Cogeneration, simply, is the generation of energy for one process from the excess energy supplied to another process. Cogeneration, then, is nothing more than an economically sound method for the conservation of resources . Thus, the benefits from the use of cogeneration may be cited as energy conservation, environmental improvement and financial attractiveness to investors. In the near future energy efficiency must no longer be a choice, but a commitment-hence the timely importance of this review. © 1993.