Geothermal Power and Heat


Geothermal resources provide energy in the form of electricity and direct heating and cooling, totalling an estimated 600 PJ (167 TWh)i in 2013.1 Geothermal electricity generation is estimated to be a little less than half of the total final geothermal output, at 76 TWh, with the remaining 91 TWh (328 PJ) representing direct use.ii Some geothermal plants produce both electricity and thermal output for various heat applications.

At least 530 MW of new geothermal power generating capacity came on line in 2013, bringing total global capacity to 12 GW, generating an estimated 76 TWh annually.2 Accounting for the replacement of some existing units, the net increase in total world capacity was at least 465 MW. This growth in cumulative capacity of about 4% compares to an average annual growth rate of 3% for the two previous years (2010-12).3

Countries that added capacity in 2013 were New Zealand, Turkey, the United States, Kenya, Mexico, the Philippines, Germany, Italy, and Australia.4 (See Figure 8.) At the end of 2013, the countries with the largest amounts of geothermal electric generating capacity were the United States (3.4 GW), the Philippines (1.9 GW), Indonesia (1.3 GW), Mexico (1.0 GW), Italy (0.9 GW), New Zealand (0.9 GW), Iceland (0.7 GW), and Japan (0.5 GW).5 (See Figure 9.)

New Zealand installed 241 MW of new geothermal power capacity in 2013, for net additions of 196 MW, increasing total capacity by 30% to 0.9 GW. The Te Mihi plant (159 MW) came on line in 2013, but problems with well pumps delayed full commissioning into 2014.6 Te Mihi will eventually replace parts of the Wairakei station, which was built in 1958, operating at a higher efficiency level and with a smaller environmental footprint.7 Currently, the result is a net capacity increase of about 114 MW.8 Late in the year, New Zealand also commissioned the 82 MW Ngatamariki geothermal power station.9 Reportedly the world's largest binaryiii installation, Ngatamariki re-injects all used geothermal fluid back into the underground reservoir without depleting it, thereby minimising emissions and other environmental impacts.10

Turkey added at least 112 MW of geothermal generating capacity in 2013, for a total of at least 275 MW.11 Most notable may be the installation of a 60 MW triple-flash turbine in the Denizli field.12 Other capacity to come on line in Turkey in 2013 was made up of smaller binary units.13 Turkey promises to be an important market in the region in the near future, with over 300 MW of additional capacity under licence or construction at year's end.14

The United States added 84 MW of geothermal generating capacity in 2013, for a total of 3.4 GW, representing nearly 29% of total world operating capacity. One of the larger U.S. plants to come on line in 2013 was Enel Green Power's 25 MW binary plant in Fort Cove, Utah.15 Although relatively small in capacity, perhaps the most significant U.S. project completed in 2013 was the Desert Peak 2 (1.7 MW) in Nevada, the first commercial grid-connected EGS (enhanced or engineered geothermal system) installation in the United States (see more on EGS below).16 Desert Peak 2 is located within an existing operational geothermal field ("in-field") and serves to enhance its overall productivity.17 Nevada is also home to the new Don A. Campbell binary plant (16 MW), notable for cost-effective power generation from a relatively low-temperature resource, and the first 30 MW phase of the Patua plant.18 In addition, 12 MW of repowering and refurbishment took place at two U.S. facilities during 2013.19

i - This total does not include the output of ground-source (geothermal) heat pumps.

ii - The estimated value for direct use output is subject to great uncertainty due to incomplete and conflicting data.

iii - In a binary plant, the geothermal fluid heats and vaporises a separate working fluid, which drives a turbine for power generation. Each fluid cycle is closed, and the geothermal fluid is re-injected into the heat reservoir. In a conventional thermal power plant, the working fluid is water. Organic Rankine Cycle (ORC) binary geothermal plants use an organic fluid with a lower boiling point than water, allowing effective and efficient extraction of heat for power generation from relatively low-temperature geothermal fields. The Kalina cycle is another variant for implementing a binary plant. (See for example: Ormat, "Binary Geothermal Power Plant,", and U.S. Department of Energy, Geothermal Technologies Office, "Electricity Generation,"

Kenya is one of the fastest-growing geothermal power markets in the world. In 2013, the country added 36 MW of capacity at the Olkaria III complex. A further 16 MW was added to Olkaria III in early 2014, bringing the complex to a total of 110 MW.20 As of early 2014, Kenya had another 280 MW of geothermal power capacity under construction.21

Mexico completed the second of two 25 MW units of the Los Humeros II project, replacing 15 MW of existing capacity.22 Ongoing reforms to Mexico's energy laws are expected to spur growth and involvement of private parties in the country's geothermal development.23

Also in 2013, the Philippines began operations at the 20 MW Maibarara geothermal power plant.24 Atyear's end, the country's portfolio of geothermal power plants stood at 1.9 GW, second only to that of the United States, with another 40 MW expected to come on line in 2014.25 The three new plants in Kenya, Mexico, and the Philippines are all registered CDM projects underthe UN Clean Development Mechanism, and thus credited for reducing greenhouse gas emissions.26


Figure 8. Geothermal Power Capacity Additions, Share of Additions by Country, 2013

Source: See Endnote 4 for this section.

Figure 9. Geothermal Power Capacity and Additions, Top 10 Countries and Rest of World, 2013

Additions are net of repowering and retirements.

Source: See Endnote 5 for this section.

Several relatively small plants came on line in Europe during the year. Southern Germany has been active in development of binary plants with two 6 MW units completed near Munich in late 2012 and early 2013.27 In addition, Germany's co-generating Sauerlach binary plant (5 MW / 4 MWth) was inaugurated in January 2014, delivering heat in addition to electricity.28 In Italy, a 1 MW binary plant was installed at the volcanic area of Monte Amiata (Tuscany).29 While Europe still has far more conventional dry-steam and flash geothermal capacity than the low-temperature binary variety, future growth potential for binary plants is very promising.30

With growing reliance on variable renewable resources, such as solar PV and wind power, there is also increasing interest in the potential for geothermal power to provide renewable balancing power and storage capability. It has been noted that geothermal power can be designed with the necessary flexibility, especially in locations where the growing need for balancing resources and geothermal potential coincide, as in California.31

Geothermal direct use refers to direct thermal extraction for heating and cooling, exclusive of heat pumps.i 32 (See Sidebar 4, page 42.) The main applications for direct use of geothermal energy are space heating (including district heat networks), domestic hot water supply, direct and indirect heating of public baths and swimming pools, greenhouse heating, industrial process heat, aquaculture, and agricultural drying.33

Geothermal direct use continued to grow during 2013, with capacity added in at least a number of European countries. It is estimated that global direct use was in the range of 280-375 PJ during 2013, with a mean of 328 PJ (91 TWh).34 This wide range reflects widely varying data for China, which is a significant user of geothermal for heat purposes.35 The collection of data on direct use of geothermal energy is lacking.36

Direct use is concentrated among the few countries where good geothermal resources coincide with heat demand that can easily be served by the resource, such as Iceland, and where geothermal heat has served both industry and social traditions, such as thermal baths in Japan, Turkey, and Italy.37 The countries with the largest geothermal direct use capacity are China (3.7 GWth in 2010), Turkey (2.7 GWth in 2013), Iceland (2.2 GWth in 2013), Japan (2.1 GWth in 2010), Italy (0.8 GWth in 2012), and Hungary (0.7 GWth in 2012).38 Together, these countries account for about half of total global capacity, estimated to be in the range of 19-26 GWth, with a mean of 22.6 GWth.39

China remains the presumptive leader in direct geothermal energy use, but estimates range from 13 TWh in 2009 to 45 TWh in 2011, or about 20-50% of global output.40 Other top users of direct geothermal heat are Turkey (estimated 16.4 TWh in 2012)ii, Iceland (7.8 TWh in 2013), Japan (7.2 TWh in 2013), and Hungary (2.8 TWh in 2012).41

Among notable new thermal plants that opened in 2013 is a district heating plant (60-70 MWth) in Miskolc, Hungary.42 The project exceeded initial expectations and is considered to be among the better low-temperature wells in mainland Europe, producing 70-90 litres per second at 100 °C.43 In Italy, a 6 MWth district heat system was inaugurated by Enel Green Power in April to serve municipalities in Tuscany.44 In early 2014, a cogeneration plant with thermal capacity of 4 MWth (noted above) was inaugurated in Sauerlach, Germany.45

In Europe, there have been recent efforts to improve accounting of direct use geothermal energy across all sectors, specifically balneology (e.g., spas, swimming pools), which may not have been fully reported before.46 Such examination reveals divergent profiles for geothermal heat applications. For example, district heating commands a relatively minor share of geothermal heat capacity in Hungary (19%), Turkey (30%), and Italy (10%), but very substantial shares in France (81%), Iceland (80%), and Germany (77%).47

i - Direct use refers here to deep geothermal resources, irrespective of scale, as distinct from shallow geothermal resource utilisation, specifically ground-source heat pumps. In addition, the term hydrothermal energy is reserved for energy stored in the form of heat in surface water, as per Article 2(d) of European Council Directive 2009/28/EC. Heat pumps—whether geo-, hydro, or aerothermal—are discussed in Sidebar 4.

ii - Estimate based on 2012 capacity and 2010 capacity factors. Of this total, 11 TWh is associated with bathing and swimming, of which the 2010 data on capacity utilisation is notably high at 100%. See Endnote 38 for this section.


In 2013, the geothermal industry, often with the support of governments, continued to pursue technological innovation for expanded resource access and improved economies of extraction. Objectives include improving the efficiency of conventional geothermal resources utilisation, as well as advancing technologies that allow expanded use of low-temperature fields for both power and heat, thereby increasing the application of geothermal energy beyond high-temperature locations.

Among notable industry advances in 2013 was Australia's first EGS facility, one of only a handful of such projects in the world. Geodynamics' (Australia) Habanero Pilot Plant (1 MW) in the Cooper Basin of South Australia successfully completed its initial 160-day trial in 2013, with production and injection wells extending more than four kilometres into hot granite.48 In Italy, Enel Green Power (Italy) started operation of its 1 MW binary plant at Monte Amiata, fitted with a first-of-its-kind radial outflow ORC turbine by Exergy (Italy), which is said to advance generating efficiency.49 The industry also saw some repowering and refurbishment of existing facilities. Ormat Industries (United States) refurbished a 7.5 MW unit in California and repowered a 4 MW plant in Utah.50

The geothermal industry, whether it is in power or heat generation, is made up of a relatively few firms that work on the various segments of geothermal project development, from exploration, drilling, engineering, and design, through construction and, finally, plant operation. Some of these firms are vertically integrated, in that they work on most or even all stages of geothermal project development, while others are highly specialised.51 For example, Enel, Ormat Industries, and Chevron (United States) are vertically integrated energy companies.52 Highly specialised firms include drilling contractors like Thermasource (United States) and Iceland Drilling (Iceland), as well as engineering firms with specialised knowledge of the geothermal projects, such as Mannvit (Iceland), Verkis (Iceland), and Power Engineers (United States).

Some firms possess particular expertise and proprietary technology within the industry. These include, for example, Ormat, which specialises in design, engineering, and construction of binary (ORC) power plants and their components, such as the Ngatamariki plant that opened in New Zealand in 2013; Turboden (Italy), which specialises in binary turbine-generators, such as the 5.6 MW unit inaugurated in 2013 near Munich, Germany; and Exergy, which implemented a new turbine design in Italy, as noted above.53 Other suppliers of turbine-generator components count the industrial heavyweights that also operate in the thermal (fossil and nuclear) and hydropower sectors, such as Mitsubishi Heavy Industries, Toshiba, Fuji Electric (all Japan, commanding about two-thirds of the turbine-generator market), Alstom (France), Ansaldo Energia (Italy), and Siemens (Germany).54

Whether for heat or power generation, the industry continues to face many technology challenges. Areas that need improvement include discovery, access, maintenance, and monitoring of the geothermal resource, whether it is conventional geothermal, ow-temperature, or a candidate for Enhanced geothermal Systems (EGS).55 To that end, the industry is applying innovations that include directional drilling and other lessons from the oil and gas sectors.56 In those locations where sufficient heat demand coincides with geothermal resources, such as the newSauerlach plant in Germany, the development of combined heat and power is also helping to improve project economics.57

Enhanced geothermal systems are on the forefront of technological innovation in the industry and represent a very significant potential. This relatively newtechnologywas pioneered in the UnitedStates, but the world'sfirst grid-connected EGS plant to come on line was the 2 MW Soultz facility in France in 2008.58 EGS enhances extraction of heat by fracturing subsurface rock for greater permeability, allowing production similar to naturally occurring conventional geothermal fields.59 Unlike conventional geothermal resources, which are limited to relatively few places on Earth, the heat bound in deep rock that EGS is designed to tap into is far more widespread and plentiful, but also more difficult to harness.

Despite the large potential of EGS, attracting the requisite funds to advance EGS technologies is reportedly a challenge, largely because theymaystill be 10-15 years from commercial maturity and carry significant technological risk.60 Key priorities for the EGS industry today are continued advances in the technology of sustainable field enhancement and reduced drilling costs.61 The industry is learning to control and reduce risks of any adverse effects associated with EGS development so that the vast potential of EGS may materialise.62

Project risk is a uniquely significant aspect of geothermal development in general. A typical geothermal plant may take 5-7 years from start to finish, with up to five years devoted to exploration, test drilling, and field development before construction of the plant itself.63 Project developers face significant financial risk of high upfront cost and long lead times, but also the risk of failing to meet required parameters at each stage of development, from initial exploration to plant operation.64

To manage this risk, one urgent objective is better and more-comprehensive global geothermal resource assessment.65 Several countries have implemented risk funds, insurance funds, or loan guarantees to absorb some of the risk, with renewed enthusiasm for establishing a single fund for the European Union.66 The U.S. Department of Energy provides targeted financial support to the geothermal sector, and Japan's Oil, Gas and Metals National Corporation provides liability guarantees but also direct funding and information on geothermal resources.67 To uncork the bottleneck on behalf of developing countries, in 2013 the World Bank launched a global Geothermal Development Plan to focus the attention of donors and multilateral development banks on exploratory test drilling rather than just the production phase of geothermal projects. The Plan had an initial target funding of USD 500 million.68


Heat pumps provide heating, cooling, and hot water for residential, commercial, and industrial applications by drawing on one of three main sources: the ground, ambient air, or water bodies such as lakes, rivers, or the sea.i Heat pumps can also be employed efficiently using waste heat from industrial processes, sewage water, and buildings. The energy output of heat pumps is at least partially renewable on a final energy basis.

As the term implies, heat pumps transfer heat from one area (source) to another (sink) using a refrigeration cycle driven by external energy, either electric or thermal energy. Depending on the inherent efficiency of the heat pump itself and its external operating conditions, it is capable of delivering significantly more energy than is used to drive the heat pump. Atypical input-to-output ratio for a modern electrically driven heat pump is 4:1, meaning that the heat pump delivers four units of final energy for every one unit of energy it consumes, which is also known as a coefficient of performance (COP) of 4. That incremental energy delivered is considered the renewable portion of the heat pump output.

For a heat pump that operates at a seasonal COP of 4, the renewable component is at least 75% (3 out of 4 units) on a final energy basis. However, the renewable share on a primary energy basis can be much lower.ii The total share of renewable energy delivered by a heat pump on a primary energy basis depends not only on the efficiency of the heat pump and its operating conditions, but also on the composition of the energy used to drive the heat pump. In addition, for electrically driven heat pumps, the overall efficiency and renewable component depends on both the generation efficiency and the primary energy source of the electricity (renewable, fossil fuel, or nuclear). When the energy source is 100% renewable, so is the output of the heat pump.

Data on the global heat pump market, installed capacity, and output are fragmented and limited in scope. Recent versions of the GSR have provided estimates of global ground-source heat pump installations and output, based largely on comprehensive survey data prepared in 2010. Such surveys have been updated for Europe in 2013 but updates for other regions are not yet published. For air- and water-source heat pumps, less is known about current global capacity and output, again with the exception of Europe.

The European heat pump market saw steady growth until about 2008 but has since shown relative stagnation and actually contracted overall from 2011 to 2012. Europe saw at least 0.75 million units sold in 2012, with most of the market (86%) dominated by air-source heat pumps. For use in new buildings, there is an ongoing shift from ground-source to air-source units as they improve in efficiency and economy. As new buildings become more efficient, the economics of ground-source heat pumps makes the pumps attractive for large and very large buildings, while growth is limited for single-family homes. Overall, heat pumps have achieved a relatively stable 15% share of European heating system installations.

The most significant trend related to heat pumps is towards the use of hybrid systems that integrate several energy resources (such as solar thermal or biomass with heat pumps) for the range of heat applications. There is also growing interest in the use of larger-scale heat pumps for district heating as well as industrial processes. For example, Denmark has been developing the use of absorption heat pumps for district heating, the latest being a 12.5 MW plant at Sønderborg, commissioned in 2013. In neighbouring Norway, Star Refrigeration (U.K.) opened a 14 MW hydrothermal heat pump system in the municipality of Drammen in early 2014, utilising sea water for district heating.

In 2009, the European Commission set out to standardise calculation of heat pump output and to define the renewable component thereof, noting first that the final energy output of any heat pump counted in this context would have to "significantly" exceed the primary energy consumed. At the time, the Commission provided a formula for calculating the renewable component of heat pump output that took into account both the operating efficiency of the heat pump itself (seasonal performance factoriii) and the average ratio of primary energy input to electricity production across the EU. This serves to standardise assumptions about the renewable energy contribution of heat pumps in Europe and to ensure that the net final energy output that is counted under these new rules will always exceed the primary energy (including primary energy in electricity generation) used to drive the heat pumps.

In March 2013, the Commission issued remaining rules for applying its formula, includingdefault values for climate-specific average equivalent full-load hours of operation and seasonal performance factors for various heat pumps. The default values resulted in a minimum COP of 2.5 for electrically driven heat pumps in 2013, well below the average value of new units.

i - Also called geothermal, aerothermal, and hydrothermal sources. Ground-source heat pump applications generally rely on shallow geothermal energy (covering depths of up to 400 metres), clearly distinguished from deep geothermal (medium-to-high temperature) resources, mostly for direct use and geothermal power generation.

ii - A heat pump providing four units of final energy for every one unit of energy input (COP of 4), driven by electricity from a thermal plant at 40% efficiency, provides about 1.6 units of final energy for every one unit of primary energy consumed (4/(1/0.4)= 1.6).

iii - Seasonal Performance Factor (SPF) refers to the net seasonal coefficient of performance (sCOPnet) for electrically driven heat pumps or the net primary energy ratio (sPERnet) for thermally driven heat pumps, per Commission Decision of 1 March 2013 (2013/114/EU).

Source: See Endnote 32 for this section.

1 Based on electricity generation of 76 TWh (273 PJ)and heat output of 91 TWh (328 PJ). Electricity estimate based on global capacity of 12 GW and average capacity factor of 72%, which is based on 2012 global capacity of 11.4 GW and 2012 global generation of 72 TWh, from International Energy Agency (IEA), Medium-Term Renewable Energy Market Report 2013 (Paris: Organisation for Economic Co-operation and Development (OECDVIEA, 2013), p. 173. Heat estimate derived from the average of two estimated values. The first (376 PJ) was derived from global annual direct use in 2011 of 335 PJ, from IEA," World Energy Statistics," (Paris: OECD/IEA, 2013), and escalated at the observed two-year average growth rate (2009-2011) to 2012 and 2013; the second (281 TJ) was derived from global direct use in 2009 of 223 PJ, from John W. Lund, Derek H. Freeston, and Tonya L. Boyd, "Direct Utilization of Geothermal Energy 2010 Worldwide Review," Proceedings World Geothermal Congress 2010, Bali, Indonesia: 25-29 April 2010, which was escalated first at the annual growth rate from IEA data ("World Energy Statistics," op. cit. this note) to 2011 and then by the two-year average growth rate (2009-2011) to 2012 and 2013, as above. The average of these two values is the estimated global direct use of 328 PJ (91 TWh). Capacity estimate derived from the average of two estimated values. The first (25.8 GWth) was derived from global annual direct use in 2009-2011, from IEA,"World Energy Statistics," op. cit. this note, and capacity factor of about 46% for 2009, calculated from Lund, Freeston, and Boyd, op. cit. this note, and escalated at the observed two-year average growth rate (2009-2011) to 2012 and 2013; the second (19.3 GWth) was derived from global capacity of 15,346 MWth in 2009, from Lund, Freeston, and Boyd, op. cit. this note, which was escalated first at the annual growth rate from IEA data ("World Energy Statistics," op. cit. this note) to 2011 and then by the two-year average growth rate (2009-2011) to 2012 and 2013, as above. The average of these two values is the estimated global heat capacity at 22.6 GWth, with estimated increase of 1.3 GWth during 2013. The divergence between the two sources for geothermal heat output, and the need to extrapolate over 2-4 years, makes these estimates of output and capacity subject to great uncertainty. The difference between the two datasets is due largely to different heat output data for China, diverging by a factor of three (difference of about 100 PJ). The IEA reportsdirect use in China being 150.7 PJ (41.9 TWh) in 2010, while Lund, Freeston, and Boyd report direct use in China in 2009 being 46.3 PJ (12.9 TWh).

2 Total global installed capacity in 2013 of 12 GW is based on inventory of existing capacity and installed capacity in 2013, from Geothermal Energy Association (GEA), per Benjamin Matek, GEA, personal communication with REN21, March 2014; and from additional sourcesfor capacity additions by country provided throughout this section. The total difference between newly installed capacity and net additions (net of replacements) in 2013 is estimated to be 65 MW. Capacity additions for Turkey in 2013, according to latest government sources (149 MW), are higher than those represented here (112 MW), per Energy Market Regulatory Authority of the Turkish Republic, provided by Mustafa Sezgin, Secretary General and Member of the Board, Turkish Energy Foundation (TENVA), personal communication with REN21, May 2014. Estimated annual generation is based on global capacity of 12 GW and average capacity factor of 72%, which is based on 2012 global capacity of 11.4 GW and 2012 global generation of 72 TWh, from IEA, Medium-Term Renewable Energy Market Report 2013, op. cit. note 1, p. 173.

3 Capacity values from current Inventory of existing capacity and additions from GEA, op. cit. note 2.

4 Figure 8 and country installed capacity in 2013 based on inventory of existing capacity and installed capacity in 2013, from bid. and from additional sources for capacity additions by country provided throughout this section.

5 Figure 9 and country installed capacity in 2013 based on inventory of existing capacity and installed capacity in 2013, from ibid.

6 Contact Energy, "Continued performance improvement," press release (Wellington, New Zealand: 18 February 2014),

7 Robert Peltier, "Contact Energy Ltd.'s Te Mihi PowerStation Harnesses Sustainable Geothermal Energy," Power Magazine, 1 August 2013,

8 Contact Energy, "The Te Mihi Project," http://www.contactenergy

9 Mighty River Power, "PM opens showcase Geothermal plant: boost for MRP, benefits for NZ," press release (Auckland, New Zealand: 3 October 2013),

10 Ormat, "Ormat Successfully Completed The Ngatamariki Geothermal Plant," press release (Reno, NV: 3 September 2013),

11 Inventory of existing capacity and installed capacity in 2013 from GEA, op. cit. note 2. Highervalueforcapacity addition of 149 MW and a total capacity of 311 MW from Energy Market Regulatory Authority of the Turkish Republic, op. cit. note 1. Additional information from the following: Phillip Dumas, European Geothermal Energy Council, personal communication with REN21, February 2014; Özgür Çağlan Kuyumcu, "Middle East Geothermal Potential," presentation at the Geothermal Resources Council Annual Meeting 2013, Las Vegas, NV, 29 September-2 October 2013,; Mahmut Parlaktuna et al., "Geothermal Country Update report of Turkey (2012-2013),"prepared for the European Geothermal Congress 2013, Pisa, Italy, 3-7 June 2013, http://www.geothermal-energy org/pdf/IGAstandard/EGC/2013/EGC2013_CUR-32.pdf.

12 Fuji Electric, "Introduction to Fuji Electric's Recent Experiences in Geothermal Power Plant Business," presentation, October 2013,; "Zorlu's geothermal power plant opened," Hurriyet Daily News, 30 September 2013,

13 MB Holding [Menderes Geothermal Elektrik Üretim (MEGE)], "Dora-3 Produces, Turkey Wins," 17 September 2013,; Kuyumcu, op.cit. note 11; BM Holding, "Gümüşköy GEPP Project,"

14 Dumas, op. cit. note 11; Parlaktuna et al., op. cit. note 11.

15 Enel Green Power, "Enel Green Power: The Cove Fort Geothermal Power Plant Starts Operations in Utah," press release (Rome and Boston: 27 November 2013), http://www.enelgreenpower com/en-GB/ena/events_news/press_releases/release. aspx?iddoc=1661220.

16 U.S. Department of Energy (DOE), "Nevada Deploys First U.S. Commercial, Grid-Connected Enhanced Geothermal System," 12 April 2013,

17 In-field and near-field EGS are located within or near existing conventional geothermal installations, while greenfield projects would be located on previously undeveloped sites, per GEA, 2013 Geothermal Power International Market Overview (Washington, DC: September 2013).

18 Ormat, "Ormat Completes the Don A. Campbell Geothermal Power Plant with Full 16 Megawatt (net) Output," press release (Reno, NV: 6 January 2014),; Alexander Richter, "Gradient Resources starts operation of Patua plant in Nevada," Think Geoenergy, 15 January 2014,; Gradient Resources Web site,

19 Ormat, "Ormat Becomes Sole Owner of the Mammoth Complex in Mammoth Lakes, California," press release (Reno, NV: 2 August 2010), moth-lakes-california; Ormat, "Ormat Reaches Commercial Operation of the Newly Refurbished Mammoth Gl Power Plant," press release (Reno, NV: 23 January 2014),

20 Ormat, "Ormat Technologies Commences Operation of 36 MW Geothermal Power Plant In Kenya," press release (Reno, NV 2 May 2013),; Ormat "Olkaria III Geothermal Complex in Kenya Reaches 110 MWwith Commercial Operation of Plant 3," press release (Reno, NV 4 February 2014),

21 GEA, op. cit. note 17; global inventory of geothermal power plants from GEA, op. cit. note 2.

22 Alstom, "Los Humeros II, Units 9 &10," com/Global/Power/Resources/Documents/Brochures/los-humeros-II-mexico-geothermal-power-plant-datasheet.pdf; Alstom, "Alstom to build "Los Humeros III" geothermal project in Mexico," 19 December 2013,; United Nations Framework Convention on Climate Change (UNFCCC), "Project 8861: Los Humeros II Phase A+B Geothermal Project,"

23 Luis Gutierrez-Negrin, Mexican Geothermal Association, personal communication with REN21, April 2014.

24 Maibarara Geothermal Inc., "20 MW Maibarara Geothermal Power Project Starts Commercial Operations," 9 February 2014,; Maibarara Geothermal Inc., "Maibarara Geothermal Power Project Gets CDM Approval," 15 May 2013,

25 Manuel S. Ogena and Ariel Fronda, Philippines Department of Energy, "Prolonged Geothermal Generation and Opportunity in the Philippines," presentation at the Geothermal Resources Council Annual Meeting 2013, Las Vegas, NV, 30 September 2013,

26 Jørgen Fenhann, United Nations Environment Programme Risø Center, "CDM project pipeline," 1 April 2014, http://cdmpipeline. org/publications/CDMPipeline.xlsx.

27 The plants are in the localities of Kirchstochach and Dürrnhaar at the outskirts of Munich. Turboden, "References: 277,"; Süddeutsche Geothermie-Projekte Gesellschaft, "Projekte,"; capacity rating from Bundesverband Geothermie,"Tiefe Geothermieprojekte in Deutschland,"; new installed capacity of 19 MW in 2013, from Arbeitsgruppe Erneuerbare Energien-Statistik (AGEE-Stat), Erneuerbare Energien im Jahr 2013 (Berlin: Bundesministerium für Wirtschaft und Energie(BMWi), Berlin, 2014), p. 3 and Table 5, http://www.bmwi. de/BMWi/Redaktion/PDF/A/agee-stat-bericht-ee-2013.

28 Stadtwerke Munchen, "Geothermie-Heizkraftwerk Sauerlach geht offiziell in Betrieb," press release (Munich: 30 January 2014), rgung20140130/Pressemitteilung%20vom%2030.01.2.014.pdf; "SWM Geothermie-Kraftwerk in Sauerlach eroffnet,", 31 January 2014,

29 Exergy, "Exergy Brings Geothermal Energy into the Future for Enel Green Power," translated by Exergyfrom article in La Stampa, 10 June 2013,; Exergy, "Radial Outflow Turbine,"

30 Dumas, op. cit. note 11.

31 Benjamin Matek and Karl Gawell, "Report on the State of Geothermal Energy in California" (Washington, DC: GEA, February 2014).

32 Sidebar4from the following sources: Miklos Antics, Ruggero Bertani, and Burkhard Sanner, "Summary of EGC 2013 Country Update Reports on Geothermal Energy in Europe," presented at European Geothermal Congress, Pisa, Italy, 3-7 June 2013; use of waste heat from Burkhard Sanner et al., Strategic Research and Innovation Agenda for Renewable Heating and Cooling (Luxembourg: European Commission, European Technology Platform - Renewable Heating and Cooling, March 2013), Figure 17,; heat pump efficiency from idem; overall energy efficiency dependence on efficiency of electricity consumption from idem, Section 3.5; 2010 survey data from Lund, Freeston, and Boyd, op. cit. note1; 2013 update from Antics, Bertani, and Sanner, op. cit. this note; European market figures from Thomas Nowak, European Heat Pump Association, personal communication with REN21, April 2014, and from EurObserv'ER, Heat Pumps Barometer(Paris: October 2013); 2012 sales from Nowak, op. cit. this note. EurObserv' ER, which may have greatergeographic coverage, indicates significantly larger market size, at 1.65 million units, but similar overall market decline from 2011 to 2012; Heinz Kopetz, World Bioenergy Association, personal communication with REN21, 13 February 2014; attractive for large buildings from Nowak, op. cit. this note, January 2014; 15% share from Nowak, op. cit. this note, April 2014; use of hybrid systems from Sanner et al., op. cit. this note, p. 30. For hybrid systems, see, for example, Stephanie Banse, "Thailand: Government Continues Subsidy Programme in 2013," Solar Thermal World, 15 February 2013,, and "Solar + Heat Pump Systems," Solar Update (IEA Solar Heating and Cooling Programme), January 2013; interest in larger-scale pumpsfrom Nowak, op. cit. this note, 16 April 2014; Denmark from Søren Berg Lorenzen, Danish Geothermal District Heating, "Deep Geothermal projects in Jutland," presentation at the FURGY Congress 2014, Husum, Denmark, 21 March 2014,; Norwayfrom Star Refrigeration, "World's Largest Zero Carbon 90°C District Heat Pump Opens Its Doors 25th Feb,"; EU standardisation from "Directive 2009/28/EC of the European Parliament and the Council of 23 April 2009," (Article 5(4)), Official Journal of the European Union, 5 June 2009; Commission Decision of 1 March 2013 (2013/114/EU), Official Journal of the European Union, 6 March 2013. According to the Commission Rules, the renewable share of heat pump energy output would be: [ERES = Qusable * (1-1/SPF)], Where Qusable is the usable heat delivered and defined as the product of equivalent full-load hours of operation and the capacity of the heat pump; and where the SPF of any electrically driven heat pump considered shall always be greater than [1.15* 1/ŋ], where ŋ is the ratio of gross production of electricity to primary energy used in electricity generation across the EU. With the EU powersystem efficiency (ŋ) established at 45.5% in March 2013, the minimum SPF for electrically driven heat pumps (sCOPnet) was thereby set at the value of 2.5 to qualify as being considered renewable energy under the Directive.

33 See, forexample, Lund, Freeston, and Boyd, op. cit. note 1.

34 See sources in Endnote 1.

35 Ibid.

36 Dumas, op. cit. note 11.

37 See, forexample, Lund, Freeston, and Boyd, op. cit. note 1, and Antics, Bertani, and Sanner, op. cit. note 32.

38 Country data from the following sources: China: capacity of 3,688 MW from Lund, Freeston, and Boyd, op. cit. note 1; output of 156.2 PJ in 2010 and 162 PJ in 2011 from IEA, World Energy Statistics for 2011 (Paris: OECD/IEA, 2013); output of 46.3 PJ in 2010, excluding heat pumps, from Lund, Freeston, and Boyd, op. cit. note 1; Turkey: capacity of 2,667 MWt across three categories of space heating, greenhouses, and baths, from Parlaktuna et al., op. cit. note 11; geothermal direct use output of 16.3 TWh based on 2012 capacity for each use category (per idem) and 2010 capacity factors for each category, as implied by reported 2010 capacity and output values (per Lund, Freeston, and Boyd, op. cit. note 1); according to capacity and output figures for 2010 (per Lund, Freeston, and Boyd, op. cit. note 1), Turkish direct use for "bathing and swimming" in 2010 suggests a 100% capacity factor of associated thermal capacity, which is much higher than the average across other countries in the same source. Alternatively, the capacity value may be understated; additional sources include Antics, Bertani, and Sanner, op. cit. note 32, and Dumas, op. cit. note 11; Iceland: capacity of 2,155 MWfrom Antics, Bertani, and Sanner, op. cit. note 32; 7.8 TWh based on direct use being 60% of total final energy use for heat and power of 46.7 PJ, or 28 PJ, from Orkutölur 2013, Orkustofnun (Energy Statistics in Iceland 2013) (Reykjavik: April 2014),; Conversely, anothersource suggests 8.2 TWh for 2012 (Antics, Bertani, and Sanner, op. cit. note 32); Japan: capacity of 2,086 MWfrom Lund, Freeston,and Boyd, op. cit. note 1; output of 7.2 TWh from Institute for Sustainable Energy Policies (ISEP), Renewables Japan Status Report 2014 (Toyko: 2014),, via Hironao Matsubara, ISEP, personal communication with REN21, April 2014; Hungary: capacity of 695 MW and output of 2.8 TWh from Antics, Bertani, and Sanner, op. cit. note 32; Italy: capacity of 779 MW and output of 2.4 TWh from idem.

39 See sources in Endnote 1.

40 The IEA ("World Energy Statistics," op. cit. note 1) reports direct use in China being 162 PJ (45 TWh) in 2011 and global direct use being 335 PJ (93 TWh), while Lund, Freeston, and Boyd (op. cit. note 1) report direct use in China in 2009 being 46.3 PJ (12.9 TWh) and global use 223 PJ (62 TWh).

41 See all sources in Endnote 38.

42 PannErgy, "Projekt bemutatása,"

43 Mannvit, "Geothermal Energy Development in Hungary,"

44 Enel, "Monteverdi M.Mo(PI): Inaugurato L'lmpianto di Teleriscaldamento. Collaborazione Tra Comune, Regione ed Enel Green Power," 4 April 2013, aspx?iddoc=1658368.

45 Stadtwerke München, op. cit. note 28; "SWM Geothermie-Kraftwerk in Sauerlach eröffnet," op. cit. note 28.

46 Antics, Bertani, and Sanner, op. cit. note 32.

47 Ibid.

48 Geodynamics, "Completion of 1 MWe Habanero Pilot Plant demonstration," press release (Milton, Australia: 8 October 2013),; Geodynamics, "Innamincka (EGS) Project,"

49 The turbine is referred to as "radial outflow turbine" and is said to excel at several operational parameters, including generating efficiency. Exergy, "Exergy Brings Geothermal Energy into the Future for Enel Green Power," op. cit. note 29; Exergy, "Radial Outflow Turbine," op. cit. note 29.

50 Ormat, "Ormat Reaches Commercial Operation of the Newly Refurbished Mammoth Gl Power Plant," op. cit. note 19.

51 See for exam pie, Magnus Gehringer and Victor Loksha, World Bank Energy Sector Management Assistance Program (ESMAP), Geothermal Handbook: Planning and Financing Power Generation (Washington, DC: June 2012), Figure 1.11, p. 28.

52 Chevron, "Geothermal - Harnessing Renewable Energyfor Power Generation,"; Ormat, "Company Profile,"; Enel Green Power, "Geothermal Energy,"

53 Ormat, op. cit. note 52; Ormat, "Ormat Successfully Completed the Ngatamariki Geothermal Plant," press release (Reno, NV: 3 September 2013),; Turboden, "Company,"; Turboden, op. cit. note 27; Exergy, "Exergy Brings Geothermal Energy into the Future for Enel Green Power," op. cit. note 29.

54 Japan based on data compiled by Bloomberg New Energy Finance, provided by Dumas, op. cit. note 11; see, forexample, Gehringerand Loksha, op. cit. note 51, Figure 1.11, p. 28; Siemens, "Steam Turbines for Geothermal Power Plants,"; Ansaldo Energia, "Ansaldo Energia,"

55 Doug Hollett, Geothermal Technologies Office, DOE, "Hot Rock and Hard Places," presentation for the Geothermal Resources Council Annual Meeting 2013, Reno, NV, 30 September 2013,

56 Ibid.; DOE, "Geothermal Technologies Program Coproduction Factsheet" (Washington, DC: February 2012),

57 Another example of this is the 1 MWe/12.4 MWth ORC plant in Altheim, Austria, which supplies the town of 5,000 people with district heat but engages powergeneration during peak load periods for additional revenue and improved plant economics. Bundesverband Geothermie, "The Altheim Rankine Cycle Turbogenerator,"

58 Géothermie Perspectives, "Central EGS Soultz-sous-Forets, Alsace," 16 January 2014, http://www.geothermie-perspectives. fr/article/centrale-egs-soultz-forets-alsace.

59 DOE, "How an Enhanced Geothermal System Works,"

60 Adam H. Goldstein and Ralph Braccio, 2013 Market Trends Report, prepared by Booz Allen Hamilton (Washington, DC: DOE, Office of Energy Efficiency and Renewable Energy (EERE), Geothermal Technologies Office, January 2014), p. vi.

61 Ibid., p. 39; Philippe Dumas, European Geothermal Energy Council, personal communication with REN21, May 2014.

62 The hydro-shearing used to enhance permeability of the rock is different from shale gas fracturing in that it uses only water at lower pressure and no chemicals, but instances of small f racture-nduced seismic activity have still raised public concern. Burkhard Sanner, President, European Geothermal Energy Council, personal communication with REN21, 14 January 2013.

63 Gehringerand Loksha, op. cit. note 51, Figure 2.1, p. 52.

64 Ibid.

65 Dumas, op. cit. note 61.

66 S. Fraser et al., European Geothermal Risk Insurance Fund EGRIF, June 2013,

67 Japan Oil, Gas and Metals National Corporation (JOGMEC), "Geothermal,"; DOE, EERE, Geothermal Technologies Office, "Financial Opportunities,"

68 World Bank, "Full Steam Ahead: World Bank Seeks 'Global Push' for Geothermal Energy Revolution," 6 March 2013,; Pierre Audinet, World Bank ESMAP, "Global Geothermal Development Plan," presentation for Knowledge Exchange Forum, Paris, 27-28 November 2013,