The Cogeneration Process

The University of Michigan's Central Power Plant is an example of a combined-cycle cogeneration system. Cogeneration is the simultaneous production of electrical and thermal energy from one energy source. A combined-cycle system uses gas turbines driving electrical generators and boilers heated by the gas-turbine exhaust, which then produce steam to drive steam turbine generators. The use of cogeneration optimizes energy production and increases energy efficiency to over 80% as compared to less than 40% efficiency for conventional electric utility plants. A combined-cycle cogeneration plant increases the ratio of electrical power to thermal energy as compared to a regular cogeneration plant.
Steam is produced by the CPP primarily for heating, cooling, and hot water distribution to the university campus. However, before distribution, the steam passes through turbines for electric generation. The CPP therefore meets its primary purpose of providing heating, cooling, and hot water, and concurrently produces electricity, processes often done by separate plants much less efficiently.

Content modified: February, 2001