Biomass for direct combustion can be obtained from short rotation willow coppice harvested in annual or 2-3 year cutting cycles and as a supplement, from some perennial crops of C₄ photosynthesis as miscant and spartina and, on a smaller scale, also from Virginia mallow. The results of studies into other potential energy crops discussed do not seem to recommend them. The research into biomass production technologies, especially solid fuels processing, are less advanced. The reports show a potential application of selected crops to production of bioenergy usually neither with a precise technical solution nor with a financial and energy analysis of the project as a whole.

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