Repowering Steamboat 2 and 3 Plants with New Axial Flow Turbines

Abstract

The Steamboat 2 and 3 geothermal power plants owned and Operated by Ormat Nevada, Inc. included four radial flow turbo-expanders originally supplied by Atlas Copco. The turboexpanders have experienced significant maintenance costs and unscheduled down time during the period 2006 through early 2008. The Ormat Technologies group undertook to repower the Steamboat 2 and 3 plants by replacing the four turbo-expanders with axial flow Ormat engineered turbines. The plant repowering was completed in mid 2008. The repowering was successfully performed with minimal plant down time using cross-functioning Ormat teams. The project required coordinated planning utilizing expertise from all aspects of a multifunctional team including engineering, manufacturing, construction and operation. Plant performance and reliability has been greatly improved. In addition to improved performance and reliability, on going maintenance costs are expected to be significantly less than with the turbo-expanders due to elimination of intermediate speed reduction gear boxes and complicated lubrication and shaft sealing systems.