The California Public Utility Commission (CPUC) selected a team led by Energy and Environmental Economics, Inc. (E3) to model the electricity sector’s compliance with AB32, California’s Global Warming Solutions Act. This law requires a reduction in statewide greenhouse gas (GHG) emissions to 1990 levels by 2020.

E3’s modeling work was initially completed in May 2008 and provided the CPUC and California Energy Commission (CEC) with critical information on how different policies and initiatives will achieve emission reduction savings in the electricity and natural gas sectors and affect utility costs and consumers’ electricity bills. This information was used by the CPUC and CEC to advise the California Air Resource Board (CARB) on setting and implementing GHG standards for the electricity sector in the Joint Final Opinion on GHG Regulatory Strategies D.08-10-037.

In October 2009, a revised version of the GHG Calculator (version 3) was released, along with a final report describing the findings and methodology applied in the GHG Calculator. In November 2009, version 3b of the GHG Calculator was released with minor changes.  In October 2010, version 3c of the GHG Calculator was released, with a change to the treatment of CHP.