Biogas Production Prospects for West Africa
Currently, climate change has become the most discussed subject globally. It has however, been induced by the effect of increasing greenhouse gases which cause great environmental concern.
Development of bioenergy technology has become one focal area which is currently a primary source of energy for approximately 2.7 billion people around the globe, playing a vital role in meeting energy demand for developing countries. About 90% of the populations in sub-Saharan Africa use biomass, such as wood or residues, for cooking and heating and 60% of African women living in rural areas have to deal with the firewood scarcity and supply.This has resulted in deforestationwiping out almost 90% of the original forests in West Africa.West Africa has abundantbioenergy potential. However, the inefficient direct combustion methods impose severe pressure on the environment as well as the respiratory diseases associated with the smoke produced from firewood is shifting the focus to clean and renewable alternative sources in the sub-region.
The production of biogas via anaerobic digestion of agricultural residues, municipal wastes and industrial wastewaterwould benefit the African society by providing a clean fuel from renewable feedstocks and as such: reduce energy poverty, serve as an indirect way of solving sanitation and health problems, help in soil nutrient recycling, reduce groundwater pollution, help reduce the rate of desertification, as well as safeguard food security and solve varied and myriad environmental problems.Biogas provision actually also helps provide energy to especially rural areas decentrally, independent of the energy grid. Some countries in West Africa have taken significant steps in using the biogas technology as one of the tools to provide access to clean energy by constructing several small and medium size biogas plants.
Biogas technology is not common in mostof West African countries and so are the laws that could promote and regulate them.Very few West African countries have approved renewable energy laws and specific penetration targets in their energy mix as shown in the table.
Country |
Approved |
Target |
Cape Verde |
Yes |
50% by 2020 |
Ghana |
Yes |
10% by 2015 |
Senegal |
Yes |
15% by 2020 |
Livestock rearing plays a key role in the economies of West African countries providing about 44% of agricultural GDP. With 60 million heads of cattle and 160 small ruminants, 400 million poultry, the Sahel and West Africa is an exceptional region for livestock rearing. Livestock production should be given the needed attention asproduction as there is an enormous potential of biogas from livestock manure in West Africa. However, the manure is mostly left on pastures and ranges.A partial adaptation of the hitherto system that could promote manure (dung and urine mixture) collection during milking could support decentralised biogas production in many ways and promote biogas provision. Between 1998 and 2008 manure from cattle, Pig, Goat, Sheep and Chicken in Ghana, Nigeria, Mali and Burkina Faso could generate about 845 Gg of Biomethanetranslating into about 47 PJ of energy. About 13.45 Tg of firewood would be needed to provide equivalent amount of energy between that period. If the mechanism of manure management in the fourcountries remain unchanged and the biomethane (used here due to the biogenic nature of the substrate) is untapped, estimatespredict that in 2010,2018 and 2028, about 92 Gg, 113 Gg and 139 Gg of biomethane would be emitted into the atmosphererespectively from the manure alone. The figure shows the projections of biomethane potential from the selected livestock manure from each country.
Linear fitting showing projections of methane emission from the selected livestock in Nigeria, Ghana, Burkina Fasoand Mali(2)
However, this is just one of the many valuable substrates that we mostly leave to go waste in the subregion. There are lots more of such substrates of organic origin that could better be exploited for bioenergy production and used to resolve adjacent pending problems in the environment and/ or energy provision.
Biogas production can also help provide organic fertilizer for agricultural use and the gas produced can be used to generate energy for cooking, water heating, or lighting for laboratory experiments in institutions or immediate environs of the toilet facility. Additionally, health centres in rural communities without access to electricity can use cooling effect from tigeneration technology (electricity, thermal energy and cooling) to store their medical supplies. There is the need to develop national biogas programme with a three-pronged focus: agriculture (organic fertilizer production), sanitation, and energy for sustainable development.
Article contribution made by Dr. Kwasi Glover of DeutschesBiomasseForschungsZentrum (DBFZ), Germany and Richard Arthur of Energy Systems Engineering Dept., Koforidua Polytechnic, Ghana
(1) http://www.oecd.org/dataoecd/12/26/49257862.pdf(2) Arthur R, Baidoo M. Harnessing methane generated from livestock manure in Ghana, Nigeria, Mali and Burkina Faso. Biomass and Bioenergy; 35 (11) 4648-4656, 2011.
Author Kwasi A. Glover - Read More about the Author