Increasing political and public environmental awareness, especially with reference to the possibility of global warming resulting from the continual burning of fossil fuels has, during the 1990s, encouraged a search for energy derived from renewable resources which do not pollute the atmosphere with carbon dioxide. Popular rejection of the nuclear alternative for generating electricity has also focused more attention on renewable sources. So far biomass, and especially energy crops has remained the cinderella source in the shadow of the high-tech renewables such as waves, tides, wind and sun which have received the most attention especially in the media. In these cases, the resources are already available and require only the application of in situ technology Energy crops, on the other hand, have to be provided and replenished on a large scale involving extensive areas of land and this will require considerable social political, cultural and economic adjustments to be made. This article reviews some of the advantages, disadvantages and geographical implications, from a global perspective, of deriving significant supplies of renewable energy from energy crops, especially trees.