A prospective review of renewable energy developments in Ethiopia [version 1; peer review: awaiting peer review]

Ethiopia has a vast renewable energy potential in the context of hydro, wind, solar, and geothermal energies. The unsustainable use of biomass coupled with drought has caused a paradigm shift towards wind, geothermal, and solar energies. There have been significant strides by the Government of Ethiopia to actualize these potentials in the context of developing massive projects in these aforementioned areas with the private business sector in the goal of jettisoning the industrial base of Ethiopia in conjunction with increasing the installed power capacity from 4,300 MW to 17,346 MW by 2020. The major challenge still lies in assessing the comprehensive renewable energy resource potential of Ethiopia including the lack of local content development in the context of establishing an industrial base. There have been notable initiatives by the Government of Ethiopia to adhere to the Paris Climate Accord in conjunction with the Green Growth framework and Sustainability Development Goals. However, the top down approach of grand targets to the various regions is not the pragmatic approach to solving the Achilles heel of energy poverty. A more plausible approach is from the bottom up, whereby energy frameworks and policies are generated by conducting a needs assessment of a specified region. The appropriate technology concept needs to be reflected in the innovation aspects of renewable energy technologies. There has to be a framework of translating invention to innovation by actualizing the tripartite structure of Government, Academia, and Industry.


Introduction
Energy is the key input in economic growth and there is a close link between the availability of energy and the growth of a nation. Energy is essential to conduct the process of production that requires higher energy consumption in the context of economic development. Ethiopia's energy consumption is predominantly based on overutilization of biomass energy sources in conjunction with a low rural electrification rate of 5% and urban electrification rate of 25% (MOWIE, 2012). An overwhelming proportion of 94% of the country's energy demand is met by traditional energy sources such as fuel wood, charcoal, branches, dung cakes and agricultural residues in an unsustainable manner (MOWIE, 2012). The balance is met by commercial energy sources such as electricity and petroleum. The most important issue in the energy sector is the supply of household fuels, which is associated with massive deforestation and the resultant land degradation. The increasing scarcity of fuel wood is compounded by Ethiopia's high population growth rate of 2.3% (Bekele, 2017). The average annual GDP growth rate is approximately 10% (Bekele, 2017).
The potential scaling-up of renewable energy program (SREP) investments have been prioritized in accordance with assisting the Government of Ethiopia in meeting the overall demand for energy and improve access to energy at international standards, as per the growth and transformation plan (GTP), while adhering to the low-carbon mission statement of the climate resilient green economy (CRGE) and addressing the broader structural concerns regarding energy access and productive energy use for rural communities.
The GTP II, which has been implemented as of September 2017, emphasizes some of the major energy goals: ➢ increase power generation capacity from 2,000 MW to 10,000 MW; ➢ increase grid access from 41% to 75% of the population; ➢ double grid connections from 2 million to 4 million households; ➢ increase households supplied with at least one kind of modern, efficient and renewable energy source/ technology from 16% to 80%; ➢ electrify more than 1,500 towns/villages per year' ➢ disseminate more than 3 million solar lanterns and solar home systems in tandem with 9 million efficient cook stove with the assistance of development partners' Ethiopia is endowed with vast energy resources, namely hydro, solar, wind, geothermal, biomass, natural gas. The major challenge is that Ethiopia has not been able to develop, transform and utilize these resources for optimal economic development (MOWIE, 2012). Therefore, the Government of Ethiopia believes it is imperative to provide the economy with the necessary energy inputs at the right time and affordable prices. This will speed economic development and help the country attain the objectives of the economic reform program the Government has adopted (MOWIE, 2012). The formulation of a comprehensive national energy policy is vital in the development of an energization plan for Ethiopia.
The Government of Ethiopia has recently initiated a 1000 MW geothermal project in the areas of Tulu Moye and Corbetti. Additionally, the Government of Ethiopia in cooperation with investors has built the first waste to energy plant in Ethiopia with an installed capacity of 50 MW, which will be fully operational in 2018. The Government of Ethiopia also intends to be the wind power capital by 2020 by increasing the wind installed capacity to 5,200 MW in addition to being the fifth largest investor in renewable energies that is valued at US$100 million. Enel Green Power is also intending to build a 100 MW solar park in Ethiopia, which is valued at US$120 million. The Government of Ethiopia intends to build three solar parks with a combined capacity of 300 MW in Semera, Awash Arba, and Afar regional state. There have also been techno-economic studies of renewable energy technologies conducted in the rural part of the Tigray region in Ethiopia (Gezahegn et al., 2018). The master plans of wind and solar energy for Ethiopia have been developed (Jiangtao et al., 2012). There have been incentives by the Ethiopian Government in the development of the Fuelwood-Efficient Stoves Investment Plan (MOWIE, 2012(MOWIE, -2015.

The current energy situation in Ethiopia
The current installed grid capacity of Ethiopia is 4,284 MW (Bekele, 2017). The generation accounting for wind energy, hydro power, geothermal energy, and diesel is shown in Figure 1. Ethiopia has a hydro power potential of 46 GW; geothermal energy potential of 10 GW; and wind energy potential of 1000 GW at 50 m height (Bekele, 2017). However, the current installed grid capacity is underutilized and requires a systematic resource management plan. The geographic access to the grid is about 56% with a household connectivity of 25% (Bekele, 2017). Ethiopia's annual per capita electricity consumption is 100 kWh in conjunction with a low densification rate (Bekele, 2017). The existing plants that are connected to the national grid are shown in Table 1, including future power plants. The location of the hydropower dams in the form of a GIS map are shown in Figure 2 (Bekele, 2017). The future works include the 62% completed Grand Ethiopian Renaissance Dam with an installed capacity of 6000 MW (Bekele, 2017). The primary energy production of Ethiopia is shown in Figure 3 (Buzanakova, 2015). Figure 4 shows the various power plants connected to the national grid, with hydro power being the dominant power source, as substantiated by the fact that Ethiopia is a mountainous region. The self-sufficiency of Ethiopia based on energy imports is shown in Figure 5 (WDI, 2014) The current electricity demand forecast for the various sectors are shown in Figure 6 (Bekele, 2017). Figure 6 shows the increase in electricity demand for the Universal Electricity Access Expansion Program (UAEP), irrigation, transport, new industry and commercial sectors from the year 2012 to 2033. The electricity generation plan is shown in Figure 7 (Bekele, 2017). Figure 7 shows the increased use of hydro, geothermal, and wind energies up to the year 2037 compounded with a very small proportion of solar energy in the mix. Ethiopia needs to incorporate solar energy in the mix, as Ethiopia has an excess of 5.5 kWh/m 2 /day global horizontal irradiance (GHI) potential (Bekele, 2017). Figure 8 shows the load forecasts of the transport, agriculture, industrial, and service sectors (Bekele, 2017). The industrial sector has the highest load forecast as expected followed by the agriculture, service, and transport sectors.

Solar energy
Ethiopia's solar photovoltaic potential is shown in Figure 9. The areas that are favorable are to the north, north-west, and eastern regions of the country including a few locations in the south. Ethiopia has a favorable GHI in the northern and eastern regions of the country, as depicted in Figure 10. The relatively high GHI potential of Ethiopia makes it ideal for photovoltaics, solar water heaters and non-concentrating solar power systems implementation in general. On the contrary, Ethiopia is    not favorable for concentrating solar power (CSP) as the favorable DNI is restricted to very few places in the north and at the border with Somalia in the east, as shown in Figure 11. The lack of availability of water and lack of access to the grid in these areas compounded with dilapidated infrastructure hinders CSP development in Ethiopia.
The solar PV capacity installed in Ethiopia for the various sectors in the year 2011 is shown in Figure 12 (ISEI, 2012).
There have been several notable researches conducted on solar resource assessment in Ethiopia in conjunction with the application of solar energy for powering rural communities in the   context of hybrid systems, as substantiated below in the solar resource assessment conducted in the Geba catchment area, which has an average GHI potential of 5.59 kWh/m 2 /day. This favorable GHI potential posits an opportunity of using the village as a power park concept for the rural communities (Mahmud et al., 2014). In addition, the Geba catchment has potential for large scale concentrating solar power systems to be implemented (Mahmud et al., 2014). There have also been studies on developing detailed solar energy maps for Ethiopia (Mekonnen, 2007).
There have been studies focusing on solar PV grid connectivity aspects in the context of assessing the techno-economic viability of a 5 MW Solar PV grid connected system for 35 locations in Ethiopia (Kebede, 2017). In addition, there have been studies focusing on developing a roadmap for solar PV systems in Ethiopia (Kebede, 2017) compounded with studies done on the different types of solar energy technologies that are applicable in the rural region of Tigray, Ethiopia (TRWRDME, 2017).
There have been studies on the application of a hybrid solar PV wind system for rural communities in Ethiopia (Bekele & Tadesse, 2012) and (Bekele & Palm, 2010). There have also been studies on having a hybrid system for rural electrification composed of solar PV, wind, and hydro-power (Bekele & Boneya, 2012).

Wind energy
There is significant wind energy potential in Ethiopia to be effectively utilized in the context of electricity generation. The current installed capacity of 324 MW is a testament to the under-utilization of the wind energy potential in Ethiopia. The Danish International Development Agency has developed a framework for realizing the wind energy potential in Ethiopia in the context of improving the resource assessment of wind; government incentives and policy frameworks; wind power integration aspects; and developing a roadmap for wind energy in Ethiopia (Danida, 2016). The framework hierarchy is shown in Figure 13.
The average wind power density and wind speed for Ethiopia is shown in Figure 14. The northern, southern, and eastern locations in Ethiopia are suitable for grid integration of wind energy, as shown in Figure 15. There are a significant number of locations with energy densities greater than 400 W/m 2 in conjunction with wind speeds greater than 8 m/s at 50 m height, as shown in Figure 14.
There have been several researches conducted in the resource mapping of wind energy, focusing primarily on the development  of a wind atlas for the Geba catchment in northern Ethiopia (Bayray et al., 2013). The wind energy potential of Addis Ababa, Mekele, Nazret, and Debrezeit has been assessed to be favorable (Bekele & Palm, 2009). There have also been studies focusing on replacing hydro power in Ethiopia with wind energy (Asress et al., 2013) compounded by researches focusing on grid integration of wind energy (Bekele & Tadesse, 2012).

Bio-energy
There is a major reliance on bio-energy resources in Ethiopia, which is utilized in an unsustainable manner. The utilization of  High-level, with key partners biomass fuels, which accounts for more than 90% of the energy source for the household and commercial sectors are used for thermal applications (EREDPC, 2008) (Woldegiorgis, 2002. The inability to supply affordable, efficient, and environmentally friendly bio-energy technologies has been the Achilles heel of the bio-energy sector in Ethiopia (Mengistu et al., 2016).
The majority of rural households depend on solid biomass fuels for cooking including 84% of urban households (CSA, 2012). The use of solid biomass fuels has increased from 78% in 2004 to 84% in 2011 in urban households in Ethiopia. Solid biomass fuels are the only option in rural areas, which leads to the unsustainable use of biomass. The majority of the rural households cannot afford to pay for electricity despite the relatively low electricity prices in Ethiopia. There are about 1.65 million households connected to the grid, of which 18% of those households use electricity for cooking (CSA, 2012).
There are over 10 million improved biomass cooking stoves disseminated in Ethiopia, of which firewood stoves accounts to about one half of the total disseminated cook stoves (MOWIE, 2010(MOWIE, -2015. There are still some technical challenges in the dissemination of improved cooked stoves in the context of substandard design. There still exist over 10 million households that don't have access to improve cooked stoves and lack awareness in the importance of sustainable cooking.
Biogas technology has been promoted for cooking in rural households by the Ethiopian Government through the introduction of the National Biogas Program in 2008. There were about 8,000 domestic biogas plants installed in the year 2012/2013. The introduction of these plants has replaced about 50% of the households using conventional woody biomass. There have been incentives of constructing biogas plants in over 100 Institutions in Ethiopia. The use of biofuels have to be incentivized, as Ethiopia spends 80% of its foreign revenues earned to import petroleum for the transportation, household, and industrial sectors. There has to be an energy balance conducted for conventional and renewable fuels achieved through a comprehensive energy demand and supply modeling, which will yield a pragmatic energization plan for Ethiopia. This fact is exemplified by the households in Addis Ababa consuming about 56% of the total national consumption of kerosene in Ethiopia.
Biogas energy from animal waste is a potential area of research that Ethiopia needs to consider in its energy balance and management framework. According to the Central Statistical Agency of Ethiopia, the total cattle population in Ethiopia is estimated to be about 49.3 million. There have been researches conducted on the comprehensive review of biomass in Ethiopia (Berhanu et al., 2017) and (Guta, 2012). In addition, there have been studies focused on establishing the linkage between biogas technology adoption and the health  (Abadi et al., 2017), in conjunction with research work done on assessing the domestic biogas sector in Ethiopia (Kamp & Forn, 2016). In addition, there has been research conducted on assessing the potential sites for Jatropha production in Ethiopia using geographical information systems (GIS) (Taddese, 2016), compounded with studies focusing on the techno-economic assessment of biogas energy in rural Ethiopia (Gwavuya et al., 2012).

status of households in rural Tigray
The proportion of biogas plants in Ethiopia that are not functional is about 60% (Eshete et al., 2006). The fixed dome and floating drum installations accounts for 68% and 16% of the installed biogas plants respectively. Studies conducted indicate that fixed dome installations are more reliable than floating drum installations (Eshete et al., 2006).
The failure on demand for the majority of the biogas plants is due to poor preventative maintenance in conjunction with substandard design and lack of trained personnel (Asres, 2012).
The potential sites for Jatropha in Ethiopia are shown in Figure 16 (Tadele, 2014).

Geothermal Energy
There are 22 locations in Ethiopia that are favorable for large scale electricity generation from geothermal energy, as shown in Figure 17 (Kebede, 2017). The geothermal energy potential of Ethiopia is over 10 GW (Kebede, 2017). Figure 18 shows the detailed surface explorations completed up to date (Kebede, 2017). The test well drillings of three wells in the Doubti area have recorded temperatures of 270°C and 250°C in the deep and shallow wells, respectively. The temperatures recorded are ideal for cogeneration (Kebede, 2017). There exists a 7.2 MW installed capacity geothermal power plant at Aluto Langano since 1998 (Kebede, 2017). The other locations such as Sodere, Wondo Genet, and Filhiwa are used for direct use (Kebede, 2017). However, the Aluto Langano power plant has a reduced installed capacity due to the lack of preventative maintenance.
There are plans to expand the capacity of Aluto Langano geothermal power plant to 70 MW in 2018(MOWIE, 2010. Additionally, the first phase of the 25 MW Tandeho Alalobeda was conducted in 2017 (MOWIE, 2010(MOWIE, -2015. The Tandeho Dubti shallow reservoir project of 12 MW will be initiated in 2018 (MOWIE, 2010(MOWIE, -2015. Finally, the first phase of the Corbetti project of 500 MW will be initiated in 2018 (MOWIE, 2010(MOWIE, -2015. There have been notable researches conducted on geothermal exploration and development in Ethiopia (Kebede, 2012) and (Kebede, 2014) compounded with research conducted on the Aluto geothermal field (Hochstein et al., 2017). In addition, there has been geothermal exploration conducted in the northern Lake Abaya area, which has shown favorable geothermal potential (Minissale et al., 2017). In addition, there has been research conducted on developing a three-dimensional conductivity model of the Tendaho high enthalpy geothermal field in north eastern Ethiopia (Didana et al., 2015).

Market deployment of renewable energy technologies in Ethiopia Solar and wind energy
The interplay of technical, capacity, information, economic, institutional and policy constitute as barriers with regards to the implementation of solar and wind energy technologies in Ethiopia (ERED, 2007). The implementation barriers of solar and wind energy are shown in Table 2.
The major stakeholders and the activities in the solar PV industry in Ethiopia are illustrated in Table 3 (ISEI, 2012).

Geothermal energy
Geothermal energy has been given a top priority to replace hydro power, which is prone to drought. The long-term power development is to have 2,500 MW by 2030 and 5,000 MW by 2037 (MOWIE, 2010(MOWIE, -2015. The strategic implementation in conjunction with a comprehensive review of the geothermal sector has been conducted (MOWIE, 2010(MOWIE, -2015.
Geothermal energy is expected to contribute 30% of the energy generated in the grid, which is approximately 40,000 GWh in tandem with having a capital cost of US$4 million per MW (MOWIE, 2010(MOWIE, -2015. This investment will generate US$20 billion in 25 years (MOWIE, 2010(MOWIE, -2015. There has been research conducted on the strengths, weakness, opportunity and threat analysis (SWOT) of geothermal energy, as shown in Table 4 (MOWIE, 2010(MOWIE, -2015.

Bioenergy
There are several challenges identified in the biogas sector in Ethiopia, as shown in Table 5 (Kamp & Forn, 2016). The main drivers and barrier of the biogas sector in Ethiopia are shown in Table 6 (Kamp & Forn, 2016).

Category Issue
Technical Development • Domestic biogas installations cannot supply the full domestic energy demand • Non-local materials increase investment costs and maintenance problems • In relation with the available dung, most installations are over-sized • Without proper technical back-up, any plant will fail sooner or later • "Single actor construction" weakens local technical back-up facility • Standardization will improve quality Development of the user context • Farmers need proper instruction to maximize the benefits from their investment • Biogas installation as a "stand-alone" application are likely to fail • The plant's water requirement shall not be underestimated Government context and regulatory framework • EREDPC seems the best placed lead agency for a federal domestic biogas programme • The Bureaus of Energy would seem the best placed coordinating, supervising and integrating agencies at regional level • The extension network of the Bureaus of Agriculture would be an asset for a large scale dissemination programme • The regional micro-finance Institutions can play an important role in a large scale domestic biogas programme

Conclusion
• Ethiopia has invested 100 million US Dollars in renewable energy and is by far the fifth largest investor in Africa. Ethiopia intends to become the wind capital of Africa by 2020 with an installed wind capacity of 5.2 GW. Ethiopia has also initiated large scale geothermal projects in the Corbetti and Tulu Moye areas, which will have a combined capacity of 1 GW.
• Ethiopia under the newly implemented GTP II intends to increase the current installed power capacity of 4,300 MW to 17,000 MW by 2020. Ethiopia has a vast renewable potential, which is unrealized due to the lack of a comprehensive resource management and assessment.
• Ethiopia intends to transition from the unsustainable use of biomass in conjunction with replacing the dominant hydropower source with geothermal and wind. The plan is to have 5,000 MW of installed geothermal capacity by 2037.
• There stills exists technical, capacity, economic and Institutional barriers with regards to the uptake of solar, wind, geothermal, and bio-energy technologies in Ethiopia. The problem manifests itself due to the top down approach being applied to the different Generating revenue by exporting power to other African countries Sub optimal legal and regulatory framework (upstream mineral -downstream energy/power) regions of Ethiopia, whereby grand targets are applied without conducting the energy needs assessment of a given region. A better approach is the utilization of the bottom up approach in conjunction with the effective articulation of the tripartite structure of Government, Academia, and Industry in order to overcome these barriers.
• Ethiopia has initiated engagement with Independent Power Producers (IPP) in the ongoing geothermal projects. However, appropriate Feed-in Tariff (FiT) topologies needs to be assessed for the different renewable energy technologies including appending the renewable energy policy document to the current energy policy document. The current energy policy document needs to have clearly defined policies for solid, liquid, and gaseous biomass fuels in order incubate a conducing environment for investors.

Data availability
All data underlying the results are available as part of the article and no additional source data are required.