Development of bioenergy technologies in Uganda: A review of progress

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Abstract

Biomass is a renewable energy resource; however, its exploitation raises concerns about its ability to sustain the growing demand and its negative impacts on the environment, particularly in developing countries. These concerns are more prominent on the African continent where high population growth rates is leading to high rates of deforestation due to expansion of agricultural land and increased demand for bioenergy. Use of traditional and inefficient bioenergy technologies and appliances also exacerbate the problem. This paper presents a review of the efforts and progress made by different organisations in promoting improved bioenergy technologies in Uganda. The study was based on an extensive review of available literature on improved bioenergy technologies introduced in the country. It was found that there is high level of wastage of biomass resources since an estimated 72.7% of the population use traditional cooking stoves with efficiency estimated to be less than 10%. Inefficient cooking stoves are also blamed for indoor air pollution and respiratory illness reported amongst its users. Modern bioenergy technologies such as biomass gasification, cogeneration, biogas generation, biomass densification, and energy-efficient cooking stoves have been introduced in the country but have certainly not been widely disseminated. The country should pursue policies that will accelerate proliferation of more efficient bioenergy technologies in order to reduce the negative environmental impacts of bioenergy utilisation and to ensure sustainability of biomass supplies.

Introduction

Adequate supply of energy is crucial for the development of any nation. Currently, fossil fuels are the dominant global source of energy [1]. However, use of fossil fuels is associated with greenhouse gas emissions (GHG), which is blamed for global warming, and consequently, climate change. Therefore, emphasis is currently focused on promoting use of renewable energy sources such as biomass, solar, wind and tidal energy. Biomass, in particular, is seen as a possible substitute to fossil fuels, and many developed countries are striving to increase the proportion of their primary energy supply from it [2].

The situation in developing countries is however different because biomass has all along been the major source of energy [3]. In Africa for example, biomass accounts for about 30% of the energy consumption. Its use is more prominent in sub-Saharan Africa where it account for up to 80% of energy supply [4]. In Uganda, biomass contributes over 90% of energy requirements. However, despite the high contribution, the production and supply of biomass is still managed by the informal sector. Technologies employed from the production to consumption of biomass fuels are majorly traditional and inefficient and are associated with high levels of pollutants' emission. Extensive use of inefficient bioenergy technologies implies that biomass resources are being wasted; thus, contributing to increased rates of deforestation and related environmental concerns such undesirable change in biodiversity, degradation of soil and water resources. Improving the efficiency of bioenergy technologies could therefore, play a major role in conserving energy; hence, reducing the rate of environmental degradation.

In this perspective, the Government of Uganda, non-governmental organisations (NGOs), and several private agencies are currently promoting improved bioenergy technologies in the country. Examples of technologies promoted include improved (energy-saving) biomass cooking stoves, biogas, and biomass gasification technologies. Overtime, several independent reports of these programmes have been produced by the different actors in the sector. However, because they are made by different projects and individuals, it is very difficult to understand the overall impact of the bioenergy technology programmes in the country. Therefore, the aim of this study was to a conduct review of the progress made in the implementation of improved bioenergy technology programmes in Uganda. The objective is to present a succinct account of the level of proliferation of improved biomass technologies in the country.

Uganda is a land locked country located in East Africa, between latitudes 01°30′S and 4°00′N; and longitudes 29°30′E and 35°00′E [5]. It is bordered by Kenya in the east, Tanzania and Rwanda in the south, Democratic Republic of Congo in the west and South Sudan in the north. Fig. 1 shows the location of Uganda on the African continent. The area of the country is approximately 241,550 km2, out of which 41,743 km2 is covered by open water bodies and swamps. The topography comprises plateaus in the central and northern parts of the country and mountains of Elgon and Rwenzori on the eastern and western borders, respectively. Overall, the elevation ranges from 620 m to 5110 m above mean sea level [6]

According to UBOS [7], by the year 2002, the country had a population of 24.4 million, characterised by an annual population growth rate of 3.4%. At the time, about 88% of the population lived in rural areas. Recent estimates by UBOS [6] indicate that the country's population by mid-year 2010 had grown to 31.8 million. A summary of the demographic and economic information on Uganda is given in Table 1.

The per capita energy consumption of Uganda is estimated to be 39 kg oil equivalent (kgOE), which is very low compared to that of Kenya at 80 kgOE and Italy at 2959 kgOE [8]. Energy supply in the country is predominated by biomass in form of firewood, charcoal and agricultural residues. Electricity and petroleum fuels are also used, but contributes less than 10% of the total energy use. The contributions of the various forms of energy are illustrated in Fig. 2.

Electricity and petroleum fuels are considered as commercial energy in the country; however, biomass is not included in this category, probably because trade in biomass is predominantly informal, and in some cases illegal. In Uganda, biomass energy is used for cooking and heating in households, commercial and public institutions such as hotels, schools and hospitals. It is also used in small scale industries such as brick production and in various industries to supply process heat [9]. Urban households predominantly use biomass in form of charcoal, while firewood and agricultural residues are principally used by rural dwellers. Table 2 shows the distribution of biomass consumption by sector [10], from which it can be observed that the residential sector is the biggest consumer of biomass energy in the country. However, bioenergy technologies used in Uganda are mainly traditional and inefficient. Therefore, several organisations are currently promoting improved bioenergy technologies in the country. Table 3 gives a list of the organisations that are currently promoting improved bioenergy technologies in Uganda.

Petroleum fuels contribute about 7.4% of Uganda's primary energy consumption. The major forms of petroleum products used are: gasoline, diesel fuel, kerosene, fuel oil, aviation fuel and liquefied petroleum gas (LPG). Diesel fuel takes the biggest share of petroleum consumption and is mainly used to power heavy vehicles, and for electricity generation. Gasoline is used for powering light vehicles and small engines. Kerosene is mainly used by the rural households for lighting. Most petroleum products are imported into the country and their prices usually fluctuate with international rates. Recent development in the petroleum sector includes a discovery of an estimated 2.5 billion barrels of petroleum reserves in the western part of the country [11]. In the short term, the government plans to build a mini-refinery of 6000 to 10,000 barrels per day to supply the country's growing petroleum fuel needs [12].

Electricity, mainly from hydropower generation stations is also used in the country. However, the level of access to electricity in Uganda is estimated to be only 5%, making it one of the lowest in Africa. In rural areas where about 84% of the population leave, access to electricity is less than 2% [13], [14]. Even in urban areas, with higher accessibility rates, majority of households still heavily rely on charcoal to meet their daily energy needs. The low level of access could be explained by the low generation capacity and the high capital and operating costs for developing the electricity sector, especially for less developed economies like Uganda [14]. Currently, the installed capacity of the main hydroelectric power complex located in Jinja is 380 MW. However, the effective generation capacity dropped considerably to about 100 MW in 2005, before rising eventually to about 140 MW in the year 2010 [15]. The drop in generation capacity was attributed to the drastic fall in Lake Victoria water levels as a result of prolonged drought in the East African region [6]. As a result, the country faced a major electricity crisis since the year 2005. In order to overcome the shortfall, the government contracted independent power producers, which by the year 2010, were supplying about 150 MW of electricity mainly from diesel powered generation plants to the national grid [6].

Meanwhile, to meet the shortfall, construction of a 250 MW Bujagali hydroelectric power station is currently on-going. Biomass, mainly bagasse from sugarcane processing, is also used in Uganda to produce about 22 MW of electricity through cogeneration [12]. Several stand-alone diesel and gasoline powered generators are also installed in the country by individual consumers. However, their contribution to the total electrical power consumption is not known.

Nevertheless, Uganda has high potential to produce hydroelectricity. It is estimated that the hydroelectric power potential along the river Nile alone is about 2000 MW. Additional potential of about 200 MW is available from several other smaller waterfalls distributed all over the country [16]. Uganda is also rich in other energy sources such as solar and geothermal resources. Currently, there is effort to promote solar photovoltaic (PV) and thermal systems but their contributions still remain insignificant to the country's energy supply.

There are several routes through which biomass can be converted into different forms of liquid, solid or gaseous fuels. These processes are classified broadly as thermo-chemical, biochemical and mechanical extraction [17], [18]. A detailed illustration of the processes is shown in Fig. 3. In this study, we examined the level of penetration of each of these bioenergy conversion routes in Uganda. In addition, we also discussed the combined heat and power generation (CHP) and biomass densification technologies. A brief explanation of the principles behind these processes is introduced in each section followed by a detailed review of the level of penetration of each technology in Uganda.

Section snippets

Traditional biomass combustion technologies

It is estimated that three billion people worldwide use solid fuels such as coal, wood and animal dung to meet their domestic energy needs [19]. Such fuels are mainly used in developing countries, where an estimated 2.2 billion people burn them in traditional cooking stoves. Use of traditional stoves is more prominent in sub-Saharan Africa, where it is estimated that 94% of the population use them for cooking and heating [20]. For the case of Uganda, it is estimated that 87.5% of households use

Discussions

The present review has shown that biomass remains the predominant source of energy in Uganda. The level of adoption of improved bioenergy technologies in the country is still very low. It is predicted that the in the near future, the country's demand for biomass energy will increase in line with population growth. High rate of urbanisation in the country is likely to result in increased demand for charcoal fuel. Dissemination of improved bioenergy technologies could play an important role in

Conclusions

From this study, it can be concluded that that the rate of adoption of improved bioenergy technology remains very low in Uganda. The reasons for the slow technological adoption and diffusion have been attributed to high capital costs, and lack of technical expertise, amongst others. However, more effort is still required in developing clear understanding of the reasons for the low levels of dissemination of improved bioenergy technologies, and to developing suitable policy frameworks for

Acknowledgement

This study was funded by the University of Naples Federico II and Gulu University under the collaborative project of GULUNAP. None of these institutions was involved in the study or in the writing of this article. The decision to submit this article for publication was entirely made by the authors; the funding institutions take no responsibility whatsoever. The authors extend their sincere appreciation to these institutions for the financial support.

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