Each electric supplier, or utility, serving retail customers in Washington must disclose to its customers the mix of fuels used to generate the electricity sold to those customers in the previous year. Utilities must disclose the information, similar to a content label on a food product, to new customers and post the information on their public websites. The disclosure must show the percentage of electricity by fuel type, such as coal, hydroelectricity, natural gas, nuclear, wind, and solar. If the utility does not know the source of some electricity, it must label that portion as “unspecified source.”

The Department of Commerce fuel mix program supports disclosure by ensuring consistent reporting. More than 60 utilities submit information to Commerce about specific generating resources that the utility uses to serve Washington customers. The Bonneville Power Administration provides the same information for the electricity that it delivers to utilities in Washington. Commerce compiles the individual reports, checks the information in comparison to published data on power plant generation, and summarizes it in a statewide fuel mix estimate.

Commerce also uses the fuel mix reports to estimate the statewide greenhouse gas emissions from electricity consumed in Washington. The Department of Ecology uses this information as an input for the overall greenhouse gas inventory for the state.

Starting in 2021, each utility must calculate and report the greenhouse gas content of the electricity it provides to retail customers in Washington. This calculation must be based on the amounts and fuel sources claimed in the fuel mix disclosure program. Emissions must be calculated using a methodology established by the Department of Ecology. Utilities are not required to post or publish these results, but Commerce will publish the information on this page.

Utility Data

Utilities provide the following information to us in megawatt-hours (MWh):

  • Total electricity retail sales including power purchases necessary to cover line losses.
  • Amounts of specified sources acquired by contract or ownership, by generating resource and fuel.
  • Amounts of market or unspecified power used to serve retail load.
  • Amount of electricity purchased from BPA.