The use of woody biomass for large-scale generation of power

Growth of wood as an agricultural crop, for use in the large-scale production of electricity, provides a biomass fuel using intensive, but sustainable, agricultural practices. Short-rotation cropping (SRC) schemes, in which trees are grown in large plantations, could be used to produce electricity on a scale sufficient to form a significant part of a national energy supply system. The net CO2 emissions from biomass-based electricity are substantially less than from conventional fossil-fuel fired generation. The objective of the study reported in this paper is to assess the extent to which this approach to power generation could be adopted if climate change considerations lead to the implementation of measures to reduce emissions of CO2 to atmosphere. In the study reported here, 1GWe of electricity is produced from a number of SRC-based power stations, selected so as to minimize cost. The study is based in Spain a country believed to be reasonably well suited to SRC and representative of countries with a temperate climate. The best site produces electricity at 9.2 c/kWh. The other sites are more expensive, the average over 22 sites being 10.1 cents/kWh. These costs are for fluidized-bed combustion with a cumulative installed capacity approaching 1GWe; additional capacity will be more expensive. It is likely that the cost of biomass based SRC would be reduced as new technology, such as biomass gasifiers working in combined cycles, is introduced and the number of installations is increased. SRC biomass could supply about 5% (2.3GWe) of the present Spanish electrical capacity. Conceivably, this could be raised to about 10% if less suitable land is also used and SCR biomass is able to compete with some agricultural crops