacity by 2010 is approximately 10,800 MWe (Fig. 3). Country Reports on Geothermal Power Generation The situation in each country currently producing electric energy from geothermal 93

International Geothermal Development Table 4. Variation in geothermal installed capacity over the last 30 years, and in geothermal electricity generation over the last 10 years.


Installed Capacity (MWe)

1975 1980 1985 1990 1995 2000 2005

1,300 3,887 4,764 5,832 6,832 7,972 8,933

Electricity Generation (GWh/y) n/a n/a n/a n/a 38,035 49,261 56,786

Figure 3. Predicted increase in installed geothermal power generation capacity worldwide to 2010.

Table 5. Geothermal power plants that came on line during the 2000-2005 period.


New Project Completed in 2000-2005


Costa Rica France Iceland Indonesia Italy Kenya Mexico Nicaragua Papua-New Guinea Philippines Russia United States

Miravalles V Guadeloupe-La Bouillante II Nesjavellir Sulawesi-Lahendong Larderello, Travale, Bagnore Olkaria II & III and Oserian Los Azufres and Las Tres Vírgenes Momotombo Lihir Leyte-Tongonan Kamchatka - Mutnovsky Salton Sea V

18 10 30 20 250 86 110 7 6 22 50 60



Editor's note: For the United States, the table does not include new geothermal projects brought online during 2005 at Heber (10 MW) in Imperial Valley, CA, and the Steamboat Geothermal Complex (20 MW) at Reno, NV. Personal communication, Dan Schochet, ORMAT 6/9/06. 94

resources, along with relevant data, is described in the following pages. Tables and figures are provided only for countries, but in the case of the United States, information is provided for states with more than 200 MWe installed capacity. Australia. At the moment, only one unit is generating electric power from geothermal resources, the 150-kilowatt (kW) binary cycle plant at Birdsville, southwest Queensland (Chopra, 2005). Electricity demand for the small town of Birdsville follows a familiar seasonal pattern, with highest demand in the hot summer months when air-conditioning is used extensively (250 kW) and relatively low demand in winter (120 kW). The geothermal power plant, with a nominal power rating of 150 kWe, supplies the baseload, using 98°C fluid from a 1,200 m well. The power plant, installed in 1992, was upgraded and refurbished in 1999, and is currently in operation. Australia has also conducted research on Hot Dry Rock (HDR) technology. The most advanced project is in the Cooper Basin region of northeastern South Australia, where two wells have already been completed, for a total drilled depth of 6 km. A third is scheduled to reach 4 km. So far, downhole measured temperatures are 248°C, but stabilized conditions have not yet been reached. The government's Mandatory Renewable Electricity Target (MRET) Scheme introduced in 2001 requires that by 2010 approximately 2 percent of Australia’s annual electricity needs be supplied by renewable energy resources. Geothermal energy, and in particular, HDR technology, are expected to contribute to these goals. Austria. Geothermal research is fairly active in Austria, but focused mainly on tapping low-temperature geothermal waters for use in balneology. Two small binary power plants have been installed, at Altheim (in the northwest) and Blumau (in the southeast) (Goldbrunner, 2005). Altheim is an excellent example of a successful geothermal exploration and exploitation project by a small community (5,000 inhabitants). A production/injection doublet with bottomhole at 2,500 m produces fluid at a wellhead temperature of GRC BULLETIN

International Geothermal Development 105°C. The fluid is utilized both for district heating and for electricity generation, in an Organic Rankine Cycle (ORC) power plant. Net output is 500 kWe, after accounting for a 350-kWe parasitic load, mainly for a submersible pump. The Blumau project taps the hottest geothermal water in Austria found so far: 110°C at 2,000-3,000 m depth. It is used to heat a spa facility and to generate electricity in a 180-kWe net output ORC plant that has been in service since 2001. China. Geothermal exploration effectively began in China in the early 1970s. During the socialist economy, geothermal exploration was managed by government entities using public funds. Productive wells were transferred free-of-charge to the final user. Since the mid-1980s, as a result of privatization and liberalization of the economy, there has been a steady decrease in national investment in geothermal exploration. No new geothermal power plants were commissioned in the period 2000-2005 (Battocletti and Zheng, 2000; Zheng et al., 2005). The only fields used for electricity generation are those in Tibet. The most important of the Tibetan fields is Yangbajain, with eight double-flash units for a total capacity of 24 MWe. Eighteen wells with an average depth of 200 m tap a shallow, water-dominated 140-160°C reservoir. The field covers an area of only 4 km2, although there are clear indications that the thermal anomaly is spread over 15 km2. Annual energy production is approximately 95 GWh, about 30 percent of the needs of the Tibetan capital, Lhasa. A deeper, high-temperature reservoir has been discovered at Yangbajain, but has not yet been exploited. A 2,500 m deep well was drilled in 2004, reaching the deep reservoir at 1,000-1,300 m. Temperatures in the 250-330°C range have been measured at 1,500-1,800 m depth. Geothermal potential for Yangbajain is estimated at about 5090 MWe. A total of 80 geothermal wells have been drilled in Tibet for electricity production, to an accumulated depth of 20 km. Additional plants have been installed in Langju, western Tibet (two 1-MWe double-flash units) and a 1-MWe binary power station (using brine at inlet temperature of 110°C) in Nagqu. Two small 300-kWe plants are operating in Guangdong and Hunan. In Taiwan, a 3-MWe single-flash unit MAY / JUNE 2006

Figure 4. Location of geothermal fields, power plants and volcanoes in El Salvador (from Rodriguez et al., 2005).

Table 6. Geothermal power plants under construction in early 2005.


Geothermal Field/Power Plant

El Salvador Guatemala Iceland Italy Mexico New Zealand Nicaragua Papua New Guinea Philippines Portugal Russia

Berlín III Amatitlán Hybrid Plant Nesjavellir, Hellisheidi and Reykjanes Larderello La Primavera Wairakei, Rotokawa and Mokai San Jacinto-Tizate Lihir Palinpinon Azores-Pico Vermelho Kamchatka, Mutnovsky and Pauzhetka


went online in the Qingshui field in 1981 (the reservoir is shallow, less than 500 m depth, with 150-220°C temperatures). A 300-kWe binary unit (Tu Chang) was installed in the same field, exploiting fluid with a maximum temperature of 170°C. In 1994, both power plants stopped operations. Costa Rica. The only operational field in Costa Rica is Miravalles, which extends over a 20-km2 area. The reservoir, at 1,0002,000 m depth, is water-dominated with a temperature of 240°C (Mainieri and Robles, 1995). The first power plant (single-flash,

Installed Capacity (MWe) 40 20 210 60 50 55 10 30 20 16 40 551

55 MWe) came online in 1994, followed by a small 5-MWe wellhead back-pressure unit and a second single-flash 55-MWe unit (Miravalles II) in 1998. In 2000, Miravalles III (single-flash 29.5 MWe), and in 2003 the binary Miravalles V (18 MWe), brought total installed generating capacity in the field to 162.5 MWe. Total electricity generated in 2003 was 1145 GWh/yr (Mainieri, 2003; Mainieri, 2005). The project uses 52 deep wells (32 for production and the remainder for gravity injection). The binary Miravalles V has been the major improvement since 2000. This power plant exploits heat from 95

International Geothermal Development separated brine on the injection streamline. At present, geothermal installed capacity represents 8.4 percent of the country’s total, and 15.1 percent of electricity produced. To date, 131 geothermal wells have been drilled in Costa Rica, to a total depth of 124 km. There are plans to extend the Miravalles field further eastward. Recently, well PGM-55, drilled to 1.5 km, identified a new high-permeability productive zone, hydraulically connected with the reservoir presently under exploitation. The potential of this well is estimated at 4 MWe. Since it is located near a protected natural area (virgin rain forest), directional drilling will be required for environmental reasons. This will be the first time in Costa Rica that multiple wells are drilled from the same pad. Geothermal energy is the second most important contributor to electricity generation in Costa Rica. It is of strategic economic importance, because of the country’s strong dependence on imported oil for its thermal power plants. Although these facilities represent 17 percent of total installed capacity, they contribute only 2 percent of

electricity produced annually. With such important geothermal (and hydropower) resources available, it is possible to operate the oil-burning plants as reserve units. In the northern part of the country near the Nicaraguan border, a second geothermal area near the Rincón de la Vieja volcano will be exploited in the near future. On the southern slope of the volcano, in the Las Pailas field, five exploration wells were drilled in 2001-2002. A proven resource associated with the 250°C reservoir is estimated at 18 MWe, with possible expansion to 35 MWe. On the northwestern slope of the Rincón de la Vieja volcano, in the Borinquen field, the first of four planned exploratory wells is being drilled. Preliminary results have confirmed the presence of an important thermal anomaly. El Salvador. Electricity has been generated from geothermal resources in El Salvador since 1975 (Rodriguez and Herrera, 2005). In the competitive energy market adopted in this country, geothermal electricity supplies 22 percent of national

Figure 5. First regional electricity grid: the SIEPAC (Sistema Eléctrico para América Central) line (from Lippmann, 2003).


requirements, with production in 2003 of 967 GWh. There are two major geothermal fields, Ahuachapán and Berlín (Fig. 4). The Ahuachapán field has been exploited since 1975, with three condensing units (two 30MWe single-flash, and one 35-MWe double-flash). Because of reservoir decline, only two of the three units are currently in operation. A project for reaching the units’ full capacity (Ahuachapán optimization) is underway. The 230-240°C reservoir is at shallow depth (600-1,500 m). There are 19 production and five reinjection wells over a 3-4 km2 area. In 2004, total injection of all produced fluid was achieved at Chipilapa, 6 km from the Ahuachapán area. A former policy of sending cooled geothermal fluids to the ocean through a canal has been abandoned. The possibility of utilizing residual heat through a 3.5-MWe binary power plant is being investigated, with plans to begin operations in 2006. The Berlín geothermal field was explored in the 1970s, but because of civil unrest commercial operation did not begin until 1992, when two 5-MWe wellhead units came online. They were decommissioned in 1999, and two 28-MWe single-flash units were installed. The 300°C reservoir is at approximately 2,000-2,500 m depth. There are nine production and 15 reinjection wells in the field. An extensive upgrading, aimed at installation of an additional 40-MWe, is currently scheduled. The first four wells for this project have already been drilled near the southern border of the reservoir. The presently exploited area is quite small, only 2-3 km2. An additional 6.5-MWe binary unit is under evaluation. Projects are ongoing in other geothermal areas of the country. In Cuyanausul, near the Chipilapa injection field, an exploratory well is being drilled. Should estimates of field potential be confirmed, one or two 5-MWe back-pressure units might be installed. Further concessions have been released for exploration in San Vincente, Chinameca and Obrajuelo. The overall potential of these fields could be around 100 MWe. In 2002, the Salvadoran and Honduran electricity grids were interconnected via a 230-kilovolt (kV) transmission line. This is the final link of the Central America grid. Now power can be traded from Panama to Guatemala within the GRC BULLETIN

International Geothermal Development Regional Electricity Market (MER) (de la Torre, 2002; Lippmann, 2003). The new regional SIEPAC (Sistema Eléctrico para América Central) transmission line with a transfer capacity of 300 MW (Fig. 5) is expected to be online during the first half of 2008. Ethiopia. Aluto-Langano is the only geothermal area currently exploited for electricity production in Ethiopia. It is located on the floor of the Ethiopian Rift Valley, about 200 km southeast of Addis Ababa. Eight deep wells (maximum depth of about 2,500 m) have been drilled in the field, four of them productive (Teklemariam and Beyene, 2005). Maximum reservoir temperature is about 350ºC. The potential of the field has been evaluated at up to 30 MWe for 30 years. A 7.3-MWe binary geothermal plant was installed in 1999. It is not fully functional because operational experience is lacking. The government's five-year plan includes rehabilitation of the power plant, and possible installation of an additional 20-MWe unit if financial support becomes available. In the Tendaho field, in the Northern Afar, three deep (2,100 m) wells found temperatures above 270ºC. France. At present, the only geothermal power production by France is under the French Overseas Department, at La Bouillante on the Caribbean Island of Guadeloupe. The old Bouillante-1 doubleflash power plant is still operating after its rehabilitation in 1995-1996. An 11-MWe power plant (Bouillante-2) came online in 2004, bringing total capacity of the field to 15 MWe (Laplaige et al., 2005), with production in 2004 of 102 GWh. Three new production wells were drilled for Bouillante-2 (single-flash, 10-MWe plant). The Bouillante-3 project is currently in its pre-feasibility phase. After installation of the third unit, geothermal electricity should provide nearly 20 percent of the island's electricity needs. Geothermal exploration programs are planned for the near future on the islands of Martinique and La Réunion, in the French Antilles. The HDR project at Soultz-sous-Forêts, in Alsace, is now in the scientific pilot plant stage, with module construction underway. The enhanced MAY / JUNE 2006

geothermal project, based on a three-well system in granite at a depth of 5,000 m, is expected to go online during 2006. Germany. The first geothermal power plant in Germany, at Neustadt-Glewe, has been online since 2003 (Schellschmidt et al., 2005). It has an installed capacity of about 230 kWe using an ORC. In addition, 10.7 MWt are used for district and space heating. Energy production of 1.5 GWh/y will provide 500 households with electric power. The plant uses a flow rate of 100 m³/h at a temperature of 98°C; at the end of the cycle the water is cooled to 72°C. Currently, six new installations for power generation are being planned at

Groß Schönebeck, Bad Urach, Offenbach, Speyer, Bruchsal and Unterhaching. Guatemala. Geothermal exploration began in Guatemala in 1972, but commercial exploitation started in 1998 at Zunil. This area has two geothermal fields located close together, Zunil I and II. Despite their proximity, they have separate reservoirs with different heat and fluid sources. Zunil I, located on the border of the Quetzaltenango caldera west of Guatemala City, has temperatures of 300°C at 1,5002,300 m depth. There are seven binary units with a total installed capacity of 28 MWe (24 MWe running capacity). A research and development project for Zunil I was

Figure 6. Location of geothermal fields in Iceland (from Ragnarsson, 2005)

Table 7. Geothermal fields in Iceland.


Installed Capacity (MWe) a

Number of Units a

Annual Electricity Production (GWh/yr) b

Nesjavellir Krafla Svartsengi Namafjall Husavik Reykjanes

90 60 46 3.2 2 0.5

3 2 11 1 1 1

692 401 368 12 9 1





Note: a: Early 2005 data; b: 2004 data 97

International Geothermal Development Table 8. Geothermal fields in Indonesia (early 2005 data).



Installed Capacity (MWe)

Number of Units

Gunung Salak Kamojang Darajat Wayang Windu Dieng Lahendong Sibayak

Java Java Java Java Java Sulawesi Sumatra

330 140 135 110 60 20 2

6 3 2 1 1 1 1

n/a n/a n/a n/a n/a n/a n/a




Total a

Annual Electricity Production (GWh/yr) a

The only data available are for total production referred to late 2004 (Ibrahim et al., 2005)

Figure 7. Location of the geothermal fields in Indonesia (from Sudarman et al., 2000, modified).

completed recently with installation of an injection facility. There are nine producing and four injection wells in this field, with six production and two injection wells currently operative. At Zunil II, a small steam cap linked to a deep hot aquifer has been discovered at shallow depth. Its potential has been estimated at up to 50 MWe. A development project was launched in 2003, with the drilling of two production wells and one for injection. In the near future, a long-term test will be performed to evaluate the reservoir and its possible decline with fluid production. The other Guatemalan field, at Amatitlán, also came online in 1998. An old 5-MWe back-pressure unit 98

is still in operation. Following the first four deep exploratory wells (two of which produce steam), two new wells have been successfully drilled to define the extension of the geothermal anomaly. As a result of a positive field assessment, a five-year project has been initiated to gradually increase installed capacity with modular binary units totaling up to 50 MWe. A 20.5-MWe hybrid power plant at Amatitlán was expected to go online in 2005 (Lima Lobato et al., 2003; Roldán Manzo, 2005). In 2003, total geothermal power production in Guatemala was 212 GWh/yr. Developments at Zunil and Amatitlán are supported by a new renewable energy law (2004), that provides

tax exemptions for renewable energy projects. The government’s commitment to renewables has also been confirmed in a four-year geothermal development program, signed in 2003. Geothermal exploration is under way in other parts of the country at Tecaumburro, San Marcos, Moyuta, and Totonicapán, but drilling has not been carried out. Iceland. The locations of geothermal areas in Iceland are shown in Figure 6, and listed in Table 7. Geothermal electricity generation has increased significantly in Iceland since 1999, with installation of new power plants at Nesjavellir and Husavik. Total installed capacity in Iceland is now 202 MWe. An additional 30-MWe singleflash unit at Nesjavellir is at an advanced stage of construction (Gunnlaugsson, 2002; Ragnarsson, 2005). Two other geothermal power plants are currently under construction, at Hellisheidi and Reykjanes. Their combined installed capacity will be about 180 MWe, which will almost double Iceland’s total. At Krafla, in the northern part of the country, there are two 30-MWe double-flash power plants. The geothermal projects at Svartsengi and Nesjavellir include power plants with an installed capacity of 46 and 90 MWe, respectively, and transmission of hot water to the Reykjavik and Hitaveita Sudurnesja district heating systems. Hellisheidi, a new field that is part of the large Hengill geothermal area in the southwestern part of the country, is currently under exploration, with plans to install 80 MWe and increase the amount of hot water supplied to the City of Reykjavik. There has been a great deal of drilling activity in Iceland over the last five years, with 39 new wells that reach a total depth of 55 km. Indonesia. Despite the huge geothermal potential of Indonesia, there has been relatively little development during the 2000-2005 period, mainly because of a severe economic crisis that has adversely affected power demand and growth (Ibrahim et al., 2005). Currently, the 797 MWe of installed geothermal capacity from the fields listed in Table 8 and shown in Fig. 7 are being fully utilized. Note that total running capacity for the country is 838 MWe. A GRC BULLETIN

International Geothermal Development 20-MWe geothermal unit at Lahendong is the only installation in Indonesia after 2000 (it came online in 2002), but the situation may change in the future. An investment plan for a new 100-MWe power plant at Darajat was approved in 2004. A tender has been launched for an additional 20 MWe at Lahendong. There are also plans to expand Kamojang by 60 MWe, but the project has not yet started.

Figure 8. A century of electric power production in Italy (from Cappetti et al., 2005).

Italy. A major event during 2000-2005 was the centennial celebration of the first successful experiment in producing geothermal electricity, which took place at Larderello in 1904. The first commercial power plant in that field went online in 1913 (250 kWe). Since then, geothermal power generation in Italy has increased steadily to the current 791-MWe installed capacity (699-MWe running capacity). Electricity generation Table 9. Geothermal fields in Italy. reached a historical maximum of 5,340 Location Installed Capacity Number Annual Electricity GWh in 2003, as shown in Figure 8 (Cap(MWe ) a of Units a Production (GWh/yr) b petti et al., 2000; Cappetti and Ceppatelli, 2005). Geothermal fields in Italy are listed Larderello 543 21 3,606 in Table 9 and their locations shown in FigTravale-Radicondoli 160 6 1,109 ure 9. The two major fields are LarderelloMt. Amiata 88 5 625 Travale/Radicondoli and Mt. Amiata. Ten (Bagnore and Piancastagnaio) new power plants (254-MWe installed caTotal 791 32 5,340 pacity) have been commissioned and gone online at Larderello-Travale/Radicondoli Note: a Early 2005 data; b 2003 data during the last five years, to replace old and obsolete units and to develop a deeper reservoir found Figure 9. Location of geothermal regions and power plants in Italy (from Cappetti et al., 2005). in old, shallow fields. A deep exploration program has also been launched, which includes a 3D seismic survey and 11 deep (3,000-4,000 m) wells. Twenty-one wells with a total depth of 64 km were drilled between 2000 and 2005. The adjacent Larderello and Travale/ Radicondoli areas are part of the same deep field that extends over a large (approximately 400 km2) area. The deep, super-heated steam reservoir has the same temperature (300-350°C) and pressure (4-7 MPa) throughout the field (Bertani et al., 2005). The exploited area at Larderello covers 250 km2, with 180 wells and 21 power units totaling 543-MWe installed capacity. MAY / JUNE 2006


International Geothermal Development The Travale/Radicondoli area (50 km2) has 22 wells, which send steam to six units totaling 160 MWe installed capacity. Condensed water from Travale is carried

through a 20-km pipeline to the center of the Larderello field, where it is injected. An additional 60 MWe are under construction (Nuova Larderello 3 and Nuova San

Martino). The Mt. Amiata area comprises two water-dominated geothermal fields, Piancastagnaio and Bagnore. In the 1980s, a deep reservoir was discovered in both fields, under the shallow geothermal reservoir exploited at that time. The deep Table 10. Geothermal fields in Japan. resource is characterized by 20 MPa, 300Location Installed Capacity Number Annual Electricity 350°C water (at 3,000 m). Objections by lo(Prefecture) (MWe) a of Units a Production (GWh/yr) b cal communities have delayed development of this high-potential deep system. At presOita 153 7 1,108 ent, there are five units totaling 88 MWe Iwate 104 3 643 installed capacity at Mt. Amiata, one in Akita 88 3 619 Bagnore and four in Piancastagnaio. A 20Fukushima 65 1 400 MWe unit online since 1987 was decomKagoshima 60 2 416 missioned in 2000. In 2003, the 40-MWe Hokkaido 50 1 185 power plant at Latera was closed because Miyagi 12 1 81 of environmental and technical problems. Tokyo 3.3 1 15 This field is no longer under exploitation. Total 535 19 3,467 Liberalization of the electricity market has been completed in Italy, with an incentive Note: a Early 2005 data; b 2003 data scheme for renewables (Green Certificates) that should lead to further exploration and development of Figure 10. Location of geothermal plants in Japan ( Kawazoe et al., 2005, modified, see Table 10). deep geothermal resources. On the basis of positive results achieved so far, some 100 MWe are expected to be installed in Italy within the next five years. Japan. Seventeen geothermal power plants are in operation in Japan, most of which are located in the Tohoku and Kyushu districts (Fig. 10) with total installed capacity of 535 MWe (Kawazoe and Combs, 2004; Kawazoe and Shirakura, 2005). Geothermal locations in Japan are listed in Table 10. Because financial support and favorable regulations are lacking, there have been no major geothermal developments in recent years. Only a small, 2-MWe binary unit was set up at the Hatchobaru geothermal power station in February 2004. This is the first binary-cycle geothermal power plant in Japan. On the other hand, there has been significant drilling activity 100


International Geothermal Development during 2000-2005, with 41 geothermal wells (totaling 74 km depth) equally distributed for exploration, production and injection. Deregulation of the Japanese power generation market started in 2000. As a consequence, electric power companies changed their investment policies regarding new power plants. This process, in addition to a drastic reduction in commitment to geothermal by the New Energy and Industrial Technology Development Organization (NEDO), was responsible for the decline in recent Japanese geothermal development. A recent Renewable Portfolio Standard (RPS) law promulgated in 2003 may be a useful tool for attracting private investment in geothermal energy development. It should be noted that only binary-cycle geothermal power plants are covered by the RPS, encouraging a trend in development of small-scale geothermal fields. In 2004, NEDO launched its Geothermal Development Promotion Surveys, based on the concept of “local energy for local areas.” Three new target areas were carefully selected, based on economic and social factors, and on estimated potential for installing binary power plants of 10 MWe or less. Though these units may be relatively small, the program may lead to further utilization of geothermal energy. Results of the surveys will be evaluated by the end of March 2006. A strategy has recently been proposed by the Ministry for Education, Culture, Sports, Science and Technology (MEXT) for developing Japanese geothermal resources in ways consistent with global environmental expectations for the 21st Century, the socalled EIMY, or “Energy in My Yard.” The idea is that local energy requirements should be met by an optimum combination of local renewable sources. Shortfalls and surpluses would be accommodated through interface with the national electricity grid (Niitsuma and Nakata, 2003). These integrated renewable energy systems offer a considerable advantage over independent utilization of renewable resources. In rural areas of Japan, such systems could reduce CO2 emissions and energy costs. Geothermal energy will play a key role in these EIMY systems. Heat pumps are of primary importance, together MAY / JUNE 2006

Figure 11. Location of geothermal fields in Mexico (from Gutiérrez-Negrín et al., 2005).

Table 11. Geothermal fields in Mexico.


Installed Capacity (MWe) a

Number of Units a

Annual Electricity Production (GWh/yr) b

Cerro Prieto Los Azufres Los Humeros Las Tres Vírgenes

720 188 35 10

13 14 7 2

5,112 852 285 33





Note: a Early 2005 data; b 2003 data

with other geothermal technologies such as injection, HDR, “Hot Wet Rock”(HWR), and binary systems. This innovative concept is expected to give a welcome boost to geothermal power generation, as it will obviate many problems with local permits and encourage local acceptance of small-scale installations. Kenya. Geothermal electricity generation capacity in Kenya has increased by 84 MWe since 2000. Olkaria is the only geothermal field developed to date. Exploitation has grown from 45 MWe in 1999 to 129 MWe in 2004, a 186-percent increase (Mwangi, 2005). Production in 2003 was 1,088 GWh. The Olkaria

geothermal system is located in the East Africa Rift valley about 120 km northwest of Nairobi. The greater geothermal anomaly covers 80 km2; only three sectors (east, west and northeast) are being exploited at this time. In the Olkaria East field, three 15-MWe turbo-generating units at Olkaria I have been online for 23 years. The first of 33 drilled wells were shallow (