Biogas Gets Chequered Growth
From the beginning of last century to 2008, the use of wood fuel has contributed to a decrease in Ghana's forestfrom 8.13 million hectares to 1.6 million hectares and Cote d’Ivoire’s from 16 million hectares to 6.38 million hectares. Despite this evident threat of deforestation, forests remains the most viable source of energy to many rural dwellers and urban poor. Because biogas provides a simpler, less cost effective and more environmental friendly alternative means of generating power through animal wastes, crops, sewages and human excreta, it seems to make this alternative and renewable energy the way to go. Overreliance on the use of wood fuel and diesel poses more and more danger to the environment. In the West Africa region, poor power supply often grinds economic and domestic activities.
In Kaolack, Senegal, barrels are strategically placed using biogas as a source of fuel for its 20,000 residents. A National Biogas Programme has been introduced in the country. The programme is seeking to implement subsidies ranging between 35% and 50% of the costs to encourage residents to turn to biogas as means of generating electricity.The future is already looking bright for residents of Dakar as about 8,000 biogas digesters would be built by 2013 in the city, at the cost of about $920. Up on their heels are Mauritania and Burkina Faso. Mauritania claims to have subsidised price and Burkina Faso is also attempting to do same.
With a population of over 150 million people, Nigeria is in the position to take the lead in biogas sector if wastes from various means are properly harnessed. In its south-western city of Ibadan, Dr. Joseph Adelegan, through his “Cows to Kilowatts” initiative, has developed an anaerobic reactor to process animal waste and blood into quality biogas. About two-thirds of the animals in Oyo State (which Ibadan is capital of) are slaughtered inthe Bodija Municipal Abattoir located in the city. The methane biogas generated through this process is used for cooking gas, to fuel household gas generators, and can be used as biofuel for transportation. Yet the remainder sludge is still useful as fertiliser. With a UN Development Programme grant of $500,000, Adelegan was able to build the plant in Ibadan and with another $200,000 from a World Bank competition, he built a bioreactor to generate electricity from cassava waste in Ilorin, a city in central Nigeria.The impact of the plant is felt in about 5,400 homes where it is used as cooking gas by generating around 1,800 cubic metres of biogas per day.
In Lagos, it is estimated that an average street could produce 1,720 litres of biogas a day, enough for an engine-powered water pump to serve the daily domestic needs of at least 50 families. 29 year-old Obayomi, who has already won a TED fellowship, for inventing how to convert toilet wastes usually stored in septic tanks underground by using new waste entry pipes that remove oxygen from the decaying process. This allows a mixture of carbon dioxide and methane stored in an adjacent underground chamber to be used to power cooking stoves, heat homes or even generate electricity. His vision is aimed at alleviating power issues for slum areas in the city.
In 2010, the Manufacturers Association of Nigeria (MAN) and Rosebank Consulting Limited in a 'Waste to Energy Roundtable' decided that the association searchfor investors that can construct and sell biogas energy to manufacturers in designated industrial clusters. Biogas generation data showed that 1 metric tonne poultry farm waste will be needed to produce 1 mega watt of electricity, 1 metric tonne of human excreta equals 4 m3 biogas, 1 metric tonne of green waste equals 60 m3 bio gas and about 0.06 m3 may be generated from 1 kg of cow dung at 28 degree centigrade, 500 m3 of biogas is required to produce 1 mega watt of electricity, and land area required for such biomethanation plants is around two acres."
But biogas inventions are not entirely new. Usman Danfodiyo University, Sokoto, designed a simple biogas plant (with additional gas storage system) that could produce 425 litres of biogas per day which could be sufficient to cook meals for one person (Dangogo and Fernado, 1986). Ezekoye and Okeke (2006) designed and constructed a plastic biodigester and used it to produce biogas from spent grains and rice husk mixed together. There are a lot more perhaps, on scales lower than ones reported in the media.
Despite these scattered achievements. It seems awareness of biogas is limited and the growth in the nearest future lies in individual, private organisations, community and international aid as some governments are either unwilling or unable to throw their weight behind it. Ahiataku-Togobo, director of renewable energy at Ghana's Ministry of Energy, claims it is more expensive to produce electricity from biogas than from diesel power plants. In contrast though, Cote d’Ivoire established a Renewable Energy Directorate within the Ministry of Mining and Energy in 2005 thereby setting a distinctive hallmark in the official renewable energy development policy. More of such measures will not only harness the handful of biogas inventions going on but will attract and encourage investors.
– Oluchi Agbanyim
Nigeria: MAN May Seek Investors for Bio-Gas Energy By Franklin Alli, 7 April 2010