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Today in Energy

September 11, 2020

EIA expects U.S. hydroelectric generation to increase in 2020 despite drought conditions

annual U.S. hydroelectric generation
Source: U.S. Energy Information Administration, Short-Term Energy Outlook

In its latest Short-Term Energy Outlook (STEO), the U.S. Energy Information Administration (EIA) forecasts that electricity generation from hydroelectric power plants in the United States will grow by 4% in 2020 from 2019 levels, to 280 billion kilowatthours, despite current drought conditions and extensive wildfires in parts of the country, including in the Pacific Northwest.

States in the Pacific Northwest, home to the Columbia River Basin, are the largest hydroelectric power producers in the United States. Idaho, Montana, Oregon, and Washington, the four states that make up the Pacific Northwest, generated 47% of all U.S. hydroelectric power in the first half of 2020. As such, drought conditions in these states can have noticeable impacts on overall U.S. hydroelectric generation, especially if the drought is severe or long lasting.

share of total U.S. monthly hydroelectricity generation
Source: U.S. Energy Information Administration, Electric Power Monthly

Many factors affect how much water is available to generate hydroelectric power, including precipitation levels in current and previous years. Seasonal precipitation for the 2020 water year (October 2019 to September 2020) has been mixed in the Columbia River Basin. Most of the stations in the eastern half of the basin have reported between 70% and 130% of normal precipitation, and some stations in the western half have reported less than 50% of normal precipitation.

As of September 2020, 14 counties in Oregon and 4 counties in Idaho have issued drought emergency declarations. This year’s droughts, however, aren’t expected to have noticeable impacts on hydroelectric power production because reservoirs in the region have stored water from near-normal to above-normal precipitation in recent years.

Pacific Northwest drought status and hydroelectric dam reservoir storage capacity
Source: U.S. Drought Monitor; U.S. Geological Survey (USGS), Water Resources

According to data from the U.S. Department of Agriculture’s National Water and Climate Center (NWCC), which produces a comprehensive database on water supply conditions (including reservoir storage), reservoirs in most of the states in the Pacific Northwest have been able to retain precipitation from recent years. As of the end of August 2020, reported reservoir storage levels were at or higher than the 30-year (1981–2010) normal in Washington, Idaho, and Montana. In Oregon, reported reservoir storage was at 37% of maximum capacity, lower than the historical average of 45%.

reservoir storage levels, by Pacific Northwest state
Source: U.S. Department of Agriculture, Natural Resource Conservation Service (USDA-NRCS), National Water and Climate Center
Note: Includes all storage reservoirs that reported capacity levels for August 2020 in the respective states.

So far this year, monthly hydropower generation in these states has been within the 10-year (2010–2019) historical range, with the exception of April’s hydropower generation in Oregon, which was 10% lower than the 2010–2019 monthly range. If the 2021 water year has near-normal precipitation levels, impacts from this drought could be minimal.

monthly hydropower generation
Source: U.S. Energy Information Administration, Electric Power Monthly

Principal contributor: Michelle Bowman