Biomass-gasifier/aeroderivative gas turbine combined cycles .B. Performance calculations and economic assessment

Gas turbines fueled by integrated biomass gasifiers are a promising option for base-load electricity generation from a renewable resource. Aeroderivative turbines, which are characterized by high efficiencies in small units, are of special interest because transportation costs for biomass constrain conversion facilities to relatively modest scales. Part A of this two-part paper reviewed commercial development activities and major technological issues associated with biomass integrated-gasifier/gas turbine (BIG/GT) combined cycle power generation. Based on the computational model also described in Part A, this paper (Part B) presents results of detailed design-point performance calculations for several BIG/GT combined cycle configurations. Emphasis is given to systems now being proposed for commercial installation in the 25-30 MW(e) power output range. Three different gasifier designs are considered: air-blown, pressurized fluidized-bed gasification; air-blown, near-atmospheric pressure fluidized-bed gasification; and near-atmospheric pressure, indirectly heated fluidized-bed gasification. Advanced combined cycle configurations (including with intercooling) with outputs from 22 to 75 MW are also explored. An economic assessment is also presented, based on preliminary capital cost estimates for BIG/GT combined cycles and expected biomass costs in several regions of the world.