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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge

 

Sacha Grodzinski

Assessing the sustainability of biogas use in East Africa

Sacha Grodzinski

Assessing the sustainability of biogas use in East Africa

Through undertaking a gap analysis of Energy from Waste projects that exist in East Africa it was evident that there is a current trend in the development of biogas plants. Reasons for this include: their ability to process a variety of feedstock; their scalability; and their success in facilitating poverty alleviation in other parts of the developing world. International actors and local technical institutions are assisting in the development of medium and large-scale facilities. The biogas from these projects is being used directly for cooking, run through generators to produce electricity and there are a number of ambitious proposals to compress the biogas for vehicle and domestic use. The electricity from some of the larger projects is going to the grid, but with only circa 10 per cent of the population connected and around 90 per cent of the region’s energy demand being heat for cooking it prompts the question ‘is there a more sustainable use for this biogas?’ The aims of this project were to evaluate the sustainability of the different means of using biogas produced from medium and large-scale facilities in East Africa, by considering the technical, social, economic and environmental aspects. The scenarios that were investigated were: 1) the direct use of biogas for cooking; 2) the generation of electricity from biogas; 3) the compression and use for cooking; and 4) the compression and use in vehicles. In addition research was undertaken to better understand the challenges facing the projects which have been proposed to compress biogas, but which have not come to fruition. In conclusion the current barriers to the development of compressed biogas facilities are due to a lack of finance, time and the lack of capacity at plants. There appeared to be no technical reasons that would oppose the realisation of all the scenarios. No single scenario was identified as being the most sustainable, but nor were any discounted. One big finding was that the use of biogas to generate electricity had the least impact with regards GHG carbon abatement. Other observations were the increased prevalence of biogas will have a negative impact on those involved within the charcoal industry. Finally all scenarios were all in-line with the current energy policies of the Tanzanian government and adequate finance seemed available to support the projects.