Energy Research Knowledge Centre. Overcoming Research Challenges for Geothermal Energy

Transcription

1 Energy Research Knowledge Centre Overcoming Research Challenges for Geothermal Energy

2 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e This publication was produced by the Energy Research Knowledge Centre (ERKC), funded by the European Commission to support its Strategic Energy Technologies Information System (SETIS). It represents the consortium s views on the subject matter. These views have not been adopted or approved by the European Commission and should not be taken as a statement of the views of the European Commission. The manuscript was produced by Massimo Angelone and Stefano Sylos Labini from the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). The purpose of this brochure is to summarise comments and recommendations reported in previous documents from national and international organisations working on renewable energy or involved in geothermal activities. While the information presented in this brochure is correct to the best of our knowledge, neither the consortium nor the European Commission can be held responsible for any inaccuracy, or accept responsibility for any use made thereof. Additional information on energy research programmes and related projects, as well as on other technical and policy publications is available on the Energy Research Knowledge Centre (ERKC) portal at: setis.ec.europa.eu/energy-research Manuscript completed in September 2014 European Union Reproduction is authorised provided the source is acknowledged. Cover: GOPAcom Photo credits: Istockphoto, ECN, Shutterstock Printed in Belgium

3 Overcoming Research Challenges for Geothermal Energy 1 Contents Key messages 2 Current status of geothermal energy 3 Challenges and potential of geothermal 5 Figuring out the future for geothermal 6 - Geothermal energy in EU Member States 11 - Geothermal strategies in non-eu countries 14 Research and opportunities 17 - Exploring and drilling technologies 17 - Electricity production 17 - Heating and cooling 20 - Desalination 21 - Environmental impact mitigation and public acceptance 22 Looking to the future 23 Policy implications and recommendations 26 References 28 Selected websites on geothermal energy 31 List of Acronyms 32

4 2 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e Key messages Emerging technologies for electricity production are at early-commercial stage and technological innovation for cost reduction is required as well as deployment of large-scale Enhanced Geothermal System plants RD&D financial support and a new regulation framework are necessary for electricity exploitation Demand pull in the exploitation of heating and cooling is crucial Pilot projects for volcanic islands are advisable in order to achieve a higher energy independence Need for environmental and socio-economic assessment and information to population involved in deep geothermal exploitation Natural geothermal energy plant in Pisa, Italy. istockphoto

5 Overcoming Research Challenges for Geothermal Energy 3 Current status of geothermal energy This Geothermal Energy Policy Brochure summarises the current status of developments in geothermal energy. Emphasis is placed on the results of geothermal energy research programmes and their implications on future policy decisions and technological challenges. There is a mismatch between research, development and demonstration (RD&D) and industrial applications: the current large research programmes are not connected to immediate industrial applications, but look towards future developments, while current applications, such as heating and cooling (HC), are not associated with large RD&D projects because they are related to consolidated technologies that require incremental innovations. In 2013, shallow geothermal was the largest sector in terms of installed capacity with 63 % of total capacity, followed by direct use with 30 % and electricity with 7 %. In 2012, about geothermal heat pumps (GHP) were installed in the European market and total number of GHP in operation within the European Union (EU) is about 1 million units. The number of operational geothermal power plants is 68, providing an installed capacity of 935 MWe (megawatt electric) and producing GWe (gigawatt electric). The direct and indirect jobs provided number about units in the geothermal electric sector and about units in the GHP sector. These data show that the exploitation of deep geothermal energy for electricity production, in particular Enhanced Geothermal Systems (EGS), has a low impact on the economy, notwithstanding the fact that major research projects are focusing on this field. On the contrary, geothermal applications that are economically important, mostly heating and cooling, are not linked to major research projects, but mainly depend on the new construction market trend and on investments in renovating old buildings. For these reasons, a relevant increase in RD&D investment for exploiting electricity production requires effective policies to stimulate innovation and experimentation by launching new demonstration projects in order to move to large-scale EGS plants (the so-called technology push strategy). This approach implies a qualitative leap by governments and banking systems as well as in the involvement of large corporations which should play an active role in the network of universities and public research centres. In the HC sector it is important to set up financial incentives and legislative rules in the new construction market to stimulate the use of geothermal technologies ( demand pull policies) and thereby growth in production and innovation processes in the heat pump sector. Furthermore, it is essential to reduce permissions and authorisations in order to liberalise installations of heat pumps.

6 4 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e Last but not least, gas emissions and micro-seismicity are factors that reduce public confidence in EGS development. For this reason, it is still worthwhile fully assessing the social and environmental impact of the activities by developing new tools for analysis and involving the population in the geothermal projects in order to achieve wide public acceptance. Geothermal power plant production line. istockphoto

7 Overcoming Research Challenges for Geothermal Energy 5 Challenges and potential of geothermal The importance of geothermal energy originates from the availability and continuity of the source for heat exploitation, and the fact that it is clean energy which produces low harmful emissions and ensures cost stability for end-users. Furthermore, geothermal energy presents no geopolitical risk and can be used with the current industrial technology for HC, which has a significant impact on EU employment and gross domestic product (GDP). HC technologies are competitive, are characterised by a good level of diffusion, and are more dynamic than those in the electricity sector. Conversely, geothermal energy has some limitations and barriers to overcome: high temperatures are concentrated in specific areas, geothermal energy has a lower capacity factor compared to fossil fuel and nuclear energy, and there are frequent mismatches between optimal energy site locations and district requirements. Furthermore, electricity grids need to be upgraded. The negative impacts are mainly related to hot water and gases released into the environment and to the occurrence of induced earthquakes triggered by rock fracturing, as has been observed at some experimental EGS plants. Technological barriers lie mainly in high exploration and high investment costs for electricity production, long-term investment return, and the risk of failure during the exploration and drilling/stimulation phase of a geothermal project, while technologies for offshore and magmatic exploitation are still at the experimental stage. In addition, regulations and administrative procedures represent obstacles that do not encourage the application and diffusion of this renewable energy. This brochure aims to provide suggestions for promoting awareness of geothermal technologies and their real potential. It highlights the current status of the different applications for geothermal energy development. The main issues to be tackled are: improvements needed for resource assessment and forecasting; improvements in modelling and drilling technologies; fracturing techniques, water supply, and seismic 3D reservoir assessment; transmission and system integration; environmental impact mitigation. The Geothermal Energy PB also focuses on the current status of energy research regarding different technologies, based on the main European and international programmes, in order to show where the research should be focused to facilitate the spread of geothermal technologies. Finally, suggestions are made for the development and diffusion of innovative geothermal applications in different sectors (residential, industrial, water desalination).

8 6 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e Figuring out the future for geothermal Geothermal energy is a dynamic and flexible source of renewable energy which is recognised as making a significant contribution to Europe s energy mix since it could provide continuous heat production almost everywhere. First, the European strategy for geothermal energy development is related to the Directive on the promotion of the use of energy from renewable sources, adopted on 23 April 2009 (Directive 2009/28/EC). According to Article 4 of this Directive, Member States must adopt a National Renewable Energy Action Plan (NREAP) setting out national targets for the share of energy from renewable resources in electricity, heating and cooling, and transport, and the measures to be taken to achieve those targets. The following tables show the NREAP energy production targets from geothermal resources for each Member State for the years 2015 and Most electrical applications should double their output in 2020 (10.9 TWh with MW of installed capacity). Among the EU countries, France, Germany, Italy and Portugal should expand their existing installed capacity, while Greece, Hungary and Spain should develop their own sectors, in particular by operating binary cycle plants. (EurObserv ER, 2013). The energy output from geothermal installations should increase significantly by 2020 to reach 2551 ktoe (thousand tonnes of oil equivalent), with an interim target of 1296 ktoe by 2015 (ECN, 2011). In the Working Document SEC(2011) 131 Review of European and national financing of renewable energy in accordance with Article 23(7) of Directive 2009/28/EC, the European Commission pointed out that the feed-in tariff is the main instrument in the EU for supporting geothermal electricity. The costs of capital for renewable energy system (RES) investments observed in countries with established tariff systems have proven to be significantly lower than in countries using other instruments that involve higher risks for future return on investments (ECOFYS et al., 2010). Austria, Czech Republic, France, Germany, Greece, Hungary, Portugal (Azores only), Slovakia, Slovenia, Spain and Switzerland have dedicated feed-in tariffs for geothermal energy. The most attractive schemes are found in Switzerland (max. ct 33/kWh), Germany (ct 25/kWh for all projects and an additional ct 5 for EGS) and France (ct 20/ kwh with an energy efficiency bonus of up to ct 8/kWh). Estonia, Italy, the Netherlands and Slovenia promote geothermal electricity generation by means of feed-in premiums (a bonus paid on top of the electricity market price) as an alternative to feed-in tariffs. Currently, Belgium (Flanders), Romania and the UK have a quota system in place based on green certificates (EGEC, 2013).

9 Overcoming Research Challenges for Geothermal Energy 7 Table 1: Projected geothermal electricity generation for the period , GWh Belgium 0 29 Czech Republic Germany Greece Spain France Italy Hungary Austria 2 2 Portugal Slovakia TOTAL Source: NREAPs, ECN (2011) Table 2: Projected total geothermal heat energy for the period , ktoe Belgium 4 6 Bulgaria 3 9 Czech Republic Denmark 0 0 Germany Greece Spain 5 10 France Italy Lithuania 4 5 Hungary Netherlands Austria Poland Portugal Slovenia Slovakia TOTAL Source: NREAPs, ECN (2011)

10 8 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e In the HC sector, given the existence of consolidated technologies, it seems more effective to use a demand pull mechanism that works by incentives granted to geothermal technology applications in order to stimulate the growth of production and innovation processes. Operational aid similar to a feed-in tariff system is now beginning to be explored in some Member States, partly because of the inclusion of the sector in the European regulatory framework. The Communications Energy Roadmap 2050 (COM(2011) 885) and Renewable energy: A major player in the European energy market (COM(2012) 271) point out how crucial it is to invest in new renewable technologies and to improve existing ones through RD&D. The Implementing Agreement for the Cooperative Programme on Geothermal Energy Research and Technology provides a framework for international co-operation on RD&D. Activities include information sharing; developing best practice in the use of technologies and techniques; exploration, development and utilisation of geothermal; and producing and disseminating authoritative analysis and databases. There are currently 15 contracting parties, including Iceland and Mexico, as well as five sponsors. Strategic research priorities in terms of scientific research and development in the geothermal sector were also identified in two noteworthy documents: Strategic Research Priorities for Geothermal Technol- Production line in thermal power plant. istockphoto

11 Overcoming Research Challenges for Geothermal Energy 9 ogy (European Technology Platform on Renewable Heating and Cooling TP RHC 2012) and Strategic Research Priorities for Geothermal Electricity (European Technology Platform on Geothermal electricity - TP Geoelec 2012). The aim of these Platforms is devoted to reducing Europe s dependency on imported fossil fuels, stabilising energy prices, and achieving climate change mitigation goals. The Geothermal Technology Roadmap of the European Technology Platform on Renewable Heating and Cooling (March 2014) highlights the technological challenges for an accelerated deployment of geothermal heating & cooling across Europe. These are to develop innovative solutions especially for refurbishing existing buildings, but also for zero and plus energy buildings and to develop geothermal District Heating (DH) systems in dense urban areas at low temperature with emphasis in the deployment of Enhanced Geothermal Systems. Finally, the third goal is to contribute to the decarbonisation of the industry by providing competitive solutions for heating & cooling. RD&D support from Member States must be coordinated at European and national level. Initiatives like Geothermal ERA NET, a consortium of funding agencies working together to coordinate geothermal RD&D support programmes, and supported by the EU s Seventh Framework Programme (FP7), should enable this coordination to be set up. Figure 1: RD&D expenditure on geothermal energy in 2011 in some European countries (EUR million prices and exchange rates) Germany Switzerland Italy Spain France Netherlands Belgium Austria Ireland Source: IEA, RD&D Statistics Database

12 10 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e Geothermal RD&D spending shows major variations among the Member States, although some research priorities are common in some technologies among groups of countries. Synergies should be exploited in these areas, which are particularly important for capital-intensive RD&D activities. In 2011, overall public RD&D expenditure on geothermal energy amounted to EUR 48 million, representing about 6.2 % of the total public budget for RD&D activities in the RES sectors for those countries analysed (Fig. 1). Germany represents the country with the highest public expenditure for RD&D activities in the geothermal sector by far, spending more than EUR 18 million in 2011, which corresponds to 38 % of the total geothermal budget for the countries under consideration. Switzerland follows with EUR 9.8 million, then Italy with EUR 8.1 million, Spain with EUR 5.7 million and France with EUR 4.7 million. Until 2012, the EU RD&D funding allocated to geothermal energy during FP6 and FP7 amounted to EUR 29.4 million which was as much as 10 times lower than the funding for photovoltaic (The Geothermal Technology Roadmap of the European Technology Platform on Renewable Heating and Cooling - March 2014). Moreover, to date the geothermal sector, together with biomass, has experienced a proportional reduction in FP7 funding (from EUR 17.3 million in FP6 to EUR 12.1 million) (Pezzuto et al., 2012). The NER300 programme is another financing instrument which exists at the EU level. In the first call, a Hungarian EGS project near Ferencszállás received EUR40 million. In the 2 nd round of the European NER300 programme two geothermal projects were selected for support. The first project in Croatia concerns the production of electricity and heat from a geothermal aquifer and its associated natural gas. The project, located in Draskovec, close to the city of Prelog in Croatia, will generate 3.1 MWe from geothermal hot brine using an Organic Rankine Cycle (ORC). The second project is GEOSTRAS, a French- German cross-border project that aims to produce electricity and heat from a high temperature geothermal resource near Strasbourg. It involves creating a circulation loop several kilometres long at a depth of between 4 km and 5 km that will function as a semi-open underground heat exchanger. The proposed geothermal plant is expected to produce 6.7 MWe electricity and 34.7 MWth heat. In the context of the European Energy Research Alliance (EERA), a main Joint Programme on Geothermal Energy (JPGE) 1 has been defined involving a total of 420 people who have been assigned different roles and responsibilities. The research infrastructures are shared among the participants and the comprehensive budget is about EUR 30 million per year. The main objectives of the EERA concern increasing the contribution by geothermal energy to global power production. The research programme aims to: prepare EGS for large-scale deployment; enhance the production from current operational plants; explore on a large scale new, untapped deep-seated (up to 6 km) hydrothermal systems; access high potential resources such as supercritical fluids and magmatic systems. Beside the technological challenges, other relevant aspects for the further development 1 For further information see:

13 Overcoming Research Challenges for Geothermal Energy 11 of geothermal energy need to be addressed with innovative approaches and tools to: improve risk assessment and management for a reliable evaluation of the technical, environmental and economic sustainability of the projects; secure the social acceptance of geothermal projects by ensuring that potential site and technology-specific side effects are typically relatively minor compared to the benefits; provide guidelines for the regulatory authorities and policy-makers for the sustainable development of geothermal initiatives. The JPGE will be developed over 10 years and is divided into five sub-programmes: Resource assessment Exploration Accessing and engineering of the reservoir Process engineering and design of power systems Sustainability, environment and regulatory framework Geothermal energy in the EU Member States National strategies for geothermal energy in the EU Member States have a significant impact on geothermal technology development because critical issues for technological improvement and applications are being addressed. The cases of France, Germany, Italy and Spain have been highlighted because these countries are very active in this field, as shown in Fig. 1 above. France The National Committee for geothermal energy was established in 2010 with the task of promoting the development of this important renewable energy source, upon which the country has been focusing in recent years. The committee in question is composed of 35 experts who have already started working on three guidelines: the simplification of bureaucracy and regulations regarding the facilities, staff training, and information for the general public. Geothermal plant in Tuscany. istockphoto

14 12 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e So many projects have already been completed in the country over the last 40 years and the French objectives for geothermal energy development in the medium term appear to be even more ambitious: by 2020, the production of geothermal energy will have increased sixfold. Substantial investment has also been made available for the creation of a network of geothermal power plants of the last generation, amounting to EUR 20 billion. To date, France represents the third country per total capacity installed in the EU, both for electricity generation (17 MW) and direct heat use (365 GWth) from geothermal sources. The country has two high-temperature geothermal plants, both in the overseas territories where the highest geothermal energy potential is to be found. In the coming years, the total capacity at the Bouillante and Guadalupe plants is expected to reach 20 MW. In the low-and medium-energy sectors, there are about 50 plants in France which are mainly used for district heating. In particular, in the Paris area there are 36 geothermal doublets that are directly connected to heating networks (IEA-GIA, 2012). In 2011, a strategic geothermal roadmap was published by the ADEME (the French Agency for Environment and Energy). It describes the challenges and issues in the geothermal sector, gives a vision for 2020, and identifies the technical and scientific barriers to defining R&D priorities and the need for demonstration operations. Progress varies considerably among the various geothermal uses: Electricity: many projects are emerging on the mainland (combined heat and power), but fewer are planned for the overseas regions, due to a less-favourable framework (notably, the feed-in tariff); Direct use: a few installations are built each year in the Paris Basin, which is encouraging but not sufficient. To reach the objective, the number of installations in the Paris Basin must be increased and other projects must be launched in a variety of aquifers and geological contexts; Ground-source heat pumps: the installed capacity is growing very slowly, so the pace must increase to reach the target. Germany In Germany, according to AGEE-Stat (the Ministry of Environment working group on renewable statistics), net installed geothermal capacity increased by 4 MW in 2012 via the new Insheim plant. The country now has seven geothermal cogeneration plants and the geothermal electric output is reaching 35 GWh (Agemar et al., 2014). Two more plants were commissioned in 2013 at Durrnhaar (5.5 MW) and Kirchstockach (5.5 MW), both in Bavaria. Germany intends to significantly increase its geothermal electrical capacity by an attractive feed-in tariff of 0.25/kWh over 20 years. The country plans to develop geothermal resources of about 280 MW by 2020, compared to 12 MW currently installed. To date, there are about ten projects under construction in Germany with a capacity of more than 36 MW, and even more at the development stage. From 2003 to 2013, the annual production of geothermal district heating stations increased from 60 GWh to 530 GWh. During the same time, the annual power production increased from 0 GWh to 36 GWh. Currently, almost 200 geothermal facilities are either in operation or under construction in Germany. Italy It is well known that Italy is rich in geothermal energy, and since the beginning of the last century it has exploited this source to produce

15 Overcoming Research Challenges for Geothermal Energy 13 electricity using large plants. In addition, Italy is one of the countries with great technological know-how in this field. The historical and important applications of geothermal energy are located in Tuscany. Over 30 manufacturing plants, with an installed capacity of 875 MW, an output energy of more than GWh per year, and about of direct and indirect jobs, represent about a quarter of the electricity consumed in the region itself, and nearly 2 % of the national supply. All activities aimed at growing geothermal electricity production are made by the national electric company Enel. Geothermal energy has great potential for development and may allow the country to reach the target of 25 % of energy produced from clean sources more easily. At present, geothermal energy supplies 10 % of electrical energy from renewable sources and with the new legislative tools is expected to double within a short time (UGI, 2011). In the Italian legal system, geothermal energy does not belong to the landowner but is the exclusive heritage of the state, like mineral resources. Consequently, geothermal exploitation requires a public concession. With the launch of the legislative Decree No. 22 of 11 February 2010, the rules for obtaining the necessary permits for the implementation of geothermal resources development projects for energy purposes, in particular, have been simplified. In this legislative decree, particular emphasis was placed on the production of geothermal energy for non-electric uses and introduced a special and innovative discipline related to geothermal heat pumps. Such technology, with or without the extraction of water from the shallow subsoil, can be exploited in areas not characterised by high geothermal gradients. Spain Cercs thermal plant chimney. istockphoto

16 14 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e The applications of geothermal energy used by private citizens heating and cooling of buildings, greenhouses and sports facilities are regulated by simplified forms of authorisation comprising incentives provided for renewable energy and energy efficiency. In this way, it should be possible to stimulate the use of geothermal technologies and, thus, development of the geothermal industry. As far as RD&D is concerned, an important project for geothermal energy exploitation the Campi Flegrei Deep Drilling Project has been launched in the suburban area close to Naples. This area is characterised by temperatures of about 150 C at some hundred metres and has huge potential for heat supply and electricity production. Spain The estimated geothermal potential for electricity production (conventional and new EGS) is close to MWe. There has been an increasing trend in renewable energies in Spain over the last decade. In 2013, primary energy consumption of renewable energy reached 17 million toe (14.2 % of the total energy mix) and 7.5 % higher than the previous year (IDAE, 2013). This trend has been seen as an example of successful policies to promote renewables energies. In 2013, the electricity generated from renewable sources accounted for 33.5 % of gross electricity consumption in Spain (Eurostat database). Despite the importance of Spanish geothermal resources, the importance of geothermal energy is low, notwithstanding the very large number of studies and investigations conducted up until the end of the 1980s. However, recently, there has been renewed interest in geothermal exploitation. Currently in Spain there are no high-enthalpy geothermal plants for electricity generation, although there is a large and growing interest in developing such projects in the short to medium term. Therefore, for deep geothermal energy the technological challenge is to find ways of using existing geothermal resources in a technically and economically viable manner, which is only possible via the technological development of new drilling methods for reducing costs and stimulating wells. At the end of 2012, the installed capacity of shallow geothermal energy was 50 MWth (EGEC, 2013). Spain s target for geothermal heat use, in the decade from , has been fixed at 50 ktoes, to be achieved by using direct thermal applications and heat pumps. Studies on geothermal district heating development are ready to begin, and there are several projects for district heating networks in Madrid, Burgos and Barcelona, for example. However, some of these projects are at the initial geothermal exploration phase. Geothermal strategies in non-eu countries Over the next few years, global growth is expected in geothermal energy, according to the most recent report by the Geothermal Energy Association (GEA) on the global geothermal market, which estimates the current installed geothermal capacity worldwide at MW. According to the Renewable Energy Policy Network s Renewables 2013 Global Status Report, the United States is leading the installed generating capacity in the world with MW, followed by the Philippines (1 900 MW), Indonesia (1 300 MW), Mexico (1 000 MW), Italy (900 MW), New Zealand (800 MW), Iceland (700 MW) and Japan (500 MW).

17 Overcoming Research Challenges for Geothermal Energy 15 It is important to point out the increase from 30 to 64 in the number of countries which are showing an interest in the development and applications of geothermal energy. This increase depends on several factors which are mainly related to the discovery of new resources, technological improvements in exploration and the ability to exploit resources in the medium- and low-enthalpy range at greater depths, together with the opening up of new prospects and markets besides the traditional ones. In the near future, the United States will be the country making the greatest effort in this field, followed by certain countries in the Pacific area, such as Indonesia which, considering its huge theoretical geothermal potential of MW, aims to produce more than MW of geothermal power by 2025, thereby becoming the world s leading geothermal energy producer. Recently, China has expressed a great interest in geothermal energy with the aim of using this resource to cover 1.7 % of primary energy demand by 2015, as reported by the Ministry of Land and Resources. The goal is to replace the use of 68.8 million tonnes of coal and reduce 180 million tonnes of carbon dioxide emissions. In the field of spa tourism, this resource is already widely used in some regions, especially in the province of Chongqing (south-west China), where there are 107 thermal sites. Currently in China, geothermal explorations are under way in 29 provinces, with public funding for research activities alone in 2011 reaching 164 million yuan (EUR 17 million). The objective is to provide systems for the production of electricity across the country In Canada, the largest conventional resources for geothermal power are located in British Columbia, Yukon and Alberta, regions which also have the potential for EGS exploitation. In 2007, it was estimated that geothermal energy could meet half of British Columbia s electricity needs. Canada officially reports about earth-heat installations providing space heating to residential and commercial buildings. The most advanced project Cogeneration in China. istockphoto

18 16 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e In Switzerland, 22 deep geothermal projects are currently at the planning stage, their main objective being to produce electricity. Nevertheless, in July of 2013, earthquakes of magnitude 3.5 in Basel and St Gallen, produced by an unexpected encounter of gas at a depth of 4450 m, have significantly reduced the population s confidence in EGS geothermal plant development. Geothermal plant in California. istockphoto exists as a test geothermal electrical site in the Meager Mountain-Pebble Creek area of British Columbia, where a MW facility could be developed. An important contribution could also come from South American countries, where there is large geothermal potential along the Andean Ridge and on the Central Pacific side. Ecuador has announced feasibility studies to analyse the country s geothermal potential. The government has announced five projects that will exploit geothermal energy the total potential has been estimated at > 500MW the aim being to increase the percentage of energy from alternative sources. Pre-feasibility studies to the value of 1.1 million dollars have been planned in Carchi province where the potential has been estimated at between MW. However, the number of projects remains limited and those that could be accomplished relate mainly to the policies of foreign companies that have been awarded concessions for exploitation. Africa has huge geothermal potential, mostly unexplored, that has attracted the interest of many countries in geothermal resources development. Potential areas are: the Republic of Congo, Eritrea, Ethiopia, Kenya, Madagascar, Malawi, Mozambique, Rwanda, Tanzania, Uganda and Zambia with an estimated potential greater than 15 GW. In Ethiopia, where it is up to 5 GW, the government is aiming to increase the power developed with the help of foreign sponsors such as the World Bank. However, the most promising geothermal area in Africa is in the Rift Valley where Kenya is planning the construction of a number of plants although it is not known when they will become fully operational. In Australia, the government has provided research funding for the development of EGS technology. One of the most important projects in the world is being developed in Australia s Cooper Basin by Geodynamics. The Cooper Basin project has the potential to develop MW. Australia now has 33 firms involved in exploration, drilling and EGS project development. The country s industry has been helped significantly by a national Renewable Portfolio Standard of 25 %, renewable by 2025, a Green Energy Credit market, and supportive collaboration between government, academia and industry.

19 Overcoming Research Challenges for Geothermal Energy 17 Research areas and opportunities The main research areas and applications contributing to geothermal energy development and deployment are: exploring and drilling technologies electricity production heating and cooling desalination environmental impact mitigation and public acceptance. Exploring and drilling technologies The main goal is to greatly improve modelling techniques for assessing the geothermal potential, to reduce drilling costs and the number of boreholes that are very costeffective. For the same reason, in the assessment of geothermal resources, research and exploration synergies with the oil and gas industries should be considered. New drilling technologies should be developed to reduce costs and drilling times. In this context, it is also necessary to improve and develop new 3D models of geothermal reservoirs to reduce drilling and exploitation risks. Drilling typically accounts for % of the total development cost of electricity generation. For example, two boreholes to a depth of m. can cost up to EUR 14 million, while piping costs vary from EUR 200 to EUR million in urban areas. Improving drilling technologies and modelling accuracy to better estimate geothermal potential are crucial steps for assessing the cost and investment time return. Experience suggests that this is the way to greatly improve geothermal energy development. Electricity production Nowadays, there are about MW of geothermal power plant installed capacity in the world and MW of geothermal power under construction. However, these data represent a small fraction when compared to the data for wind energy ( MW) and photovoltaic ( MW). The average annual growth rate for electricity produced from geothermal heat is 5 %, which is much lower than wind and solar electricity (20-30 %). The electricity produced by geothermal heat using new technological approaches such as EGS does not attract significant investments in RD&D from large energy companies in relation to actual electricity surplus in industrialised countries. This overproduction is the consequence of both the economic crisis and the concomitant expansion of solar and wind energy, which are the most convenient clean energies requiring only a short time for implementation. In addition, EGS power plant is still in the prototype stage and a further step

20 18 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e towards large-scale demonstration plant is crucial, as is the reduction of costs and time for geothermal power plant construction. Compared to other technologies in Europe, asset financing for geothermal energy is quite low: EUR 124 million for a new capacity of 34 MW. Furthermore, scaling and corrosion represent one of the most important challenges facing deep geothermal exploitation. RD&D activities are required in new materials and operational methods, bearing in mind the significant impact of scaling and corrosion on the cost and efficiency of geothermal technology. The development of new components from polymers or plastics, optimised coating, the use of aluminium, and new materials to tackle deterioration resulting from UV exposure should all be taken into account. It is also important to remember that startup costs are relatively high: an average geothermal plant costs EUR per kilowatt (kw) installed versus EUR per kw installed for a natural gas plant. A conventional 20 MWe high-temperature plant costs EUR million and a 5 MW EGS plant costs EUR million. The most important RD&D project on EGS to be launched by the EU was carried out at Soultz-Sous-Forêts in France where it has recently connected its 1.5 MW demonstration plant to the grid. The surface geothermal Table 3: Main EGS research projects in the world Project Country MW Plant Type Depth (km) Soultz France 1.5 ORC 5.0 Landau Germany 3.0 ORC 3.0 Insheim Germany 4.8 ORC 3.6 Unterhaching Germany 3.0 Kalina 3.5 Desert Peak U.S.A 1.7 Binary 4.0 Paralana Australia 3.8 Binary 4.0 Cooper Basin Australia 25.0 Kalina 4.0 Hijiori Japan 0.13 Binary 1.1 Redruth U. K Binary 4.5 Eden U.K. 4.0 Binary 3/4 Source: Data collected from the Geothermal Energy Journal and other sources

21 Overcoming Research Challenges for Geothermal Energy 19 energy installations in this pilot scientific project, which started 20 years ago, have been supplying power to the grid continuously for a year, following the introduction of the new feed-in tariff in July The Soultz project has explored the connection of multiple stimulated zones and the performance of triplet-well configurations (one injector/two producers). This pilot project, which draws on heat sources (up to 200 ºC) from to m deep, operates on a binary cycle principle ORC (Organic Rankine Cycle). The hot fluid arriving at the wellhead circulates in a closed loop and passes through a heat exchanger which transfers heat to an organic fluid with a lower boiling point which allows it to drive a turbine. Having contributed to scientific work on well stimulation with a view to developing the site, in parallel with its operations related to the European Economic Interest Group (EEIG) on Heat Mining, the BRGM (Bureau de Recherches Géologiques et Minières), financed by ADEME, is now working on the sustainability of the operation. The aim is to identify the circulation routes between the wells (by improving tracer tests and circulation modelling) and to understand how they evolve during operations. Recently, in the field of low and middle enthalpy, a new application called the Green Machine has been developed to produce electricity. This machine exploits the ORC technology and is able to produce energy by heat sources at low temperatures, mainly between 77 C and 116 C. The mini and micro sizes in which ORC technology is provided by the Green Machine allow flow rates to be converted at low temperatures in renewable electricity with zero CO 2 emissions in a range of nominal electric power from 20 to 110 kwe. It requires little space, thanks to its very compact dimensions and different options for installation. To summarise, the Green Machine is an apparatus with a versatile technology which is mainly devoted to the exploitation of low-temperature geothermal systems 2. Geothermal power station in Iceland. istockphoto 2 See

22 20 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e Heating and cooling In Europe, the geothermal heating sector is led by Germany and Sweden, although in Austria, Finland and France the installed capacity of geothermal heat pumps is considerable. Residential and commercial heating may be a more profitable option both in timing and costs with respect to the generation of electricity because these technologies are already competitive from the commercial standpoint. Within this sector there are no large research projects but mainly a minor upgrading of current technologies. According to the industry association (European Heat Pump Association EHPA), the total number of geothermal heat pumps installed in Europe from 1998 to 2012 was about 1 million units. There are two options in the heating sector: heating through deep wells with a distribution network for neighbourhoods (centralised heating with direct uses, also known as district heating), and heating/cooling through geothermal heat pumps for single buildings or residential centres. Centralised heating exploits the deep wells to extract hot water which is then distributed to the neighbourhoods via a district heating network. The most interesting examples are found in Ferrara, Oradea (Romania), Paris and Reykjavík. This type of geothermal application presents some technical and social problems because it requires the involvement of local authorities which should provide the necessary authorisation. Delays may be caused because the building of the district heating network and infrastructure is a complex task that can create considerable inconvenience for the resident population. District heating in Vienna. istockphoto

23 Overcoming Research Challenges for Geothermal Energy 21 Residential heating may be more easily achieved by small enterprises, especially when new buildings are planned and geothermal probes can be associated with the foundations. The best technologies are those that exchange the heat through a liquid in a closed circuit. This approach avoids direct liquid interaction with the groundwater, thereby greatly reducing the environmental impact. It can also be applied to old buildings which have to be restructured. In this case, fan coil heat pumps could be more convenient. To promote the development of residential geothermal heating without water exchange, it is essential that the geothermal installations do not require any permission. In fact, restrictions like those required for well drillings could be an obstacle to the growth of this technology which works as a closed loop system and does not involve water exchange. Financial incentives should be considered for new buildings to improve the use of this technology. Financial incentives to improve geothermal technology applications for the residential sector could drive demand and thus growth of the production sector related to these technologies. To date, it could be possible to set in motion an innovative mechanism that would push producers to achieve increasingly efficient technologies at a lower cost to meet the growing demand. To support such a mechanism it might be very useful to implement a special industrial incentive law which allows the buyer to pay for the new technologies in instalments at a subsidised interest rate and enables the seller to receive all the payments immediately from the authorised bank. In other words, it is crucial to establish a connection among producers, buyers, government and banks with the aim of setting in motion a virtuous interaction that can stimulate a large diffusion and innovation processes in residential geothermal technologies. Desalination Seawater desalination by geothermal heat plants represents a new and interesting perspective to enable volcanic islands to achieve greater energy independence. In Europe, most of the Mediterranean islands can be identified as volcanic islands with high geothermal gradient A successful demonstration of the application of geothermal to desalination was provided by the European Commission research project THERMIE.GE HE, known as the Kimolos project. The pilot project ( ) used a low-enthalpy geothermal energy source with the aim of verifying the technical feasibility of seawater desalination. The Multi-stage distillation process (MED) was selected for this project because it needs less energy compared to other technologies, requires working temperatures of <70 C and low vessel pressure. In addition, the feed water forms a thin film layer that reduces the formation of scaling. The water produced is of good quality as testified by the result- Desalination at Trapani in Sicily. istockphoto

24 22 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e ing salinity which is less than 10 ppm. This technology is also energy efficient because the heat released by condensing vapour is utilised to boil feed water, too. Compared to Multi-stage-flash distillation (MSF), it is a cost-saving technology which produces fresh water and requires fewer stages. It would appear that the potential of lowenthalpy geothermal energy for desalination via MED is significant and many countries are now showing interest in this technological option. Among others, Middle Eastern countries, Algeria, Australia and Mexico have considered the possibility of exploiting lowenthalpy geothermal energy for desalination even if this process has yet to be developed significantly on a commercial scale and technical design problems and high investment costs have still to be overcome. Environmental impact mitigation and public acceptance Although geothermal energy is regarded as a source of energy with a low level of polluting emissions compared to traditional energy sources, geothermal fluids, especially those at medium and high temperature, contain some potentially toxic elements such as mercury (Hg), arsenic (As) and gases such as hydrogen sulphide (H 2 S), which could prove hazardous to the environment. For these reasons it is necessary to put greater effort into developing new technologies and systems to remove the solid residues and condensable gases associated with geothermal fluids. In relation to EGS, it is also important to consider the seismic activity induced by this technology. The critical issue is to obtain the acceptance of the general public. Earthquakes triggered by rocks fracturing should be reduced as much as possible, and experience shows that public acceptance can only be achieved if the population is involved in all stages of the procedure. For example, in St Gallen, Switzerland, the government has given advanced warning and informed the public about the possible risks linked to the construction of an EGS plant. Following a low-intensity earthquake related to the application of EGS technology, the authorities compensated residents for any damage and, following a discussion with the public, secured the authorisation to proceed with geothermal exploitation. To summarise, gas emissions and micro-seismicity are factors that reduce public confidence towards geothermal development. So, it remains worthwhile to fully assess the social and environmental impact of the activities, to develop new tools for analysis, and to inform the population in order to achieve greater public acceptance.

25 Overcoming Research Challenges for Geothermal Energy 23 Looking to the future The most recent SET-Plan integrated roadmap 3 pays special attention to the Smart Cities Initiative which aims to improve energy efficiency and to deploy renewable energy in large cities above and beyond the levels envisaged in the EU s energy and climate change policy. This initiative will support cities and regions in taking ambitious and pioneering measures to progress by 2020 towards a 40 % reduction in greenhouse gas emissions through the sustainable use and production of energy. Geothermal heat exploitation may provide an important contribution to the Smart Cities Initiative. In the geothermal heat-pump sector, the RD&D priorities are to maximise efficiency (coefficient of performance COP, and seasonal performance factor SPF) and reduce costs. The focus is on developing components that are easy to connect and disconnect from the surface, as well as advanced control systems, natural and more efficient working fluids, single-split and multi-split heat-pump solutions for moderate climate zones, and the increased efficiency of auxiliaries, such as pumps and fans. The key component areas are heat exchangers, compressors, fans and pumps, expansion valves, defrosting strate- Iceland s geothermal plant in the Krafla volcanic region. istockphoto 3

26 24 E n e r g y R e s e a r c h K n o w l e d g e C e n t r e gies, and new materials. In order to reach maximum efficiency, these advanced components should be perfectly designed into one system and controlled and operated by smart systems, including automatic fault detection and diagnostic tools, too. For relevant growth in RD&D investment for new geothermal technologies for electricity production (EGS) it will be essential to adopt effective policies to stimulate innovation and experimentation by launching new demonstration projects. This implies a qualitative leap in government and banking systems as well as the involvement of large corporations which should play an active role in the network of universities and public research centres. The main efforts should focus on lowering the cost of exploration and drilling, reducing the time and costs involved in power plant constructions, optimising efficiency, and increasing the longevity of installations. Scaling and corrosion represent one of the most important challenges facing deep geothermal exploitation. RD&D activities are required for new materials and operational methods, bearing in mind the significant impact of scaling and corrosion on the cost and efficiency of geothermal technology. The development of new components from polymers or plastics, optimised coating, the utilisation of aluminium, and new materials to tackle deterioration resulting from UV exposure should all be taken into account. Since deep geothermal fluids contain some potentially toxic elements, such as Hg, As and gases like H 2 S, which could damage the environment, it is necessary to carry out further and advanced research to develop new technologies and systems able to remove the solid residues and condensable gases associated with geothermal steam. Future research programmes will increasingly focus on offshore and magmatic geothermal energy exploitation. In fact, most of the areas with the highest geothermal potential are located at sea where geological frameworks characterised by high geothermal gradients (> 100 C/km) are diffused. In particular, supercritical fluids are present in the deep ocean surface in sub-marine volcanic areas. The main research challenge in this field is to develop technologies to exploit these supercritical fluids at high temperatures in deep marine environments in order to exploit the enormous geothermal sub-marine reservoirs. In this respect, the first offshore geothermal project has been proposed in Italy to exploit the heat produced by the sub-marine volcano Marsili, located in the southern Tyrrhenian Sea, close to the Aeolian Islands volcanic arc. The project has been developed by a private company, Eurobuilding, in collaboration with certain Italian public research centres and universities. In 2009, the Marsili project received the approval of the Italian Ministry of Economic Development. The Marsili volcano is the largest volcanic structure in Europe and releases fluids at high temperatures, around 300 C. When fully operational, the plant will produce 4.4 billion kwh per year 4. In Iceland a country where approximately 87 % of the houses are heated using geothermal energy and 27 % of the electricity comes from this energy source a project is being carried out which aims to produce 4 For further information see: energetica/2011_10_28-eurobuilding.pdf