Residual Mix Applications and Existing Data

This document, released by CRS’s Clean Energy Accounting Project (CEAP), is intended to provide background on how residual mixes (electricity delivered as part of system mix and untracked or unclaimed energy) and associated emissions should be defined and calculated in the U.S. for different uses. Residual mix calculations are often used for greenhouse gas emissions calculations and reporting by either electricity providers or customers, and is currently produced by both governmental agencies and NGOs. Even when residual mixes are developed for the same application, they can vary in terms of data sources, treatment of clean generation resources used for compliance and voluntary purposes, and geographic and temporal boundaries. This backgrounder is intended to provide a baseline of available information, but is not comprehensive list of applications, residual mix emission factors, or considerations.