Status of Steam-Injected Gas Turbines

The injection of exhaust-heat-generated steam into gas turbines for power augmentation has been proven to provide exceptional flexibility of operation in cogeneration applications. The chronology of development of this technology is presented, including a list of available turbines. A description is then given of the design process for converting existing gas turbines to steam injection. Finally, the water purification issue, which is perceived by some as a barrier to cost-effective implementation of such installations, is addressed. It is shown that water purification cost is of the order of 5 percent of the fuel cost and is therefore not a decisive factor.