Each electric supplier or utility in Washington must tell customers what fuels were used to generate the electricity they sold last year. This disclosure, shared on public websites, acts like a food label, helping customers understand what they are receiving. 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 an “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 Commerce 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.
Electric utility greenhouse gas content reporting
During the 2024 legislative session, the Legislature passed and Governor Inslee signed House Bill 1955 which repealed the greenhouse gas content calculation requirement in the Clean Energy Transformation Act. However, utilities are required to comply with the law for the years it was on the books. Commerce revised the reporting process for those years (2020-2022) to help utilities comply with the law. Commerce utilized the fuel mix disclosure to estimate the greenhouse gas content of electricity for each utility for calendar years 2020-2022, and Commerce received confirmations and adjustments from utilities on the greenhouse gas content estimates.