Biomass is the most com- monly used source of rural energy in Nigeria because fuel-wood is the cheapest and most accessible source of fuel even in urban households. In fact, fuel-wood is the traditional fuel source, which, in spite of the availability of conventional domestic fuels, remains in very high demand at the expense of Nigerian forests.
Even in the ecologi- cally fragile Sudan-Sahel belt of northern Nigeria where desertification poses a serious threat to man and the environment, there are hardly any large scale shifts from traditional biomass energy to mod- ern fossil fuels. Supplies appear to be diminishing, overall, in the face of increasing consumption, and massive forest/woodland and farm tree losses. The human and environmental cost of obtaining and consuming fuel-wood appear to be increasing.
The total annual consumption of fuel-wood in the country in 1987 was estimated at about 80 mil- lion cubic metres. Because of the inefficiency of the local fuel-wood stoves, the bulk of the energy avail- able from wood-burning was lost, amounting to 97 per cent. In terms of the average per capita wood consumption, urban dwellers use about 360 kg/per- son, while in the rural areas the average per capita consumption has been put at 511.2 kg/person or 0.71m of solid wood.
Communal bushes constitute the largest source of wood for fuel, a situation that engenders severe deforestation. In extremely stressed environments in the Sudan-Sahel region, grasses and cow dung are used for fuel because of wood- deficiency. Wood-processing mills provide a small source of wood energy in parts of southern Nigeria. Fuel-wood plantations are of negligible importance even though the first such plantation was established in Lagos in 1912. There were oth- ers at lbadan and ljebu-Ode. More fuelwood plan- tations are needed in the country to conserve the natural forests. Another solution, recently embarked upon, is to transport coal from the south to the north, and market it there as an alternative to firewood.
Solar Energy: Situated approximately between 4°N and 13°N, Nigeria is geographically favourably located to tap unlimited solar energy, the most dependable renewable energy source. It has been estimated that a yearly average of about 2,300 kwh/m2 of solar energy tails on a horizontal surface in Nigeria, and that in Lagos the intensity of solar radiation is about 930w/m2 on a clear sunny day. (FMST, 1987).
At the International Institute for Tropical Agriculture at lbadan, incident solar energy varies from S.lkwh/malday during the least favourable day in August to 5.8kwh/m~/day in March and April. What Nigeria requires is an affordable solar energy technology and cheap appliances. Potential solar energy applications in the country include drying of agricultural products (the traditional use), water pumping, air-conditioning and refrigeration, electricity generation, desalination and distillation, cooking and water heating.
