Gas turbines and renewable fuels ― the technologies, the risks, and the rewards

摘要

As efforts are made by the Electricity Supply Industry to reduce carbon dioxide emissions, many commentators see biomass and organic wastes as providing the backbone of renewable electricity. Direct combustion of biomass and Municipal Solid Waste (MSW), with heat recovery and power generation via steam turbine, is a well-proven technology. However the low efficiencies of these schemes affect the ability of these technologies to compete on a p/kWh basis with fossil fuel power generation, and other forms of renewable electricity generation such as wind turbines. The environmental acceptability of incineration technologies with regard to dioxin emissions has also been questioned. Gasification and pyrolysis technologies, when combined with gas turbines or combined cycle plant, offer the potential for higher energy conversion efficiencies and hence lower cost electricity, with low emissions. However, these technologies are relatively immature and viewed as high risk, both technically and commercially. This paper looks at the operating experience already gained by ALSTOM Poweron biomass gasification schemes and describes the technological development currently being carried out to further improve performance, fuel flexibility and reliability of the gas turbine. The described programme aims to address the technical and commercial issues associated with the gas turbine as an integrated part of the overall plant, so providing improved potential for lower cost biomass power generation. The -risks and rewards for the other technology suppliers, the renewable fuel supplier and the project developer are also reviewed.