Cogeneration: Small Turbine-Generator Case Study

Cogeneration, simply stated, is the sequential production of two forms of energy, usually steam and electricity. Three factors have recently made the use of cogeneration in industry more advantageous than in the past. First, the high cost of energy has caused industry to turn to cogeneration as an economical alternative to escalating power bills. Second, the Public Utility Regulatory Policies Act (PURPA) requires utilities to offer qualified customers monetary incentives to use cogeneration, thus making cogeneration both efficient and profitable to that customer. Third, compact low-cost small (less than 1000 kW) turbine-generator hardware is now available. The installation of a small cogeneration system based on a back-pressure turbine-generator set is discussed. Topics covered include cogeneration background, type of system chosen, economic analysis, and physical installation. Particular attention will be devoted to the electrical interface required in the installation of this cogeneration facility.