Abstract Biomass is the world's fourth largest energy source and the first in developing countries representing 14% and 35%, respectively, of primary energy. The provision and use of biomass energy is a complex issue; it is an integral part of the problems associated with sustainability of all types of vegetation which in turn is a key to ensuring stable socioeconomic development. The financial costs of producing biomass are also very complex since they depend upon many different factors and tend to be quite site specific, eg agricultural and forestry costs, type of feedstock and its productivity, equipment requirements, etc. The last two decades have witnessed numerous proclamations of failure and success of biomass schemes. There is no short cut to trying to understand the factors required for success except by extensive investigation. We consider the socioeconomic and technological implications of four case studies where we have had long-term direct experience of evaluation at the local, national and international levels. These case studies are: ethanol from sugarcane in Brazil and Zimbabwe; community biogas in an Indian village; and, land rehabilitation for fuel and fodder in Baringo, Kenya.