Preliminary Estimates of Combined Heat and Power Greenhouse Gas Abatement Potential for California in 2020

Publication Type


Date Published



The objective of this scoping project is to help the California Energy Commission's (CEC) Public Interest Energy Research (PIER) Program determine where it should make investments in research to support combined heat and power (CHP) deployment. Specifically, this project will:

  • Determine what impact CHP might have in reducing greenhouse gas (GHG) emissions,
  • Determine which CHP strategies might encourage the most attractive early adoption,
  • Identify the regulatory and technological barriers to the most attractive CHP strategies, and
  • Make recommendations to the PIER program as to research that is needed to support the most attractive CHP strategies.

This study derives a range of potential GHG emissions abatement estimates for the state of California in year 2020 achieved by wider deployment of CHP. Additionally, the study estimates the contribution CHP might make towards the State's AB-32 objective of reducing GHG emissions to 1990 levels by 2020. This work seeks to shed light on how much GHG emissions might be reduced at various levels of CHP penetration, and not to forecast the likely level under any particular economic or policy regime. Thus, the question being addressed is akin to "how much CO2 abatement could be achieved in 2020 if a given percentage of car owners stop driving and take mass transit," rather than the question "how much CO2 abatement will mass transit save the state in 2020?" Note that drivers are heterogeneous in driving patterns, vehicle preferences, etc., and so the ones that opt for mass transit may not represent the average or the biggest emitters. Also, mass transit may not always be a GHG improvement. One passenger on an otherwise empty bus is a bigger emitter than a car carrying only its driver. Likewise with CHP, systems are heterogeneous and not all will be an improvement over conventional energy supply. Any analysis of CHP's potential benefits must consider these issues, and while we do not intend to address such questions in this work, any policy intended to promote CHP should be crafted to avoid one-passenger-bus problems.

Year of Publication