Energy & Climate Change Consulting
Global Experiences with Geothermal Energy
This page provides a summary of experiences in developing geothermal energy systems in different parts of the world [1]. It provides important lessons for developing policy and law in Uganda. It is organised as follows:
[1]The information outlined is a snapshot of a more detailed paper prepared for the project. Please contact us for more information.
1. Experiences with Geothermal Energy Around the World
Presently geothermal power generation is carried out in 28 countries around the world, mainly focussed around the Pacific Rim “Ring of Fire”, with over 12,500 MW of installed power generation capacity, albeit on a small-scale in many countries. The top five countries using geothermal power today are the USA (3,354 MWe), Philippines (1,875 MWe), Indonesia (1,342 MWe), New Zealand (1,189 MWe) and Mexico (1,062 MWe). The fastest growing geothermal energy producers are Kenya (590 MWe) and Turkey (397 MWe). Kenya (5 main plants at Olkaria) and Ethiopia (1 small plant at Alto Laguno) are the only geothermal power generators in Africa. The Andean countries of Chile, Peru and Ecuador are notable for their absence of geothermal power use, as is Japan for its low level of utilisation (Figure 1).
Figure 1. Geothermal power generation capacity worldwide, 1960-2015
Source: Data from IGA Database with authors updates
* C. America = Costa Rica, El Salvador, Nicaragua and Guatemala. ROW = Rest of the World.
Lower temperature direct use is much more widespread, with almost 50,000 MWth installed around the world across more than 70 countries. The main direct uses of geothermal heat are ground source heating (heat pumps) and balneology; experiences with industrial and agricultural applications are generally limited (approx. 3,000 MWth worldwide). New experiences and uses are emerging that may be of direct relevance to Uganda, however. For example, in Kenya, a pilot cascade system was recently launched at the newly-developed Menengai field, involving a diary (heat used for milk pasteurisation), then a laundry followed by a fish farm and, finally, to maintain night time temperatures in a greenhouse growing tomatoes (see here).
1.1 Historical trends and drivers for development
The history and drivers for development of geothermal energy tend to differ across different parts of the world. Interest in has tended to fluctuate according to global trends in oil prices, with significant progress linked to both the 1973 and 1979 oil crises, and lower rates of development during times of cheaper oil (mid-90's to mid-00's).
Motivations for public expenditure on geothermal development historically include over-reliance on uncertain or increasingly scarce hydropower resources (e.g. New Zealand, Ethiopia, Kenya, Central America) and in some cases the clear quality of the geothermal resources and its cost competitiveness with other sources of power generation (e.g. El Salvador, Costa Rica). In other cases development has been locally important for power generation (e.g. Mexico, Philippines, Indonesia, Turkey) and/or linked to exploration programmes for other resources (minerals; hydrocarbons). Developers include both national (parastatal) power utilities – typically with support of national minerals agencies – and national oil companies – typically in countries with active oil and gas industries.
More recently, concerns over climate change, the volatility of commodity prices, the need to address energy security and the desire to support economic development through improved provision of clean, reliable and affordable base-load electricity means that geothermal resource development is high on the political agenda for many countries where potential exists. Interest is emerging across East Africa, facilitated by a wide range of donor initiatives, Turkey, where the European Investment Bank is supporting a large programme for geothermal development, and across South East Asia, where renewed political efforts to incentivise private sector developers have emerged recently.
What is common to most jurisdictions, however, is that the public sector has been the primary developer for at least the first-of-a-kind geothermal power plant in the country (Figure 2). This is largely a consequence of the costs and risks involved in resource development, as discussed further below.
Figure 2. First-of-a-kind Geothermal Plants around the World (green = public led; red = private-led)
Source: Carbon Counts analysis compiled from various soruces
2. Costs
2.1 Cost estimates for geothermal power projects
Typical costs for geothermal power plant development are cited in the range of US$3-5 million per MW installed (Table 1). This would result in full overnight capital cost of a 30 MW geothermal plant in the region of US$90-150 million. The figures in Table 1 also show the variability between different technologies, with binary plant generally being more expensive than flash plants.
Table 1. Cost estimates for geothermal power generation
There is also fairly wide variation in the estimated levelised cost of electricity (LCOE) in the literature, ranging US¢5/kWh to US¢15/kWh generated. The range in the LCOE reflects a number of variables including capital costs, O&M costs, plant capacity factor and weighted average cost of capital (and discount rate i.e. financing costs). In general, however, the range of LCOEs suggest that geothermal power can be competitive with different power generation sources at the lower end of the range. The higher LCOEs may be reflective of poorer geothermal resources in the areas being developed and/or the financing costs. At the upper end, geothermal energy starts to look quite expensive compared to sources such as hydropower or thermal (combined cycle natural gas) plant, and, from a private developer’s perspective operating in a competitive market, would face challenges to be dispatched to the power grid without an off-take obligation such as might be gained through a REFiT.
Once proven and up and running, the costs for geothermal power are low because fuel is in theory free. The more challenging element is upfront development costs, which can make up 15-20% of overall project costs. The risks involved also mean that financing is difficult and expensive. The main factors affecting project development costs are:
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Resource identification and development costs – this is the primary challenge for geothermal energy (see here). Surface studies and shallow slim-hole drilling can only go so far in confirming the existence of a heat source and hydrothermal system, but test drilling of deep, usually full-size, wells is necessary to confirm or otherwise its presence and quality. This is an expensive undertaking (Figure 3), and these costs are fairly fixed at a minimum level irrespective of whether a viable resource is found or its size;
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First-of-its-kind premium – for frontier geothermal provinces, additional one-off costs associated with early-phase developments of greenfield sites will be incurred, as can be seen for some of the new developments in Kenya.
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Risks and financing costs – even with the best surface studies, drilling is an expensive and risky prospect. Because of the risks involved, the financing of steamfield development can be a challenge and expensive. Further, an additional risk premium will apply to the financing of greenfield sites, further affecting access to, and cost of, capital i.e. financing costs.
Therefore, although geothermal energy can offer a cost competitive source of base-load power generation, its development is not without significant challenges that affect the costs of development. These issues are discussed further below.
2.2 Costs of resource identification and development
In terms of resource identification, the types of geological survey methods are outlined in the Technology section. Because of the costs and risks involved, the biggest challenge is moving from Phase 2 (Survey) to Phase 3 (Exploration drilling). However, this stage is essential to understand the nature of the resource and consider whether and how it could be economically developed. This relationship between risk and costs is shown schematically below (Figure 3).
The typical costs involved in each stage of geothermal power plant development are outlined below (Figure 3).
Figure 3. Risks and costs for geothermal power development (indicative costs for a 50 MW power plant)
Source: Gehringer and Loksha, 2012
3. Risk and Financing for Geothermal Energy
The risk of geothermal development failure is fairly high. As highlighted previously, test drilling is needed to confirm the presence of a viable resource or otherwise, and if no viable resources is found, US$10’s of millions will be lost. These risks are augmented in the development of greenfield prospects, and in particular in frontier provinces such as the Western Branch of the EARS system as in Uganda, where no geothermal energy developments have yet materialised.
Empirical evidence suggests that the probability of drilling a successful well in a greenfield geothermal prospect is between one in three (ESMAP, 2012; 33%) to one in two (or 50%, as cited by IFC, 2013). The evidence also shows that the likelihood of drilling a successful well increases significantly for the second, third, fourth and fifth well, where it rises to almost 60%. The average can rise to almost 75% (3 in 4) during the development phase, and 83% for incremental drilling in operational fields (IFC, 2013). As a consequence, the risks of exploration are inversely proportional to the costs, or in other words, spending more money on drilling can reduce risks.
Since development costs (Phase 1-3) could be in the range US$12-40 million for a 50 MW power plant (Figure 3), there is a need to spend a lot of money upfront against an unknown prospect of returns, if at all. Whilst this risk-reward proposition may be tolerated in the oil and gas industry, where significant returns can be realised swiftly on developing a successful field, the case for geothermal energy is much more marginal since the return is usually incremental due to the need to manage the resource (see here), and longer-term as dictated by the price available for electricity in the power market, often with regulated tariffs. This creates a significant challenge for project finance, and especially the involvement of private capital. Hence, nearly all geothermal development around the world have relied on public sector investment, at least in initial stages (Figure 2).
3.1 Structuring geothermal project development
Notwithstanding the financing challenge, these problems are clearly not insurmountable since over 12 GW of plant have been built globally over the past 100 years or so (as highlighted above), and several models – up to eight according to Gehringher and Loksha (2012) – have emerged around the world to accommodate the unique characteristics and risks associated with geothermal investment (see Figure 4). This covers a full spectrum between the extremes of:
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Vertically integrated, fully private sector financed
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Vertically integrated, fully public sector financed
The range of approaches are shown graphically below (Figure 4). The figure shows that there are a range of alternatives models that divide responsibility for development of different phases of the geothermal energy chain between public and private sector actors. In some cases projects maybe fully public sector led by a single integrated entity, or with multiple public entities, or with some parts of the chain – usually the most risky parts of steamfield exploration and development – being undertaken by public entities, with private entities stepping in once the steam resource is proven. In other cases, the risk of steamfield development is either born by the private sector developer in its entirety, or through various joint approaches between public and private sector. The latter most typically can happen in an established (brownfield) geothermal province where the reliability of the resource and enabling policy environment has been proven.
Figure 4. Models for Geothermal Project Development
Source: Carbon Counts, based on Gehringer and Loksha, 2012 and Musembi, 2015
3.2 Issues for Private Sector-led Development
In the case of private sector led development, the costs and risks involved in steamfield identification and development are a major deterrent to investment. As such, it relies on an IPP company or individual investor with a high risk appetite taking on an equity investment since commercial banks are unlikely to provide loans for such high risk prospects. This means the cost of capital will be very high (>25%), severely affecting overall project financing costs. This can make the LCOE untenable, meaning a fully-private financed project will struggle to go ahead, suggesting that public-private partnership models is the only realistic means of engaging private finance in greenfield development.
Even then, additional policy measures and incentives such as capital subsidies, risk mitigation funds (e.g. drilling insurance – see also below for international support mechanisms)[1] and fiscal measures (e.g. tax breaks and reliefs) must be introduced by government to successfully incentivise private investors to take on the full investment risk. Such approaches generally tend to work only in mature geothermal provinces with a proven track-record in successful project development, and more typically for brownfield development opportunities. Even in these cases, complex deal structures reliant on risk guarantees are usually necessary, as for example, at the 330 MW Sarulla project under development in Indonesia (Figure 5).
[1] For example, the Icelandic National Energy Fund is a government resource for geothermal developers that reimburses up to 80% of the actual costs for unsuccessful drillings (although all developments have been by public utilities). Similar approaches are also reported for Japan.
Figure 5. Sarulla Project Structure
Source: PFI, 2014. Note: PGE = Pertamina Geothermal Energy. PLN = State Electric Co.
A fully private-sector led approach is broadly applied in the Philippines, Ethiopia, Indonesia, Honduras, Guatemala, Nicaragua, Chile, Italy, and Australia today. Uganda can also be included in this group. Neither Chile, Honduras nor Uganda has any active geothermal power plants, whilst in other jurisdictions, successful projects have tended to be repowering and "brownfield" step-out developments rather new greenfield projects. Examples of recent geothermal private sector led geothermal power project developments in some of the countries mentioned is outlined below (Figure 6).
Figure 6. Recent Private-sector led Geothermal Development Projects
Source: Carbon Counts, compiled from a wide number of sources
The nature of the challenge was was summed up rather succinctly by Micale et. al. (2014) who - based on a review of a large number of geothermal power plant developments - concluded that:
“There is little appetite from the private sector to fund projects where the nature and extent of the resource are unknown. The private sector only financed all stages of the project in 7.5% of the utility-scale projects in our database. 58.5% of projects had the costs entirely borne by the public sector, while 34% projects had the private sector bear costs at later stages in the development chain once the resource had been proved.” and that: “private financiers are not willing to provide financing until all or at least 70% of the MW capacity has been drilled”.
These experiences show that expectations must be realistic in considering the role that the private sector can take in developing geothermal power projects, especially in greenfield locations. This must therefore be reflected in any geothermal energy policy if it is to be effective in kick-starting an the industry and accelerating deployment.
4. Policy and Legal Frameworks
4.1 Policies for Geothermal Resources
The main objective of any geothermal energy policy is to define the objectives and ambitions of government in pursuing the technology, and the structure, approaches, legal, regulatory, institutional arrangements and financing and incentives options it wishes to adopt in achieving the objectives in its territory. In many cases, these ambitions will be encompassed into broader energy or renewable energy policies and objectives. It can also involve the development of a Geothermal Resources Master Plan or Roadmap to help dictate the future direction of geothermal resource development.
The range of the different approaches for geothermal energy development being adopted around the world were highlighted previously. This suggests that – at least in initial stages – geothermal developments have tended to be publicly-led, but also that policies tend towards being evolutionary; changing towards more mixed approaches over time as experience and confidence in the technology is gained, and the opportunities for step-out expansion and brownfield development arise. This can be seen in Kenya, Indonesia, and the Philippines.[1] It is also apparent that two broad categories of drivers have served to promote differing policies towards geothermal development:
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Necessity. In some situations, such as in New Zealand, Kenya, and Central America, a lack of other obvious sources of energy, and in particular an over-reliance on variable hydro-power, have given rise to the importance of geothermal energy for baseload generation, leading to significant government efforts to get the industry off-the-ground;
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Opportunity. In other situations the quality of the resource has tended to be manifest (e.g. some Central American countries, Mexico, Italy) and information and data on geothermal resources has been acquired as a co-benefit from other activities such as oil and gas exploration (e.g. in Philippines and Indonesia, where geothermal resource development has mainly been led by national and international oil companies). In these situations, geothermal energy has also emerged in response to the clear opportunity presented.[2]
In reality, it is often a mixture of the two, but it useful to be mindful of whether clear drivers exist for embarking on what can be a long, complex and potentially capital intensive endeavor in comparison with other types of power generation technologies.
Consequently, the choice of policy approach for geothermal energy requires some measured consideration in terms of the urgency of development, driven in turn by resource quality, cost, security and environmental issues. This will be central in dictating the pace of development between on the one hand, government taking a proactive role and investing heavily at significant cost to public finances, or on the other, taking a more passive role and relying on organic evolution of the technology by the private sector.
[1] In the Philippines the major sector reforms introduced in the 2008 Renewable Energy (RA9513) built upon almost 30 years of geothermal operating experience in the country
[2] Some anomalies to this model exist however. For example, Japan has the opportunity and the necessity to develop geothermal power but has failed to develop much of the country’s significant capacity, even in the wake of the post-Tsunami, post-Fukushima nuclear disaster. This is mainly due to land-use concerns.
4.2 Legal Frameworks for Geothermal Resources
Many countries around the world have established dedicated geothermal energy laws and regulations to facilitate its development (Figure 7). It is not necessarily essential to develop dedicated geothermal laws, however, and a large number of countries still use a range of other related laws to implement geothermal energy regulation, such as minerals and mining laws. In some countries no specific laws exist, primarily as state-owned enterprises have traditionally led development, waiving the requirement to specifically regulate the activity (e.g. in Costa Rica, although geothermal development in protected areas is prohibited; Mexico, although this changed since the national Energy Reform of 2014; New Zealand repealed its 1953 Geothermal Energy Act in 1991, replacing it with the more holistic Resources Management Act, which vests the management of geothermal resources in regional councils).
Figure 7. Geothermal Laws in place aroudn the World (selected)
Source: Carbon Counts
In most countries around the world, perhaps with the sole exception of the USA, the constitution vests sole ownership of minerals and other subsurface resources in the citizens as represented by the government (Regalian doctrine). On this basis, when considering private sector led development of geothermal resources (including parastatal agencies), laws and regulations are required to pass on the title and tenure rights to private sector developers via concessions, using either mining, water or dedicated geothermal laws. A geothermal legal framework also typically includes provisions for government to declare and define a given area as being available for geothermal resource development (unitisation), and a regulatory regime by which the practical requirements of the laws are set down (licensing procedures, reporting etc.).
A dedicated geothermal law should not necessarily deal with aspects such as water management, construction, land clearance, emissions to air and environmental and social authorisations (e.g. impact assessments). Typically, these are enacted through other existing pieces of legislation which can be conferred onto geothermal activities. Consequently, geothermal projects tend to require multiple permits and authorisations from multiple regulators. As such, a centralised coordination unit within government – such as a dedicated geothermal resources department – is typically necessary to expedite permits processing in a timely and consistent manner. The main elements for a dedicated geothermal resources law are summarised below (Box 1).
Box 1. Typical elements in dedicated geothermal energy laws
The main elements to be included within a dedicated geothermal are, inter alia:
1. To vest powers in the Minster and/or Government department or agency to:
(a) define, delineate and declare areas for geothermal resource exploration and development (optional)
(b) grant licenses (concessions) to both public and private bodies to undertake activities within defined geothermal areas (or otherwise).
2. To confer the rights (as a concession, lease, license etc.) to individuals to:
(a) explore for geothermal resources within a defined area
(b) exploit geothermal resources within a defined area
Rights conferred by a concession should:
(c) include time limits on both exploration and exploitation (to avoid passive speculation)[1]
(d) be independent from surface and land ownership rights
(e) be transferable between exploration and exploitation
(f) allow for the lease of the resource to a steamfield operator
(g)allow for the sale of produced steam or hot brine
(h) include clear terms for renewal, transfer, surrender, forfeiture, withdrawal and/or termination of a license;
(i) clarify the rights or otherwise regarding the extraction of minerals from geothermal fluids;
3. To set down requirements for the concessionaire in terms of:
(a) technical experience and know-how, financial status and good standing of applicant;
(b) describing technical work to be carried out under the licenses, and the costs of such work
(c) construction and operational standards, such as for well bores.
(d) environmental and occupational health and safety obligations;
4. To establish procedures for:
(a) license (exploration and exploitation) applications, evaluation and approval/rejection
(b) reporting and oversight (regulatory) including:
(i) reporting and archiving of geological data obtained during exploration
(ii) requirement for operators to report on operations (exploration and exploitation) to a regulator, and
(iii) the right of government agencies to undertake inspections, collect and archive data and information from operators etc
(c) license fees, payment of any royalties due and the basis for any penalty payments;
(d) remedies and compensation in the event of conflicting interests, damages and access requirements
(e) implementing any secondary legislation such as regulations, guidelines, directives etc.
These are a generalised set of elements, and it is likely that in additional aspects will be needed according to the norms and standards of the jurisdiction to which the laws apply.
[1] Passive speculation involves buying the concessions with a view of onward sale in the event that over time it acquires value through changes in demand for the mineral to which the license pertains. The opposite is active speculation, where a developer seeks to add value to the concession through acquisition of new information that could enhance the value of exploiting the area.
Source: Carbon Counts
5. References and Further Reading
AUC-RGP, 2011. Draft Guidelines for Instituting Harmonised Geothermal Policy, Legislative, Regulatory and Institutional Mechanisms. Report by the Geothermal Exploration, Development and Utilization in the Region of the African Union Commission’s Regional Geothermal Programme (AUC-RGP). Energy Division, Infrastructure and Development Department, UAC. Draft 1, 12/1/2011.
Dickson, M.H. and Fanelli, M., 2004. What is Geothermal Energy? Paper published on the website of the International Geothermal Association (www.geothermal-energy.org)
DiPippo, R., 2008. Geothermal Power Plants: Principles, Applications, Case Studies and Environmental Impact. Second Edition. Elsevier, Oxford/New York.
Dolar, F.M., 2006. Ownership, financing and licensing of geothermal projects in the Philippines. Paper Presented at Workshop for Decision Makers on Geothermal Projects in Central America, organized by UNU-GTP and LaGeo in San Salvador, El Salvador, 26 November to 2 December 2006.
EGS Inc, Downloadable maps & graphics. Available at: http://www.envgeo.com/Publications.html Accessed, April 2016.
ESMAP, 2012. Drilling Down on Geothermal Potential: An Assessment for Central America. Report by the World Bank Energy Unit, Sustainable Development Department Latin America and the Caribbean Region/Energy Sector Management Assistance Programme. Washington D.C. March 2012.
Farias, D.A., 2014. Geothermal Development in Chile. Presented at Short Course VI on Utilization of Low- and Medium-Enthalpy Geothermal Resources and Financial Aspects of Utilization, organized by UNU-GTP and LaGeo, in Santa Tecla, El Salvador, March 23-29, 2014
Fronda, A.D., Marasigan, M.C., and Lazaro, V.S., 2015. Geothermal Development in the Philippines: The Country Update. Proceedings World Geothermal Congress 2015, Melbourne, Australia, 19-25 April 2015
Gehringer, M. and Loksha, V. 2012. Geothermal Handbook: Planning and Financing Power Generation. Energy Sector Management Assistance Programme (ESMAP). Technical Report 002/2012. Washington D.C. June 2012.
Goldstein, B., G. Hiriart, R. Bertani, C. Bromley, L. Gutiérrez‐Negrín, E. Huenges, H. Muraoka, A. Ragnarsson, J. Tester, V. Zui, 2011: Geothermal Energy. In IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation [O. Edenhofer, R. Pichs‐Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Hodgson, S.F. Focus on Chile. Geothermal Resources Council Bulletin, Vol. 42 (1), Janary/February 2013.
IEA, 2010. Renewable Energy Essentials: Geothermal. Fact sheet produced by the International Energy Agency, Paris.
IFC, 2013. Success of Geothermal Wells: A global study. International Finance Corporation with input from GeothermEx Inc. Washington DC, June 2012.
IGA, 2014. Geothermal Energy Database. Maintained by the International Geothermal Association. Available at: http://www.geothermal-energy.org
Kindap, A., Kaya, T., Tut Haklıdır, F.S., Bükülmez, A.A., 2010. Privatization of Kizildere Geothermal Power Plant and New Approaches for Field and Plant. Proceedings World Geothermal Congress 2010, Bali, Indonesia, 25-29 April 2010
Lumb, J.T., 1981. Prospecting for geothermal resources. In: Rybach, L. and Muffler, L.J.P., eds., Geothermal Systems, Principles and Case Histories, J. Wiley & Sons, New York, pp. 77-108.
McNitt. J.R., 1982: The geothermal potential of East Africa. Proceedings of the Regional Seminar on Geothermal Energy in Eastern and Southern Africa, Nairobi, Kenya, June 15-21 1982 .
Mejia, M., 2015. 2015: year of Geothermal Energy in Mexico. Article on VertigoPolitico.com, 22 December 2015.
Micale, V., Oliver, P., and Messent, F., 2014. The Role of Public Finance in Deploying Geothermal: Background Paper. Report by Climate Policy Initiative to the San Giorgio Group/Climate Investment Funds, October 2014.
Micale, V., Trabacchi, C., and Boni, L., 2015. Using Public Finance to Attract Private Investment in Geothermal: Olkaria III Case Study, Kenya. Report by Climate Policy Initiative to the San Georgio Group/Climate Investment Funds, June 2015.
Musembi, R., 2014. GDC’s Geothermal Development Strategy for Kenya: progress & opportunities. Presentation during the Power Africa-Africa Union Commission Geothermal Roadshow, September - October 2014
Sanchez-Alfaro, P., Sielfeld, G., VanCampen, B., Dobson, P., Fuentes, V., Reed, A., Palma-Behnke, R., and Morata, D., 2015. Geothermal barriers, policies and economics in Chile – Lessons for the Andes. Renewable and Sustainable Energy Reviews, Vol. 51, pp. 1390-1401.
Sanyal, S.K. and Enedy, S.L., 2011. Fifty years of power generation at the Geysers Geothermal Field, California – the lessons learned. Proceedings of the Thirty-Sixth Workshop on Geothermal Reservoir Engineering, Stanford University. Stanford, California, 31 January - 2 February 2011
Swandaru, R.B., 2015. The History of the Earliest Geothermal Power Plants in Indonesia. Proceedings World Geothermal Congress 2015, Melbourne, Australia, 19-25 April 2015
Tassed, M., 2015. Expansion Work and Experience Gained in Operation of Aluto Langano Geothermal Power Plant. Proceedings World Geothermal Congress 2015, Melbourne, Australia, 19-25 April 2015
Thain, I.A., 1998. A Brief History of the Wairakei Geothermal Power Project. GHC Bulletin.
Van Nguyen, M., Arason, S, Gissurarson, M., and Pálsson, P., 2015. Use of geothermal energy in food and agriculture: Opportunities for developing countries. Report for the Food and Agriculture Organization of the United Nations, Rome. 2015.
World Bank, 2012. Drilling Down on Geothermal Potential: An Assessment for Central America. Report by the Energy Unit of the Latin America and Caribbean Region of the World Bank. March, 2012.