Combined heat and power systems and power recovered from waste energy can represent important contributions to meeting an Energy Efficiency Resource Standard and complying with carbon reduction policies. In order for these resources to be credited towards such targets, a consistent methodology to approximate associated energy savings and emissions reductions is needed. This is a complex task for CHP systems because they produce both thermal and power outputs. Net savings need to be properly attributed to either the displaced thermal or power system (or both) without attributing the same savings twice. This is further complicated because the thermal output typically displaces an onsite thermal-only system and the power typically displaces power generated remotely and purchased from the local electric power pool. As a result, the savings are represented by the net reduction in fuel, compared to the combined fuel from the displaced local thermal system and the displaced generation in the electric pool. This paper provides a context for developing a methodology to address these issues, and proposes an approach that can fairly credit CHP systems for their energy savings and reductions in greenhouse gases.