Combined heat and power (CHP) captures the heat that would otherwise be rejected in traditional fossil fuel generation of electrical power so that the total efficiency of these integrated systems is much greater than from central station power plants and separate thermal systems. CHP systems also produce lower emissions compared to traditional fossil fuel generation. Other benefits include reduction in peak demand, releasing of electrical grid system capacity, and reduction in overall electrical system transmission and distribution losses.
The treatment of CHP under the ASHRAE 90.1 – 2004 Performance Rating Method (PRM, Appendix G) comes under the purview of G2.4 Energy Rates. G2.4 adequately
addresses on-site CHP systems but does not provide a methodology for recognizing the potential benefits of district CHP. This document provides guidance for both cases, using a LEED-specific methodology for district systems.