The U.S. Energy Information Administration (EIA) anticipates a 5% increase in U.S. hydropower generation for 2026, reaching an estimated 259 billion kilowatthours (BkWh). Despite this projected recovery, the generation levels are expected to remain 1.8% below the 10-year average. This forecast follows a period where hydropower generation in 2025 increased to 245 BkWh, surpassing the record-low generation of 2024 by approximately 4 BkWh. The EIA projects that the 2026 generation would constitute 6% of the nation's total electricity production.
Seasonal precipitation, encompassing both rain and snowpack accumulation, serves as the primary determinant for water supply available to hydropower facilities. Adequate rainfall contributes to soil moisture, which in turn helps preserve the snowpack, acting as a crucial natural reservoir. According to data from the Western Regional Climate Center, precipitation levels across the western United States have generally been within normal ranges. However, many states in this region have experienced record warm winter temperatures, contributing to widespread snow drought conditions. Compounding these issues, a heat wave in March across much of the western United States accelerated snowmelt, particularly in California, the Southwest, and portions of the Northwest. The EIA expects these conditions will likely affect hydropower generation, leading to reduced water supply during the critical spring and summer months.
The Northwest region, which includes the Columbia River Basin, accounts for over one-third of the nation's hydropower capacity. This area alone generates sufficient electricity to power more than 4 million homes. Fluctuations in water supply within the Northwest can influence the demand for other electricity-generating fuels, such as natural gas, and affect regional electricity trade dynamics. The EIA forecasts hydropower generation in the Northwest and Rockies region to reach 125 BkWh in 2026, marking a substantial 17% increase from 2025 levels. However, this figure is still projected to be 4% below the 10-year average for the region.
The EIA's hydropower outlook for the Northwest is partly informed by unusually high hydropower generation observed in December 2025 and January 2026. This surge was attributed to a series of atmospheric rivers that, while bringing much-needed precipitation, also caused severe flooding across the region. The EIA's hydropower forecast for this area is further refined by water supply projections from the National Oceanic and Atmospheric Administration’s Northwest River Forecast Center.
In California, hydropower generation is forecast to be 28.5 BkWh in 2026, according to the EIA's April Short-Term Energy Outlook (STEO). This represents a 6% decrease compared to the previous year's generation but is expected to be 15% above the 10-year average for the state. As of April 1, reservoir levels across most of California's major reservoirs were reported to be above their 30-year historical averages. Specifically, the state's two largest reservoirs, Shasta and Oroville, were at 114% and 124% of their respective historical averages. The state had also experienced three consecutive weeks with no drought conditions or, at worst, drier-than-normal weather.
Despite the favorable reservoir levels, California's snowpack conditions as of April 1 were significantly below normal. Data from the California Department of Water Resources indicated that the Northern Sierra Nevada snowpack was at 7% of its historical average, the Central Sierra at 25%, and the Southern Sierra at 39%. The warmer-than-average temperatures experienced in March across the state contributed to an early melt of the existing snowpack, a factor that will influence water availability in the coming months.
The interplay of precipitation, temperature, and snowpack dynamics presents a complex outlook for hydropower generation. While overall precipitation has been adequate in many areas, the timing and form of that precipitation, coupled with unseasonably warm temperatures, are critical factors. The EIA's projections highlight a regional recovery in hydropower output, particularly in the Northwest, driven by recent atmospheric river events. However, the persistent snow drought in some western areas, including California, tempers the overall national recovery, keeping generation levels below historical norms.
This situation underscores the sensitivity of hydropower to climatic conditions. The reliance on snowpack as a natural reservoir means that warmer winters and early melts can significantly diminish water resources available for electricity generation during peak demand periods. The EIA's forecast reflects these competing influences, balancing the positive impact of recent wet periods with the ongoing challenges posed by warmer temperatures and reduced snowpack in key regions.
