Geothermal power generation in the world 2005–2010 update report

Geothermics 41 (2012) 1–29

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Geothermal power generation in the world 2005–2010 update report Ruggero Bertani ∗ Enel Green Power, via Regina Margherita 135, 00198 Rome, Italy

a r t i c l e

i n f o

Article history: Received 26 June 2010 Accepted 11 October 2011 Available online 16 November 2011 Keywords: Geothermal World installed capacity Electricity generation Geothermal potential

a b s t r a c t We have analyzed the major activities carried out for geothermal electricity generation since WGC2005. New data have been taken from WGC2010 country update reports, private communications from IGA members and affiliated organizations. Other updates have been collected from websites of private and public organizations involved in geothermal development. Plants commissioned in 2010 (after WGC2010) have been included in the installed capacity, even though their produced energy has not been accounted for. An increase of about 2 GW (herein we use MW and GW for the electrical capacity and MWth and GWth for thermal capacity) in the five year term 2005–2010 has been achieved (about 22%), following the rough linear trend of approximately 400 MW/year, with an evident increase of the average value of about 200 MW/year in the 2000–2005 period (Bertani, 2005a,b, 2006, 2007). The most significant data to be highlighted from this paper are:

• a total of 24 countries now generate electricity from geothermal resources; • the total installed capacity worldwide is 10,898 MW, corresponding to about 67,246 GWh of electricity (early 2010 data);

• Germany, Papua – New Guinea, Australia, Turkey, Iceland, Portugal, New Zealand, Guatemala, Kenya, and Indonesia have increased the capacity of their power plant installations by more than 50% with respect to the year 2005; • the top five countries for their electricity production are USA, Philippines, Indonesia, Mexico and Italy; • five countries realized an increase above 100 MW with respect to 2005: USA, Indonesia, Iceland, New Zealand and Kenya. The prospective for growth during 2010–2015 are good, with a strong possibility of realizing a big increase in the installed capacity up to 19 GW, if all the currently identified projects would be realized all around the world. © 2011 Elsevier Ltd. All rights reserved.

1. Introduction The total installed capacity from worldwide geothermal power plants is given in Table 1 and Fig. 1. For reaching the forecast for installed capacity in 2015, based on an accurate accounting of all the projects under development, a change in the present linear growth trend is necessary. In Table 2 data from all the countries currently generating geothermal electricity are presented, with the 2005 and the updated 2010 values of installed capacity and the produced energy per year, the increment since 2005 both in absolute terms and in percentage, and the forecast to year 2015 for the installed capacity. In Fig. 2 the world map of the year 2010 installed capacity is presented. In Fig. 3 the forecast for year 2015 is shown.

∗ Tel.: +39 3299506574. E-mail address: [email protected] 0375-6505/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.geothermics.2011.10.001

Data of Table 2 can be aggregated for each continent for an easy comparison of the differences in geothermal development and perspectives. In Fig. 4 the present installed capacity both for electricity and direct utilization (Lund et al., 2010b) are presented. Figs. 5 and 6 show the expected growth from 2010 to 2015, both in MW and in the number of countries with geothermal electricity. The number of geothermal countries is expected to increase from 24 in 2010 to 46 in 2015, almost doubling the present value. Binary plant technology is playing a very important role in the modern geothermal electricity market. The binary plants can be used to generate additional electricity from the reservoir fluid after its primary utilization in standard flash plants, achieving a better energy efficiency for the overall system. In the dry steam reservoirs (Larderello – Italy, The Geyser – USA), a large fraction of the energy of the steam can be utilized to produce electricity. In liquid-dominated systems the majority of the thermal energy from the extracted fluid is lost, being injected at high temperature (typical value 100–180 ◦ C) and not-used. The binary

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R. Bertani / Geothermics 41 (2012) 1–29

Table 1 Total worldwide installed capacity from 1950 up to the end of 2010 and forecast for 2015. Year 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Installed capacity (MW)

Produced energy (GWh/year)

200 270 386 520 720 1180 2110 4764 5834 6833 7972 8903 10,898 19,800

Moreover, the utilization of low temperature resources can be achieved only with binary plants, increasing the overall exploitable potential worldwide. The ambitious target presented in this paper can be attained only though an extensive use of binary plants. The binary generation in 2010 was only 1.1 GW, even though 44% of the geothermal power plants are of the “binary” type. 2. Geothermal power generation 2.1. Armenia The recent field investigations, supported by World BankGeoFund program, discovered a promising resource with a potential capacity of 150 MW in the Jermaghbyur area, where a first unit is planned.

38,035 49,261 55,709 67,246

2.2. Algeria (Fekraoui, 2010) plants on the injection stream could be a very effective way of producing cheap energy, because there will not be any additional fluid production costs associated with this extra electricity generation.

The geothermal resources of the country are used only for direct utilization. A pilot binary plant is planned near Guelma, in the NE of the country.

Table 2 Installed capacity and produced energy for 2005, 2010, and forecast for 2015. Country

Algeria Argentina Armenia Australia Austria Bolivia Canada Chile China Costa Rica Czech Rep. Djibuti El Salvador Ethiopia France Germany Greece Guatemala Honduras Hungary Iceland Indonesia Iran Isl. Rep. Italy Japan Kenya Latvia Mexico Nevis New Zealand Nicaragua Papua – New Guinea Peru Philippines Poland Portugal Romania Russia Slovakia Spain Switzerland Thailand The Netherland Turkey UK USA Total

Installed in 2005

Energy in 2005

Installed in 2010

Energy in 2010

Forecast for 2015

Increase since 2005

MW

GWh/year

MW

GWh/year

MW

MW

0 0 0 1.1 1.4 0 0 0 24 166 0 0 204 7.3 16 7.1 0 52 0 0 575 1197 0 843 535 202 0 958 0 762 88 56 0 1904 0 29 0 82 0 0 0 0.3 0 91 0 3098 10,898

0 0 0 0.5 3.8 0 0 0 150 1131 0 0 1422 10 95 50 0 289 0 0 4597 9600 0 5520 3064 1430 0 7047 0 4055 310 450 0 10,311 0 175 0 441 0 0 0 2.0 0 490 0 16,603 67,246

1 30 25 40 6 100 493 160 64 207 5 50 287 47 41 15 18 121 35 5 1285 3451 50 923 568 585 3 1115 35 1237 248 75 40 2519 1 60 5 194 5 40 3 1 5 206 13 5437 19,803

0 0 0 0.2 1.1 0 0 0 28 163 0 0 151 7.3 15 0.2 0 33 0 0 202 797 0 791 535 129 0 953 0 435 77 6.0 0 1930 0 16 0 79 0 0 0 0.3 0 20 0 2534 8903

0 0 0 0.5 3.2 0 0 0 96 1145 0 0 967 0 102 1.5 0 212 0 0 1483 6085 0 5340 3467 1088 0 6282 0 2774 271 17 0 9253 0 90 0 85 0 0 0 1.8 0 105 0 16,840 55,709

GWh/year

Capacity (%)

Energy (%)

1 0

0 1

633 27

−5 19

−4 3

54 −14

−13 2

57 −1

53 0 2 7

455 10 −7 49

35 0 10 2987

47 −7 3249

19

77

58

36

373 400

3114 3515

184 50

210 58

52 0 73

180 −404 342

7 0 57

3 −12 31

5

766

1

12

327 11 50

1281 39 433

75 14 833

46 15 2547

−26

1058

−1

11

13

85

78

94

3

356

4

419

0

0

0

11

71

385

356

368

564 1995

−237 11,538

22 22

−1 21

R. Bertani / Geothermics 41 (2012) 1–29

3

World Geothermal Electricity 80,000

Installed Capacity

60,000

Produced Electricity

10,000

40,000

20,000

0 1950

1960

1970

1980

1990

2000

2010

Produced Electricity, GWh

Installed Capacity, MW

20,000

0 2020

Years Fig. 1. Installed capacity from 1950 up to 2015 (left, MW) and produced electricity (right, GWh).

2.3. Argentina (Pesce, 2010) The only geothermal plant in the country, the small demonstration binary unit at Copahue (670 kW), installed in 1988 was decommissioned in 1996. It was powered by a single well with 171 ◦ C fluid, at 800–1200 m depth and flow rate of about 2 kg/s. A new 30 MW plant at that site is under consideration. Six other projects are at different stage of development. 2.4. Australia (Beardsmore and Hill, 2010) Despite the low inventory of traditional hydrothermal resources in Australia, a big effort is on the way, both from the government and the private sector, to exploit the EGS prospects in the country.

Several projects are under development, and many new leases have been awarded to a number of companies. There is the hope to have in the near future the first industrial scale exploitation of EGS. The Birdsville geothermal power plant was Australia’s only operating source of geothermal electric power at the end of 2009. The organic Rankine cycle binary plant operates on 98 ◦ C water supplied at a rate of 27 kg/s from a 1200 m deep well generating net 80 kW. Additional 300 kW capacity is planned. Geodynamics Ltd. plans to commission a new 1 MW pilot plant at its Habanero EGS project at Innamincka. This plant is the first stage in a planned 40 MW initial development at the site. A temperature of 250 ◦ C at a depth of 4400 m has been reported. Panax Geothermal Ltd. operates the Penola Geothermal Project. The reservoir at about 3500 m depth yields water at

Fig. 2. Worldwide installed capacity in 2010 (10.9 GW).

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R. Bertani / Geothermics 41 (2012) 1–29

Fig. 3. Forecast of the installed capacity in 2015 (19.8 GW).

an average temperature of 145 ◦ C from a naturally permeable formation. Petratherm Ltd. is developing a project at Paralana to extract heat from meta-sedimentary formations at a depth of 3500–4000 m. The total geothermal EGS installed capacity is expected to reach 100 MW by 2020. 2.5. Austria (Goldbrunner, 2010) Three small binary plants are operating: Altheim, Bad Blumau and the cross-border project of Simbach/Braunau, commissioned in 2009 (Fig. 7).

At Altheim a 106 ◦ C fluid is utilized both for district heating and for electricity production using a binary plant. The net output is 500 kW, after accounting for a parasitic load of 350 kW for the submersible pump. The Bad Blumau project with 110 ◦ C fluid includes heating for a Spa facility and a binary plant of 180 kW net output. At Simbach/Braunau, the district heating project utilizes 40 MWth of geothermal heat in addition to a small binary unit of 200 kW. The obstacles and barriers to the geothermal development in this country are quite severe, and only a moderate increase up to 6 MW is forecast for the year 2015.

Installed Capacity for Direct Uses and Electricity 30,000

Installed Capcity, MW

DIRECT USE ELECTRIC POWER

23,608

20,000 14,600 11,819

10,000 4565

3717 1643

130 209

427 763

0 Africa

Americas

Asia

Europe

Fig. 4. 2010 installed capacity (electricity and direct utilization) by continent.

Oceania

R. Bertani / Geothermics 41 (2012) 1–29

5

Installed Capacity: present value and short term forecasting 8308 2015

8000

2010

Installed Capacity, MW

6753 6000

4565 3717

4000

2833 2000

1643 1277 763

633 209 0

Africa

Americas

Asia

Europe

Oceania

Fig. 5. 2010 installed capacity and forecast for 2015 by continent.

Number of Countries with Geothermal Electricity: 2010 and 2015 20

19 2015

Number of Countries

2010

15 13

10 8

8 6

5

5 4 3 2

2

0 Africa

Americas

Asia

Europe

Oceania

Fig. 6. Number of countries in 2010 and 2015 with geothermal electricity by continent.

The Bolivian state power company, ENDE, is starting the exploitation phase of Laguna Colorada, after a hiatus following the exploration done by the Italian company Enel in 1990.

high elevation, in severe climatic and logistic conditions, without an easy access to the national electricity grid. A joint venture of Enel Green Power and the ENAP (Chilean national oil company) is going to develop four projects, in different locations of the country,

AUSTRIA

The geothermal potential of the country is still untapped. By the year 2015, the first plant, the South Meager Creek project, owned by Ram Power, where an hydrothermal reservoir at 220–275 ◦ C has been confirmed by 8 wells, is likely to become operational. Seven other projects are in advanced stages of planning, with an expected output of about 500 MW, a very ambitious target for 2015. 2.8. Chile (Lahsen et al., 2010)

Installed Capacity, MW

2.7. Canada (Thompson, 2010)

Installed Capacity

6

6 6 4 4 2 2

1

1

2005

2010

00

0

0 1995

Although no geothermal power plant has been installed to-date, a vigorous geothermal exploration program is under way. The high temperature fields are located in the Andes mountains, at very

Produced Electricity

8

2000

2015

Year Fig. 7. Installed capacity and electricity in Austria.

Produced Electriciy, GWh

2.6. Bolivia

6

R. Bertani / Geothermics 41 (2012) 1–29

200

80

64

150

60 100 40

29

29

28

24

50

20

0

0 1995

2000

2005

2010

Installed Capacity, MW

Produced Electricity

100

Produced Electriciy, GWh

Installed Capacity, MW

Installed Capacity

Installed Capacity

Produced Electricity

250

1200

207 200

166

163

143

150

800

100

400

55 50

0

0 1995

2000

2015

2005

2010

Produced Electriciy, GWh

COSTA RICA

CHINA

2015

Year

Year Fig. 9. Installed capacity and electricity in Costa Rica. Fig. 8. Installed capacity and electricity in China.

At present, only electric production is from the Yangbajain field, in Tibet (24 MW, Fig. 8). Its exploitation (operated by Electric Power Tibet) started in 1977, and its installed capacity increased continuously up to 1991, when further investments were halted, despite the discovery of the high temperature deep geothermal resources below the shallow one. A 2500 m deep well was drilled in 2004, reaching the deep reservoir. Temperatures in the 250–330 ◦ C range have been measured at 1500–1800 m depth. Geothermal potential for Yangbajain is estimated at about 50–90 MW. 2.10. Czech Republic (Delbos, 2009) The total exploitable capacity of the country is not exciting, and only recently a project for a first small pilot plant in Liberec region has been announced. 2.11. Costa Rica (Protti, 2010) No new geothermal power plant was added during 2005–2010. The current geothermal capacity, 165 MW at Miravalles, constitutes 13% of the electric generation in the country. Costa Rica has a mix of renewable energy generation, with hydro accounted for 80% of the total electricity, and wind for an additional 2%. The exploitation of Miravalles, operated by Instituto Costarricense de Electricidad (ICE), with temperature of about 240 ◦ C, started in 1994, and it reached its steady state in 2003 (Fig. 9). Two new projects are at different stages of planning: a 41 MW binary plant from reservoir fluid at 260 ◦ C is under construction at Las Pailas, and a feasibility plan has been completed at Borinquea. The installed capacity of the country is expected to exceed 200 MW in a few years. By 2020, electricity produced from renewable sources is planned to constitute 94% of total generation, and geothermal energy will reach 8% of installed capacity and 12% of generation. 2.12. Djibuti (Houssein, 2010) The geothermal potential of the country in estimated at about 300–400 MW, and is still untapped. The project for a 50 MW unit in Asal area in currently on going, and is expected completed in a few years by Reykjavik Energy.

There are two major geothermal fields in this country: Ahuachapán and Berlín (95 and 109 MW, respectively), for a total capacity of about 200 MW, producing 26% of the electricity needs of the country. Both the fields are operated by LaGeo, in partnership with Enel Green Power (Fig. 10). The increase in installed capacity since 2005 was 53 MW (35% in capacity, 47% in energy), for the two new units at Berlin of 44 MW (flash type) and 9 MW (binary type). In the Ahuachapán area (temperature of 250 ◦ C) two 30 MW single flash and one 35 MW double flash are currently online (1975–1981); due to the reservoir decline, only 84 MW is currently being generated. A project for reaching the full capacity loading of the units (Ahuachapán optimization) is under study. In the injection reached the target of 100% of the exploited fluid. The possibility of repowering unit 2, which will add 5 MW to the total capacity of the field, is under consideration. At Berlín (with a temperature exceeding 300 ◦ C) two 28 MW single flash units were installed before 2005 (1992–1999); two major additions have been placed online since 2005: a bottoming cycle binary unit for 9.4 MW (on line in 2008) and a single flash 44 MW unit (commissioned in 2006), built by Enel Green Power under an agreement with LaGeo. In 2003, the most productive well in Latin America was drilled at Berlín, with a production capacity of 20–30 MW from the steam cap at about 1000 m depth. A new unit for 28 MW is planned. In the Chinameca field feasibility studies for a 50 MW units are ongoing (a single well at 1900 m reached temperature around 240 ◦ C). The total installed capacity of the country is forecasted to be about 290 MW by 2015.

El SALVADOR Installed Capacity

Produced Electricity

400

3000

287 2000

204 200

161

151

105

1000

0

0 1995

2000

2005

2010

2015

Year Fig. 10. Installed capacity and electricity in El Salvador.

Produced Electriciy, GWh

2.9. China (Zheng et al., 2010)

2.13. El Salvador (Herrera et al., 2010)

Installed Capacity, MW

for an aggregate capacity of about 150 MW. The expected reservoir temperature is above 200 ◦ C at depths of less than 2000 m. Several other geothermal developers are also active in Chile. The growth of the geothermal market in this country is impressive.

R. Bertani / Geothermics 41 (2012) 1–29

7

120

80 80

60

41 40 20

40

15 4

16

4

0

0 1995

2000

2005

2010

2015

Year Fig. 11. Installed capacity and electricity in France.

2.14. Ethiopia (Teklemariam, 2010) Despite the great geothermal potential of the country (estimated at about 5000 MW), and its location on the African rift geothermal anomaly, no new plant has been commissioned since 1999. The 7.3 MW unit at Aluto-Langano field (Ethiopian Electric Power Corporation), after several operational problem, is currently producing about 3 MW, from a reservoir with 300 ◦ C at 2000 m depth. According to a feasibility study, the second proven field of the country (Tendaho, 250 ◦ C at shallow depth) can sustain a power project of about 20 MW. Six additional geothermal prospects have been identified, but the lack of foreign investors is the most important limiting factor for the future development of geothermal resources in this country. 2.15. France (Boissier et al., 2010) The electricity production in France is only in the French Overseas Department, at Bouillante on Guadeloupe island (Geothermie Bouillante). Its exploitation started in 1984, and a second unit was commissioned in 2004. The reservoir temperature is 250 ◦ C at shallow depths between 300 and 1200 m. The total capacity of 15 MW, not increased since 2005, produces 95 GWh, corresponding to 8% of the local consumption. After completion of a planned third unit of 20 MW, geothermal contribution will reach 20% of the electricity usage (Fig. 11). On the islands of La Martinique and La Réunion, geothermal exploration programs are planned in the near future. The EGS project at Soultz-sous-Forêts is now operating a scientific pilot plant of 1.5 MW. The enhanced geothermal system, exploited with a three-well system in the granite formation at a depth of 5000 m, is expected to stabilize its operation in the near future. In December 2008, the thermal output ranged around 12 MWth from a flow-rate around 28 l/s. 2.16. Germany (Schellschmidt et al., 2010) High-enthalpy reservoirs do not occur in Germany. Its electricity production, strongly supported by local administration and central government, is limited to binary plant applications, along with utilization of the hot water for district heating. The first geothermal plant for electrical power generation in Germany was commissioned at Neustadt–Glewe, with an installed capacity of about 230 kW with a binary cycle using 98 ◦ C geothermal fluid. In addition 10.7 MWth are used for district and space heating. Two new plants at Landau and Unterhaching started in 2008, each with a capacity of about 3 MW, and a heating capacity of about 3.5 and 38 MWth respectively. Additional projects totaling about 10 MW are planned at several sites (Fig. 12). A binary Kalina unit

Installed Capacity

Installed Capacity, MW

100

Produced Electriciy, GWh

Installed Capacity, MW

Produced Electricity

Produced Electricity

60

20

15 40 10

7 20

0

0

0

1995

2000

2005

0

0 2010

Produced Electriciy, GWh

GERMANY

FRANCE Installed Capacity

2015

Year Fig. 12. Installed capacity and electricity in Germany.

at Bruchsal for 0.5 MW was commissioned in 2009, and is operated by EnBW. For a minimum of at least three projects (Hagenbach/Upper Rhine Graben and two in the Munich region), drilling works are already scheduled. Construction has also started on a biomass/geothermal energy hybrid plant at Neuried (Upper Rhine Graben). Research activities at the EGS R&D site at Groß Schöneck are ongoing. According to official statements by German Geothermal Association, about 150 geothermal projects are expected to produce 280 MW of electricity by 2020. 2.17. Greece (Andritsos et al., 2010) Geothermal energy in Greece, despite its relative high potential in the volcanic arc islands, does not have the support of the government and local population. The small 2 MW unit at Milos, installed in 1987, has been decommissioned and dismantled. Several other projects are under evaluation (Nisyros, Thrace), both by PPC/Renewables (the Greek electricity company for renewables) and foreign investors, but the authorization process (from the Ministry issuing the tender of geothermal leases) is slowing the development. The most advanced is the 8 MW binary plant project in Lesvos, where few wells have already been drilled, and a shallow resource has been identified. 2.18. Guatemala (Asturias and Grajeda, 2010) The geothermal resource potential of Guatemala is about 4000 MW. Two geothermal fields, Zunil and Amatitán (28 and 24 MW, respectively), are currently under production. These fields are operated by Instituto Nacional de Electrificatión (INE) and Ormat. The decline of production from 200 GWh in 2000 down to 142 GWh in 2006, due to low permeability and poor hydrogeological connection between injection and production areas, has been partly reversed and a new 24 MW binary unit has been installed at Amatitlán (Fig. 13). The increment in electric production, compared to 2005, was about 58%. Zunil, located to the west of Guatemala City, is divided into two areas; the first has temperatures up to 300 ◦ C, and an estimated capacity of 50 MW whereas the second one, with 240 ◦ C has an estimated capacity of 50 MW. The installed capacity is 28 MW, but only 16 MW is being generated, due to reservoir decline. Drilling and testing of new wells is in progress. Amatitlán geothermal area is located about 25 km to the south of Guatemala City in the active volcanic chain. This field, with a temperature of 285 ◦ C, has an estimated total capacity of 200 MW. After decommissioning the old 5 MW backpressure unit (to be moved to

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R. Bertani / Geothermics 41 (2012) 1–29

Installed Capacity

Produced Electricity

150

300

121 100

200

52 50

33

33

2000

2005

100

0 0

0 1995

2010

Produced Electriciy, GWh

Installed Capacity, MW

GUATEMALA

2015

Year Fig. 13. Installed capacity and electricity in Guatemala.

Zunil), a new 24 MW binary plant was commissioned in 2007, and a second one is under construction. An exploration of the Tecuamburro field, with a projected capacity of 40 MW, is currently under preliminary stage of permitting. There is another development project in the Moyuta area. Both of these projects are being undertaken by Enel Green Power. 2.19. Honduras (Lagos and Gomez, 2010) Although several geothermal resources are present only the Platanares project is in an advanced stage of development, with indications for a 200–220 ◦ C geothermal resource at 1200–1500 m. A 35 MW plant is planned. 2.20. Hungary (Toth, 2010) Low and medium temperature geothermal resources are abundant in Hungary. The national oil company (MOL) has drilled several wells, and some of these can be used for geothermal energy generation. A pilot project of 5 MW is planned at Ortaháza. 2.21. Iceland (Ragnarsson, 2010) The geothermal electricity production in Iceland has increased significantly since 2005 (about 370 MW representing 18% of 2005 value, the highest among the countries with significant geothermal electricity production), with the installation of new plants at Nesjavellir (30 MW), Hellisheidi (5 units for 213 MW), Svartsengi (30 MW) and Reykjanes (100 MW). The currently producing fields of the island are: Bjarnaflag (3 MW), Husavik (2 MW), Krafla (60 MW), Nesjavellir (120 MW), Svartsengi (76 MW), Hellisheidi (213 MW), and Reykjanes (100 MW).

Krafla is in the northern part of the island; its operation started in 1977. There were some initial difficulties in producing enough steam for the plants, due to the volcanic activity in the area. Now, after 20 years, some degassing of the productive reservoir has been achieved, and two 30 MW double flash turbine are in operation with an additional 40 MW planned. Bjarnaflag (Námafjall) is the oldest geothermal field in Iceland, and has been in operation since 1969, with an old 3 MW backpressure unit. In Husavik an experimental Kalina binary unit (using 120 ◦ C hot water, operated by Orkuveita Husavikur) of 2 MW was installed in 2000, commercial operation was commenced in 2008. Hellisheidi is located on the active volcanic system of Hengill; it generates 210 MW of electricity, and provides 400 MWth of thermal output for district heating of the Reykjavik area (27 km away). The electricity is supplied mainly to local aluminum refineries. All the plants at Hellisheidi were commissioned after 2005 by Orkuveita Reykjavikur: 2 × 45 MW in 2006 (Unit I), 35 MW in 2007 (Unit II) and 2 × 45 MW in 2008 (Unit III). Nesjavellir, located in the southern part of the country, has four 30 MW units (total 120 MW), and provides 300 MWth for district heating (about 1800 l/s of hot water). The most recent unit was commissioned in 2005. Reykjanes, located in south-western peninsula, is operated by Hitaveita Sudurnesja, and was commissioned in 2005 and 2006, with two 50 MW units, and an additional 50 MW is under construction. Svartsengi is near the international airport and the famous outdoor swimming/spa facilities of Blue Lagoon (visited yearly by about 400,000 people, probably the most popular Icelandic touristic attraction), which is fed by the discarded geothermal water (rich in surplus mineral). In addition to two flash units (reservoir fluid at 240 ◦ C) for about 66 MW and an 8 MW binary; hot water (energy content of about 150 MWth ) is provided for district heating. The most recent addition was a 30 MW unit in 2005. Other projects are also ongoing in Iceland. The Icelandic Deep Drilling Project (IDDP) is situated near Krafla geothermal area, in the northern part of the country. The goal of the project is the exploitation of supercritical fluids at 4–5 km depth and 400–600 ◦ C of temperature. Unfortunately, in 2009, the well reached a magma body and the project was placed on stand-by. An agreement has been signed between the Century Aluminum Co. and two major Icelandic geothermal producers (Hitaveita Sudurnesja and Orkuveita Reykjavikur) for supplying electricity for the production of 150,000 tons of aluminum per year, utilizing 250 MW of geothermal electricity. The initial stage of the project was commissioned in 2010. The agreement is expandable up to 435 MW, for the production of 250,000 tons of aluminum. The total installed capacity of the country is 575 MW, and an additional 230 MW is under construction (Fig. 14a). The country

Fig. 14. (a) Installed capacity and electricity in Iceland. (b) Primary Energy Consumption in Iceland (from Orkustofnun Energy Statistics 2008).

R. Bertani / Geothermics 41 (2012) 1–29

Installed Capacity, MW

Installed Capacity

Produced Electricity

4000

3451

10000 8000

3000

6000 2000

590

797

4000

1197

1000

2000

310 0

0

1995

2000

2005 Year

2010

Produced Electriciy, GWh

INDONESIA

2015

Fig. 15. Installed capacity and electricity in Indonesia.

with 300,000 inhabitants is 100% powered by renewable energy, with 25% of its electricity and 90% of heating needs provided by geothermal energy (Fig. 14b). The total geothermal electric generation capacity is well above 4000 MW, almost twice the present country consumption. Geothermal energy contribution to the total energy consumption in Iceland is 62%, probably the highest in the world. Space heating is the main use of geothermal power in Iceland which amounts to about 25 PJ/year; an extensive district-heating system has been established. The share of geothermal in space heating is almost 90%, whereas the remainder is provided by electricity, so that fossil fuels account for only a small fraction of the total. As an example, the Reykjavik district heating system, serving 200,000 inhabitant of the capital, with a thermal capacity of 1.2 GWth and about 80 million m3 of hot water provided yearly, is one of the largest in the world; 100% of the heat for this system is derived from geothermal energy. 2.22. Indonesia (Darma et al., 2010) Indonesia has embarked on a geothermal power plant construction and exploration, strongly supported by Government, through regulation and policies (Fig. 15). The new plants commissioned since 2005 are 110 MW at Darajat, 117 MW at Wayang Windu, 2 × 20 MW at Lahendong, 60 MW at Kamojang, and 10 MW at Sibayak, reaching a total installed capacity of about 1.2 GW (including the upgrading of the six units of Salak, 60 MW and two in Darajat, 15 MW). Indonesia is currently ranked third among the countries producing geothermal electricity. The geothermal fields of the country are as follows: Sibayak (13 MW), Lahendong (60 MW), Gunung Salak (MW), Kamojang (200 MW), Wayang Windu (227 MW), Darajat (260 MW) and Dieng (60 MW). 2.22.1. Sulawesi At Lahendong, three 20 MW units have been installed (the first in 2002, the other two in 2008 and 2009, respectively) and a further 20 MW is under construction, following a development plan of an additional 60 MW. After the past negative experience with binary plants in Indonesia (only an old 2.5 MW experimental unit, which has never been operated), the first new generation 7.5 MW binary bottoming unit is planned at Lahendog for year 2012. The field is operated by Pertamina Geothermal Energy and the national electrical utility PLN. 2.22.2. Sumatra At Sibayak, the exploitation started in 1996, with a small 2 MW unit. Two new units, for a total of 13.3 MW were commissioned in 2007; a further 10 MW are planned provided an expansion of the

9

production area is confirmed by the surface exploration activities being carried out by Pertamina Geothermal Energy. 2.22.3. Java A new unit of 60 MW was commissioned at Kamojang in 2007, increasing the total generation to 200 MW. Kamojang, a steamdominated geothermal field, was the first exploited geothermal field in Indonesia, when in 1978 a small 250 kW unit was commissioned. The three power units have performed quite well since their installation (unit 1, 30 MW in 1982, units 2 and 3, 55 MW each, in 1987 and 2007). An additional 60 MW unit is currently under construction by Pertamina Geothermal Energy and PLN (Perusahaan Listrik Negara, i.e., State Electricity Company). At Dieng, one 60 MW unit was installed in 1998, first step of a four-plant project. The ownership of the field was transferred to Geodipa and the plant started its operative life. Two additional 55 MW plants are planned. In 2009 a new 117 MW plant was added to the old 110 MW plant at Wayang Windu, in operation since 2000. The field is operated by Star Energy, an Indonesian oil company. Drilling activity and resource evaluation are ongoing with the goal of doubling the production from the field. Since 1997, no new plants have been constructed at Gunung Salak. The six 65 MW units are currently operated 20% above the reference installed capacity (55 MW), due to the power shortage in Java/Bali, for a total of 375 MW. The BOT (Build, Own, Transfer) scheme will end in 2012, and the three units currently operated by Chevron will be transferred to PLN. The geothermal resource at Darajat is vapor dominated, and has been exploited since 1994. A new unit of 110 MW was commissioned in 2008; further development of an additional 110 MW is ongoing. The field and power plant are operated by Chevron since 2006, and the two old units have been upgraded to a total of 15 MW. 2.22.4. Bali The Bedugul field is a liquid reservoir at 280–320 ◦ C and 1500–2000 m depth. Bali Energy Ltd. plans to develop a total of 175 MW, with a 10 MW pilot plant and three 55 MW units. 2.22.5. New areas At Sarulla, in North Sumatra, the development of three 110 MW projects has been assigned to an international consortium, including Medco Power, Itochui, Ormat, Kyushu Electric and Pertamina as field operator. The plan is to reach 330 MW in 2013. In Central Sumatra, Hulu Lais field has been explored and a development plan has been initiated. In Ulu Belu, South Sumatra, the liquid reservoir at 240–260 ◦ C is at an advanced exploration stage, and four 55 MW unit will be commissioned in the coming years. A similar development is scheduled for the areas of Lumut Balai and Sungai Penuh, where the first units are expected in 2012. At Pathua, Java, the original exploration was done before the economic crisis. After the arbitration, the resource was transferred to Geodipa. Three 60 MW units are planned. In the nearby area of Karaha Bodas, 140 MW are planned, with the first 30 MW for 2012. Finally, in Sulawesi two new projects at Kotamobagu and Tompasu identified a 250–290 ◦ C reservoir; 120 MW in total are planned. A great amount of effort will be required to reach the target of 3.5 GW in 2015. It is a very challenging task to triple the present capacity in only five years. However, as evident from Fig. 15, this tremendous increase in installed capacity in only five years is unlikely. A value in the range of 2–2.4 GW can be considered as an affordable and realistic goal. In the last five-year term (2005–2010), the installed capacity increased of 400 MW, corresponding to an increment of about 50%.

10

R. Bertani / Geothermics 41 (2012) 1–29

Fig. 16. (a) History of net electricity generation and steam flow at Larderello. (b) Installed capacity and electricity in Italy.

2.23. Iran (Yousefi et al., 2010) An active exploration program has resulted in an advanced project in the Sabalan field, where a first 50 MW plant is planned by the Ministry of Energy (MOE) and Renewable Energy Organization of Iran (SUNA). 2.24. Italy (Cappetti et al., 2010) There are two major geothermal areas in Italy: Larderello–Travale/Radicondoli and Mount Amiata. In the year 2008, with the installed capacity of 810.5 MW (711 MW available capacity) the gross electricity generation reached 5.5 TWh, and in 2009 two additional units were commissioned, increasing the capacity to 843 MW (Larderello 594 MW, Travale/Radicondoli 160 MW, Bagnore 20 MW and Piancastagnaio 68 MW). All the Italian fields are operated by Enel Green Power. The geothermal production is only 1.8% of total national electricity production, but it is about 25% for the Tuscany region. Larderello and Travale/Radicondoli are two parts of the same field, covering a huge area of approximately 400 km2 , producing super-heated steam at a pressure of 2 MPa and temperature in the range 150–270 ◦ C. At Larderello, the exploited area is 250 km2 , with 22 units for a total of 594 MW installed capacity; the Travale/Radicondoli, covers a surface of 50 km2 , and the installed capacity is 160 MW (6 units). The condensed water from Travale is injected into the core of the Larderello field through a 20 km long water pipeline. Four additional units (Nuova Lagoni Rossi, 20 MW; Nuova Larderello, 20 MW; Nuova San Martino, 40 MW; and Sasso 2, 20 MW) were installed in the period 2005–2009 with a total capacity of 100 MW, of which 52 MW represent a net capacity increase, while 48 MW replaced old units that were decommissioned. The very long exploitation of Larderello and Travale/Radicondoli fields is an excellent example of sustainable production from a geothermal system (Fig. 16a). After the stabilization of production in the period 1970–1980, the exploitation of the deep reservoirs (with pressure of 6–7 MPa and temperature of 300–350 ◦ C, at depth of 3000–4000 m) and injection into the field have contributed to a large increase in steam extraction. The much greater increase in electricity production is a consequence of the introduction of new and more efficient power plants after year 2000. Mount Amiata area includes two water dominated geothermal fields: Piancastagnaio and Bagnore. Their exploitation started in 1960. In both the fields a deep water dominated resource has been discovered under the shallow one, with a pressure of 20 MPa and a temperature around 300 ◦ C. Opposition from local communities is slowing down the project for the full exploitation of this high potential deep reservoir. Presently, there are 5 units with 88 MW of installed capacity: one in Bagnore and four in Piancastagnaio.

2.24.1. New projects Projects for a further 112 MW have been approved and will be developed in the coming years (Fig. 16b): new plants in Larderello/Travale, Bagnore and Piancastagnaio, with a net increase of 80 MW (including the decommissioning of some older units). In southern Italy, the drilling of a 4 km depth well in the volcanic area of Campi Flegrei (Naples) will evaluate the possibility of supercritical fluid utilization. This project, funded by public research bodies, if successful, may be able to generate up to 50 MW/well. In Tuscany several new geothermal leases have been released to different private investors for binary plant projects. In response to the growing demand for renewable energy, and as a result of commitments signed by many governments to reduce CO2 emissions, a new company, Enel Green Power, fully owned by Enel Group, was established in December 2008. At present, Enel Green Power operates in 16 countries and is one of the world leaders in renewable energy sector, with about 20 TWh annual generation (equivalent to the energy consumption of 8 million families and avoiding 16 million tons of CO2 emissions every year). The installed renewable capacity is around 4.5 GW and there are over 500 plants currently in operation or under construction around the world. For the “zero-emission in geothermal program”, an investment plan has been launched to eliminate the release of H2 S and Hg to the environment using a technology designed and developed by Enel. AMIS plant (Baldacci et al., 2005) has a very high efficiency in H2 S and Hg removal, lower capital and O&M costs in comparison with other commercial process, no solid sulfur by-products (liquid streams injected in the reservoir) and unattended operation (remote control). Approximately 80% of the effluents from Enel Green Power geothermal plants are currently treated by AMIS systems. 2.25. Japan (Sugino and Akeno, 2010) Japan is one of the most tectonically active countries in the world, with nearly 200 volcanoes and tremendous geothermal energy resources. Geothermal development started in 1925, with an experimental unit, and the first commercial plant at Matsukawa started in 1966. About 20 geothermal power plants are in operation at 17 locations nationwide, scattered all over the country. Most are located in the Tohoku and Kyushu districts. In recent years, only two small binary units, at Hatchobaru and at Kirishima Kokusai Hotel, have been commissioned. Total geothermal power capacity in Japan has changed little since 1995. No new plants are planned in the coming years (Fig. 17a). The only exception is an early stage 30 MW project at Wasabizawa, in Akita, being undertaken by Mitsubishi Material Company and J-Power.

R. Bertani / Geothermics 41 (2012) 1–29

11

Fig. 17. (a) Installed capacity and electricity in Japan. (b) History of l installed capacity and energy production in Japan.

The historical trend is shown in Fig. 17b. The reduction in new investment in geothermal power plants and field maintenance has resulted in a decrease in energy production. 2.26. Kenya (Simiyu, 2010) An important addition since 2005 has been the installation of a 36 MW unit at Olkaria III by Ormat; this completes, the initial planned target of 48 MW at Olkaria III. In addition, projects for additional units at Olkaria I, II and IV (a total of 202 MW) have been approved and are expected to be completed within two years. The 35 MW Olkaria II unit 3 become operational in 2010. During the period 2005–2010, the installed capacity at Olkaria increased of 57%. The contribution of geothermal energy in Kenya is significant: 14% of the capacity and 22% of the energy. The geothermal production at Olkaria started in 1981, with a 15 MW unit. Since then, the power generation has been expanded and the resource has been continuously exploited, with the power plants at Olkaria I and II, operated by KenGen (Fig. 18). Two small power plants with a capacity of 2 MW are operared by Oserian Development Company. Oserian began as a 5 hectares vegetable-growing farm in 1969. Today it has grown to be a 210 hectares farm specializing in floriculture with an annual export of 400 million stems to Europe, about 30% of the cut-flowers market in Europe. The company has to make sure that the thousands of flowers growing in its massive greenhouses have a constant mild temperature. The wells Oserian uses are not suitable for the mass power production (e.g., KenGen power plants), but are perfect for supplying the heat and CO2 needed for growing roses. The greenhouse heating system is powered by a 2 MW Ormat binary-cycle power plants commissioned in 2004 and

Installed Capacity, MW

Installed Capacity

Produced Electricity

600

535

2000

400

129 200

45

45

1995

2000

1000

202

0

0 2005

2010

2015

Year Fig. 18. Installed capacity and electricity in Kenya.

Produced Electriciy, GWh

KENYA

an additional Elliot 2 MW steam turbine in 2007, making the company self-sufficient in electricity needed for heating and controlling the humidity in the greenhouses, which in turn protects the flowers from fungal diseases and reduces the usage of fungicides. The only other field outside of Olkaria is the adjacent region of Eburru, where a small 2,5 MW single flash pilot plant is planned. The geothermal potential of Kenya is very high, about 7000 MW, and there are plans to develop 2000 MW by 2020.

2.27. Latvia (Fortins et al., 2010) A small EGS project of few MW for electricity and heating is under development in the capital city of Riga. The pilot project will include a geothermal power plant with a capacity of 3–4 MW for electricity generation and 30–40 MW for heating. The developers intend to tap international financial funds (still to be identified) for the project, under the coordination of Riga’s Energy Agency.

2.28. México (Gutiérrez-Negrín et al., 2010) The installed geothermal capacity in México is 958 MW from 37 units, currently operating in four geothermal fields: Cerro Prieto (720 MW), Los Azufres (188 MW), Los Humeros (40 MW) and Las Tres Vírgenes (10 MW). The only new power plant since 2005 has been one 5 MW unit at Los Humeros. However, two new projects, Cerro Prieto V (100 MW) and Los Humeros 9–10 (50 MW), have been approved and both will be completed soon (Fig. 19a). All the geothermal fields are operated by Comisión Federal de Electricidad (CFE). The project Cerritos Colorados (75 MW), formerly known as La Primavera, has been programmed for completion in 2014. With the planned decommissioning of some old units, the net increase in installed capacity over the next five years (2010–2015) will be about 160 MW. Cerro Prieto is the oldest and largest Méxican geothermal field in operation. It is located in the northern part of Mexico, and its first power units were commissioned in 1973. There are currently 13 operating units of condensing type: four 110 MW double-flash, four 37.5 MW single-flash, four 25 MW single-flash, and one 30 MW single-flash (low pressure), for a total of 720 MW. Los Azufres is the second largest geothermal field operating in México. It is located in the central part of the country, 250 km from México City. The first power units were commissioned in 1982, and presently there are 14 power units in operation: one 50 MW condensing unit, four 25 MW condensing units, seven 5 MW back-pressure units, and two 1.5 MW binary cycle plants. The total installed capacity is 188 MW.

12

R. Bertani / Geothermics 41 (2012) 1–29

MEXICO Produced Electricity

1500

8000

953

1115

6000

958

1000

753

Electricity Generated, GWh

Installed Capacity, MW

Installed Capacity

(b)

755 4000

500 2000

Produced Electriciy, GWh

(a)

Mexico 8000

6000

4000

2000

0

0

0 1995

2000

2005

2010

2015

Year

Year

Fig. 19. (a) Installed capacity and electricity in México. (b) Geothermal Electricity production in Mexico since 1990 (from UN statistic division web site).

The geothermal field of Los Humeros is located in the easterncentral part of México, at the eastern end of the Méxican Volcanic Belt. The first two power units started to commercially operate in 1990, and currently there are eight back-pressure units of 5 MW each with a total operating capacity of 40 MW. The most recent unit (Unit 8) was commissioned in April 2008. Las Tres Vírgenes is located in the middle of the Baja California peninsula, in the north of the state of Baja California. There are only two condensing 5 MW power units in operation that were commissioned in 2002. The electricity production from geothermal resources is quite stable and plays a very important role in the energy market of the country, despite of its minimal value of 3% on the national basis. The long term yearly production is shown in Fig. 19b. 2.29. Nevis (Huttrer, 2010) In 2008, West Indies Power drilled three 1000 m deep slim holes, and confirmed temperatures up to 225 ◦ C. A 35 MW project has been launched. The excess of production could be exported to St. Kitts via sub-sea cable crossing the narrow strait that separates the two islands. 2.30. New Zealand (Harvey et al., 2010) All the geothermal projects in this country are in the central North Island or the Northland region (Ngawha), Wairakei 232 MW, Reporoa 103 MW, Mokai 112 MW, Kawerau 122 MW, Rotokawa 167 MW, and Ngawha 25 MW. Since 2005 the following new plants

(a)

have been installed: a binary unit of 14 MW at Wairakei, a second stage at Mokai (19 MW flash and 17 MW + 4 MW × 5 MW of binary units), 100 MW flash plus an 8 MW binary unit at Kawerau, 15 MW binary at Ngawha and 132 MW flash at Rotokawa. The total geothermal capacity is over 760 MW, and geothermal generation is about of 10% of the total electricity generation. Several additional geothermal projects are under development, with a target for year 2015 to reach 15% of total electricity generation (Fig. 20a). In 2008, Wairakei celebrated 50 years of operation, since the commissioning of its first turbo-generator in 1958. It is operated by Contact Energy. Many modifications have been made over the years, the latest being the installation of a 14 MW net binary plant in 2005. Future plans call for the replacement of several old units with a new power plant at Te Mihi, with a net increase in installed capacity of 65 MW. At Reporoa, the Ohaaki plant was originally rated at 114 MW, and after the decommissioning of one unit it was downgraded to 103 MW; however, the actual electricity production was dramatically lower at 25 MW. Since 2006 the operator (Contact energy) has invested in new wells, and increased electricity production to 65 MW. Alternative production and injection strategies are used to minimize concerns over subsidence affecting Waikato River. Since 1999, Mokai has been progressively developed (current installed capacity is 112 MW, including the new 39 MW unit in 2005 and 17 MW of repowering of the first stage in 2007) using binary cycle technology. It is operated by Tuaropaki Power Company. Kawerau field started electricity production with a small generator in 1966, which was replaced in 2005. Mighty River Power

(b)

NEW ZEALAND

Ngawha 2, 15MW Kawerau 100MW, KA24 8.3MW (2008)

1500

5000 1237 4000

1000

3000

762 500

437

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435

286 1000

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10,000 Installed Capacity

9,000

Wairakei Bin 14.4MW, Mokai 2 39MW (2005)

8,000 7,000

Rotokawa Ext 6MW (2003) Kawerau Mokai 1 TG2 3.5MW 55MW (1999) (1993)

6,000 5,000 4,000 3,000

Wairakei TPP 192MW 8MW (1958-64) (1966)

Ohaaki 114MW, Kawerau TG1 2.4MW (1989)

2,000 1,000

Mokai 1A 17MW (2007)

Ngawha 10MW (1998) Rotokawa 29MW(1997) Wairakei BP 5MW (1996), Poihipi 50MW (1996)

0

1950

1960

1970

1980

1990

2000

2010

Fig. 20. (a) Installed capacity and Electricity in New Zealand. (b) Annual geothermal electricity production in New Zealand since 1950. From Harvey et al. (2010).

2020

R. Bertani / Geothermics 41 (2012) 1–29

13

NICARAGUA

400

600

300

248

400

200 100

70

70

77

88

200 0

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56

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6

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PAPUA-NEW GUINEA

0

0 2005

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Fig. 21. Installed capacity and electricity in Nicaragua.

Fig. 22. Installed capacity and electricity in Papua – New Guinea.

commissioned a 100 MW double flash power station in August 2008. The field is operated by Ngati Tuwharetoa Geothermal Assets. In addition, a 8 MW binary unit (KA24) has been added to the overall field capacity. Rotokawa field is large, hot and permeable and has significant potential for large scale development (Ngati Tuwharetoa Geothermal Assets and Mighty River Power). The first development for electricity generation took place in 1997 with the commissioning of a 29 MW binary cycle plant, later expanded to 35 MW. The new Nga Awa Purua triple flash, single Fuji unit of 132 MW, was commissioned in May 2010: it is the largest single geothermal turbine in the world. Top Energy in association with local Maori Trusts, installed in 1998 a 10 MW Ormat binary plant at Ngawa. In October 2008 a 15 MW binary extension was commissioned. The field capacity is estimated to be larger than the current installed capacity, but it is not known when further development will be undertaken. The geothermal electricity generation in New Zealand, started in 1950, had a long stabilization in production. An impressive new construction phase started in late 1990s; the target is to double the present capacity by 2015. The 2005–2010 period had about 200 MW of new generation capacity installed, which amounts to an increase of 44% (Fig. 20b).

an unusual combination of the geothermal resource, the gold mine and the isolated location remote from the power grid. The geothermal resource has a temperature of 240–250 ◦ C at a depth of about 1000 m. The wells have good productivity: some with an output up to 10 MW. An initial 6 MW plant was constructed in 2003. Five additional units for a total of 50 MW were commissioned in stages (three 10 MW modules in 2005 and two 10 MW modules in 2007). The total capacity of 56 MW, provides 75% of the current electricity needs of the island, with savings estimated at approximately 40 million USD, replacing heavy fuel oil for power generation. It will also generate revenues of 4.5 million USD per year from the sale of carbon credits on global market. This geothermal power plant was the first project in Papua New Guinea to be registered for carbon credit trading under the Clean Development Mechanism of the Kyoto Protocol. The plant reduces greenhouse gas emissions by approximately 280,000 tons/annum, which equates to approximately 4% of Papua New Guinea’s total CO2 emissions (Fig. 22). Several new areas are under exploration.

2.31. Nicaragua Despite the impressive geothermal potential of the country (estimated at about 1500 MW), only a minor addition has been made since 2005. Polaris (now Ram Power) installed two 5 MW back pressure units in 2007 at San Jacinto-Tizate. A project for an expansion to 34 MW and subsequently to 72 MW is on-going. At Momotombo, three units with a capacity of 77 MW were installed in 1983, but the current generation is only 28 MW. This field is operated by Ormat. An exploration program at El Hoyo-Monte Galan and ManaguaChiltepe, for two 44 MW projects each has been launched jointly by Enel and LaGeo; the exploration project is expected to be completed by year 2011 (Fig. 21). In the first field a shallow well showed high temperature (220 ◦ C), but the permeability was low. In the second area, a slim hole registered a very low temperature (80 ◦ C). 2.32. Papua – New Guinea (Melaku and Mendive, 2010) The geothermal potential of Papua – New Guinea is estimated to be about 3000 MW. A geothermal power project has been developed at a major gold mine on the tiny Lihir Island, located about 900 km northeast of the national capital. Its exploitation arises from

2.33. Peru (Vargas and Cruz, 2010) No geothermal electricity has been produced till now, despite the estimated geothermal potential of 3000 MW. Recently two foreign companies (Hot Rock Ltd., Australia and Magma Energy, Canada) started exploration in the southern areas of the country. 2.34. Philippines (Ogena et al., 2010) The Philippines is the world’s second largest producer of geothermal energy for power generation, with an installed capacity of 1.9 GW for an available capacity of about 1.8 GW (Fig. 23a), accounting for 12% of the nation’s total electric generation capacity. The relatively high availability of the geothermal plants resulted in the delivery of about 10 TWh of generation in 2010, 17% of the nation’s electricity production. The most important event in the period was the expiration of several BOT contract, with the transfer of ownership of the plants in Lyete and Mindano from Cal Energy, Ormat and Marubeni to EDC. In addition, state-owned PNOC (Philippines National Oil Company) was privatized, and now as EDC operates steam fields and power plant in the country. EDC is 100% owned by Red Vulcan, a subsidiary of the FirstGen group. The Government plans to double the current installed capacity from renewable energy in the next decade and the geothermal sector will undoubtedly see an expansion.

14

R. Bertani / Geothermics 41 (2012) 1–29

PHILIPPINES Produced Electricity

4000

15000 12000

3000

2519 1909

2000

1930

8000

1904

1227 4000 1000 0

0 1995

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2010

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(b)

Produced Electriciy, GWh

(a)

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5000

0

2015

Year

Year

Fig. 23. (a) Installed capacity and electricity in the Philippines. (b) Geothermal electricity production in The Philippines since 1990 (from UN statistic division web site).

2.35. Poland (Kepinska, 2010) In Lodz, a small heating and electricity project has been launched, on the premises of the Technical University of Lodz. The total cost of the project will be approximately 22 million euros, of which 50% will be financed by the European Union. 2.36. Portugal (Cabec¸as and Carvalho, 2010) Geothermal resources are being exploited for electric power generation on Sao Miguel, the largest and most populous island in the Azores), by SOGEO–Sociedade Geotérmica dos Ac¸ores S.A., part of EDO – Electricidade dos Ac¸ores. A binary unit of 13 MW was installed at Pico Vermelho area of the Ribeira Grande field (temperature about 250 ◦ C) in 2006. The geothermal field now has a total installed capacity of 28 MW, and provides a about 40% of the electricity needs of the island (23 MW net). The contribution of geothermal electricity is expected to double in the coming years (Fig. 24). On Terceira island a project for installing 12 MW is ongoing (Pico Alto field with temperatures above 300 ◦ C), Despite the potential presence of good geothermal resources on other small islands, development is hindered by a lack of interest. 2.37. Romania (Rosca et al., 2010) The geothermal electricity potential of the country is not great. In Oradea, a medium-temperature reservoir (about 120 ◦ C) was

PORTUGAL Produced Electricity 200

80 60 60

100

40 29 20

16

16

2000

2005

5 0

0 1995

2010

2015

Year Fig. 24. Installed capacity and electricity in Portugal.

Produced Electriciy, GWh

Installed Capacity

Installed Capacity, MW

The Northern Negros plant with a capacity of 49 MW, operated by Energy Development Corporation (EDC), was completed in 2007. Also, the plant at Mak-Ban was upgraded and rehabilitated in 2009 for a net addition of 25 MW. The decrease of installed capacity between 2005 and 2010 is mainly due to the decommissioning of a 110 MW unit at Tiwi. The geothermal areas in the Philippines are listed below. Leyte (Tongonan) has five flash (661.5 MW), and 3 topping cycle back pressure turbines, 1 bottoming cycle flash, and 1 bottoming cycle binary plant, with a total capacity of 61 MW, The total installed capacity of 722 MW. All plants were transferred from CalEnergy and Ormat to EDC at the end of the BOT period. At Bac-Man (Bacon-Manito, Sorsogon/Albany), exploitation started in 1993–1998 (EDC and National Power Corporation – NPC) with a small 1.5 MW back pressure turbine plant (combined with drying plant). Since then, two 55 MW units and two for 20 MW units have been added, for a total installed capacity of 152 MW. Mindanao (Mount Apo, North Cotabato/Davao): has two flash units (one single and one dual pressure) for a total of 103 MW. These plants were transferred from Marubeni to EDC in 2009. A new 50 MW unit is planned. At Northern Negros (Negros Occidental), EDC commissioned in 2007 one flash (dual pressure) unit of 49 MW. It is operated by EDC as “merchant plant”, selling electricity to the local consumers. It will provide stability in the supply of power in Negros Island. In terms of power generation mix, Negros Island now utilizes 100% renewable energy with geothermal providing 99.6% while the remaining 0.4% comes from hydro. South Negros (Palinpinon, Negros Oriental) has five flash units for 192.5 MW which have been in stable operation since 1982; an optimization project for 20 MW binary is under development by EDC/NPC. Mak-Ban (Mount Makiling-Banahaw, Laguna/Quezon) is owned by Chevron and has been in operation since 1979. There are 72 production and 16 reinjection wells; the average production is 6 MW/well. The total installed capacity is 458 MW with 10 flash plants and one 15.7 MW binary plants. Four units were rehabilitated by Chevron in 2005. Tiwi (Albany) started operations in 1979. Today there are four operating flash units (out of a total of six) for 234 MW, rehabilitated in 2005. The field is exploited through 38 production and 21 reinjection wells, with 5.5 MW/well. The field is operated by Chevron. The electricity production from geothermal resources shows period of stable generation, followed by a jump over 10 TWh around year 2000. The long term yearly production is shown in Fig. 23b.

R. Bertani / Geothermics 41 (2012) 1–29

15

RUSSIA

500 400 300

79

100

82 200

11

23

100 0

0 1995

2000

2005

2010

2015

Installed Capacity, MW

194

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Fig. 25. Installed capacity and electricity in Russia.

Fig. 26. Installed capacity and electricity in Turkey.

recently considered for a pilot binary unit; unfortunately it did not reach the construction stage. The possibility of some minor development is still under evaluation.

400

Produced Electriciy, GWh

Produced Electricity

Produced Electriciy, GWh

Installed Capacity, MW

Installed Capacity

TURKEY

Authority of Thailand (EGAT) is using the 80 ◦ C exhaust from the power plant to demonstrate direct heat use to the local population. 2.43. The Netherlands (Van Heekeren and Koenders, 2010)

2.38. Russia (Povarov and Svalova, 2010) No new geothermal plants have been constructed since 2005. The geothermal resources of the country are located in Kamchatka and the Kurili islands, and are estimated to be about 2000 MW, Two projects, i.e., construction of a binary unit at Verkhne–Mutnovsky (6.5 MW) and the second 100 MW plant at Mutnovsky, are under development (Fig. 25). The two geothermal fields at Pauzhetsky and Mutnovsky on the Kamchatka peninsula, are operated by SC Geoterm. Paushetsky has been in operation since 1967 with a capacity of 14 MW; and a bottom binary cycle is under construction. Mutnovsky has a shallow steam zone, and a liquid reservoir (250–310 ◦ C) at a depth between 1000 and 2000 m. The current installed capacity is 62 MW; an additional 100 MW (flash) unit and a bottoming binary cycle of 6.5 MW are under construction. An intensive exploitation of the huge potential of Kamchatka region is expected in the coming years. 2.39. Slovakia (Fendek and Fendekova, 2010) In Slovakia the low temperature geothermal potential is located in the south-eastern region of Kosice, where a 5 MW binary project is under evaluation. 2.40. Spain (Sanchez-Guzma and de la Noceda, 2010) The volcanic resources of the Canary islands are still unexploited despite several studies. Two 20 MW projects in Tenerife and Gran Canaria are under evaluation.

Dutch interest in geothermal energy is something quite new. The Oil & Gas industry is very active in the country, bringing drilling and geological expertise to the local geothermal sector. The feasibility of a pilot binary project is being investigated. 2.44. Turkey (Mertoglu et al., 2010) Since 2005 several new plants have been constructed. Four new binary units of about 8 MW each have been installed, three for exploiting medium enthalpy reservoir (two by Dora – MB group, in Aydin-Salavatli area, and one by Tuzla – Dardanel Energy, at Canakkale and one using the separated brine (140 ◦ C)) from the Kizildere plant, before its use for district heating, operated by Bereket. The old plant at Kizildere, now privatized and owned by Zorlu group, has been refurbished and is operating at full capacity (15 MW as the generator capacity), and a new 60 MW plant is under construction. The reservoir temperature is about 240 ◦ C. The plant also produces 120,000 tons/year of pure CO2 for the food industry. A new 47 MW double flash unit was commissioned in 2009 at Germencik, by the Gurmis group, with the possibility of a second 47 MW unit. It is one of the largest plants in Europe, just behind the Italian standard 60 MW units. The brine temperature is 230 ◦ C. Several additional areas have been allocated to private companies for further surface and deep exploration (Fig. 26). Since 2005 an increase of about 70 MW in installed capacity has been achieved. The target for 2015 is about 200 MW. The geothermal potential of the country is estimated to be about 30,000 MW. 2.45. United Kingdom (Batchelor et al., 2010)

2.41. Switzerland (Rybach and Signorelli, 2010) Despite the closing of the deep drilling project at Basel due to induced seismicity problems, the geothermal energy is still alive in Switzerland, with a small heating and electricity project under evaluation in St. Gallen. 2.42. Thailand A small (300 kW) binary-cycle power plant was commissioned in 1989 in Fang. This plant has operated successfully, with an 85–90% availability factor. In addition, the Electricity Generating

UK was a pioneer in the EGS research in the past. An EGS project in Cornwall is under consideration. 2.46. USA (Lund et al., 2010a) Geothermal electric power plants are located (or planned) in Alaska, California, Florida, Hawaii, Idaho, Nevada, New Mexico, Oregon, Utah and Wyoming. The total installed capacity of the country is around 3 GW of which only about 2 GW are available. Since 2005, new plants totaling about 560 MW have been commissioned, (see Fig. 27a and Table 3). New projects with a capacity of

16

R. Bertani / Geothermics 41 (2012) 1–29

(a)

(b)

2500

20,000

5437

6000

2228

4000

2534 10,000

3098

2000 0

0 1995

2000

2005

2010

Electricity Production, GWh

Produced Electricity

Installed Capacity

400

1500

300

1000

200

500

100

Installed capacity, MW

2000

Produced Electriciy, GWh

Installed Capacity, MW

Net Output

8000

2817

500

Gross Production

USA Installed Capacity

NEVADA

0

0

2015

Year

Year

Fig. 27. (a) Installed capacity and electricity in USA. (b) Nevada gross/net electricity production and installed capacity.

about 2.4 GW are currently under construction or in advanced planning stages. The total geothermal electricity production is about 17 GWh, equivalent to 4% of the entire renewable energy production in the country. 2.46.1. Alaska The first geothermal power plant in this state was installed in 2006, at Chena Hot Springs. It is a binary plant, producing 225 kW from the coldest geothermal resource worldwide: only 74 ◦ C. A second twin unit has been added, and a third one of 280 kW is under construction; the total installed capacity of 730 kW provides offgrid power in a rather remote location. 2.46.2. California Since 2005, the following new plants have been commissioned in California: 10 MW (Gould), 10 MW (Heber South), and 49 MW (North Brawley) binary units in the Imperial Valley, and the new 55 MW Bottle Rock 2 for dry steam plant at The Geysers. The geothermal capacity of about 2.5 GW contributes about 4.5% of the electricity generation in the state, with an electricity production of about 12 TWh. Several new projects are in advanced stages of planning or completion. The geothermal power plants in California are: Honey Lake 4 MW, The Geysers 1585 MW, Mammoth 40 MW, Coso 270 MW, Salton Sea 329 MW, Heber 212 MW, and East Mesa 120 MW. Calpine and Northern California Power Agency own 26 dry steam units at the Geysers, for a total of about 1.6 GW installed capacity (only 900 MW are available). The newest addition at The Geysers is 55 MW Bottle Rock 2 plant, commissioned in 2007. Table 3 Installed capacity in USA. State

2005 (MW)

2010 (MW)

2015 (MW)

Alaska California Florida Hawaii Idaho New Mexico Nevada Oregon Utah Wyoming USA Total

0 2239 0 30 0 0 239 0 26 0 2534

0.7 2559 0 35 16 0.2 440 0.3 47 0.2 3098

30 3400 0.2 60 130 20 1300 200 240 0.2 5400

The Geysers geothermal field, the largest geothermal field in the world, is about 100 km north of San Francisco, California. The field started production in 1960, and by 1987 the production peaked at 1500 MW (installed capacity 2043 MW). Unfortunately, a rapid decline in production occurred. An unique public–private collaboration between field developers and several municipalities constructed a 42 km long pipeline to transport treated effluent to The Geysers for injection in 1997 (Ali Khan, 2010). By the end of 2003, another pipeline was completed. The current mass replacement from both pipelines and other sources is about 85% of production. This has resulted in sustained steam production, a decrease in non-condensable gases, improved electric generation efficiency, and lower air emissions. The additional electricity generated as a result of these two pipelines is about 155 MW/year. East Mesa geothermal field in the Imperial Valley has 6 units for 120 MW of installed capacity. The field, in operation since 1986–1989, is currently operated by Ormat. Heber geothermal field (Imperial Valley) has an installed capacity of 212 MW with 25 binary units, Ormat, the field operator, is planning to increase the installed capacity to 270 MW. Since 2005 several new plants have been completed at Heber: Gould (2 × 5 MW binary, in 2006), Heber South (10 MW binary, in 2008) and the North Brawley (7 × 7 MW binary, in 2009) Salton Sea geothermal field, operated by CalEnergy, has 13 units for an installed capacity of 333 MW. New units for a total of 330 MW are in planning stages. Coso geothermal field, operated by Terra Gen, has nine units for an installed capacity of 270 MW; the field has been in operation since 1987–1989. Mammoth geothermal field with 10 units for a total of 40 MW is operated by Constellation and Ormat; the plants were commissioned in 1984 and 1990. At Honey Lake, three small binary units have been operating since 1988 (Amedee) and 1985 (Wineagle). The geothermal contribution from the hybrid Honey Lake Power, which uses geothermal heat for drying wood chips dryer and for preheating fluid for the boiler for a 36 MW biomass unit, is estimated to be about 1.5 MW. Enel Green Power is launching a 20 MW green field project in Surprise Valley.

2.46.3. Florida A small binary unit of 200 kW will be installed in 2015 (Jay/Mobile ORC project) in Quantum Resources’ Jay Oil Field, northwestern Florida.

R. Bertani / Geothermics 41 (2012) 1–29

2.46.5. Idaho In 2007 the construction of the first geothermal power plant in Idaho was completed at Raft River by US Geothermal. The binary plant has a nameplate production capacity of 15.8 MW. Currently, net electrical power output is between 10.5 and 11.5 MW. The facility is using existing wells of the decommissioned 5 MW binary plant (operated from 1974 to 1982). An expansion to this plant as well as several other projects in the state are in planning stages. 2.46.6. Nevada Several companies are actively involved in geothermal development in Nevada: Enel Green Power, Ormat, TerraGen, Magma and Nevada Geothermal Power. As of 2010, the geothermal power plants in Nevada were Beowawe 17 MW, Blue Mountain 50 MW, S. Emidio 5 MW, Desert Peak 23 MW, Dixie Valley 67 MW, Brady Hot Spring 26 MW, Stillwater 48 MW, Salt Wells 24 MW, Steamboat 136 MW, Steamboat Hills 14 MW, Soda Lake 26 MW, and Wabuska 2 MW. Several of the above listed binary plants were commissioned during 2005–2010: 50 MW at Blue Mountain (Faulkner) in 2009, 23 MW at Desert Peak II in 2006, the new Enel Green Power plants at Salt Wells (24 MW) and Stillwater (2 × 24 MW) in 2009, Galena II (13 MW) in 2007, III (30 MW) in 2008 and Burdett (2 × 15 MW) in 2005 at Steamboat (5 units for 75 MW). In addition, refurbishment of the old Steamboat II was completed. At Steamboat Hills (Ormat) a new 12 MW binary plant is planned, as an addition at the existing 20 MW flash unit, commissioned in 1988. Ormat also plans to increase the installed capacity at Desert Peak from 23 MW to 30 MW. In Fig. 27b shows the impressive trend of gross and net generation in the State.

160

140

140 120 100

GW

2.46.4. Hawaii No new addition to the existing 10 binary units with an installed capacity of 35 MW (30 MW operating capacity, after rehabilitation and work over) has been made since 2005. This power plant, commissioned in 1993, supplies approximately 20% of the total electricity needs of the Big Island (160,000 inhabitants). An addition of 25 MW is planned by Ormat, with a target of 60 MW installed capacity in the near future.

17

70

80 60 40

10

20 0 Current

Today's Technology

Technology Improvement

Fig. 28. 2010 installed capacity (red), and forecast of 2050 installed capacity with present technology (blue) and with EGS (green). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

2.46.7. New Mexico Raser Technologies installed a pilot binary unit of 240 kW at Lighting Dock. The Lightning Dock project is designed to produce 10 MW of electrical power, and is expected to go online in the next several years. 2.46.8. Oregon The Oregon Institute of Technology completed on its campus the installation of a small 280 kW binary unit, which will be on line in 2012. Two projects at Newberry and Crump Geyser are in advanced stages of planning or field development. 2.46.9. Utah The Cove Fort plant has been shut down. The Roosevelt geothermal field, with two binary units of 25 MW and 11 MW (commissioned in 2007) is operated by Pacific Corporation. Utah got its second power plant in 2008, when Thermo Hot Springs went online, with 50 small binary units for an aggregate capacity of 10 MW (Raser Technologies). Enel Green Power is launching a project to install binary units at Fort Cove, with an initial capacity of 20 MW projects and a future expansion to 40 MW.

Fig. 29. Installed capacity for the 18 GEA regions, in TWh/year: 2010 (black), 2015 (blue) and 2050 (red). The total capacity is 10.9 GW for 2010, 19.8 GW for 2015 and 140 GW for 2050 (the EGS contribution of 70 GW is included in the forecast for 2050). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

18

R. Bertani / Geothermics 41 (2012) 1–29

Table 4 Utilization of geothermal energy in the 18 GEA regions. GEA region

USA Canada West Europe Central/East Europe Former USSR North Africa East Africa West/Central Africa South Africa Middle East China East Asia India South Asia Japan Pacific Asia Oceania Latin America World

(a)

Installed Capacity (MW)

0%

Electricity (TWh/year) 2000

2005

2010

14.0 0.0 3.9 0.0 0.0 0.0 0.4

16.8 0.0 7.1 0.0 0.1 0.0 1.1

16.6 0.0 10.9 0.0 0.4 0.0 1.4

0.0 0.0 0.0 0.1 0.0 0.0 0.0 1.7 8.3 2.4 7.3 38

0.0 0.0 0.0 0.1 0.0 0.0 0.0 3.5 15.4 2.8 8.9 56

0.0 0.0 0.0 0.2 0.0 0.0 0.0 3.1 20.4 4.1 10.2 67

2015 38.1 3.5 18.3 0.1 1.6 0.0 4.4 0.0 0.0 0.05 0.4 0.0 0.0 0.0 4.0 42.4 9.0 16.7 139

11%

2050

Binary

27%

508 8.3 125 25 67 0.0 25 0.0 0.0 17 42 0.0 17 0.0 17 166 25 125 1167

1% Back Pressure Single Flash Double Flash Dry Steam

41%

Hybrid

20%

0%Electricity Produced (GWh)

(b) 9%

4% Binary

24%

Back Pressure Single Flash

2.46.10. Wyoming The Rocky Mountain Oilfield Testing Center (RMOTC) is located at the Teapot Dome oil field, also known as the Naval Petroleum Reserve, operated by the Department of Energy as a test site for oil and gas and renewable energy related technologies. A small binary unit of 250 kW was installed in 2009. In summary, In the USA there are about 2 million km2 of geothermal areas, with an estimated potential of 9 GW. Most of the resources are located in the western states, with Nevada and California representing more than 80% of all the planned projects. Strong legislative support to reduce the duration from the beginning of a geothermal project (lease acquisition) to the generation of electricity, which can range from five to eight years, is needed for reaching the ambitious target of an exponential increase in the geothermal electricity in the US.

Double Flash Dry Steam

42%

21%

(c) 0%

Hybrid

Number of Units

12%

Binary Back Pressure

11%

45%

Single Flash Double Flash Dry Steam

3. Long term forecast

Hybrid

27%

Table 4 shows the recent rapid expansion in the utilization of geothermal energy for 18 world regions. The data are taken from the Global Energy Assessment (GEA), produced by International Institute for Applied Systems Analysis (IIASA), Austria, under the sponsorship of the United Nations and the World Energy Conference (WEC) organizing committee (UNDP, 2004; WEC, 2004, 2007; IEA, 2007). Growth rates in many regions have been over 10%. At the end of 2010, geothermal energy supplied 67 TWh/year of electricity. The forecast for 2015 indicates a generation of 140 TWh/year, and the expected maximum achievable for year 2050 is about 1200 TWh/year. Several authors (Bertani, 2003; Muffler and Cataldi, 1978; Fridleifsson et al., 2008; Fridleifsson and Ragnarsson, 2007) have estimated the global geothermal potential. The estimated potentials differ by orders of magnitude depending on the inclusion or exclusion of enhanced geothermal systems (EGS) technology and on the type of energy conversion technologies being considered. For example, low-temperature power generation with binary plants has opened up the possibilities of producing electricity in countries which do not have high-temperature fields. EGS technologies are still under development. If EGS proves to be economically feasible at commercial scale, the development potential of geothermal energy will be enormous in most countries.

5% Fig. 30. (a) Percentage of installed capacity by power plant type. (b) Percentage of produced energy by power plant type. (C) Percentage of units by power plant type.

The geothermal exploitation techniques are being rapidly developed, and the understanding of the geothermal reservoirs has improved considerably over the past years. In the broadest sense, the geothermal resources refer to the thermal energy stored below earth‘s surface. Globally the energy stored in the earth’s crust up to a depth of 5000 m is estimated to be 140 × 106 EJ (WEC, 1994, 1998) – an enormous theoretical resource base. A detailed estimate of the heat stored to a depth of 3 km under the continents dates back to 1978 (EPRI, 1978). The study applied an average geothermal temperature gradient of 25 ◦ C/km for normal geological conditions and accounted separately for diffuse geothermal anomalies and high enthalpy regions located nearby plate boundaries or in regions of recent volcanism. The high enthalpy regions cover about 10% of the Earth’s surface. The total amount of heat is huge, about 42 × 106 EJ. With the present world energy consumption of 500 EJ/year, the geothermal heat can fulfill the world needs for about 100,000 years.

R. Bertani / Geothermics 41 (2012) 1–29

3.1. Theoretical potential The value of 42 × 106 EJ represents the theoretical potential. It is practically impossible to extract all the heat from underground, both because of technical difficulties in using the lowest temperature resource, and also because of the inaccessibility of the bulk of the rock to water, which is required to mine the heat energy. The rate at which the heat is continuously replenished from the higher temperature regimes below the 3–5 km depth is about 65 mW/m2 which corresponds to an average thermal energy recharge rate of about 315 EJ/year (Stefansson, 2005). This value should be considered only as a rough approximation of the expected geothermal potential. However, from this evaluation the expected value of 10 TWth (obtained simply by transforming EJ/year in a more suitable unit) of thermal energy can be used per year as an indication of the overall technical potential of the geothermal energy utilization. Of interest, however, is the resource base that may be accessible over the next several decades with current or future technology, i.e., technical potential. To derive the technical potential from the theoretical potential, it is necessary to exclude the heat which cannot be accessed through natural or artificial circulation, and the surface of the continents which is remote from any user of heat and electricity. Since the economically drillable depth is presently limited to 5 km, the earth regions with temperatures too low for electric generation would need to be excluded. The missing information makes it virtually impossible to obtain the technical potential from the theoretical potential. 3.2. Technical potential Starting from a general correlation between the existing geothermal high temperature resources and the number of volcanoes, Stefansson (2005) inferred a total electricity generation potential of 200 GW. This value is only for the traditional hydrothermal resources. Based on a statistical analysis of heat distribution, Goldstein et al. (2009) concluded that there is a 70% chance that EGS systems have a potential of 1000 MW. Thus the total technical potential is about 1200 GW. It is possible to calculate the amount of heat needed for achieving this electrical potential, considering the conversion efficiency

19

for each range of temperature and the temperature distribution of the geothermal resource. According to the effective efficiency in the transformation of heat to electricity for different temperature ranges (10% for 120–180 ◦ C, 20% for temperature 180–300 ◦ C, 5% for EGS system- in comparison with a standard binary plant in an hydrothermal system, an efficiency reduction by a factor two is used for EGS when converting the available heat to the accessible one), it is possible to evaluate the temperature weighted average of the amount of equivalent energy extracted per year from the about 660 EJ/year of heat, which is similar at the value estimated by Stefansson as the natural heat flow (315 EJ/year). From the distribution of the geothermal resources over different temperature regimes, it is possible to estimate the low temperature potential (for direct utilization or low-temperature electricity cycles) using an empirical function (Stefansson, 2005). The value of 61 EJ/year, corresponding to a thermal capacity of 5000 GWth has been assumed (corresponding to a capacity factor of 40%), and it has been split among the different regions according to the amount of low temperature areas. 3.3. Economic potential: 2050 target For policy and investment decisions, it is the economic potential that matters. The economic resource base is that part of the technical resource base that can be exploited economically in a competitive market setting at some specified time in the future (up to 2050 and beyond). Over the short-to-medium term, the economic base consists of geothermal field that are known and have been characterized by drilling or by geochemical, geophysical and geological surveys. The economic hydrothermal potential for year 2050 is about 70 GW. This value has been calculated using all the identified and inferred geothermal resources to a depth of 3–4 km. To evaluate the contribution of EGS to the economic potential, it is important to note the lack of any commercial experience to-date for EGS systems. This technology is still in the experimental phase, and its commercial viability has yet to be proven. A successful EGS installation will need to meet certain conditions: a minimum heat exchange surface of over 1 million m2 , a reservoir volume of several cubic kilometers, maximum flow impedance of a few MPa/l/s, and a water loss of less than 10%.

Table 5 Geothermal potential for the 18 GEA regions. The values refer to the underground heat available for direct utilization or electricity, with the exception of the expected electricity production, calculated using a weighted average conversion efficiency (about 17 J of heat for 1 J of electricity) and 95% capacity factor. For the direct utilization, the thermal capacity is calculated with an average 40% capacity factor. GEA region

USA Canada Western Europe Central and Eastern Europe Former Soviet Union Northern Africa Eastern Africa Western and Central Africa Southern Africa Middle East China Other East Asia India Other South Asia Japan Other Pacific Asia Oceania Latin America World Equivalent capacity

Theoretical potential (106 EJ)

4.738 3.287 2.019 0.323 6.607 1.845 0.902 2.103 1.233 1.355 3.288 0.216 0.938 2.424 0.182 1.092 2.304 6.886 41.743

Technical potential

Economic potential

Heat for direct utilization (EJ/year)

Heat for electricity (EJ/year)

Heat for direct utilization (EJ/year)

Heat for electricity (EJ/year)

7.0 4.8 3.0 0.5 9.9 2.8 1.3 3.2 1.8 2.0 4.7 0.3 1.4 3.7 0.2 1.4 3.5 9.9 61.4 5000 GWth

75 52 32 5.1 104 29 14 33 19 21 52 3.4 15 38 2.9 17 36 109 657 1200 GWel

1.215 0.099 4.311 0.852 0.508 0.103 0.004 0.0 0.0 0.175 1.764 0.018 0.062 0.002 0.201 0.004 0.391 0.383 10.092 800 GWth

34.9 0.307 6.216 1.243 3.097 0.0 0.918 0.0 0.0 0.612 1.856 0.0 0.613 0.0 0.612 7.424 1.568 6.216 65.582

Produced electricity (TWh/year) 508 8.3 125 25 67 0.0 25 0.0 0.0 17 42 0.0 17 0.0 17 166 25 125 1167 140 GWel

20

R. Bertani / Geothermics 41 (2012) 1–29 Table 7 Top five countries for an increase in capacity during 2005–2010.

Table 6 Top five countries for installed capacity and electric generation. Country

2005 (MW)

2005 (GWh/year)

2010 (MW)

2010 (GWh/year)

Country

MW

GWh/year

% MW

% GWh/year

USA Philippines Indonesia Mexico Italy

2534 1930 797 953 791

16,840 9253 6085 6282 5340

3098 1904 1197 958 843

16,603 10,311 9600 7047 5520

USA Indonesia Iceland New Zealand Kenya

564 400 373 327 73

−237 3515 3114 1281 342

22 50 184 75 57

−1 58 210 46 31

To disseminate EGS installations widely, a technology would be needed to create EGS reservoirs independent of local ground conditions. Such a technology is yet to be developed (MIT-Led Report, 2006): a large number of problems remain to be solved. As an example, unless the fractures are evenly distribute in the reservoir, hydraulic short-circuiting may lead to rapid thermal drawdown. We hypothesize that in the near future, EGS technology will make it possible to produce geothermal electricity all around the world. In particular, it is assumed that it will be possible to reach at least 200 ◦ C at an economically drillable depth, and that would be possible to create enough artificial permeability for ensuring the necessary circulation of geothermal fluid among the wells. Goldstein et al. (2009), suggests that there is an 85% probability of producing at least 70 GW of EGS power by year 2050. Adding the 70 GW of the identified and inferred hydrothermal resources to the probabilistic estimation of 70 GW from Goldstein, we arrive at a value of 140 GW for the year 2050, corresponding to 66 EJ/year, using the same heat/electricity conversion ratio (Fig. 28). The economic potential of direct geothermal heat utilization depends to a large extent on the technology associated with its utilization (heat pumps, binary cycles, etc.). By 2050 the global potential is estimated at 800 GWth , corresponding to 10 EJ/year. Geothermal potential estimates (theoretical, technical and economic) are presented in Table 5 and Fig. 29. It should be possible to produce up to 8.3% of the world’s total electricity production (IPCC, 2000, 2007), serving 17% of world

Table 8 Top countries ranked by percentage increase in installed capacity. Country

MW

GWh/year

% MW

% GWh/year

Germany Papua New Guinea Australia Turkey Iceland Portugal New Zealand Guatemala Kenya Indonesia

7 50 1 71 373 13 327 19 73 400

49 433 0 385 3114 85 1281 77 342 3515

2987 833 633 356 184 78 75 58 57 50

3249 2547 −5 368 210 94 46 36 31 58

population; 40 countries (located mostly in Africa, Central/South America, Pacific) can be 100% powered by geothermal energy. The overall CO2 saving from geothermal electricity can be about 1000 million tons/year, if the 2050 target of 140 GW is reached. 4. Statistical highlights 4.1. Some ranking 4.1.1. Top five The “Top Five Countries” for installed capacity and produced energy are listed in Table 6: with an impressive increase both

Installed Capacity, MW

20,000

10,000

0

Year Fig. 31. Cumulative installed geothermal capacity since 1945.

R. Bertani / Geothermics 41 (2012) 1–29

21

Table 9 Big geothermal plants (COD = commissioning date). Country

Geothermal field

Plant name

Unit

COD

Type

Manufacturer

Plant owner

Installed capacity (MW)

New Zealand Indonesia USA USA USA USA USA USA Mexico Mexico Mexico Mexico Indonesia Indonesia USA New Zealand USA

Rotokawa Java – Wayang Windu CA – The Geysers CA – The Geysers CA – The Geysers CA – The Geysers CA – The Geysers CA – The Geysers Cerro Prieto Cerro Prieto Cerro Prieto Cerro Prieto Java – Darajat Java – Wayang Windu CA – The Geysers Kawerau CA – The Geysers

Nga Awa Purua Wayang Windu Grant Lake View Quicksilver Socrates Cobb Creek Eagle Rock Cerro Prieto II Cerro Prieto II Cerro Prieto III Cerro Prieto III Darajat Wayang Windu Sulfur Spring Kawerau Big Geyser

1 2 1 1 1 1 1 1 1 2 1 2 3 1 1 1 1

2010 2009 1985 1985 1985 1983 1979 1975 1986 1987 1986 1986 2008 2000 1980 2008 1980

Single flash Single flash Dry steam Dry steam Dry steam Dry steam Dry steam Dry steam Double flash Double flash Double flash Double flash Dry steam Single flash Dry steam Double flash Dry steam

Mighty River Power Star Energy Ltd Calpine Calpine Calpine Calpine Calpine Calpine Comision Federal de Electricidad Comision Federal de Electricidad Comision Federal de Electricidad Comision Federal de Electricidad PLN Star Energy Ltd Calpine Mighty River Power Calpine

132 117 113 113 113 113 110 110 110 110 110 110 110 110 109 100 97

Indonesia USA Philippines Philippines Philippines USA USA Japan Indonesia Indonesia Indonesia Philippines Philippines Philippines Philippines Indonesia Indonesia Indonesia Indonesia Indonesia Indonesia Italy Italy Italy Italy Philippines Philippines Philippines Philippines Philippines Philippines Philippines Philippines Philippines USA USA USA USA USA Indonesia Indonesia Costa Rica Costa Rica Japan Japan New Zealand Philippines Philippines

Java – Darajat CA – The Geysers Tongonan/Leyte Tongonan/Leyte Tongonan/Leyte CA – The Geysers NV – Dixie Valley Fukushima Java – Gunung Salak Java – Gunung Salak Java – Gunung Salak Mak-Ban/Laguna Mak-Ban/Laguna Mak-Ban/Laguna Mak-Ban/Laguna Java – Gunung Salak Java – Darajat Java – Dieng Java – Gunung Salak Java – Gunung Salak Java – Kamojang Larderello Larderello Larderello Larderello Tiwi/Albay Tiwi/Albay Tongonan/Leyte Tongonan/Leyte Tongonan/Leyte Tiwi/Albay Tiwi/Albay Bacon-Manito/Sorsogon/Albay Bacon-Manito/Sorsogon/Albay CA – The Geysers CA – The Geysers CA – The Geysers CA – The Geysers CA – The Geysers Java – Kamojang Java – Kamojang Miravalles Miravalles Oita Oita Wairakei Mak-Ban/Laguna Mak-Ban/Laguna

Darajat Calistoga Malitbog Malitbog Malitbog Sonoma Dixie Valley Yanaizu-Nishiyama Gunung Salak-IPP Gunung Salak-IPP Gunung Salak-IPP Mak-Ban A Mak-Ban A Mak-Ban B Mak-Ban B Gunung Salak Darajat Dieng Gunung Salak Gunung Salak Kamojang Farinello Nuova Serrazzano Valle Secolo Valle Secolo Tiwi A Tiwi A Mahanagdong A Mahanagdong A Mahanagdong B Tiwi C Tiwi C Bacman I Bacman I Bottle Rock II NCPA I NCPA I NCPA II NCPA II Kamojang Kamojang Miravalles Miravalles Hatchobaru Hatchobaru Poihipi Mak-Ban C Mak-Ban C

2 1 1 2 3 1 1 1 1 2 3 1 2 1 2 3 1 1 1 2 4 1 1 1 2 1 2 1 2 1 1 2 1 2 1 1 2 3 4 2 3 1 2 1 2 1 1 2

1999 1984 1997 1997 1997 1983 1988 1995 1997 1997 1997 1979 1979 1980 1980 1997 1994 1998 1994 1994 2007 1995 2002 1991 1991 1979 1979 1997 1997 1997 1982 1982 1993 1993 2007 1983 1983 1985 1986 1987 1987 1994 1998 1977 1990 1996 1984 1984

Dry steam Dry steam Single flash Single flash Single flash Dry steam Double flash Single flash Single flash Single flash Single flash Double flash Double flash Double flash Double flash Single flash Dry steam Single flash Single flash Single flash Dry steam Dry steam Dry steam Dry steam Dry steam Single flash Single flash Single flash Single flash Single flash Single flash Single flash Single flash Single flash Dry steam Dry steam Dry steam Dry steam Dry steam Dry steam Dry steam Single flash Single flash Double flash Double flash Single flash Single flash Single flash

Fuji Fuji Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Mitsubishi Fuji Toshiba Fuji General Electric/ Nuovo Pignone Mitsubishi Toshiba Fuji Fuji Fuji Mitsubishi Fuji Toshiba Fuji Fuji Fuji Mitsubishi Mitsubishi Mitsubishi Mitsubishi Fuji Mitsubishi Ansaldo/Tosi Ansaldo/Tosi Ansaldo/Tosi Fuji Ansaldo/Tosi Ansaldo/Tosi Ansaldo/Tosi Ansaldo/Tosi Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Toshiba Ansaldo/Tosi Ansaldo/Tosi Fuji Fuji Fuji Toshiba Toshiba Mitsubishi Mitsubishi Toshiba Ansaldo/Tosi Mitsubishi Mitsubishi Fuji Mitsubishi Mitsubishi

in capacity and produced energy since 2005, Indonesia is now ranked third. Italy is stable at 5th position. The “Top Five Countries” for absolute increase in installed capacity are highlighted in Table 7. In USA, Indonesia, Iceland and New Zealand, the increase in geothermal capacity was more than 100 MW. This indicates that

PLN Calpine Energy Development Corporation Energy Development Corporation Energy Development Corporation Calpine Terra Gen Tohoku Electric Power Chevron Chevron Chevron Chevron Chevron Chevron Chevron PLN PLN Geodipa PLN PLN PLN Enel Green Power Enel Green Power Enel Green Power Enel Green Power Chevron Chevron Energy Development Corporation Energy Development Corporation Energy Development Corporation Chevron Chevron National Power Corporation National Power Corporation US Renewables Northern California Power Agency Northern California Power Agency Northern California Power Agency Northern California Power Agency PLN PLN Instituto Costarricense de Electricidad Instituto Costarricense de Electricidad Kyushu Electric Power Kyushu Electric Power Contact Energy Chevron Chevron

90 80 77.9 77.9 77.9 72 67.2 65 65 65 65 63.2 63.2 63.2 63.2 62 60 60 60 60 60 60 60 60 60 60 60 59 59 59 57 57 55 55 55 55 55 55 55 55 55 55 55 55 55 55 54.6 54.6

even in countries where geothermal development started more than 50-year ago, the industry is presently proactive in launching new projects, and the economical environment is positive in terms of incentives and support measures. Kenya is not a newcomer to geothermal energy. The Olkaria geothermal field is undergoing

22

R. Bertani / Geothermics 41 (2012) 1–29

Table 10 Geothermal plants installed since 2005. Country

Geothermal field

Plant name

Italy Italy Turkey Kenya New Zealand USA Turkey Germany USA

Larderello Larderello Aydin-Salavath Olkaria Rotokawa AK – Chena Hot Springs Aydin-Germencik Bruchsal CA – Heber

Nuova Radicondoli 2 Chiusdino 1 Dora Olkaria II Nga Awa Purua Chena Germencik Bruchsal North Brawley

Indonesia Italy Italy

Java – Wayang Windu Larderello Larderello

USA USA USA USA Austria Indonesia USA USA

Unit

COD

Type

Manufacturer

Plant owner

Installed capacity (MW)

1 1 2 3 1 3 1 1 1–7

2010 2010 2010 2010 2010 2009 2009 2009 2009

Dry steam Dry steam Binary Single flash Single flash Binary Double flash Binary Binary

Ansaldo/Tosi Ansaldo/Tosi Ormat Mitsubishi Fuji UTC/Turboden Mitsubishi Null Ormat

Enel Green Power Enel Green Power MB KenGen Mighty River Power Chena Power, LLC GURMAT Municipality Germany Ormat

20 20 9.5 35 132 0.3 47.4 0.5 7

Wayang Windu Nuova Lagoni Rossi Sasso 2

2 1 1

2009 2009 2009

Single flash Dry steam Dry steam

Star Energy Ltd Enel Green Power Enel Green Power

117 20 20

Faulkner Salt Wells Stillwater OIT Simbach Braunau Lahendong Thermo Hot Spring Rocky Mountain Oilfield Berlin Heber South Kizildere Binary Hellisheidi III Raft River Darajat KA24 Kawerau Landau Lightening Dock Ngawha 2 Galena III Olkaria III Soultz-sous-Forets Lahendong Unterhaching Amatitlan Bottle Rock II Hellisheidi II Okeanskaya Kamojang Mendeleevskaya Lihir

1 1–2 1–4 1 1 3 1–50 1

2009 2009 2009 2009 2009 2009 2009 2009

Binary Binary Binary Binary Binary Single flash Binary Binary

El Salvador USA Turkey Iceland USA Indonesia New Zealand New Zealand Germany USA New Zealand USA Kenya France Indonesia Germany Guatemala USA Iceland Russia Indonesia Russia Papua New Guinea

NV – Blue Mountain NV – Salt Wells NV – Stillwater OR – Klamath Falls Simbach Braunau Sulawesi – Lahendong UT – Thermo Hot Spring WY – Naval Petroleum Reserve Berlin CA – Heber Denizli – Kizildere Hellisheidi ID – Raft River Java – Darajat Kawerau Kawerau Landau NM – Lightening Dock Northland NV – Steamboat Olkaria Soultz-sous-Forets Sulawesi – Lahendong Unterhaching Amatitlan CA – The Geysers Hellisheidi Iturup Island Java – Kamojang Kunashir Island Lihir Island

Fuji Ansaldo/Tosi General Electric/Nuovo Pignone Ormat Mafi Trench Mafi Trench

4 1 1 1–2 1 3 1 1 1 1 1 1 4–6 1 2 1 1 1 1 1–2 4 1 3a–b

2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2008 2007 2007 2007 2007 2007 2007 2007

Binary Binary Binary Single flash Binary Dry steam Binary Double flash Binary Binary Binary Binary Single flash Binary Single flash Binary Binary Dry steam Single flash Single flash Dry steam Single flash Single flash

Mexico

Los Humeros

Los Humeros

8

2007

Back Pressure

Enex Ormat Ormat Mitsubishi Ormat Mitsubishi Ormat Fuji Ormat UTC/Turboden Ormat Ormat Ormat UTC/Turboden Fuji Siemens Ormat Fuji Toshiba Kaluga Turbine Works Fuji Kaluga Turbine Works General Electric/Nuovo Pignone Mitsubishi

New Zealand Philippines

Mokai North Negros

Mokai 1 A Mambucal

1 1

2007 2007

Binary Single flash

Ormat Fuji

USA Kenya

NV – Steamboat Olkaria

Galena II Oserian

1 2

2007 2007

Binary Back Pressure

Ormat Elliot

Nicaragua Indonesia USA USA Turkey El Salvador

San Jacinto-Tizate Sumatra – Sibayak UT – Roosvelt AK – Chena Aydin-Salavath Berlin

San Jacinto-Tizate Sibayak Blundell I Chena Dora Berlin

1–2 2–3 2 1–2 1 3

2007 2007 2007 2006 2006 2006

Back Pressure Single flash Binary Binary Binary Single flash

USA Iceland Japan USA Japan Iceland Portugal Italy Italy

CA – Heber Hellisheidi Kagoshima NV – Desert Peak Oita Reykjanes Ribeira Grande Larderello Larderello

Gould Hellisheidi I Kirishima Geothermal Desert Peak II Hatchobaru Reykjanes Pico Vermelho Nuova Larderello Nuova San Martino

1–2 1–2 1 1 3 2 1 1 1

2006 2006 2006 2006 2006 2006 2006 2005 2005

Binary Single flash Binary Binary Binary Single flash Binary Dry steam Dry steam

Papua New Guinea

Lihir Island

Lihir

2a–c

2005

Single flash

New Zealand New Zealand Iceland USA Iceland New Zealand

Mokai Mokai Nesjavellir NV – Steamboat Reykjanes Wairakei

Mokai 2 Mokai 2 Nesjavellir Richard Burdett Reykjanes Binary

1 2–5 4 1–2 1–2 15–16

2005 2005 2005 2005 2005 2005

Single flash Binary Single flash Binary Single flash Binary

Alstom Harbin Ormat UTC/Turboden Ormat General Electric/Nuovo Pignone Ormat Mitsubishi Fuji Ormat Ormat Fuji ORMATORMAT Ansaldo/Tosi General Electric/Nuovo Pignone General Electric/Nuovo Pignone Mitsubishi Ormat Mitsubishi Ormat Fuji Ormat

Siemens Fuji UTC/Turboden Ormat

Nevada Geothermal Power Enel Green Power Enel Green Power OIT Municipality Austria BPPT Raser Technologies DOE LaGeo/Enel Green Power Ormat BEREKET Orkuveita Reykjavikur US Geothermal PLN Ormat Mighty River Power Municipality Germany Raser Technologies Top Energy Ormat Ormat European EGS Interest Group BPPT Municipality Germany Ormat US Renewables Orkuveita Reykjavikur SC Energiya PLN SC Energiya Lihir Gold Ltd mine Comision Federal de Electricidad Tuaropaki Power Co Energy Development Corporation Ormat Oserian Development Company Polaris PT Dizamatra Powerindo Pacific Co Chena Power MB LaGeo/Enel Green Power

50 12 12 0.3 0.2 20 0.2 0.2 9.4 10 6.8 45 15.8 110 8.3 100 3 0.2 15 27.5 12 1.5 20 3.4 24 55 33 1.8 60 1.8 10 5 17 49 15 2 5 5.6 11 0.2 7.4 44

Ormat Orkuveita Reykjavikur Daiwabo Kanko Ormat Kyushu Electric Power HS Orka EDA Enel Green Power Enel Green Power

5 45 0.2 23 2 50 13.5 20 40

Lihir Gold Ltd mine

10

Tuaropaki Power Co Tuaropaki Power Co Orkuveita Reykjavikur Ormat HS Orka Contact Energy

19 5 30 15 50 8

R. Bertani / Geothermics 41 (2012) 1–29

23

Table 11 Plant types by country (MW installed).

Australia Austria China Costa Rica El Salvador Ethiopia France Germany Guatemala Iceland Indonesia Italy Japan Kenya Mexico New Zealand Nicaragua Papua New Guinea Philippines Portugal Russia Thailand Turkey USA Total

Hybrid

Back pressure

Binary

Single flash

Double flash

Dry steam

Total

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2

0 0 0 5 0 0 0 0 0 0 2 0 0 2 75 47 10 6 0 0 0 0 0 0 147

1 1 0 21 9 7 2 7 52 10 0 0 2 14 3 138 8 0 209 29 0 0 24 656 1193

0 0 0 140 160 0 10 0 0 474 735 88 350 186 410 387 70 50 1330 0 82 0 20 60 4552

0 0 24 0 35 0 5 0 0 90 0 0 160 0 470 190 0 0 365 0 0 0 47 796 2183

0 0 0 0 0 0 0 0 0 0 460 755 24 0 0 0 0 0 0 0 0 0 0 1584 2822

1 1 24 166 204 7 16 7 52 575 1197 843 535 202 958 762 88 56 1904 29 82 0 91 3098 10,898

intense development. The future of geothermal energy in Kenya is very promising. The countries with a percentage increase in installed capacity greater than 50% since 2005 are presented in Table 8. Because of the very small installed capacity, the values for Germany and Australia are not meaningful. On the other hand, Papua – New Guinea, with MW in operation, can be proud of its 833% increase since 2005, Turkey and Iceland, with increases of 300% and 200%, respectively, were among the most active geothermal countries during 2005–2010. Excluding Germany and Australia, the 4th and 5th geothermal countries in terms of percentage increase are Portugal (78%) and New Zealand (75%), followed by Guatemala (58%), Kenya (57%) and finally by the Indonesian giant, with 50% in the 8th position.

4.1.2. Large plants (>55 MW) The big plants are not often utilized for generating electricity from geothermal resources, even if their economy of scale is advantageous: adequate geothermal fluid supply for these plants is only available where the resource is abundant and well characterized. Table 9 lists plants with an installed capacity greater than 55 MW. The average capacity of all the 536 geothermal units in operation as of 2010 is only 20 MW, whereas for the 65 units presented in Table 9 the average is 74 MW. 4.1.3. Small plants (<10 MW) It is almost impossible to present a similar list of the small plants, with capacity less than 10 MW: there are about 270 units in operation, with an average capacity of 3.2 MW. The majority of these

GWh or MW

FIELD OWNER 9000

8260 ENERGY

8000

7160

MW

7047

7000

6017

5931

6000 5000 4000 3000 2000

1329

1212

1000

958

1309 915

0 Chevron

Energy Development Corpo ration

Comisión Federal de Electricidad

Calpine

Enel Green Power

Fig. 32. Installed capacity and electricity production for the biggest geothermal field operators.

24

R. Bertani / Geothermics 41 (2012) 1–29

GWh or MW

PLANT OWNER 8000

7047

ENERGY

7000

MW

6017

5931

6000

4734

5000 4000

3151 3000 2000

1309 1000

958

915

887

756

0 Comisión Federal de Electricidad

Calpine

Enel Green Power

Energy Development Corporation

Chevron

Fig. 33. Installed capacity and electricity production for the biggest geothermal power plant operators.

units are binary (207 units), 23 are back pressure, 21 are single flash and 17 double flash. Since 2005, 146 new units have been commissioned. The “New Plants” are presented in Table 10, collecting together the units of the same plant with same date of starting of operation and equal capacity.

Table 12 Average MW capacity and energy produced for each plant type (hybrid excluded). Type

Average energy (GWh/unit)

Average capacity (MW/unit)

Binary Back pressure Single flash Double flash Dry seam

27 96 199 236 260

5 6 31 34 46

4.2. Plant classification We have followed the standard definitions of binary, back pressure, single/double flash and dry steam plants. In the pie charts of Fig. 30a–c, the installed capacity in MW, the produced energy in GWh and the total number of units for each category are presented. The average capacities for three major size categories are: small

GWh

8000

(binary, back pressure) about 5 MW/unit, medium (flash plants, around 30 MW/unit) and big (dry steam, 45 MW/unit). The plant types for each country are given in Table 11, and the average values per unit of the installed capacity and the produced energy are given in Table 12.

PLANT OWNER

7000 6000 5000 4000 3000 2000 1000 0

Fig. 34. Geothermal power plant operators with an annual generation greater than 200 GWh.

R. Bertani / Geothermics 41 (2012) 1–29

25

Fig. 35. Map of the top 12 geothermal fields. The dots are proportional to the produced energy.

4.3. Commissioning date

still linear) increase since 2005. The average increase in installed capacity since 1990 is about 300 MW/year. In the last five years, however, the increase has been about 350 MW/year. Table 13 gives the starting date for production of geothermal energy for each country. The first double flash plant was installed in 1977 at Hatchobaru, Japan (1 × 55 MW), whereas large-scale installation of binary plants started in 1984 with the commissioning of four 2.5 MW Ormat units at Mammoth I in California, USA.

The geothermal power plant development history can be deduced from the commissioning date of each individual power plant. Fig. 31 shows the cumulative capacity on a yearly basis. Note that decommissioned plants are included in Fig. 31. There was an initial exponential growth phase from 1946 to 1990, followed by a linear growth (1991–2004), and a somewhat greater (but

Turbine Manufacturer Market 3500 3000

2000 1500 1000 500

g en

h

en Ji ao gd in

Q

on ps om Th

sh iti Br

af iT re nc

on st ou H

W in e

a Ka lu g

Fig. 36. Installed MW capacity by turbine manufacturer.

M

or

ks

es us Tu rb

lI ca ci so As

G

en

er

al

at

El

ed

ec

El

tri

c/

ec

N

tri

uo

An s

vo

nd

Pi

Al

gn

st

tri

om

e on

AT O

al do /

R M

To s

i

ji Fu

ib sh To

its

ub

is

hi

a

0

M

MW

2500

26

R. Bertani / Geothermics 41 (2012) 1–29

Table 13 Initial geothermal electricity development by country. Country

COD

Italy Japan New Zealand USA Russia Iceland China Mexico Turkey El Salvador Philippines Indonesia Portugal Kenya Taiwan Nicaragua France Australia Greece Argentina Thailand Costa Rica Guatemala Ethiopia Austria Papua New Guinea Germany

1914 1925 1958 1960 1966 1969 1970 1973 1974 1975 1977 1978 1980 1981 1981 1983 1984 1987 1987 1988 1989 1994 1998 1999 2001 2001 2003

From 1980 and 1990 there was an impressive array of new plants, but the “geothermal year” can be considered 1997, when a total of 680 MW were commissioned, all single flash. The largest installation of binary plants, 183 MW was in 2009, for double flash in 1986 with 368 MW, for dry steam in 1985 with 489 MW. 4.4. Geothermal companies 4.4.1. Field owners The companies currently operating geothermal fields are shown in Fig. 32, with the installed capacity and produced energy. The five with the largest capacity are Chevron (USA, operating in the Philippines and Indonesia), EDC/Firstgen (Philippines), Comisión Federal de Electricidad (México), Calpine (USA) and Enel Green Power (Italy, presently operating in USA). 4.4.2. Plant operators The companies currently operating geothermal plants are presented in Fig. 33, with the installed capacity and produced energy. The top five are Comisión Federal de Electricidad (México), Calpine (USA), Enel Green Power (Italy), EDC/Firstgen (Philippines) and Chevron (USA). The full list of geothermal plants operators is presented in Fig. 34, with the produced energy (only for operators with generation above 200 GWh).

Table 14 List of the geothermal fields with production >100 GWh/year. Produced energy Installed capacity (MW) (MWh/year)

Geothermal field name

Nation

CA – The Geysers Cerro Prieto Tongonan/Leyte Larderello Java – Gunung Salak CA – Salton Sea CA – Coso Mak-Ban/Laguna Java – Darajat Java – Wayang Windu Hellisheidi Wairakei Java – Kamojang Los Azufres Olkaria Palinpinon/Negros Oriental Travale–Radicondoli Miravalles Oita Tiwi/Albay Nesjavellir Mokai Reykjanes Berlin Mindanao/Mount Apo CA – Heber NV – Steamboat Ahuachapan Svartsengi Akita CA – East Mesa Ohaaki Java – Dieng Sulawesi – Lahendong Krafla Mt. Amiata – Piancastagnaio Kawerau Lihir Island Iwate NV – Dixie Valley Bacon-Manito/Sorsogon/Albay Severo-Mutnovsky Fukushima Aydin-Germencik Kagoshima UT – Roosvelt NV – Stillwater Los Humeros Momotombo Rotokawa HI – Puna CA – Mammoth NV – Blue Mountain Ribeira Grande Mt. Amiata – Bagnore Amatitlán Yangbajain Northland Zunil NV – Beowawe NV – Brady Hot Spring Hokkaido NV – Desert Peak Miyagi Sumatra – Sibayak

USA 1584 Mexico 720 Philippines 716 Italy 595 Indonesia 377 USA 329 USA 270 Philippines 458 Indonesia 260 Indonesia 227 Iceland 213 New Zealand 233 Indonesia 200 Mexico 188 Kenya 202 Philippines 193 Italy 160 Costa Rica 166 Japan 152 Philippines 234 Iceland 120 New Zealand 111 Iceland 100 El Salvador 109 Philippines 103 USA 212 USA 136 El Salvador 95 Iceland 76 Japan 88 USA 120 New Zealand 103 Indonesia 60 Indonesia 60 Iceland 60 Italy 68 New Zealand 122 Papua New 56 Japan 104 USA 67 Philippines 152 Russia 62 Japan 65 Turkey 47 Japan 60 USA 37 USA 48 Mexico 40 Nicaragua 78 New Zealand 167 USA 35 USA 40 USA 50 Portugal 29 Italy 20 Guatemala 24 China 24 25 New Zealand Guatemala 28 USA 17 USA 27 Japan 50 USA 23 Japan 13 Indonesia 13

7062 5176 4746 3666 3024 2634 2381 2144 2085 1821 1704 1693 1604 1517 1430 1257 1209 1131 1106 1007 960 927 800 753 751 708 696 669 611 568 556 549 481 481 480 475 473 450 447 426 390 381 363 360 347 328 314 313 275 273 237 236 177 175 170 158 150 140 131 129 123 115 106 104 104

4.6. Manufacturer ranking 4.5. Field ranking The list of all the geothermal fields with an electric generation of at least 100 GWh is presented in Table 14. The data are also shown in Fig. 35 for the largest 12 fields.

The turbine manufacturers for the plants currently in operation are presented in Table 15 and Fig. 36. Although the Japanese companies dominate the turbine business, the construction of geothermal plants is practically at a stand-still in Japan.

R. Bertani / Geothermics 41 (2012) 1–29

27

Table 15 List of geothermal turbine manufacturers. Company

Country

Total number of units

Total MW

MW decommissioned

MW in operation

MW planned

Mitsubishi Toshiba Fuji Ansaldo/Tosi Ormat General Electric/Nuovo Pignone Alstom Associated Electrical Industries Kaluga Turbine Works British Thompson Houston Mafi Trench Qingdao Jieneng Kawasaki Westinghouse UTC/Turboden Elliot Enex Harbin Makrotek Parsons Siemens Barber-Nichols Inc. Peter Brotherhood GMK

Japan Japan Japan Italy Israel USA France New Zealand Russia UK USA China Japan USA USA New Zealand Iceland China Mexico New Zealand Germany USA UK Germany

100 44 60 72 174 23 11 3 11 8 6 9 3 1 57 3 2 2 1 1 2 4 1 1

2882 2746 2387 1556 1234 533 155 90 82 82 72 62 16 14 14 13 11 11 5 5 4 2 1 0

150 222 58 398 55 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

2628 2524 2279 1158 1152 533 155 90 82 82 72 21 16 14 13 10 11 11 5 5 4 2 1 0

103 0 50 0 28 0 0 0 0 0 0 40 0 0 0 3 0 0 0 0 0 0 0 0

Table 16 Geothermal energy contribution by country in year 2010. Country/Region

% Of National/Regional capacity

Lihir Island, Papua New Guinea Tibet, China San Miguel Island, Azores, Portugal Tuscany, Italy El Salvador Kenya Philippines Hawaii, Big Island, USA Nicaragua Guadalupe, Caribbean, France Costa Rica New Zealand California, USA

75 30 25 25 15 12 12 11 11 9 8 6 4

World Geothermal Electricity 80,000

Installed Capacity, MW

70,000 60,000 50,000 40,000 30,000 20,000 10,000 0 1950

1960

1970

1980

1990

2000

2010

2020

2030

2040 2050

• Small (binary, back pressure) about 5 MW. • Medium (flash plants), around 30 MW. • Large (dry Steam), 45 MW/unit.

Four countries installed new plants with a capacity of more than 100 MW since 2005: USA, Indonesia, Iceland and New Zealand. This is an important signal in that the geothermal industry in these countries is proactive in launching new projects, and that the economic environment provides the necessary incentives and supporting measures. The largest three companies, according to the produced electricity, are: Comisión Federal de Electricidad (México), Calpine (USA) and Enel Green Power (Italy). Table 16 shows that geothermal energy is playing a very important in several nations/regions, and makes a significant contribution to the installed capacity. The target for hydrothermal resources of 70 GW for year 2050 is very ambitious (Fig. 37). Note that any contribution from EGS is not included in Fig. 37. The attainment of this target will likely require increasing the number of medium and low temperature development projects using binary plants, and an all out effort to develop the economically viable projects worldwide. Assuming EGS proves to be economically viable, it may be possible to have an installed capacity of 140 GW by 2050. In this case, geothermal will make up 8.3% of total world electricity production, serving 17% of world population. Moreover, 40 countries (located mostly in Africa, Central/South America, Pacific) could meet 100% of their power needs by geothermal electricity. The overall CO2 saving from geothermal electricity will be in around 1000 million tons/year.

Years Fig. 37. Forecast of installed capacity up to year 2050.

5. Conclusions The 2010 worldwide installed geothermal power plant capacity is 10.9 GW, and the average capacity per unit for all the 536 units in operation is 20 MW. Typical unit values for each plant type are:

Acknowledgements The author would like to express his gratitude to the IGA Board of Directors and to the IGA affiliated organizations for their contribution of data for this paper. The authors of the country update reports presented at the World Geothermal Congress 2010 are also warmly acknowledged for their help in clarifying many points.

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