Under the Power Source Disclosure Program, retail suppliers are required to annually disclose to their retail consumers the mix of sources used to provide electricity service during the previous calendar year. In those instances where a retail supplier offers consumers more than one electricity portfolio, the retail supplier is to provide information specific to each electricity portfolio offered. In addition, retail suppliers are required to report to the Energy Commission their gross purchases of electricity by source, resales of electricity, and the net electricity by source used to serve retail load for the previous calendar year. The Energy Commission uses this information, in part, to generate California’s total system power mix. Retail suppliers then disclose to their consumers the power mix associated with their electricity portfolios, as well as California’s overall power mix on an annual Power Content Label. Providing both the portfolio information and California’s total system fuel mix allows consumers to compare their electricity portfolio to other portfolios offered by the retail supplier, as well as to California’s total system power mix.