Introduction & Purpose
Many companies make green power purchasing claims with the expectation of reporting lower greenhouse gas (GHG) emissions in their corporate GHG emissions inventories (i.e., their corporate “carbon footprints”). While accelerated policy and financial support for renewable energy deployment is urgently needed to help address climate change, it is also critical to the legitimacy of GHG disclosures that emissions be calculated and reported on the basis of credible assumptions and methods that are a true accounting of environmental outcomes.
This Frequently Asked Questions (FAQ) resource addresses complicated issues in GHG emissions accounting and reporting with respect to green power purchasing claims by electricity end-use consumers. It does so using an evidence-based approach. It especially focuses on Renewable Energy Certificate (REC) and Guarantee of Origin (GO) and their application to corporate (organizational) GHG accounting. These certificates are the dominant instrument used by consumers to make green power purchasing claims and associated zero GHG emission reporting claims (associated with Scope 2 or indirect GHG emissions from the consumption of grid-supplied electricity). The question of the role of Purchase Power Agreements (PPAs) in GHG accounting is, unfortunately, lacking in evidence-based research. Once such research is completed, it will be subject of future updates to this FAQ.
This FAQ addresses voluntary purchasing green power claims. It does not address compliance tracking and reporting by electric utilities (i.e., Load Serving Entities) that employ certificates under a regulatorily mandated clean energy or renewable portfolio standard policy.
 U.S. EPA. The Benefits and Costs of Green Power. Guide to Purchasing Green Power. https://www.epa.gov/sites/default/files/2018-08/documents/guide-purchasing-green-power-3.pdf
 The fundamentals of GHG accounting discussed in this FAQ applies to other types of voluntary certificates such those for “green gas” or “renewable gas”. Additional commentary here: https:// earthjustice.org/sites/default/files/files/A1902015_Sierra_Club_Protest_04-05-19.pdf