Bio-Energy Cogeneration Systems With CO2 Separation and Storage

Abstract

This paper compares three different bio-energy cogeneration power station concepts where CO2 is sequestered and available for permanent storage instead of discharging into the atmosphere. The different bio-energy cogeneration systems are: The pre-combustion capture of CO2 the post-combustion capture of CO2 from the flue gas and the combustion in an atmosphere of pure oxygen (Graz-Cycle). The three schemes, all based on a thermal input of about 150 MWth, are compared on the basis of their technological features, their performance, projected costs of electricity and CO2 mitigation costs. Compared to a conventional bio-energy cogeneration system, CO2 removal reduces net plant efficiency by 11 to 16 percentage points and increases the cost of electricity by approximately 54 to 89%. The scheme applying reforming and shift reaction and physical absorption of the syngas fuel appears the most appealing option for the short-term implementation of CO2 sequestration bio-energy cogeneration systems. The Graz-Cycle where the syngas is burnt in pure oxygen appears the most appealing option for the long-term option for CO2 sequestration.