Renewable and Sustainable Energy Reviews 57 (2016) 786–798 Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews http://d 1364-03 n Corr E-m journal homepage: www.elsevier.com/locate/rser Renewable based distributed generation in Uganda: Resource potential and status of exploitation Ssennoga Twaha a,n, Makbul A.M. Ramli b, Patrick M. Murphy c, Muhammad U. Mukhtiar d, Hussein K. Nsamba e,f a Energy and Sustainability Division, Faculty of Engineering, University of Nottingham, NG7 2RD, United Kingdom b Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah 21589, Saudi Arabia c Ira A. Fulton Schools of Engineering, Arizona State University, USA d Electrical Engineering Department, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia e Section of Industrial Chemistry, Department of Chemistry, Makerere University, Kampala, Uganda f Invention Plus Limited, P.O BOX 8303 Kampala, Uganda a r t i c l e i n f o Article history: Received 21 June 2014 Received in revised form 14 September 2015 Accepted 17 December 2015 Keywords: Solar Hydro Wind Biomass x.doi.org/10.1016/j.rser.2015.12.151 21/& 2015 Elsevier Ltd. All rights reserved. esponding author. Tel.: þ44 7928531186 /þ2 ail address: ssennogatwaha@yahoo.com (S. Tw a b s t r a c t Uganda is gifted by nature with abundant energy resources, mainly renewables, which can potentially provide the country with sufficient capacity to meet future growth in energy demand. Surprisingly, Uganda has one of the lowest electricity penetration levels, with only 9–12% of the total population having electricity access; 2–3% of them living in rural communities. There is multitude of challenges facing the energy sector of Uganda, forcing energy demand to always exceed the supply. For decades, hydropower has been and is still the base electricity supply of the country with a supplement of limited biomass, diesel based thermal and solar electricity. The objective of this paper is to review the potential and progress of renewable based distributed generation in Uganda. The potential of the country’s natural renewable resources and existing distributed generation is described and existing government policies are assessed. The challenges facing the energy sector and the suggested remedies are discussed. Various distributed generation systems that could be incorporated into the energy system of the country to improve renewable energy (RE) utilization and possibly contribute to the electricity needs of the population are also proposed and discussed. Exploitation of abundant RE resources through distributed energy generation around the region will not only improve the electricity needs of the country but also increase the economic welfare of the growing population. & 2015 Elsevier Ltd. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787 2. Background of Uganda and the energy sector in general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788 3. Renewable energy resource potential in Uganda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788 3.1. Wind energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788 3.2. Solar energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789 3.3. Hydropower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789 3.4. Biomass energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789 3.5. Geothermal energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790 4. The status of RE application in Uganda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790 4.1. Wind energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791 4.2. Solar energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792 4.3. Hydropower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792 4.3.1. Large and small hydro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792 56703328439. aha). www.sciencedirect.com/science/journal/13640321 www.elsevier.com/locate/rser http://dx.doi.org/10.1016/j.rser.2015.12.151 http://dx.doi.org/10.1016/j.rser.2015.12.151 http://dx.doi.org/10.1016/j.rser.2015.12.151 http://crossmark.crossref.org/dialog/?doi=10.1016/j.rser.2015.12.151&domain=pdf http://crossmark.crossref.org/dialog/?doi=10.1016/j.rser.2015.12.151&domain=pdf http://crossmark.crossref.org/dialog/?doi=10.1016/j.rser.2015.12.151&domain=pdf mailto:ssennogatwaha@yahoo.com http://dx.doi.org/10.1016/j.rser.2015.12.151 S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798 787 4.4. Pico, Micro-hydro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792 4.5. Biomass energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793 4.6. Renewable energy application in rural areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794 5. Related policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794 5.1. Feed-in tariff policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795 5.2. Subsidy policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795 6. Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795 7. Efficient policies suggested to improve RE exploitation in Uganda. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796 8. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796 Acknowledgement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797 1. Introduction Recent research showed that about 2% of world diseases is due to indoor air pollution emanating from solid-fuel cooking; the rate doubles in the poorest nations to 4%. As a result, approximately 1.6 million people die prematurely every year [1]. Solid biofuels provide nearly 50% of Africa's energy requirements and statistical figures show that about 94% and 73% of the rural and urban households in Africa are dependent on wood and charcoal for their energy needs, respectively [2]. Uganda is gifted by nature with abundant energy resources, mainly renewable, which can poten- tially provide the country with a sufficient capacity to meet the energy needs of the growing population. Despite this, the level of electricity supply and access by the population remains low. The abundant energy resources however have not been fully utilized, rendering the country to have one of the lowest electricity access levels, with only 5% and 9–12% of the total population reported to have access to electricity in 2005 and 2010, respectively [3,4]. In rural areas, the access levels are even lower, at only 2–3%. By comparison, Uganda's neighbor, Kenya, had connection rates of 18% for urban populations and 4% for rural populations in 2011 [5]. This can be attributed to various factors, but continued poverty is both a cause and a result. Uganda lacks energy access because it is poor, and remains poor because it lacks access to energy [6]. Electricity accessibility is vital to achieve the Millennium Devel- opment Goals on poverty reduction and environmental sustain- ability [7]. Where private industries try to supplement the existing grid power in Uganda, they mainly do so using electricity from diesel generators. For example, Muzizi Tea Estate had no connec- tion to the national grid in 2007 and relied on two 200 kW and one 100 kW diesel generators for electricity [8]. This increases environmental pollution and greenhouse gases (GHG), leading to more global warming, while also exposing tea production to volatile fuel prices. Research has been conducted on renewable energy resource exploitation in some countries across the African continent. The main purpose of briefly reviewing the energy status of some African countries is to show how different states have developed measures to boost the use of renewable energy (RE) in their individual regions, from which Uganda can draw lessons. Mohammed et al. conducted a study on the exploitation of local RE resources, including solar, biomass, wind, hydropower, and geo- thermal, in sub-Saharan Africa [9,10]. The authors covered the necessity to integrate power generation from RE in order to improve the energy supply of these countries. In another study, Mohammed et al. showed an increase in exploitation of wood- based bioenergy in the same region, especially in Ghana, Uganda, and Nigeria. From the study, the authors exposed massive con- sumption of bioenergy in the form of wood fuel resulting in deforestation, consequently affecting the environment [11]. An economic analysis for expanding RE to provide electricity access to rural areas in sub-Saharan Africa has been presented in Ref. [12], in which the study found that decentralized RE expansion is not the only solution to universal access; however, it is an important component of the global solution for universal access to electricity. Subedi et al. performed research to assess the link between development of wood-based biomass energy and deforestation. The authors concluded that the biogas production has the poten- tial to reduce deforestation by providing a source of energy that would otherwise be provided by wood fuel [13]. In another paper, Shaaban et al. reviewed the potential of RE in Nigeria. The authors described possible government policies to realize rural elec- trification based on wider RE applications [14]. It is revealed that a RE Master Plan was formulated to increase RE investment in Nigeria. The objective of this plan was to promote sustainable energy development in this country [15]. However, the objective of the plans has not appreciatively achieved due to inherent obstacles militating against the effective implementation of an orderly energy policy in Nigeria [16]. Mohammed et al. and Hensley et al. conducted a review of biomass energy potential and evaluated bioenergy resources for rural electrification in Ghana [17,18], showing that increased investment in renewable energy resources will in the long run balance the national energy equation, ensure energy security and promote sustainable development. Challenges for sustainable development in the same country have been studied by focusing on the rural energy sector [19], the most important of which were noted as technological constraints in relation to local food systems, traditions, and environmental protection issues. In addition, Kemausuor et al. conducted a review of national policy for increasing access of energy in Ghana focusing on RE [20]. In another sub-Saharan country, Malawi, small-scale hydropower has been developing over the last two decades. Chiyembekezo pre- sented the latest status of potential and application of small-scale hydropower in the country [21]. A study on off-grid generation options based on PV and the micro-hydro hybrid system for a remote area in Cameroon was simulated in [22]. It is concluded that the micro-hydro hybrid system is the cheapest option for villages located in the southern parts, while the PV hybrid system is the cheapest option for villages in the northern parts of Cameroon with an insolation level of at least 5.55 kW h/m2/day. This indicates that whereas some RE energy resources may not provide a sizable amount of enough in one location, they can work well in another location, necessitating the diversification of the energy supply with several RE energy resources available in the country. In Ref. [5], the authors reviewed the potential of RE sources, i.e. hydropower, biomass, wind, solar and geothermal, in Kenya, a country in the East Africa region. Of the potential RE sources, biomass energy has huge potential to help meet the strong growth of energy demand in the country. A study on the potential of biomass energy in Kenya was also performed. It was concluded that the energy from biowaste residues can play a major role as a substitute for fossil fuel based electricity generation in the country $0.00 $100.00 $200.00 $300.00 $400.00 $500.00 $600.00 1962 1972 1982 1992 2002 2012 G D P pe r c ap ita Year Fig. 1. The trend of Uganda's GDP from 1962 to 2012. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798788 [23]. In addition to these efforts, Abdullah and Jeanty examined the willingness of households in Kusumu District, Kenya, to pay for energy and energy services. This was intended to promote elec- tricity access in rural communities by showing that the price households were willing to pay exceeded the cost of electricity delivery [24]. In Tanzania, another part of East Africa, the planning and reg- ulation of rural electrification were done in line with 2008 Elec- trification Act. One of the action plans was to diversify energy sources by exploiting wind and geothermal energy, as well as upgrading the existing hydropower, biomass, and solar energy sources [25]. This would provide a more secure energy supply to the country as well as benefiting from other advantages of RE. A study of agricultural and forest residues based bioenergy potential and review of bioenergy technologies development in Uganda is conducted by Okello et al. [26]. It is indicated that bioenergy can make a considerable contribution to RE diversifi- cation and the use of improved bioenergy technologies is recom- mended to minimize the negative impact on the environment and to guarantee sustainable energy production from biomass [25–27]. Despite some efforts being underway to improve the biomass sector, much efforts are still necessary to improve the level of technology used in biomass utilization such as the use of sus- tainable technologies for small-scale biochar production [28]. This is one of the solutions that is likely to strengthen the bioenergy sector in the country. Uganda's RE potential remains underused and underspecified. In this paper, the resources potential and status of exploitation of renewable based distributed generation in Uganda are investi- gated. The study covers biomass, hydropower, solar, wind, and geothermal energy resources as well as the existing policies on RE. 2. Background of Uganda and the energy sector in general Uganda is a landlocked country located in East Africa, bordered by Kenya to the east, South Sudan in the north, Democratic Republic of the Congo in the west, Rwanda in the southwest and Tanzania in the south. Located on the basin of River Nile, this country is situated between latitudes of 4°N and 2°S and long- itudes of 29° and 35°E. Almost a fifth of the country is made up of open water or swampland. This land varies in its physical features from plains to mountains and forests [29]. The population of Uganda is approximately 35 million [30]. The economy of Uganda is dependent mostly on agriculture. Uganda is bestowed with a variety of RE resources like biomass, solar, geothermal, wind and hydropower, which will be explored in detail in Section 3. Since attaining independence in 1963, Uganda experienced low levels of Gross Domestic Product (GDP) growth from a low base, growing from less than US$100 per capita in 1962, to its maximum value of about US$500 in 2012 as shown in Fig. 1. This can mainly be attributed to the difficult political times and frequent political regime changes during this period. In fact Neelsen et al. stresses that tens of years of political disorder and fierce conflicts are partly responsible for making Uganda one of the poorest countries in the world [31]. Fig. 2 shows the comparison of GDP per capita for Uganda and other countries. It can be observed that in the 1960s, Uganda was at the same level of development as countries like Malaysia, Mauritius and Republic of Korea. However, the difference between Uganda's GDP and the other countries under comparison has widened for a number of reasons, the major one being the avail- ability of energy to support economic and social activities in the country. For a long time it has been well understood that there is a direct relationship between insufficient energy supply and low levels of development [3]. For example, Malaysia with a total population of about 24 million generates 2091 MW from only hydro [32], which is already higher as compared to Uganda with about 37 million people (mid 2012) and a total generation capacity of only around 820.5 MW [33]. The total installed generation capacity of Uganda is around 820.5 MW and the available (usable) generation is 558.5 MW. Peak demand is about 487 MW and the annual average load growth is 10%. Currently, energy supply in Uganda is based on large hydro- power (82%), thermal (10%), mini-hydro (5%), and cogeneration (3%) [34]. Uganda's current base power source is the power gen- erated from hydroelectric power stations located at Nalubaale and Kiira Power Stations (formally Owen falls dam) in Jinja. In addition, there are thermal, mini- and micro-hydro power stations scattered around the country, some of which contribute to the national power grid and some that directly serve specific communities and individuals. Hydropower is the predominant source of energy to generate electricity in Uganda. The main grid obtains its rest of energy from thermal generators and bagasse power plants. Some off-grid power plants supply power to some areas. Kisiizi Hospital, West Nile Rural Electrification Company (WENRECO) and Kihihi thermal generation plants are some examples. Power is also imported from Rwanda for Kisoro town, as it is near a grid from Rwanda that provides power more affordably than that from the Ugandan grid. Uganda also exports some power to nearby areas in neighboring Rwanda, Tanzania and Kenya [35]. Increase in cogeneration in collaboration with sugarcane industries, dissemination of PV sys- tems in rural areas and supply of energy saving equipment are some of the policies under consideration. Uganda is also planning a nuclear energy program. The Atomic Energy Act 2008 was pro- mulgated on 18th February 2009 which is paving the way for a nuclear program [36]. Uganda's nuclear potential has been championed since 2009 by IBI International and recently the energy ministry signed a five-year Framework with the Interna- tional Atomic Energy Agency (IAEA) for safe application nuclear technologies. The Uranium Strategy proposes working with the Government of Uganda towards a nuclear electrical power gen- eration program to meet the current and future needs of Uganda plus potential exports of electrical power to the East African region. However, some experts have cast doubt on the country's ability to develop nuclear technology [37]. 3. Renewable energy resource potential in Uganda 3.1. Wind energy Earlier studies show that wind speed in some regions of Uganda is moderate for wind to electric energy conversion, with Fig. 2. Comparison of the GDP per capita for Uganda and other countries [32]. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798 789 mean wind speeds at heights less than 10 m ranging from 1.8 m/s to about 4 m/s, while the optimal wind speed for typical 10 kW turbines at this height being 12 m/s [38]. Wind data collected by the Meteorology Department of the Ministry of Energy and Mineral Development (MEMD) reveals that the wind speed is merely appropriate to fulfill the energy requirement for special use such as water pumping, especially in the Karamoja area in remote, northeastern Uganda. Small industries with power capacity needs ranging from 2.5 kV to 10 kV in rural areas can be satisfied using wind energy if numerous small scale wind turbines are installed throughout the region where wind resources are available. How- ever, wind energy has not received as much attention as solar energy as an alternative to hydro in Uganda. 3.2. Solar energy Solar energy plays a significant role in the family of renewable energy. Generally, there are four ways of utilizing solar energy: (1) solar photovoltaic (PV) power generation, (2) solar thermal electric power generation, (3) solar water heaters, and (4) solar houses in building applications [39]. The unit cost PV is decreasing day by day and with technological advancement and efforts to boost efficiency, PV will ultimately become the dominant energy supplier in the world [40]. It is projected that PV will provide around 345 GW equivalent to 4% by year 2020 and 1081 GW for 2030 [41]. Uganda is endowed with abundant sunshine, which is a blessing that should be turned into prosperity by transforming the available solar potential into usable electric energy. Fig. 3 displays a map that shows solar energy availability in Uganda. Available solar data visibly demonstrates that solar energy is high all over the year, even during the rainy seasons. Generally, the country has peak solar radiation of 5–6 kW h/m2/day on the horizontal surface, signifying an outstanding potential for solar energy use [42,43]. With a mean solar radiation of 5.1 kW h/m2/day on a horizontal surface, it is reported that the country has a gross solar energy potential of about 11.98�108 MW h/[day/year]. At an estimated conversion efficiency of 10%, it is estimated that this provides 11.98�107 MW h of energy per [day/year] [44], which is about 3422 kW h per capita, a value more than the electric energy con- sumption of 2967 kW h per capita for Argentina in 2011 [45]. It can be observed from the map in Fig. 3 that the highest potential of about 5.6 to 6.8 kW h/m2/day occurs in the western part in the districts of Hoima, Masindi and Kabale as well as in the North- eastern parts of Kotido, Moroto and Nakapiripit. The biggest area of the country possesses solar radiation between 4.8 to 5.6 kW h/m2/day including the Northern, Central and Southern regions. Even the colder areas such as Kabale, Kisoro, Kanungu in the Southeastern part still have solar radiation between 2.4 and 4 kW h/m2/day which is also attractive for some solar applications such as solar water heating. 3.3. Hydropower The country contains various water bodies including Lakes Albert, Kyoga, Wamala, Katwe, Bisina, Nakivale, Bunyonyi, Mburo, George and the largest Lake Victoria which is shared by Uganda, Tanzania and Kenya. Rivers include Kagera, Aswa, Nile and other small ones [35]. The main and base electricity supply is generated from the Nile River which is the major contributor of electricity, primarily from the Kiira, Nalubale and the New Bujagali hydro- power stations [42]. 3.4. Biomass energy Biomass comprises of all biological material derived from liv- ing, or recently living, organisms. In the context of biomass for energy this is often used to mean plant based material, but bio- mass can equally apply to both animal and vegetable derived material [46]. With the inflation of oil prices, biomass based power generation is becoming increasingly competitive and considerably cheaper than thermal power based on fossil fuels. The need for modern biomass energy has become more essential due to the increasing scarcity of hydropower resulting from increased elec- tricity demand in addition to unfavorable weather changes that have resulted in reduced water levels in the Lake Victoria catchment area. The cogeneration/trigeneration systems are such systems which comprise an integration of primary and secondary sub- systems that generates power, air-conditioning and refrigeration using a single energy source [47]. Energy cogeneration is one of the energy production technologies where biomass energy can be used as a clean form of energy whereby simultaneous production of two or more forms of energy such as heat and electro- mechanical energy from the same input source is possible [48]. A significant peat resources of about 25 million tons is feasibly available for power generation which is equivalent to 800 MW of potential capacity for 50 years [49]. This level of potential is quite high if well utilized with proper energy harvesting systems such as heating, ventilation and air conditioning (HVAC) systems which Fig. 3. Solar energy availability in Uganda. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798790 are noted to constitute a major part of electrical energy con- sumption [50]. 3.5. Geothermal energy Geothermal energy, one of the potential RE sources in Uganda, is mainly concentrated in the western region. More than 40 geo- thermal sites were studied for their prospect parameters like reservoir temperature, chemistry of reservoir, natural heat trans- fer, and fluid characteristics to identify specific project areas and prioritize them for more detailed investigation [34]. Fig. 4 shows a map with identified sites for geothermal power generation in Uganda. From the study carried out, three major potential areas including Kibiro, Katwe, and Bulanga were found to have high potential for geothermal power generation with combined esti- mated power potential of 450 MW. These three area sites are characterized by high reservoir temperatures and high ground permeability resulting from their tectonic and volcanic features. These are located near the western Rift Valley of Uganda [51]. 4. The status of RE application in Uganda Uganda's energy sector is undeveloped and characterized by, among other things, extremely low levels of modern energy con- sumption and heavy reliance on biomass energy which accounts for 93% of total energy consumption. It is envisaged that this trend will continue in the foreseeable future. Petroleum accounts for 6% of total energy consumption, while electricity accounts for 1% of the total national energy balance. Biomass is predominantly used at the household level for cooking and heating applications mainly in form of wood or charcoal. Wood and charcoal are respectively used on traditional “three bricks” stoves and improved efficient stoves which are Fig. 4. Map showing identified sites for geothermal power generation in Uganda [50]. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798 791 made out of steel and clay [52]. The traditional “three bricks” or “Jua kali” stoves are made of strong iron sheets, mainly collected from old dismantled buildings. In addition, a considerable amount of biomass is also used in the services/commercial, institutional, cottage industry and industrial sectors agro processing as fuel wood, and charcoal in restaurants and institutions, while bagasse is used in sugar factories. Use of biomass in other industries is relatively low but is on the increase with many industries switching from heavy furnace oil to vegetal wastes like coffee husks and rice husks for their thermal energy requirements [53]. Uganda's power sector is suffering from a shortage of generating capacity due to lengthy drought, inadequate investment in least cost- generation capacity and a relatively high load growth; the power deficit is currently estimated at 130MW. This has resulted in massive electricity rationing and has forced the country to resort to expensive thermal generation. The country currently depends on hydroelec- tricity for around 60% of its total power generation output; the remainder of Uganda's power generation comes from thermal power stations, fired by bagasse and diesel, and a small percentage of other renewable electricity (making 4%) [51]. 4.1. Wind energy Generally the wind energy resource has not been used mainly due to limited awareness of the technology behind the functioning of wind energy systems. Another reason according to our analysis is because the wind energy resource is overshadowed by the vast solar RE potential available in almost all areas in Uganda. In addition, solar products are becoming cheaper day by day and are mainly made available at various sales outlets especially in urban centers in the country. Hybrid DG systems are proved to be more reliable and effective in performance than single source power systems especially for microgrid operations. For example, a study on the application of a micro-hybrid solar PV/hydro/wind system was conducted in which six sites with small-scale hydropower potentials were identified [54]. The analysis of the results indi- cated high capability of hybrid systems to cater for the electricity needs of small communities. We have observed that in the Kar- amoja region both wind and solar potential is available while in some other areas, wind, solar and hydro energy resources have attractive potential for hybrid systems application. In our previous research in [55], a method of determining the best hybrid S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798792 renewable-based DG system with feed-in tariff (FIT) and ranking technique was presented. It was clearly observed that a hybrid wind/PV/hydro exhibited better performance compared to the PV/ hydro system with storage in terms of improved reliability and increased RE penetration levels. Similarly, wind energy can be utilized if hybrid systems are adopted especially those operating on microgrid integrations in different locations in Uganda. Gian- noulis et al. conducted a study on DG systems in an isolated island in Greece and the results indicated that the integration of RE through microgrid can result into increased environmental bene- fits with relatively high cost of energy (COE) compared to that of the main grid [56]. However, they suggested that the COE can be lowered by advocating for technologies and strategies of reducing electricity surplus in the power system, thereby rendering RE resources exploitable more efficiently. 4.2. Solar energy Currently, solar energy is used primarily for off-grid elec- trification in rural communities, as well as for solar cooking, and providing water heating and power to public buildings and hos- pitals. Over 30,000 PV systems are installed throughout the country representing about 1.1 MW of capacity. This includes both institutional and solar home systems with the former accounting for a greater portion of that installed capacity. Currently, a 50 MW solar thermal plant, at Namugoga in the Wakiso District outside of Kampala, is being investigated by a private firm, Solar Energy for Africa [57]. The Feed-in-Tariff (FIT) scheme has attracted some investors in the solar RE development and in January 2014, the Electricity Regulatory Authority (ERA) announced the construction of eight RE projects with a total capacity of 83.7 MW which were to begin soon [58]. An on grid hybrid solar project/diesel of 1.6 MW was completed by the Premier solar company under the sponsorship of Kalangala Infrastructure services project (KIS), a company which develops environmentally sensitive infrastructure services to serve Kalangala island residents with improved access to water, safer transportation, and more reliable, renewable (solar powered) electricity. KIS is a subsidiary of InfraCo Africa Ltd. which is an international NGO that funds various projects in Africa [59]. Solar cooking also holds a significant potential in the country, with a large number of the population living in well-radiated areas, with- out access to energy services [42]. There have been efforts to sensitize people to the use of solar energy and small PV in the country. Joint Energy and Environment Projects (JEEP) Uganda Nordic Folk center for RE, Denmark is one of the NGOs that have sensitized the masses in areas of Arua, Luwero and Tororo [60]. The major share of the installed solar PV systems is usually project or donor supported through the government. The appli- cations are mainly in the health, water, education and local gov- ernment sectors. The World Bank-supported rural electrification program referred to as “Energy for Rural Transformation (ERT)” is Table 1 List of some of the private solar companies in Uganda: Internet sources. Company Location Items Power Trust Uganda Limited Kira Road Ntinda, Kampala Solar panels, Solar Batteri UltraTec (U) Ltd. Kabalagala, Kampala Solar PV, Solar water hea MAK Power Systems Ltd. Namungoona, Kampala Solar Systems Sales and S Suntopway Solar (U) Ltd. Portal Avenue, Kampala Solar systems Energy Systems Solar system sales and se Solar Construct Ltd. Kibira road, Kampala RE Solar Energy for Africa Kampala, Mbarara. Soroti, Mbale Sales, installations, maint energy/power systems, eq Davis & Shirtliff Uganda PV modules, hot water he controllers [65] the core driver behind most of the government initiated projects [51]. The solar PV market in Uganda has steadily grown over the last 15 years with new players entering the market, including foreign investors. While 10 years ago there were a handful of solar companies mainly engaged in institutional solar PV installations, there are now over 30 companies involved in the solar business (both PV and solar thermal). Table 1 gives a list of some of the private solar companies in Uganda that provide sales and services [61–66]. 4.3. Hydropower As noted in Section 3 above, Uganda has a sizeable amount of hydropower potential which is favorable for large and small scale hydro power stations. Fig. 5 shows a map highlighting the pro- posed, ongoing and operational hydropower sites within the region. The map has been extracted from an interactive map that shows the energy utilities of the country. An interactive map was developed by the Energy Sector GIS Working Group (E-GIS) and received an award from the parliament of the Republic of Uganda for producing the best map in support of their contribution towards the energy sector [67]. The E-GIS is a collaboration of the major players in the energy sector in Uganda such as Uganda Electricity Transmission Company Limited (UETCL), UMEME, Rural Electrification Agency (REA), MEMD and German Agency for International Cooperation (GIZ) [68]. UMEME, named for the Swahili word for lightning, is the largest electricity distribution company in Uganda. It is mandated by the government to: operate, maintain, upgrade and expand the distribution network; retail electricity to its customers; and to improve efficiency within the electricity distribution system [69]. 4.3.1. Large and small hydro The operational hydro capacity along the river is 380 MW developed at Kiira and Nalubaale, and 250 MW at Bujagali, meaning that the unexploited potential is about 1300 MW. The large hydropower projects being developed include Karuma- 600 MW, Isimba-180 MW and Ayago-600 MW. 4.4. Pico, Micro-hydro There are micro-hydropower sites but they are not located on the Nile, and although they possess potential resources, they have not been fully exploited. These are important sources of electricity for Uganda. Over 50 potential sites for small hydro have been identified near rivers with a capacity of more than 164 MW of electricity [34]. Table 2 shows the estimated capacity of a number of identified sites which have the potential for development. Nature Date of establishment es and Appliances [61] Private Sept 2011 ting and Solar cookers [62] Private 1999 ervices Private – Private – rvices [63] private 2000 Private – enance and servicing all types of solar [64] uipment and appliances Private 15 years in existence aters, pumps, lighting accessories, inverters and Private 1945 Fig. 5. Proposed, ongoing and operational hydropower sites in Uganda. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798 793 4.5. Biomass energy Biomass contributes 85% of the total energy of the country in which 72.7% of the households use three-stone stoves and 14.8% use traditional charcoal stoves. Beyond cooking, five digester plants were installed by 2004 [26]. The traditional stoves are typical agents of indoor air pollution mainly smoke particulates, CO and CO2. Energy-saving stoves, based on the rocket stove principle, are being promoted by the government with the support of GIZ. Under this program, more than 500,000 improved stoves have been distributed since 2005. However, despite these efforts, the current level of adoption of improved biomass combustion technology is still low in the country with about 8.7% of Ugandan households using improved biomass stoves. The major causes for Table 2 Estimated capacity of a number of identified small hydro power sites. Site Estimated capacity District Estimated Pico hydro capacity and technical feasibility studies done Kakaka 7.2 Kabarole Nyamabuyo 2.2 Kisoro Yerya, Mahoma confluences 3 Kabarole Siti 2.5 Kapchorwa Nyahuka 0.65 Bundibugyo Nkusi (at Pachwa) 0.6 Kibale Sezibwa 0.5 Mukono Tokwe 0.4 Bundibugyo Ngiti 0.15 Bundibugyo Myembe/Sirimityo 9 Mbale Ririma 1.5 Kapchorwa Estimated Pico hydro capacity without technical feasibility studies Mvepi 2.4 Arua Sogahi 2 Kabarole Ela 1.5 Arua Haisesero 1 Kabale Rwizi 0.5 Mbarara Rwigo 4.8 Bundibugyo Narwodo 4 Nebbi Agoi 0.35 Arua Kitumba 0.2 Kabale Amua 0.18 Moyo Leya 0.12 Moyo Nyakibale 0.1 Rukungiri Miria Adua 0.1 Arua Nkusi (At escarpment/Lake Albert) 11 Kabale Table 3 Consumption of bioenergy in Uganda. Sector Wood (TOE/year) Charcoal (TOE/year) Residents (TOE/year) Residential 5957976 406756 488106 Commercial 1242267 195855 0 Industrial 999213 0 0 Total 8199456 602611 488106 S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798794 the low adoption of these stoves are due to limited sensitization of the masses about their importance, as well as poverty. Okello [26] reported that energy-saving stoves, based on the rocket stove principle, were being promoted by the government with support of German Agency for International Cooperation (GIZ) under the ‘‘promotion of renewable energy and energy efficiency” program, but this is limited to a small portion of the population. On the other hand, those with low incomes prefer to use the traditional stoves which are generally cheaper than the improved stoves. Table 3 shows the share of bioenergy consumed every year for each sector in the country. Kakira Sugar Works Limited and Kinyara sugar mills are officially allowed to generation and supply electricity of 12 MW and 5 MW, respectively to the national grid. 4.6. Renewable energy application in rural areas Despite the rapid urbanization that has been experienced, most people in Africa still reside in rural areas [70]. In Uganda, the majority of the population lives in rural areas with limited access to electricity. The rural electrification agency (REA) was formed by the MEMD in respect to the 2001 statutory instrument to improve electricity access to rural communities [71]. The projects under its mandate include grid extension, RE generation and developing microgrids for rural areas. The government has set out various strategies to improve energy access to the rural population. REA is mandated in the “REA Strategy and Plan (2013–2022)” with the task of fulfilling the government's goal of increasing rural electricity access to 22% by 2022, up from the current rate of 2% [72]. The REA board recently announced the bids for consultancy for the development and access expansion of electricity to seven towns, which is part of the implementation of the financial assistance received from the OPEC fund for international devel- opment [73]. Although the grid extension exercise is one of the major tasks for REA, the critics of this exercise say that the con- nection costs in rural areas are high and consequently the cost of a kW h of energy is high and power consumption is low due to few connections per kilometer [74,75]. Murphy et al. carried out the analysis of grid reliability by comparing grid extension and use distributed energy resources (DER) and they discovered that installing micro-DER systems were more cost-effective and pro- vide more reliable energy than grid extension [76]. This is because the mean time between failures of the grid system in Uganda is high which prompts the use of other sources of electricity during frequent grid outages. However, some efforts have been made to utilize the use of solar systems especially at the roof tops for individual households. Although some solar PV projects are in operation and others in the offing, the progress of RE utilization in rural areas is too slow mainly due to a lack of financing and ignorance about the usefulness of RE systems. Therefore, the REA and the government-private in general should intensify efforts to sensitize the masses especially on the use of solar systems. Limited data about RE energy resource is another challenge. For example solar data such as global solar irradiation, diffuse radiation, etc. for different parts of the country is not usually recorded. This makes the selection and operation of renewable energy system difficult. For instance it is difficult to predict the tilt angle of a PV panel for a certain location using some intelligent methods [77], without solar radiation data. 5. Related policies The Promotion of RE and Energy Efficiency (EE) Program (PREEEP) is a project championed by the Ministry of Energy and Mines in collaboration with GIZ to promote EE and RE. The gov- ernment is also encouraging the use of energy saving appliances such as energy saving bulbs. The National Energy Policy 2002 was mainly put forward to enable the energy sector to contribute to the economic and social welfare of Ugandan population in an environmentally sustainable way. This was followed by various initiatives such as the study of RE potentials and identifying the candidate sites for development. As a result, a number of solar and hydropower projects have been proposed and some are operational such as the Bujagaali 250 MW hydropower station. The MEMD in 2007 announced the RE Policy 2007 (REP-2007) whose major aimwas to increase the use of modern RE, from 4% to 61% of the total energy consumption (excluding hydropower) by the year 2017. Other secondary objectives were to support the provision of sustainable and reliable RE services while at the same time make it accessible to the population, mainly to foster the eradication of poverty. Modern bioenergy systems and technolo- gies were one of the targets. It was in this policy that the Feed-in- Tariffs (FIT) for RE and Standardized Power Purchase Agreement were established. Key targets included increasing solar water heater installations to 30,000 m2, and applying industrial energy appraising while awarding certificates of performance to out- standing industries and the distribution of efficient equipment to industries. Table 4 FIT for RE, O&M percentage, capacity limits and the valid period for the tariff [78]. RE resource Tariff (US$/kW h) O&M (%) Cumulative capacity limit (MW) Valid period of payment (Years) 2013 2014 2015 2016 Hydro (H) (94Ho¼20 MW) 0.079 7.16 30 90 135 180 20 Hydro(14o¼9 MW) Linear tariff 7.24 30 75 105 135 20 Hydro(500kW4o¼1 MW) 0.109 7.08 1 2 2.5 5.5 20 Bagasse 0.081 22.65 30 70 95 120 20 Biomass (MSW) 0.103 16.23 5 15 24 45 20 Biogas 0.115 19.23 5 15 24 45 20 Landfill gas 0.089 19.71 0 10 20 40 20 Geothermal 0.077 4.29 10 30 50 75 20 Wind 0.124 6.34 25 75 100 150 20 Fig. 6. Linear Tariff rates defined for 1 to 9 MW [78]. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798 795 5.1. Feed-in tariff policy Uganda took an early lead in East Africa to implement the FIT system. Rwanda has taken tremendous steps in developing the RES but the developments were faced with a number of regulatory challenges because the FIT was not then in place [78]. Uganda adopted the Global Energy Transfer Feed-in-Tariff (GET-FIT) scheme for RE. The Global Energy Transfer Feed-in-Tariff (GET-FIT) program is an arrangement intended to help the advancement of RE in developing countries through the creation of international public-private partnerships. In this set-up, international AAA-rated donors such as national governments, development banks, and international climate-related funds contribute premium payments for RE projects in partnership with developing country govern- ments [79]. In Uganda, the tariffs for each energy resource tech- nology are determined by means of a US$/kW h levelized cost- approach with the consideration of electricity generation costs incurred by RE energy operators [80]. Table 4 gives the details of the phase 2 REFIT tariffs, O&M percentage, capacity limits and payment period introduced in Uganda in 2012. To cope up with the unstable foreign exchange rate of the dollar in the country, the REFITs are accustomed to adjustment to accommodate the infla- tionary fluctuations by applying Eq. (1). FITy ¼ FITy�1 � 1�wð Þ� �þ FITy�1 � PPIy PPIy�1 �w � � ð1Þ where FITy is the feed-in tariff applied in the current year y; FITy�1 is the feed-in tariff applied in the foregoing year; w refers to the share of O&M in the starting FIT in the year 'y' PPI is Core Producer Price Index defined for US by the Bureau of Labor Statistics [80]. As noted from Table 4, RE technologies are assigned constant rates with the exception of hydro in the range of 1–9 MW whose rates are defined as a function of capacity as shown in Fig. 6. Further details regarding REFIT in Uganda are found in [80]. It can be observed from Table 4 that the FIT rate is based on the cumulative capacity limit (CCL) for each year. Since larger capacity is needed in the subsequent years to maintain the FIT, indepen- dent power producers (IPP) for RE will consider the assessment of solar energy generation at large scale in which choices of config- urations exist [81]. For instance, in the first configuration, they might have to consider absolute minimization of storage with excessive increase of power production capacity which is relatively cheaper due to minimized storage but with less energy security. Conversely, a configuration with extreme storage corresponding to absolute minimization of generation capacity can be applied which is more expensive, provides less power output but at the expense of increased energy security. The first configuration scheme may be one of the options to enable the IPPs to meet the required capacity limits. [80]. 5.2. Subsidy policy The partnership between the Private Sector Foundation of Uganda, the government through the Electricity Regulatory Authority (ERA) and nine donor agencies led to an offer of a 45% subsidy on solar power equipment, up from the earlier 17% value which was set by the government. The purpose was to encourage private suppliers to invest in solar products in rural areas to enable remote areas have access to electricity [82]. Subsidies and incen- tives for RE were planned and guided by The Rural Electrification Strategy and Plan covering the period 2005–2011. The aims of the strategy were to attain unbiased regional supply of energy, exploit the environmental benefits of rural electrification subsidies and promote grid expansion alongside developing off-grid electrifica- tion in remote areas. As a result, electricity has been deeply sub- sidized and the Ministry of Energy estimated that since 2005 the government has spent about €390 million on power subsidies. Although the subsidies have not been completely scrapped, it is anticipated that subsequent rounds of price hikes will be imple- mented in the near future. The decision will encourage the increase of private sector investment in the power supply sector and also enable the Uganda government to invest in large hydropower projects. 6. Challenges There is a very close linkage between energy and development. Energy policy and strategic planning can favorably converge with any form of development provided the two concepts are planned to achieve resource diversification. Among the developing nations of Southeast Asia are countries like India, Malaysia, Singapore and China that are benefiting from a positive economic outlook and significant poverty reduction due in part to increased access to electricity [10]. S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798796 Further utilization of RE resources to meet the growing energy needs of the Ugandan population can be achieved through addressing the following: ● Development of the required manpower resources Technically trained human resources are a necessary ingredient in any developmental activity. Francis observes that two of the reasons for low private sector investment in the energy sector in Uganda are technical and financial risks [83]. In Malaysia, the lack of technical expertize from the pertinent agencies is reported to result into poor quality products and give RE utilization a bad image [84]. Therefore, the concerned authorities should prioritize the area of training and development of individuals to support the energy sector. � Economic empowerment of the masses Economic empowerment indirectly means reducing the level of poverty within the population. It is not exaggeration to mention that high levels of poverty are still prevalent in Africa, particularly in Uganda. Poverty alleviation can disrupt the application of RE as non-RE is inexpensive in the short term [85]. Improving electricity generation is one of the major channels for reducing economic and social problems. Javadi et al. notes that electricity can improve the human lifestyle by raising the level of health, education, welfare and technology [86]. So, the government should concentrate on advancing energy capacity alongside poverty alleviation efforts. 7. Efficient policies suggested to improve RE exploitation in Uganda Although Uganda is one of the countries in Africa to introduce FITs, others being Tanzania, Kenya, Mauritius, Algeria, Rwanda, South Africa and Egypt [14], this policy should be well managed in order to attract potential investment companies and at the same time close monitoring of their activities should be done. Well trained personnel in the government or private audit organiza- tions should be assigned the responsibility of handling this process in order to facilitate the smooth operation of the REFIT program. In our previous research, it was presented how the FIT can be utilized to provide electricity to different regions in Uganda by using a net metering plan [87]. However, according to our observation, the major obstacle is a lack of funding. The solution to this is incor- porated in the REFIT where IPPs will be responsible for funding the power projects and sell the produced energy to the government through PPAs. Besides the grid-connected PV systems, regional based micro- grid DG systems should be adopted especially in remote areas far away from the national grid. These have the advantages of reduced blackouts in the main grid, high efficiency performance, environ- mental suitability and are becoming the preferred option for new and remote applications where the cost of grid extension is unaffordable and not the best option [88]. It is suggested that the adoption of renewable energy by the individual households be further promoted to increase the exploitation of RE in Uganda. Eder et al. in their research identified three critical dimensions that are crucial for the adoption of RE as being technical, economic and social [89]. They suggest an emphasis on the relative advantages of the new technology. In addition, there are economic requirements regarding a viable financial system for adopters, especially in such a low-income market. The social dimension is critical, particularly the impor- tance of foreign firms collaborating with local actors. Although the government has continuously subsidized elec- tricity, the subsidies schemes have failed to improve the electricity supply situation in the country. This may be attributed to the channels and ways of subsidization used by the authorities. The country has suffered the increasing burden of subsidizing power amidst a depreciating shilling, especially diesel generating com- panies, which contributed power to the grid [90]. However, this type of financing is short lived and not cost-effective as it leads to more pollution. The long term solution would be the provision of incentives to individual households or communities to install small scale RE systems in their proximity. This will definitely reduce the burden on the scarce available grid power. As an example, in Spain the government established more than 50 autonomous communities (ACs) with the powers to pass bylaws regarding the use of RE energy. There are two categories of local incentives granted to the local communities: subsidies and tax incentives [91]. The councils can authorize a non-refundable subsidization for the implementation of solar energy in which 50% of the activity cost can be funded. However, the granting process is competitive dependent on well established procedures; first based on priority and the application submitted by the com- munity or based on nomination of the local community budget. Pertaining to the future development of RE through the “vision 2040 report” [33], it is estimated that Uganda will require 41,738 MW by year 2040 thus increasing its electricity consump- tion per capita to 3668 kW h. These energy requirements are expected to be achieved through the use of the country’s RE and non-RE energy resources as well as the importation of electricity from neighboring countries. In addition, national grid accessibility is also projected to be 80% and new transmission lines will be constructed to transport power especially to the economic zones as well as supporting rural electrification programs. This can easily be achieved by adopting decentralized grid access through the application of hybrid DG systems. Given the relative importance of the development of RE resources, the government may set up a special body responsible for overseeing all the activities related to RE projects. This will help in streamlining the priority needs in this RE sector. For instance in Malaysia, the Sustainable Energy Development Authority (SEDA) was proposed to be set up with responsibilities such as advising the government on matters related to RE, pro- mote and implement the state policies concerning RES and foster their development in the country [92]. Standardization of renewable energy production processes is necessary to support those small scale RE industries such as bri- quette making industries. Ngusale et al. reported the energy situation in Kenya, briquette making process as well as the chal- lenges and opportunities in briquette making [93]. It was realized that despite the challenges faced in the briquette making process such as lack of standard ratio and specific mixture for optimum briquette production, most briquette producers are well along in the briquette business and consumers are satisfied with the use the briquette fuel as an alternative fuel. However, with standard production procedures, the quality and quantity of output would increase. In Uganda, the biomass energy strategy 2013 is a step in a right direction though more effort is needed fully empower the renewable energy industries [53]. 8. Conclusion In the beginning of the second half of the 20th century, Owen Falls dam hydropower was the first power station in the country to provide electricity for Uganda and some neighboring countries. Although other hydro power stations have been constructed sup- plemented by thermal diesel generation, bagasse from Kakira and S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798 797 other small quantities from other RE, the Ugandan population is still suffering from a lack of electricity with reported access by only about 12% of the population and per capita consumption of less than 10% of the world median consumption. Located in East Africa, Uganda is one of the countries with abundant RE resources ranging from solar, wind, hydro, geothermal and bioenergy resources. However, not even a quarter of the available RE potential is utilized at the time of writing. In this paper, we have presented the review of the potential of RE resources with regard to different regions in the country. The current status of RE application has been reviewed, and the present energy related policies and subsidy schemes have also been analyzed. Challenges facing the exploitation of RE have been discussed and efficient policies to overcome the sighted challenges and improve RE exploitation in Uganda were suggested. Future development strategies for RE in Uganda have been articulated. Although feed- in tariffs have been introduced in the country, their success will depend on how they are administered by the concerned autho- rities and power producers. The status of energy, in particular electricity in rural areas, has been discussed and ways to make the rural electrification scheme benefit the rural community have been suggested. Acknowledgement The first author (Ssennoga T) acknowledges the scholarship for PhD at University of Nottingham (UoN) from Islamic Development Bank (IDB) and UoN. He also appreciates the scholarship for Msc. at UTMMalaysia from IDB. He also extends sincere gratitude to the government as well as the people of Uganda for sponsoring his first degree at Kyambogo University. References [1] Kshirsagar MP, Kalamkar VR. A comprehensive review on biomass cookstoves and a systematic approach for modern cookstove design. Renew Sustain Energy Rev 2014;30:580–603. [2] Lee LY. Household energy mix in Uganda. Energy Econ 2013;39:252–61. [3] Hazelton JA, Windhorst K, Amezaga JM. Forest based biomass for energy in Uganda: stakeholder dynamics in feedstock production. Biomass Bioenergy 2013;59:100–15. [4] Tillmans A, Schweizer-ries P. Energy for sustainable development knowledge communication regarding solar home systems in Uganda: the consumers' perspective. Energy Sustain Dev 2011;15(3):337–46. [5] Kiplagat JK, Wang RZ, Li TX. Renewable energy in Kenya: resource potential and status of exploitation. Renew Sustain Energy Rev 2011;15:2960–73. [6] Maested O. The electricity sector of Uganda – results of development assis- tance; 2003. [7] Pasternak A.D. Global energy futures and human development: a framework for analysis; 2000. [8] Buchholz T, Da Silva I, Furtado J. Electricity from wood-fired gasification in Uganda-a 250 and 10 kW case study. In: Proceedings of the 20th Domestic Use of Energy Conference, DUE; 2012. p. 65–76. [9] Yekini M, Wazir M, Bashir N, Asiah N, Safawi A. Power sector renewable energy integration for expanding access to electricity in sub-Saharan Africa. Renew Sustain Energy Rev 2013;25:630–42. [10] Mohammed YS, Mustafa MW, Bashir N. Status of renewable energy con- sumption and developmental challenges in Sub-Sahara Africa. Renew Sustain Energy Rev 2013;27:453–63. [11] Suberu Y, Bashir N, Wazir M. Overuse of wood-based bioenergy in selected sub-Saharan Africa countries : review of unconstructive challenges and sug- gestions. J Clean Prod 2015;96:501–19. [12] Deichmann U, Meisner C, Murray S, Wheeler D. The economics of renewable energy expansion in rural Sub-Saharan Africa. Energy Policy 2011;39(1):215–27. [13] Subedi M, Matthews R, Pogson M, Abegaz A, Balana B, Oyesiku-blakemore J, et al. Can biogas digesters help to reduce deforestation in Africa ? Biomass Bioenergy 2014;70:1–12. [14] Shaaban M, Petinrin JO. Renewable energy potentials in Nigeria: meeting rural energy needs. Renew Sustain Energy Rev 2014;29:72–84. [15] Akuru UB. Renewable energy investment in Nigeria: a review of the renewable energy master plan. In: Proceedings of the 2010 IEEE international energy conference and exhibition, EnergyCon; 2010. p. 166–71. [16] Ajayi OO, Ajayi OO. Nigeria’ s energy policy: inferences, analysis and legal ethics toward RE development. Energy Policy 2013;60:61–7. [17] Mohammed YS, Mokhtar AS, Bashir N, Saidur R. An overview of agricultural biomass for decentralized rural energy in Ghana. Renew Sustain Energy Rev 2013;20:15–25. [18] Hensley M, Gu S, Ben E. A comprehensive review of biomass resources and biofuels potential in Ghana. Renew Sustain Energy Rev 2011;15(1):404–15. [19] Osei WYAW. Rural energy technology : issues and options for sustainable development in Ghana. Geoforum 1996;27(1):63–74. [20] Kemausuor F, Yaw G, Brew-hammond A, Duker A. A review of trends, policies and plans for increasing energy access in Ghana. Renew Sustain Energy Rev 2011;15(9):5143–54. [21] Kaunda CS. Energy situation, potential and application status of small-scale hydropower systems in Malawi. Renew Sustain Energy Rev 2013;26:1–19. [22] Nfah EM, Ngundam JM, Vandenbergh M, Schmid J. Simulation of off-grid generation options for remote villages in Cameroon. Renew Energy 2008;33 (5):1064–72. [23] Nzila C, Dewulf J, Spanjers H, Kiriamiti H, Van Langenhove H. Biowaste energy potential in Kenya. Renew Energy 2010;35(12):2698–704. [24] Abdullah S, Jeanty PW. Willingness to pay for renewable energy: evidence from a contingent valuation survey in Kenya. Renew Sustain Energy Rev 2011;15(6):2974–83. [25] Kihwele S, Hur K, Kyaruzi A. Visions, scenarios and action plans towards next generation Tanzania power system. Energies 2012;5:3908–27. [26] Okello C, Pindozzi S, Faugno S, Boccia L. Development of bioenergy technol- ogies in Uganda: a review of progress. Renew Sustain Energy Rev 2013;18:55– 63. [27] Okello C, Pindozzi S, Faugno S, Boccia L. Bioenergy potential of agricultural and forest residues in Uganda. Biomass Bioenergy 2013;56:515–25. [28] Nsamba HK, Hale SE, Cornelissen G, Bachmann RT. Sustainable technologies for small-scale biochar production – a review. J Sustain Bioenergy Syst 2015;5 (1):10–31. [29] Saundry Peter. Major rivers, lakes, mountains, and other terrestrial features of Uganda, [Online] Available: 〈http://www.eoearth.org〉; [accessed 22.01.14]. [30] Uganda National Bureau of Statistics. National Population and Housing Cen- sus; 2014. [31] Neelsen S, Peters J. Electricity usage in micro-enterprises – evidence from Lake Victoria, Uganda. Energy Sustain Dev 2011;15(1):21–31. [32] Ong HC, Mahlia TMI, Masjuki HH. A review on energy scenario and sustainable energy in Malaysia. Renew Sustain Energy Rev 2011;15(1):639–47. [33] MEMD. Uganda Vision 2040. Kampala; 2012. [34] Mudoko SN. Uganda's Policy on Energy and Power. Tokyo; 2013. [35] Uganda Bureau of Statistics. 2013 Statistical Abstract. Entebbe. [36] Parliament of Uganda. The Atomic energy act, 2008. Uganda: ERA; 2008. p. 1–54. [37] Monday Times. Uganda warned against nuclear energy, [Online] Available: 〈http://www.mondaytimes.co.ug/details.php?option¼acat&a¼1851#〉; [accessed 12.06.15]. [38] Bergey. The excel 10 kW wind turbine, [Online] Available: 〈http://bergey.com/ products/wind-turbines/10kw-bergey-excel〉; [accessed 12.06.15]. [39] Zhao Z, Zhang S, Zuo J. A critical analysis of the photovoltaic power industry in China – from diamond model to gear model. Renew Sustain Energy Rev 2011;15(9):4963–71. [40] Kousksou T, Allouhi A, Belattar M, Jamil A, El Rhafiki T, Arid A, et al. Renewable energy potential and national policy directions for sustainable development in Morocco. Renew Sustain Energy Rev 2015;47:46–57. [41] Tyagi VV, Rahim NAA, Rahim NA, Selvaraj JA/L. Progress in solar PV technol- ogy: research and achievement. Renew Sustain Energy Rev 2013;20:443–61. [42] Laurea University of Applied Sciences. About Uganda, [Online] Available: 〈https://www.laurea.fi/dokumentit/Documents/Uganda〉; Country Report.pdf. [43] Renewable Energy and Energy Efficiency Partnership. Uganda (2012), [Online] Available: 〈http://www.reeep.org/uganda-2012〉; 2013 [accessed 23.05.15]. [44] Electricity Regulatory Authority (Uganda). Developments and investment opportunities in renewable energy resources in Uganda; 2012. [45] World Bank; Electric power consumption (kW h per capita), [Online] Avail- able: 〈http://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC〉; [accessed 12.06.15]. [46] Roberts JJ, Cassula AM, Osvaldo Prado P, Dias RA, Balestieri JAP. Assessment of dry residual biomass potential for use as alternative energy source in the party of General Pueyrredón, Argentina. Renew Sustain Energy Rev 2015;41:568–83. [47] Siddiqui MU, Said SAM. A review of solar powered absorption systems. Renew Sustain Energy Rev 2015;42:93–115. [48] Luis D, Oliveira D, Brandao LE, Igrejas R, Lima L. Switching outputs in a bioenergy cogeneration project: a real options approach. Renew Sustain Energy Rev 2014;36:74–82. [49] Pamukcu C, Konak G. A review of the energy situation in Uganda. Int J Sci Res Publ 2014;4(1):1–4. [50] Teke A, Timur O. Assessing the energy efficiency improvement potentials of HVAC systems considering economic and environmental aspects at the hos- pitals. Renew Sustain Energy Rev 2014;33:224–35. [51] Muloni Irene. Renewable energy investment guide may 2012. Kampala; 2012. [52] Hankey S, Sullivan K, Kinnick A, Koskey A, Grande K, Davidson JH, et al. Using objective measures of stove use and indoor air quality to evaluate a cookstove intervention in rural Uganda. Energy Sustain Dev 2015;25:67–74. [53] MEMD, Biomass energy strategy (Best) Uganda; 2013. p. 1–114. [54] Bekele G, Tadesse G. Feasibility study of small Hydro/PV/Wind hybrid system for off-grid rural electrification in Ethiopia. Appl Energy 2012;97:5–15. http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref1 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref1 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref1 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref1 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref2 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref2 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref3 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref3 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref3 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref3 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref4 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref4 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref4 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref4 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref5 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref5 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref5 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref6 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref6 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref6 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref6 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref7 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref7 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref7 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref7 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref8 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref8 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref8 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref8 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref9 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref9 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref9 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref10 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref10 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref10 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref10 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref11 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref11 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref11 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref12 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref12 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref12 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref13 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref13 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref13 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref13 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref14 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref14 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref14 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref15 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref15 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref15 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref16 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref16 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref16 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref16 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref17 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref17 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref17 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref18 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref18 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref18 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref18 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref19 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref19 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref19 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref20 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref20 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref20 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref20 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref21 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref21 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref21 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref22 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref22 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref22 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref22 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref23 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref23 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref23 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref24 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref24 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref24 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref24 http://www.eoearth.org http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref25 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref25 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref25 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref26 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref26 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref26 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref27 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref27 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://www.mondaytimes.co.ug/details.php?option=acat&a=1851 http://bergey.com/products/wind-turbines/10kw-bergey-excel http://bergey.com/products/wind-turbines/10kw-bergey-excel http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref28 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref28 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref28 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref28 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref29 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref29 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref29 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref29 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref30 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref30 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref30 https://www.laurea.fi/dokumentit/Documents/Uganda http://www.reeep.org/uganda-2012 http://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref31 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref31 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref31 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref31 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref32 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref32 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref32 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref33 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref33 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref33 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref33 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref34 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref34 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref34 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref35 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref35 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref35 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref35 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref36 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref36 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref36 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref36 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref37 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref37 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref37 S. Twaha et al. / Renewable and Sustainable Energy Reviews 57 (2016) 786–798798 [55] Twaha S, Mukhtiar MU. Optimal hybrid renewable-based distributed genera- tion system with feed-in tariffs and ranking technique. In: Proceedings of the 2014 IEEE international power engineering and optimization conference, PEOCO2014; 2014. p. 115–20. [56] Giannoulis ED, Haralambopoulos DA. Distributed Generation in an isolated grid: methodology of case study for Lesvos – Greece. Appl Energy 2011;88 (7):2530–40. [57] Renewable Energy & Energy Efficiency Partnership. Renewable energy potential in Uganda, [Online] Available: 〈http://www.afribiz.info〉; [accessed 22.01.14]. [58] Ramli MAM, Twaha S. Analysis of renewable energy feed-in tariffs in selected regions of the globe: lessons for Saudi Arabia. Renew Sustain Energy Rev 2015;45:649–61. [59] InfraCo Africa. Kalangala Infrastructure Services, [Online] Available: 〈http:// www.infracoafrica.com/projects.asp〉; [accessed 23.05.15]. [60] Folkecenter. Solar energy in Uganda, [Online] Available: 〈http://www.folk ecenter.net〉; [accessed 20.01.14]. [61] Yellowpage. Solar-energy in Uganda, [Online] Available: 〈http://www.yellow. ug/category/solar-energy〉. [62] Power Trust Uganda Limited. Products, [Online] Available: 〈http://www.pow ertrusteastafrica.com/〉; [accessed 13.06.15]. [63] Ultratechworld. Solar, [Online] Available: 〈http://www.ultratecworld.com/〉. [64] Systems E. Solar power system, [Online] Available: 〈http://energysystemsug. com〉. [65] Solar Energy for Africa, [Online] Available: 〈http://www.solarafrica.org/〉. [66] D&S. Solar Products, [Online] Available: 〈http://www.dayliff.com〉. [67] Energy Sector GIS Working Group gets award for best Map, [Online] Available: 〈http://www.energyprogramme.or.ug/giz-uganda-gets-award-for-best-gis- map/〉; 2012 [accessed 17.02.14]. [68] Energy Sector GIS Working Group. Energy utilities of Uganda, [Online] Avail- able: 〈http://www.gis-uganda.de/Energy-GIS/〉; 2012 [accessed 17.02.14]. [69] UMEME. About UMEME, [Online] Available: 〈http://www.umeme.co.ug/index. php?page¼MTUw〉; [accessed 23.05.15]. [70] Mawhood R, Gross R. Institutional barriers to a ‘perfect’ policy: a case study of the Senegalese Rural Electrification Plan. Energy Policy 2014;v31024:1–11. [71] REA. Overview, [Online] Available: 〈http://www.rea.or.ug/index.php/features/ overview〉; 2013 [accessed 21.06.14]. [72] MEMD. Rural Electrification Strategy and Plan; 2012. [73] New vision Uganda. The Rural Electrification Agency (REA), New vision. Kampala; 2014. [74] Rahman MM, Paatero JV, Poudyal A, Lahdelma R. Driving and hindering factors for rural electrification in developing countries: lessons from Bangladesh. Energy Policy 2013;61:840–51. [75] Kocaman AS, Huh WT, Modi V. Initial layout of power distribution systems for rural electrification: a heuristic algorithm for multilevel network design. Appl Energy 2012;96:302–15. [76] Mark P, Twaha S, Murphy IS. Analysis of the cost of reliable electricity: a new method for analyzing grid connected solar, diesel and hybrid distributed electricity systems considering an unreliable electric grid, with examples in Uganda. Energy 2014;66:523–34. [77] Ramli MAM, Twaha S, Al-Turki YA. Investigating the performance of support vector machine and artificial neural networks in predicting solar radiation on a tilted surface: Saudi Arabia case study. Energy Convers Manag 2015;105:442–52. [78] Pigaht M, van der Plas RJ. Innovative private micro-hydro power development in Rwanda. Energy Policy 2009;37(11):4753–60. [79] Kimera R, Okou R, Sebitosi AB, Ieee M, Awodele KO. A concept of dynamic pricing for rural hybrid electric power mini-grid systems for Sub-Saharan Africa. In: Proceedings of the 2012 IEEE power and energy society general meeting; 2012. p. 1–6. [80] ERA. Uganda Renewable Energy Feed-in Tariff (REFIT). Kampala; 2012. [81] Grossmann WD, Grossmann I, Steininger KW. Distributed solar electricity generation across large geographic areas, Part I: A method to optimize site selection, generation and storage. Renew Sustain Energy Rev 2013;25:831–43. [82] ESI Africa. 45 percent solar power subsidy for Uganda, [Online] Available: 〈http://www.esi-africa.com/45-percent-solar-power-subsidy-for-uganda/ 〉; 2007 [accessed 27.02.14]. [83] Mwaura FM. Adopting electricity prepayment billing system to reduce non- technical energy losses in Uganda: lesson from Rwanda. Util Policy 2012;23:72–9. [84] Ahmad S, Kadir MZAA, Shafie S. Current perspective of the renewable energy development in Malaysia. Renew Sustain Energy Rev 2011;15(2):897–904. [85] Barry M, Steyn H, Brent A. Selection of renewable energy technologies for Africa: eight case studies in Rwanda, Tanzania and Malawi. Renew Energy 2011;36(11):2845–52. [86] Javadi FS, Rismanchi B, Sarraf M, Afshar O, Saidur R, Ping HW, et al. “Global policy of rural electrification,”. Mar.. Renew. Sustain. Energy Rev. 2013;vol. 19:402–16. [87] Twaha S, Idris MH, Anwari M, Khairuddin A. Applying grid-connected pho- tovoltaic system as alternative source of electricity to supplement hydro power instead of using diesel in Uganda. Energy 2012;37(1):185–94. [88] Entchev E, Yang L, Ghorab M, Lee EJ. Simulation of hybrid renewable micro- generation systems in load sharing applications. Energy 2013;50:252–61. [89] Eder JM, Mutsaerts CF, Sriwannawit P. Mini-grids and renewable energy in rural Africa: how diffusion theory explains adoption of electricity in Uganda. Energy Res Soc Sci 2015;5:45–54. [90] The Observer. Govt to drop power subsidies as Parliament tightens purse. Kampala; 14 July 2011. [91] Pablo-Romero MP, Sánchez-Braza A, Pérez M. Incentives to promote solar thermal energy in Spain. Renew Sustain Energy Rev 2013;22:198–208. [92] Hashim H, Ho WS. Renewable energy policies and initiatives for a sustainable energy future in Malaysia. Renew Sustain Energy Rev 2015;15(9):4780–7. [93] Ngusale GK, Luo Y, Kiplagat JK. Briquette making in Kenya: Nairobi and peri- urban areas. Renew Sustain Energy Rev, 40; 2014. p. 749–59. http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref38 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref38 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref38 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref38 http://www.afribiz.info http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref39 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref39 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref39 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref39 http://www.infracoafrica.com/projects.asp http://www.infracoafrica.com/projects.asp http://www.folkecenter.net http://www.folkecenter.net http://www.yellow.ug/category/solar-energy http://www.yellow.ug/category/solar-energy http://www.powertrusteastafrica.com/ http://www.powertrusteastafrica.com/ http://www.ultratecworld.com/ http://energysystemsug.com http://energysystemsug.com http://www.solarafrica.org/ http://www.dayliff.com http://www.energyprogramme.or.ug/giz-uganda-gets-award-for-best-gis-map/ http://www.energyprogramme.or.ug/giz-uganda-gets-award-for-best-gis-map/ http://www.gis-uganda.de/Energy-GIS/ http://www.umeme.co.ug/index.php?page=MTUw http://www.umeme.co.ug/index.php?page=MTUw http://www.umeme.co.ug/index.php?page=MTUw http://www.umeme.co.ug/index.php?page=MTUw http://www.umeme.co.ug/index.php?page=MTUw http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref40 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref40 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref40 http://www.rea.or.ug/index.php/features/overview http://www.rea.or.ug/index.php/features/overview http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref41 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref41 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref41 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref41 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref42 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref42 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref42 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref42 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref43 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref43 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref43 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref43 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref43 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref44 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref44 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref44 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref44 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref44 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref45 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref45 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref45 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref46 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref46 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref46 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref46 http://www.esi-africa.com/45-percent-solar-power-subsidy-for-uganda/ http://www.esi-africa.com/45-percent-solar-power-subsidy-for-uganda/ http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref47 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref47 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref47 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref47 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref48 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref48 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref48 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref49 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref49 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref49 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref49 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref50 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref50 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref50 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref50 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref51 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref51 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref51 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref51 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref52 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref52 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref52 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref53 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref53 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref53 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref53 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref54 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref54 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref54 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref55 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref55 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref55 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref56 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref56 http://refhub.elsevier.com/S1364-0321(15)01534-8/sbref56 Renewable based distributed generation in Uganda: Resource potential and status of exploitation Introduction Background of Uganda and the energy sector in general Renewable energy resource potential in Uganda Wind energy Solar energy Hydropower Biomass energy Geothermal energy The status of RE application in Uganda Wind energy Solar energy Hydropower Large and small hydro Pico, Micro-hydro Biomass energy Renewable energy application in rural areas Related policies Feed-in tariff policy Subsidy policy Challenges Efficient policies suggested to improve RE exploitation in Uganda Conclusion Acknowledgement References