The Potential Contribution of Renewables in Ethiopia s Energy Sector: An Analysis of Geothermal and Cogeneration Technologies

Transcription

1 The Potential Contribution of Renewables in Ethiopia s Energy Sector: An Analysis of Geothermal and Cogeneration Technologies Renewables in Eastern and Horn of Africa: Status and Prospects Sponsored By HBF-HA, Sida/SAREC and AFREPREN/FWD By Prof. Wolde-Ghiorgis Woldemariam 004

2 Executive Summary This study set out to investigate the viability of meeting 10% of Ethiopia s electricity generation using geothermal and biomass-based cogeneration within the coming decade. The study established that at least 700 MWe of geothermal energy potential exists within the Rift Valley Region of the country, but this potential is largely underdeveloped. Out of the untapped geothermal resources, it is estimated that geothermal power in the range of 100 MWe - 10 MWe can be harnessed successfully within the coming decade, thus contributing to about 4% of the current electricity installed capacity. The 5% geothermal proposal is in line with the planned expansion of the existing electric power generation capacity in the country, which is expected to grow in the range of 000 MWe MWe. Up to 30 MWe of electricity can be generated by the existing sugar factories from bagasse-based cogeneration. The maximum capital cost required to develop geothermal resources in the next decade is estimated at US$,466/kW while permanent jobs would be created at a rate greater than persons/mwe. Generation cost are estimated at 6.5 US cents per kilowatt-hour. In addition, the failed pilot geothermal plant is thought to be repairable and expandable up to 30 MWe for a lifetime of 30 years. The study also addressed the merits and demerits of developing these two technologies in Ethiopia. Developments of geothermal resources in Ethiopia will therefore be feasible and attractive for two reasons. Firstly, because constructions of dams or thermal plants based on diesel generation will be significantly minimized; leading to major economic advantages in favor of geothermal plants. Secondly, there are solid economic opportunities and benefits for exporting electricity to neighboring countries reliably and profitably in the near future using a mix of energy resources. Recent experiences with unexpected and prolonged drought have amply shown that the national supply of electricity could be severely disrupted. When the generation capacity is guaranteed and strengthened by adding geothermal energy to the hydro energy resources of the country; probable disruptions in the generated supply will be greatly minimized. However, the envisaged power development schemes using geothermal resources in Ethiopia have been greatly hampered by inadequate and/or incompetent management of the system development process, including non-definitive appraisals of resources and lack of viable designs that take into account all measures of risk elements associated with geothermal plants. While the resources are waiting to be developed, the demand for electric energy is rising from a conservative estimate of 8% to 15.8% annually. Over next decade, the growth rate could still be higher. For instance, even quadrupling the existing electricity installed capacity may not match the projected significant increase of demand for power, taking into account the estimated increase population from 70 million to 95 million in ten years. Policy recommendations needed to promote and develop both geothermal and cogeneration energy resources, within a wider framework of renewable energy technologies, are provided. To realise the above estimated potential, it is strongly recommended that modern energy services are planned and improved through the promotion and dissemination of renewable energy technologies for income-generating and socio-economic activities. On the utilization of geothermal energy, it is recommended that the 5% geothermal target can be implemented within the next ten years provided geothermal energy development is given adequate priority comparable to that given to hydro power schemes. Another recommendation is that the failed pilot geothermal power plant should be repaired and expanded. Moreover, in line with the agriculture-led industrialization national strategy, the viability of cogeneration exists and this should be accompanied by the expansion of sugar factories. The Potential Contribution of Renewables in Ethiopia s Energy Sector i

3 TABLE OF CONTENTS Executive Summary...i List of Tables... iii List of Figures... iii Abbreviations and Acronyms... iv 1.0 Overview of the Energy Sector and Status of Dissemination Of RETS in Ethiopia Introduction Overview of the Energy Sector in Ethiopia Overview of Geothermal Energy and Cogeneration Developments in Ethiopia Methodology Methodology and Approach Sources for Updated and Current Data Prospects for Geothermal Energy Development in Ethiopia Background: Global Development of Geothermal Energy Geothermal Energy in Ethiopia Challenges Encountered in the Utilization of the Pilot Geothermal Plant at Aluto Langano Future Prospects of Geothermal Energy Utilization for Power Conversion in Ethiopia Challenges Facing Dissemination of RETs In Ethiopia: Implications for Cogeneration Development Prospects of Biomass Cogeneration Development in Ethiopia Merits and Demerits of Geothermal and Cogeneration Developments in Ethiopia Merits and Demerits of Geothermal Energy Development in Ethiopia Merits and Demerits of Biomass-based Cogeneration in Ethiopia Conclusions and Recommendations Conclusions on Prospects for Geothermal and Cogeneration Energy Development in Ethiopia Policy Recommendations References Appendices Appendix I: Tables Appendix : Geothermal Potentials of Ethiopia The Potential Contribution of Renewables in Ethiopia s Energy Sector ii

4 List of Tables Table 1 Indigenous energy resources... Table Electrification and population levels in Ethiopia, Table 3 Modern Energy Consumption in Ethiopia by Sector (1996)... 3 Table 4 Status of dissemination of renewable energy technologies in Ethiopia... 4 Table 5 World Electricity Generation and Direct Use of Geothermal Energy in Table 6 Installed and planned world geothermal generating capacities ( )... 9 Table 7 Geothermal energy potential in Ethiopia Table 8 Characteristics of the Aluto-Langano wells... 1 Table 9 Aluto- Langano pilot geothermal plant: production well parameters... 1 Table 10 Proposed Phases of Geothermal Resource Development in Ethiopia Table 11 Ethiopia- Area under sugar cane cultivation, yield and cane production (1993/94-00/03)... Table 1 Finchaa Sugar Factory (FSF): Basic Operation and Performance Data... 3 List of Figures Figure 1 Energy Supply by Source in Ethiopia, Figure Electricity generation by source... 3 The Potential Contribution of Renewables in Ethiopia s Energy Sector iii

5 Abbreviations and Acronyms ADLI AFREPREN CSA EEPCO EIGS EREDPC FSF GTZ HBF HEPP ICS IPP KenGen MSF MOI MOM NBE NCG NGOs RETs SCS SMEs SSF TOR UNEP WEC WSSD Agriculture Development-Led Industrialization African Energy Policy Research Network Central Statistical Authority Ethiopian Electric Power Corporation Ethiopian Institute of Geological Studies Ethiopian Rural Energy Development and Promotion Centre Finchaa Sugar Factory Deutsche Gesellschaft fur Technische Zusammenarbeit Heinrich Böll Foundation Hydro Electric Power Plant Interconnected system Independent Power Producer Kenya Electricity Generating Company Metahara Sugar Factory Ministry of Infra-Structures Ministry of Mines National Bank of Ethiopia Nordic Consulting Group Non-Government Organizations Renewable Energy Technologies Self Contained System Small Manufacturing Enterprises Shoa Sugar Factory Terms of Reference United Nations Environment Programme World Energy Council World Summit for Sustainable Development The Potential Contribution of Renewables in Ethiopia s Energy Sector iv

6 1.0 Overview of the Energy Sector and Status of Dissemination Of RETS in Ethiopia 1.1 Introduction For sustainable development to occur in rural Ethiopia, modern energy services are required to spur income-generating activities. Currently, electricity meets motive power demand, which is only accessible in the larger towns, and mostly by diesel engines in areas without the grid. Wood and charcoal provide thermal energy for ovens, kilns and bellows (Kebede, 001). However, the demand for these services exists only in urban areas. Rural homes are mostly made of mud and relatively higher quality wood, and metal products are not affordable to rural people. With an improving transport infrastructure, these industries may flourish in rural areas due to better access to energy. Important rural indigenous and cottage non-farm activities in Ethiopia include grain and oil mills, coffee processing, bakeries, lumber mills, brick and block making. Another economic challenge facing Ethiopia is the limited use of renewable energy technologies (RETs) for income generation. Wolde-Ghiorgis (003) previously studied the technical and economic constraints limiting the wide use of RETs, especially for incomegenerating activities in Ethiopia. Assessments for provisions of modern energy services have been shown to depend on cost considerations. Electricity supplies from the centralized interconnected system are only reaching rural towns, administrative and major marketing centres with populations of 5,000 and above. Distribution is by means of 15-kV lines within 50 km from the grid, and with recently tried 33-kV lines up to distances of 100 km. Installation and wiring accessories are also imported making them unaffordable to rural communities. Decentralized electric services have also been provided by isolated selfcontained systems using diesel generator sets. However, the key limiting factors are lack of affordability and technological awareness. Except for weak and poor quality lighting with kerosene lamps, rural households have not benefited from modern fuel supplies (e.g. electricity or coal) for cooking and productive activities. So, for vast rural areas without electricity, the obvious options could have been promotions of small-scale RETs for households, rural communities and productive centres. However, both previous and latest studies appear to confirm that the introduction of RETs may remain unattainable for long (Wolde-Ghiorgis, 1988; Wolde-Ghiorgis 1990; Wolde-Ghiorgis 00; Tesfaye, 00). The rationale for the study arose from the need for clean and modern energy services, which are needed for sustainable development and improvement in socio-economic conditions. The viability of a 5% target for geothermal energy development within the growth of Ethiopia s power generation capacity in the next decade is assessed. Despite the depletion of traditional biomass energy resources, there are ample opportunities for obtaining clean and sustainable energy from cogeneration using biomass fuels. The fundamental objective of the study was thus to assess possibilities for improved energy services by harnessing these two major but hitherto under utilized renewable energy resources in Ethiopia: Geothermal and cogeneration. 1. Overview of the Energy Sector in Ethiopia Located in the Horn of Africa, Ethiopia is endowed with substantial resources that include biomass, natural gas, hydro power and geothermal energy. However, as observed from the current level of harnessing various energy sources (table 1), the country has a long way to go in order to realize high reliable delivery of energy services to its massive populace. The Potential Contribution of Renewables in Ethiopia s Energy Sector 1

7 Table 1 Indigenous energy resources Source Exploitable reserves Units Exploited percent% Hydro power 30,000 MW 3.3* Solar insolation /day 5.3 KWh/m ~0 Wind speed m/s ~0 Geothermal 700 MW 1. Wood 1,10 Million tons 50 Agricultural waste 15-0 Million tons 30 Natural gas 76.5 Billion m3 0 Coal 13.7 Million tons 0 *With new plants to be commissioned soon and projects under construction (003) Source: Wolde-Ghiorgis, 00; EREDPC, 000; AFREPREN, 003b Figure 1 Energy Supply by Source in Ethiopia, 001 Petroleum 6% Electricity 1% CWR 93% Source: IEA, 003 As shown in figure 1, biomass energy sources in the form of combustibles renewables and waste dominate Ethiopian energy statistics. This reflects significant dependency on traditional energy sources and low modern energy consumption. Access to electricity is also highly skewed and insignificant in total energy consumption. As shown in table below, majority of the Ethiopian population (majority of who reside in rural areas) are yet to be electrified by the national electricity utility, Ethiopian Electric Power Company (EEPCo) with current installed capacity of 493MW. Table Electrification and population levels in Ethiopia, 001 Region Population (million) % access to electricity National Urban Rural Source: IEA, 003; Wolde-Ghiorgis, 003; Teferra, 003; Kebede, 003 The bulk of electricity in Ethiopia comes from hydro power (98%), while fossil fuel generation produces about % (figure ). The electricity sector is dominated by the Ethiopia Electric Power Company. However, there are other key players who include municipalities, communities and the private sector (Teferra, 00). The Potential Contribution of Renewables in Ethiopia s Energy Sector

8 Figure Electricity generation by source Fossil Fuel % Hydro 98% Various assessments and studies have been conducted on the energy situation in Ethiopia (CESEN, 1986a; Wolde-Ghiorgis, 1984; Wolde-Ghiorgis, 00; Wolde-Ghiorgis, 003; World Bank, 1984; 1996). Compared to other less developed countries, provisions of modern energy services for socio-economic development programs and income-generating activities in Ethiopia are noticeably deficient, particularly in rural areas. It has also been realized by concerned authorities that energy is a fundamental input for improving the quality of life and for sustainable socio-economic development. Available literature shows that in Ethiopia, the focus has so far been on supplying modern energy services for the industrial and urban sectors whereas the rural settlements, accounting for about 85% of the total population, have been left to depend largely on traditional biomass energy sources (table 3). However, even in urban centres, access to modern energy is disproportionate because only Addis Ababa, the capital city, and other major urban towns have access to modern energy compared to other rural towns. Table 3 Modern energy consumption in Ethiopia by sector (1996) Sector Terra Joules/year Percentage (%) Household Rural 60, Urban 4,565 6 Agriculture 816* <1* Transport 17,918.5 Industry 33, Services 6, All sectors 7, * Without consideration of human and animal power which is extensively used in traditional rural farming practices Source: Wolde-Ghiorgis, 00 The energy sector in Ethiopia therefore needs to be addressed from many angles with particular emphasis on developing appropriate policy, increasing the supply/generation mix beyond hydro power, and expanding the delivery of modern energy services to a larger proportion of the population particularly in rural areas. Towards this end, there are plans to reach a generating capacity of 3,000 MW over a ten-year period. To realize the projected generation of 3,000 MW, there is an urgent need for the country to explore other potential and cost-competitive sources of energy with a view to complementing the currently available hydro power. Thus, the need for this study to investigate the viability of harnessing additional The Potential Contribution of Renewables in Ethiopia s Energy Sector 3

9 power with particular emphasis on two renewable energy sources namely geothermal and biomass-based cogeneration Status of dissemination of renewable energy technologies in Ethiopia Dissemination of RETs has been progressing in sub-saharan Africa since the early 1990s (Karekezi, 199). However, their applications and uses in Ethiopia have registered widespread success (Wolde-Ghiorgis, 00). As shown in table 4, installations of photovoltaic systems (PVs) are very low, and are mainly used in the telecommunication industry. Other than few demonstration/pilot projects, and donor-driven installations initiated by NGOs (e.g. GTZ), there are few functioning RETs, including improved stoves, to be seen throughout the country. Harnessing of potentially abundant renewable energy sources (e.g. hydro, solar energy, and wind) has therefore remained insignificant. Further, dissemination of RETs (including improved wooden stoves) is fairly modest even in rural areas of the country. This is limited to micro/mini hydro power plants providing mechanical and electrical power, and PV units. Table 4 Status of dissemination of renewable energy technologies in Ethiopia Technology Installations Capacity Photovoltaics a ~ 5000 ~100kWp Solar water heaters ~ 100 Wind pumps 00 Wind generators 1 kw for test Small hydroelectric plants (<5 MW) b MW Water mills (including those not functional) Improved stoves c ~300? 1.5-million 1 to 5kW/unit Key a Includes 575 stations of the Telecommunication Corporation with capacity of about 1,00 kwp. b Includes EEPCO s 3 mini hydro stations (with total capacity of 6.1 MW) and 7 micro hydro sites developed by a Church Organization, some of which are non-operational. c Improved stoves are included as RETs since biomass fuels are used; in any case, most of the disseminations are in major urban centres. These have been disseminated by the EREDPC and GTZ. Source: Tesfaye, 00 Based on the present low levels of dissemination of RETs, the following critical issues of concern have been noted: Slow pace of technology transfer, even for mature and proven RETs (e.g. wind pumps and biogas digesters) Inadequate human capacity building at different levels, and for specific tasks, including management and operational skills and knowhow for various RETs Lack of institutional frameworks for planning, promoting and regulating of local assembling and manufacturing of RETs Modest levels (and in some regions total non-existence) of modern energy services to support socio-economic activities, in line with the Agriculture Development Led Industrialization (ADLI) strategy Due to the immense but largely untapped renewable energy resources in Ethiopia (table 1), renewables could in principle be considered as viable options for developing Ethiopia s energy sector. However, there are constraints that pose serious challenges. The major limitations include inappropriate modes and slow pace of technology transfer. The fact that, per unit of power delivered from RETs, the cost is relatively higher is seen as a major constraint to rapid and wider dissemination. In addition, provision of credit facilities using commercial or soft loans will remain complex and unattainable unless potential users are organized into manageable and bankable groups. The Potential Contribution of Renewables in Ethiopia s Energy Sector 4

10 Further, progress in promotions of RETs would be subject to strategies and policies on technology transfer with requisite capability building for installations, operations, maintenance and repairs targeting entrepreneurs, installers, and end-users. As indicated earlier, goals and strategy formulations for energy development are yet to be devised and adopted. Besides, there are concerns that applications and uses of RETs could be too limited to meet the energy requirements for productive end-uses, hence poverty alleviation. Henceforth, implications of low disseminations of RETs will need to be considered in order to seek alternative or complementary solutions to current and future energy requirements. There exist proven and viable potential for the development of these two options in Ethiopia as discussed in the next section. 1.3 Overview of Geothermal Energy and Cogeneration Developments in Ethiopia Geothermal energy has been extensively used for power generation and direct applications in many countries of the world (Fridleifsson, 003). Except for a small pilot power plant that was started in 1998, and failed in 00, the experience in Ethiopia has so far been restricted to limited direct uses. The well-known African Rift Valley Region in the eastern corner of Africa passes through Ethiopia, and continues into Kenya, and neighbouring eastern African countries. Usable geothermal energy potentials have been known to exist in Ethiopia, along with other counties within the African Rift Valley Region. Presence of the three types of geothermal energy (i.e. hot water fields, wet steam fields and dry steam fields), with temperatures in the ranges of 50 0 C to C have been firmly ascertained. However, progress towards full utilization of the available energy, other than in bathing hot springs, has not been successful in Ethiopia. Still, there are potentials for electric power generation in the ranges of 700 MW to 3,000 MW. With regards to cogeneration, there has been over 50 years experience in sugar factories for internal use, but not for export of electricity to the interconnected grid. The oldest sugar factory in Ethiopia (Wonji) on the Awash River is over 40 years old. This was expanded to include the Shoa and Metahara factories, again on the down streams of the same river. Then in 1998, after some prolonged delays, the Finchaa Sugar Factory (FSF) was commissioned. It is worthwhile to note that the four sugar factories were found to be viable schemes as part of hydro power development projects. Of the four factories, planners and designers of the FSF had included cogeneration as a significant portion of the factory. The basic aim was to work closely with the national utility, the Ethiopian Electric Power Corporation (EEPCO) on exporting cogenerated electricity to the national grid. However, the cogeneration power strategy is yet to be fully designed and agreed upon. The other sugar factories, notably Shoa, have also plans for expansions using increased bagasse supplies for possible export to EEPCO's grid system. The Potential Contribution of Renewables in Ethiopia s Energy Sector 5

11 .0 Methodology.1 Methodology and Approach As mentioned earlier, this study is based on the need to promote two hitherto under utilized renewable energy sources within the region, namely cogeneration and geothermal. It presupposes that utilization of geothermal and cogeneration energy resources could meet about 10% of the Ethiopia s energy supply within the next decade. This is in line with proposals made at the World Summit for Sustainable Development (WSSD) in August 00. In the case of Ethiopia, the objective was to aim at 10% of total electricity generation from geothermal and biomass-based cogeneration. To test the set hypothesis, data was sought from countries and regions with geothermal energy and biomass resources for cogeneration. This included a broader review of the status of renewables in the East and Horn of Africa Region. Using local and international data on energy development and patterns, qualitative and semi-quantitative assessments of the hypothesis were carried out. A survey of local and international data on utilization of geothermal energy was done. Similarly, the viability of biomass-based cogeneration option, notably using bagasse from sugar factories, was examined. The methodology also involved conducting personal interviews, and visits to libraries, sugar factories and geothermal fields.. Sources for Updated and Current Data For data on geothermal energy prospects, results of previous studies in Ethiopia were utilized, although the data is somewhat outdated; with some data sets dated back to the early 1980s. These have been obtained from the Geothermal Division of the Ethiopian Institute of Geological Studies (EIGS). Published papers and reports prepared by consultants that focused on the geo-chemical and geophysical aspects were also useful. Modelling studies on steam flows, enthalpies, pressures and temperature characteristics are however not available. The available data was however adequate for providing definite indicators for making reconnaissance studies on prospective geothermal fields. Additional data was available from a detailed Ethiopia country study on the status of renewables conducted previously, as well as the internet. On the other hand, no elaborate studies have been done on cogeneration practices in Ethiopia, and lessons could only be taken from external sources and experiences. Aspects of feasibility studies conducted by consultants in designing the latest sugar factory were utilized (Worku, 00). These in turn have been based on experiences in the older plants. The oldest sugar factory in Ethiopia (Wonji) was commissioned in the early 1950s. Thermal energy was obtained from combusting bagasse for both industrial processes and electricity generation. However, electric supply for irrigation requirements was purchased from the electric utility. In the newer plants (Finchaa and Metahara Sugar Factories), significant portions of energy requirements are produced through cogeneration within the factory. The present study made use of data from Finchaa Sugar Factory (FSF). In future, attempts will be made to find similar data from the other sugar plants. Previous energy studies depended on data obtained from reports and surveys provided by the Central Statistical Authority (CSA) of Ethiopia. For the present study, CSA surveys on large and medium scale manufacturing and electricity industries, which include sugar industries were utilized. The annual CSA abstracts also provided data on sugar plantations. Data obtained from these sources was helpful in appraising preliminarily viabilities of cogeneration in the sugar factories. Further, by considering experiences of other developing countries in promoting cogeneration initiatives as applications of RETs, studies of great relevance and interest were found. However, detailed studies on market research linking The Potential Contribution of Renewables in Ethiopia s Energy Sector 6

12 industrial firms and utilities were not available. In this regard, the experiences of countries in the East African region would be of particular interest for future investigations. The Potential Contribution of Renewables in Ethiopia s Energy Sector 7

13 3.0 Prospects for Geothermal Energy Development in Ethiopia 3.1 Background: Global Development of Geothermal Energy Geothermal energy is the natural heat of the earth found in geologically active regions of the world (Fridleifsson, 003). These immense amounts of thermal energy are utilized for electricity generation and direct applications of thermal energy in many parts of the world as shown in table 5 and 6. Table 5 World electricity generation and direct use of geothermal energy in 1994 Country Electricity Generation Installed capacity MWe Annual output GWh Installed capacity MWe Direct Utilization Annual output GWh China 30 *** 98,814 * 8,74 * Costa Rica El Salvador France * 1,360 * Georgia ,136 Hungary * 785 * Iceland ,469 * 5,603 * Indonesia 309 1, Italy 66 3, * 1,048 * Japan 99 1, ,98 Kenya 11 **** 480 *** Macedonia Mexico 87.9 ** 5, New Zealand 86, * 1,967 * Nicaragua Philippines 1,501 5, Poland Romania Russian Fed * 1,703 * Serbia Slovakia Switzerland * 663 * Tunisia Turkey * 4,377 * USA,817 16,491 5,366 * 5,640 * Others ,935 Total 7, ,086 14,07 40,946 * 000 Data ** 001Data *** 00 Data **** 004 Data Source: Fridleifsson, 003; World Geothermal Conference, 000; Mbuthi, 004; Deutsche Gesellschaft fur Technische Zusammenarbeit (GTZ), 00; AFREPREN, 003 The Potential Contribution of Renewables in Ethiopia s Energy Sector 8

14 Table 6 Installed and planned world geothermal generating capacities ( ) Country 1995 MWe 000 MWe 005 (est MWe % Increase MWe) increase Argentina n/a n/a Australia n/a China n/a Costa Rica El Salvador Ethiopia Infinite France Guatemala Infinite Iceland Indonesia Italy Japan Kenya Mexico New Zealand Nicaragua Philippines 1,7.00 1,909.00, Portugal Russia Thailand Turkey USA,816.70,8.00, n/a TOTALS 6, , , , Source: World Geothermal Conference, 000; Amdeberhan, 004; AFREPREN, 003 In 1994 the USA had nearly two-thirds of global geothermal electrical installed capacity, with about 3,000 MW (World Geothermal Conference, 000). In Africa, Kenya was the leader and pioneer in utilising geothermal resources. Other countries making significant uses of geothermal energy have been Japan, China, Iceland, New Zealand, Hungary, France and Italy. As shown in table 6, total installed capacity around the world was estimated to be in the region of 7,000 MW. The technologies employed in exploiting the different grades of geothermal hot fluids have been built and standardized around three conversion systems (Friedleifsson, 003). These are known as: (i) direct steam conversion, (ii) flash steam conversion, and (iii) binary cycle. The direct conversion method utilizes steam from a vapour-dominated hot fluid. In the flash steam conversion system, the steam is obtained by using a separator that removes the hot water and brine. The flashed steam is piped into a turbine, while the unflashed brine is sent for re-injection or disposal. A cooling process is again employed as in the direct conversion system. The third and more recent technology has been developed for utilizing the energy content of a water-dominated hot fluid. The geothermal energy is not used to drive a turbine directly. Instead, the geothermal energy contained in the hot fluid is used to vaporize a hydrocarbon fuel (e.g. pentane or isobutane). The vaporised gas vapour is then led to drive a turbine. 3. Geothermal Energy in Ethiopia 3..1 Background Started in 1969, geothermal energy explorations in Ethiopia's Rift Valley Region have been done for quite some time (Acquater, 1996; 1996b; Genzel, Molla, 1986; Wolde-Ghiorgis, 1996). Extensive studies on the geology and geochemistry of selected areas in the northern, central and southern ends of the volcanic region have been covered (see appendix ). The theoretical investigations and engineering studies have however not been translated into feasible energy projects, specifically in the utilization of the available energy for the The Potential Contribution of Renewables in Ethiopia s Energy Sector 9

15 generation of electricity. Potential for utilization of geothermal energy for electric energy production has been firmly ascertained. The usable geothermal energy potentials in Ethiopia are as shown in table 7. Table 7 Region Lakes District Southern Afar Central Afar Danakil Depression Total Source: Acquatter, 1996b Geothermal energy potential in Ethiopia Geothermal Potential 170 MW 10 MW 60 MW 150 MW 700 MW Other sources further indicate that that the estimate for exploitable geothermal energy can be as high as 3,000 MW (Amdeberhan, 000). Ranking behind, the immense hydro power potentials of the country (approximately 30,000 MW), geothermal energy has been established as a viable source of renewable energy. Geothermal energy in Ethiopia is suitable for development within reasonable costs in view of the proximity of the potential sites to the interconnected electric grid (ICS). Geothermal energy could meet both domestic and export needs for power. Once initiated, it could be implemented as a continuing program of energy extraction in the Rift Valley Region of Ethiopia extending northwards and southwards. 3.. Pilot power plant for utilizing the Aluto-Langano geothermal field Based on a 1986 study, a geothermal pilot plant was built and commissioned in The site chosen was at Aluto-Langano in the central region of the Rift Valley, very close to the interconnected national grid. The Aluto geothermal field is located about 00 km south of Addis Ababa, between Lakes Ziway and Langano. Spread over an area of about 10 km, the site has been investigated extensively, and it has been concluded that there are proven potential energy resources. The maximum capacity of the geothermal field has been estimated at 30 MW. The pilot plant was 5.3 MW 1 (Genzl, 1995). The expected lifetime of the power plant was estimated at 30 years. The idea was that after experience has been gained in operating the relatively small power plant, the plant would be expanded to increase the installed power capacity to 30 MW. The locations of the drilled and tested Aluto Langano wells are shown in appendix. Data is based on measurements and tests made from 198 to 1985 (Belayneh, 1986), and reassessed in 1995 (Electro-consult, 1985; Genzel, 1995). The wells are closely spaced for interconnections of the necessary piping systems for delivery of the hot fluid. The characteristics of the eight wells are shown in table 8. Each well is designated as LA (for Langano-Aluto), and the numbers ranging from 1 to 8. Out of a total number of eight wells, four were selected for power generation, and one for reinjection of used fuels. These were LA-3, LA-4, LA-6 and LA-8. Well LA-7 which had lower steam production was to be used for reinjection. As indicated earlier, the success of the pilot project depended on the proposal that the estimated 5.3 MW power capacity could be raised to 7.3 MW by combining dry steam and binary conversion methods. Then, in a second development stage, it was foreseen that a 15 MW plant could be built. As recommended in the 1985 study, the final expectation was to reach 30 MW after an additional number of 17 to 0 wells were drilled and successfully tested (Genzl Consulting Group, 1995). The critical requirement was that the total production capacity of the wells to generate 7.3 MWe had first to be confirmed. The prospects of the additional 15 MW, and finally 30 MW plant capacities were to be assessed later. 1 The pilot project was originally estimated to have a capacity of 5.3 MW, but this could be increased to 7.8 MW if dry steam and binary conversion methods were used. The Potential Contribution of Renewables in Ethiopia s Energy Sector 10

16 3.3 Challenges Encountered in the Utilization of the Pilot Geothermal Plant at Aluto Langano In theory, the binary conversion process promised optimal operations of a small pilot geothermal plant with low-temperature, low-pressure and low-enthalpy processes. In practice, as experienced in the Aluto-Langano pilot project, it was full of risks and operational problems. Due to various reasons, the pilot plant at Aluto-Langano therefore ended up as being a failure, and it was stopped in June 00. Major constraints included the management and smooth operation of the pilot power plant. However, the steam supply was not a problem (Amdeberhan, 004). When the pilot project was recommended in 1997 by a team involving the Principal Researcher, and approval was given, its success was never in doubt. All design parameters were defended and explained. The only concern expressed was that the well characteristics given in table 7 were not reliable since they had been recorded 1 years earlier, and the wells had remained sealed. In this regard, it was explained that the characteristics would have had time to stabilize and relied upon. In addition, it was felt that there was no need for drilling additional wells, or for strengthening existing wells. Therefore it was strongly argued that at a cost of US$ 16.5 million for a 7. MW geothermal plant that was originally recommended as a 5 MW plant, the whole project was a bargain to be taken seriously. Grid connections were completed on time for commencement of operation to a nearby substation by means of an 11 km 15 kv transmission line, later to be stepped up to 13 kv interconnected grid. The gross output of the pilot plant was 8. MW, while the net output was 7. MW. These were to be obtained from two units of dry steam and binary converters working in parallel operation. The dry steam turbine was specified to operate at: inlet temperature of C ; inlet pressure 13 bars, steam quality 99.98%; flow rate of 8,767 kg/hr, non-condensables of 18 kg/hr steam outlet pressure of 1.3 bars; and speed 6,000 rpm The dry steam turbine was coupled to a brushless synchronous generator with a nominal output of 4,750 kw; terminal voltage of 11 kv ± 5%; rated current, 381 A; frequency 50 Hz; power factor, 0.8; speed 1,500 rpm; and insulation, class F, temperature 90 0 C. The binary conversion unit, on the other hand, was based on using low temperature and low-pressure geothermal fluid with a mix of brine to vaporize pentane and to drive a turbine by an expansion process. The inlet steam and brine conditions were specified as follows: steam flow rate of 9, 657 kg/hr with NCG of,813 kg/hr, and at a temperature of C and a pressure of 5.0 bar; inlet brine conditions of 159,31.0 kg/hr flow rate, and at a temperature of C and pressure of 5.9 bar. The turbine driven by the vaporized hydrocarbon (pentane) was coupled to a synchronous generator with the following ratings: rated capacity, 5,65 kva; terminal voltage, 11 kv; and rated power, 4,500 kw. The Potential Contribution of Renewables in Ethiopia s Energy Sector 11

17 Table 8 Characteristics of the Aluto-Langano wells Well Characteristics LA-1 LA- LA-3 LA-4 LA-5 LA-6 LA-7 LA-8 Total Depth (maximum, m) Temperature ( 0 C) maximum Shut-in pressure (bars) Total discharge (ton/hour) Steam discharge (ton/hour) Hot water discharge (ton/hour) Enthalpy (kj/kg) Thermal energy (MW) Gas contents (mm/mm moles of steam) Electrical power (MWe) Source: Belayneh, 1986 Table 9 Aluto- Langano pilot geothermal plant: production well parameters Description Units LA-3 LA-6 LA-4 LA-8 Wellhead Wellhead Wellhead Wellhead Enthalpy Kilojoule/kg Pressure Bar Temperature C High pressure steam flow Kg/hr 11,880 16,765 13,69 9,71 Non-condensable gas flow Kg/hr , (NCG flow) Brine flow Kg/hr 19,570 3,753 81,858 40,45 Total flow Kg/hr 3,190 41,600 97,600 50,900 Pipe length m Pipe diameter inch /1 10 Velocity m/sec /1 3 Pressure drop bar Elevation m Source: EEPCO, 003 Soon after commissioning in July 1998, the plant only yielded 6 MW. Then the power output dropped to 4.1 MW within a few days of operation. With time, the power output kept on decreasing. In June 00, the operation of the pilot geothermal plant had to be stopped as electrical power output had decreased to 0.8 MW from one well. Causes of failure are still being investigated. A mission of experts had since then visited the failed pilot plant. Members of the team included reservoir engineers; geochemists; as well as mechanical and electrical engineers and the main objectives of the mission were to: (Amdeberhan, 003). (i) identify the problems encountered in the operation of the plant; and (ii) assess the requirements for rectification of problems associated with the overall well characteristics. The mission of experts reached the following major findings and conclusions: Two wells (LA-3 and LA-6) have relatively high steam productions, while two wells (LA-4) and LA-8) have relatively low steam production and medium discharge pressures. Well head valves had operational or leakage problems. Two-phase fluid transmission pipes caused disc ruptures at wells LA-3 and LA-6, and there are needs for modifying bleed lines. Separators of steam and brine at each wellhead were investigated and found to be filled with rock fragments and sand. Brine accumulators at each well site, though in clean conditions, still had some sandy material deposits accumulated during opening of the wells. The Potential Contribution of Renewables in Ethiopia s Energy Sector 1

18 Rock mufflers (silencers) were found plugged by rock fragments and sand materials. A very low degree of precipitation (scaling) was observed (thickness of 1.5 mm) on a pipeline line from well LA-6. Some sections of transmission lines were without insulation to prevent heat loss. Gauges and instruments were out of order, possibly due to faulty installations of equipment and instruments. The power plant was to be supplied with high-pressure steam from wells LA-3 and LA-6, and low-pressure steam from LA-4 and LA-8 with brine from all wells going to the binary unit. The team of experts found one driven generator coupled to the two turbines. Failures in the turbines were also noted to be due to use of hydraulic oil instead of synthetic oil for lubrication of bearings. Further, belts and bearings of condensers were damaged. No major problems were found in cracking of civil structures except minor damages due to corrosion at one of the wells. The internal assessment took over 18 months, due to serious problems at the plant, but no follow up study was done to re-appraise the potential of the energy resource. In 003, consultancy service for the rehabilitation of Aluto-Langano Geothermal Electric Project Plant was advertised with the following terms of reference (EEPCO, 003): assessment and determination of the actual available geothermal resource characteristics such as average temperature, pressure, enthalpy, etc., for all geothermal wells; determination of the cause for variation of the output of the geothermal resources; investigation and determination possible scaling in the boreholes or in the surface devices and pipelines; determination of other deposits other than scaling in the pipes, brine accumulator, separator, etc.; designing a set up that could enable the smooth parallel operation of two or more wells; identification of problems of all wellhead valves; and determination of root causes for variations in the discharges of production wells. Further, the utility is in urgent need of concrete appraisals of the selected conversion methods and associated technologies used in the pilot plant. In this regard, major areas of concern have focused on six fundamental and interrelated technological and critical engineering problems, namely: establishing root causes for cooling fan failures; finding out the core problem for the pentane leakage in the binary conversion unit; examination of the main causes for failure of the system that detects fire and H S emissions; redesigning the rock muffler to resolve overflow problems; The Potential Contribution of Renewables in Ethiopia s Energy Sector 13

19 making available manual automation system; and provision of an up-to-date software program One of the discharging wells at Aluto Langano Assuming the required consultancy services are completed within 004, it is expected that the rehabilitation of the pilot project plant could be started and completed in 005 or early Future Prospects of Geothermal Energy Utilization for Power Conversion in Ethiopia At the end of 003, development of geothermal energy in Ethiopia is still in preliminary stages as was the situation in 1985; long before the commissioning of the Aluto pilot plant in Still, the availability of untapped resources make it imperative to take lessons from other countries, including neighbouring Kenya. Besides, the locations of the geothermal energy sources are suitable for launching initiatives for their developments within the coming decade. The prospects for the utilization of geothermal energy can thus be assessed broadly in terms of technical and economic viabilities as presented in the subsequent sub-sections Technical barriers against developments of geothermal energy in Ethiopia In the Ethiopian context, technical barriers exist in the dissemination and development of geothermal energy as demonstrated by the experiences of developed and developing countries. In relation to the number of wells drilled and the required professional geochemist person-years, the key technical barriers to be overcome can be identified as follows: The Potential Contribution of Renewables in Ethiopia s Energy Sector 14

20 management and planning capabilities to identify, prepare and implement feasible geothermal projects; technical and techno-economic knowledge and know-how of geothermal technologies; availability of geothermal equipment; and tools to help decision makers in prioritising and selecting suitable geothermal energy projects. Geothermal energy can be harnessed using standard conversion methodologies for natural steam flows with relatively high enthalpies, temperatures and pressures. Potentially, the harnessing of geothermal energy appears straightforward. Experience has however shown that both scientific and engineering studies will need to be accomplished in advance so as to make the final power capacity designs viable and reliable. In the case of Ethiopia, it will be important to remove or reduce the above indicated technical barriers within the shortest possible time. This will need to be done through intensified training programs of studies that may range from one to two years. The requisite training programs can be offered within local institutions and/or in recognized external institutes Technical assessments and viability of the 5% geothermal target for Ethiopia While acknowledging that past shortcomings from the initial pilot plant have hitherto hampered progress in geothermal development in Ethiopia, considerable potential in this field still exists within the next ten years. Therefore, it is possible to successfully achieve a 5% geothermal target of the national generating capacity in the next ten years. Judging from the experience of countries that have succeeded in utilizing geothermal energy resources, particularly Kenya, it appears that there are five important phases that need to be systematically managed to realize a successful geothermal project and they include: (1) exploration; () appraisal; 3) steam field development; (4) power plant planning and construction; and (5) effective resource utilization. As shown in table 10 each phase involves detailed activities to be handled by professionals trained for and employed by the concerned utility, which in the case of Ethiopia will be EEPCO. The Potential Contribution of Renewables in Ethiopia s Energy Sector 15

21 Table 10 Proposed Phases of Geothermal Resource Development in Ethiopia PHASE ACTIVITY RECONNAISSANCE SURVEYS REQUIRED PROFESSIONALS SPECIALIZATION Geologists Geophysicists Geochemists Environmentalists NUMBERS 3 EXPLORATION DETAILED INVESTIGATION Geologists Geophysicists Geochemists Environmentalists 3 APPRAISAL STEAM FIELD DEVELOPMENT POWER PLANT CONSTRUCTION RESOURCE UTILIZATION EXPLORATION DRILLING APPRAISAL DRILLING RESERVOIR EVALUATION FEASIBILITY STUDY PRODUCTION DRILLING WELL TESTING PRELIMINARY DESIGN DETAILED DESIGN CONSTRUCTION COMMISSIONING OPERATION PLANT MAINTENANCE RESERVOIR MANAGEMENT Source: Adapted from Kenya Power Generation Company, KenGen, 001 Drilling Engineers Reservoir Engineers Geologists Geochemists Environmentalists Drilling Engineers Reservoir Engineers Geologists Geochemists Environmentalists Reservoir Engineers Geochemists Geophysicists Geologists Electrical Engineers Mechanical Engineers Environmentalists Drilling Engineers Reservoir Engineers Geologists Geochemists Environmentalists Reservoir Engineers Environmentalists Electrical Engineers Mechanical Engineers Environmentalists Civil Engineers Electrical Engineers Mechanical Engineers Environmentalists Civil Engineers Electrical Engineers Mechanical Engineers Environmentalists Electrical Engineers Mechanical Engineers Electrical Engineers Mechanical Engineers Electrical Engineers Mechanical Engineers Reservoir Engineers Geologists Geochemists Environmentalists As shown in table 10, highly specialised geologists, geophysicists, geochemists and environmentalists will be required in the reconnaissance surveys of the exploration phase. The Potential Contribution of Renewables in Ethiopia s Energy Sector 16

22 Then these same specialists will move to the detailed investigations and drilling activities which are to be undertaken within the exploration phase. Drilling engineers will continue assisting up to the end of the appraisal phase. In the case of Ethiopia more engineers will need to be engaged if the geothermal power plant project is to be upgraded to steam field development followed by power plant construction, and finally resource utilisation. The other alternative is to allow the full engagement of an independent power producer (IPP). Central to the question of technical viability will also be the range of geothermal power capacity that can be viably considered for development within the coming decade. Starting from existing EEPCO's plant capacities, on going projects, and committed schemes, one can arrive at a close estimate for the ten-year power expansion plan as follows: Existing generating capacity as of mid 004: 684 MW On-going hydro power project slated for commissioning by 008: 300 MW Committed hydro power projects planned to be started soon and to be commissioned by 007 and 008: 570 MW Planned Emergency diesel power plants: 100 MW Planned wind Farms, final generating capacity estimate: 60 MW Total 1,714 MW Because the demand for electrification in Ethiopia has suddenly increased from 8% to 15.8% within one year, it is seen that the above estimate is low. Within the coming decade the actual power demand could easily increase up to,000 MW, or even,400 MW. Taking these extended estimates, then the 5% geothermal target was calculated approximately to be in the range of 100 MWe - 10 MWe geothermal power, which corresponds to 8.6% - 17.% of the proven potential of 700 MW Economic viability of the 5% geothermal target The economic viability of a 5% geothermal target in Ethiopia can be based on the technical viability, and on the costs to be incurred in developing a geothermal power plant. Assessments of the economic and financial viabilities will need to be done in comparison with the locations of the known hydro power resources of the country in relation to power generation development plans. According to Amdeberhan (004), the key factors affecting costs of geothermal power can be classified into six categories as follows: Exploration costs*: which involve costs of topographical and geological surveys. Related activities to be included are outlays for geophysical and geochemical investigations, as well as exploratory drilling and field investigations. Well drilling costs*: which will comprise the sinking of production bores. These will also include some proportion of "failure" bores at locations convenient for power production to be determined at the exploration stage. The results of the exploratory investigations should indicate the greatest probability of achieving high production. Plant and equipment costs*: which will be costs of well head collection equipment, transmission pipe works and instrumentation. The other important components are the power generation equipment (i.e. turbine and generator) and waste disposal equipment. These estimates are subject to further reviews and approvals by qualified consultants and concerned policy/decision makers. At this preliminary stage, what can be ascertained is that the geothermal option is viable and may take only three years before commissioning. Thus it is technically more viable than a hydropower scheme which would have a lead time of five or even seven years before commissioning. The Potential Contribution of Renewables in Ethiopia s Energy Sector 17