Power generation using dedicated woody crops: thermodynamics and economics of integrated plants

Biomass will continue to play a significant and probably increasing role in the world's future energy mix, due to the strategic role it has for large availability, environmental concerns and technological advances. The raw biomass has a relatively high moisture content, requiring thermal drying process in order to minimise stack losses. In this paper, integrated plant configurations burning dedicated woody crops for electric power generation and different options for pre-drying the biomass are discussed. Conventional indirect drying, using steam extracted from the turbine, and direct drying processes with hot gas turbine exhaust gases, are compared, assessing their influence on plant layout and performance. Moreover, a detailed economic analysis has been carried out for evaluating the levelized cost of the electricity produced, as well as the profitability of each plant configuration. The study shows that using the heat recovered from gas turbines for biomass drying enhances the feasibility of biomass-fired power plants, improving performance and reducing woody biomass crop requirements with respect to conventional configurations. The analysis also demonstrates that the proposed solutions allow reducing the cost of electricity produced and shorten payback periods. (C) 2002 Elsevier Science Ltd. All rights reserved.