Washington state gets roughly two-thirds of its electricity from hydropower, making it the most hydro-dependent state in the country. The remaining third comes from a mix of natural gas, nuclear, wind, and a fast-growing solar sector. That heavy reliance on dams keeps electricity cheap: Washington residents pay about 13.3 cents per kilowatt-hour, well below the national average of 17.2 cents.
Hydropower Carries the Grid
The Columbia River Basin is the engine behind Washington’s electrical grid. More than 30 federal dams feed power into the system, and the single largest producer is Grand Coulee Dam in northeastern Washington. Grand Coulee is the biggest hydropower facility in the United States, generating over 21 billion kilowatt-hours per year. That power doesn’t stay within state lines. It flows to eight western states and parts of Canada.
The Bonneville Power Administration, a federal agency, markets the wholesale electricity from these dams and delivers it across more than 15,000 miles of high-voltage transmission lines throughout the Pacific Northwest. BPA provides about 32% of all electric power consumed in the region. For most Washington utilities, especially publicly owned ones, BPA hydropower is the backbone of their supply.
Hydropower’s dominance gives Washington unusually low carbon emissions from electricity and unusually low prices. It also creates a vulnerability: in drought years, reduced snowpack means less water flowing through turbines, which forces utilities to buy replacement power on the open market, sometimes at much higher cost.
Natural Gas as the Backup
Natural gas is the second-largest electricity source in the state, fueling about 12% of generation. Gas plants fill an important role that dams can’t always handle on their own. They ramp up quickly when demand spikes on cold winter evenings or when hydropower output dips seasonally. Washington doesn’t produce much natural gas itself, so it imports supply primarily from British Columbia and the Rocky Mountain region through an interstate pipeline network.
Nuclear Power From a Single Plant
Washington has one nuclear power plant: the Columbia Generating Station near Richland, in the eastern part of the state. It’s a 1,207-megawatt reactor, large enough to power roughly a million homes. The Bonneville Power Administration markets all of the energy Columbia produces and folds the costs into its wholesale rates. Unlike hydropower, nuclear runs at a steady output around the clock regardless of weather or river conditions, which makes it a reliable baseload source year-round.
Wind Is Surging, Solar Is Close Behind
Wind power has become a significant part of Washington’s electricity mix. As of 2023, the state had about 811 average megawatts of wind capacity in operation, concentrated primarily along the ridgelines of the Columbia Plateau in eastern Washington. State utility planners project that figure will roughly double within ten years. For the first time since tracking began, Washington utilities now forecast that wind power will surpass natural gas plants in meeting their ten-year resource needs.
Solar is smaller but growing faster in relative terms. Utility-scale solar contributed just 56 average megawatts in 2023, roughly equal to the state’s biomass output. But utilities plan to expand solar capacity dramatically, projecting it will reach around 500 average megawatts within a decade. Summer solar capacity alone is expected to jump from 84 megawatts to over 1,000 megawatts in that same window.
Coal Is Gone
Washington’s last coal-fired power plant, the TransAlta facility in Centralia, shut down on December 19, 2025. A state law passed in 2011 required the plant to close by the end of that year, and a separate 2019 law now prohibits utilities from selling coal-based power in the state. The Centralia plant had been the state’s single largest source of greenhouse gas emissions. Its closure means Washington has fully exited coal-fired electricity generation.
The Push Toward 100% Clean Power
Washington’s Clean Energy Transformation Act, passed in 2019, sets two binding deadlines for the state’s utilities. By 2030, every electric utility must be greenhouse gas neutral, meaning any remaining carbon emissions have to be offset through renewable energy credits, efficiency programs, or investments in carbon reduction projects. By 2045, all electricity sold in the state must come from renewable or zero-carbon sources, with no offsets allowed.
The practical effect is that natural gas plants, which currently provide that 12% share, will need to be phased out or paired with carbon capture technology over the next two decades. Utilities are already planning for this by investing heavily in wind, solar, and battery storage. The state’s existing hydropower and nuclear capacity give it a significant head start: most of Washington’s grid is already carbon-free, so the transition is less dramatic than it would be in a coal- or gas-heavy state.
Why Electricity Is Cheaper Here
Washington residents consistently pay some of the lowest electricity rates in the country. The December 2025 average residential rate was 13.33 cents per kilowatt-hour, compared to the national average of 17.24 cents. The gap is even wider for commercial and industrial customers, where Washington’s rate of about 6.9 cents per kilowatt-hour is roughly 81% of the national average.
The reason is straightforward: hydroelectric dams, once built, produce electricity with very low operating costs. There’s no fuel to buy. The federal dams in the Columbia Basin were largely constructed between the 1930s and 1970s, and their construction costs have long been paid off or spread thin. BPA passes those low wholesale rates on to public utilities, which serve the majority of Washington’s population. Investor-owned utilities like Puget Sound Energy also benefit from access to hydropower, though their rates tend to be slightly higher because they carry more diverse (and more expensive) generation portfolios.