This study applied a simple methodology to evaluate energy contribution of selected crop residues to the possible replacement of conventional sources of energy and their specific technologies based on Nigerian situations. Using this methodology, energy content, replacement energy value, energy cost and energy return of crop residue (kJ per kg dry matter) were considered. The cost estimates of these residues using 2008 crops production data vary from US$6.45/tonne to US$23.12/tonne, depending on the type of crop residue and the transportation distance. Estimation of values of energy from maize stover, cassava peels, millet stover and sorghum straw showed that about 30 million tonnes are energetically available in Nigeria in 2010 and could replace 1.05 PJ/year if they were used exclusively for heat generation by direct combustion, or 0.58 PJ/year if used in gasification processes to generate electricity and replace the energy currently supplied by the national grid.
Keywords: crop residues, energy value, monetary value, electricity, Nigeria