We analyse present biomass utilization and the potential of biomass residues for energy use in Castilla y Leon and compare biomass with other forms of local energy production. Residual biomass supplied about 9% of the total energy consumed in 1990. About 85% of the biomass is used in the domestic sector. Exploitable potential biomass in Castilla y Leon represents 4485 kmtoe/yr, about 78% of total primary energy production in 1990. The implementation of a biomass programme will avoid desertification of set aside and marginal lands. Furthermore, substitution of coal by biomass fuels will reduce air emissions by about 11,000 kmts of CO2/yr and 350 kmts SO2/yr.