Cogeneration: Gas Turbine Multitasking

Abstract

This article describes the functioning of the gas turbine cogeneration power plant at the University of Connecticut (UConn) in Storrs. This 25-MW power plant serves the 18,000 students’ campus. It has been in operation since 2006 and is expected to save the University $180M in energy costs over its 40-year design life. The heart of the UConn cogeneration plant consists of three 7-MW Solar Taurus gas turbines burning natural gas, with fuel oil as a backup. These drive water-cooled generators to produce up to 20–24 MW of electrical power distributed throughout the campus. Gas turbine exhaust heat is used to generate up to 200,000 pounds per hour of steam in heat recovery steam generators (HRSGs). The HRSGs provide high-pressure steam to power a 4.6-MW steam turbine generator set for more electrical power and low-pressure steam for campus heating. The waste heat from the steam turbine contained in low-pressure turbine exhaust steam is combined with the HRSG low-pressure steam output for campus heating.