Perspectives for the use of biomass as fuel in combined cycle power plants

The paper analyzes the perspectives of biomass and biomass derived fuels utilization for energetic use. After a brief review about the current technologies for biomass conversion to energy and biomass based power plants, an exergy loss based economic analysis of biomass utilization is proposed. This analysis shows the opportunity of using biomass in plants with a thermodynamic efficiency higher than a minimum value. Thus the attention is focused on the use of thermal energy from biomass as integrative source together with natural gas in combined cycle power plants, considering methods for upgrading biomass energy conversion to power. The paper provides a thermodynamic analysis of combined plants using biomass to obtain exhaust gas aftertreatment with atmospheric postcombustion (reheat). Two different technical solutions are proposed. A general optimization of the two solutions shows the possibility of obtaining plant efficiency up to 60% in perspective and of 57% by using currently available gas turbine models.