Where does Idaho's electricity come from?

In 2024, plants inside Idaho generated 20,035 GWh and Idaho customers bought 26,370 GWh at retail. The gap was covered by a net 8,348 GWh from other states.

Idaho has imported power every year the series covers: the imported share was 57.6% in 1990 and peaked at 71.9% in 1992. The share fell because in-state generation grew faster than use. In 1990 generation was 9,691 GWh against retail sales of 18,003 GWh.

The full series are on Idaho electricity imports, Idaho electricity generation and Idaho electricity use.

Of the 20,035 GWh generated inside Idaho in 2024, the largest single source the U.S. Energy Information Administration (EIA) reports is conventional hydroelectric dams at 9,150 GWh, and none is attributed to coal.

The dams generated 9,115 GWh in 1990 and 9,150 GWh in 2024; the gas, wind and solar capacity was built over the same period. Across the series the dams’ output has run from 6,654 GWh in 1992 to 14,676 GWh in 1997.

The breakdown by source and year is on Idaho hydropower generation.

The border flow figure does not say where the imported power was generated. The closest public record is ownership. Form EIA-860 lists every generator with more than one owner and each owner’s share, and Form EIA-923 reports each plant’s net generation by fuel.

In 2025 Idaho Power, the state’s largest utility, held a share of two operating plants outside Idaho:

• Jim Bridger, WY: 33.33% of a coal and natural gas plant that generated 7,597 GWh, of which 4,876 GWh from coal. Idaho Power’s share of the output: 2,532 GWh.
• North Valmy, NV: 50.00% of a coal and natural gas plant that generated 1,298 GWh, of which 1,287 GWh from coal. Idaho Power’s share of the output: 649 GWh.

Those shares add to 3,181 GWh, 2,269 GWh of it from coal.

An ownership share is an entitlement to output, not a delivery record: a utility can sell its share into the market or buy more than it owns.

Source: EIA, Forms EIA-860 and EIA-923, plant ownership and output.

Idaho Power’s parent, IDACORP, files an annual report with the SEC whose first section prints the utility’s power supply by source in thousands of megawatt-hours. For 2024 it reports a total supply of 20,061 GWh.

The jointly owned plants are Jim Bridger and North Valmy, so the utility’s figure for them, 2,474 GWh, is lower than the 3,181 GWh its ownership shares would allow. An ownership share is an entitlement, not a delivery. The 10-K says Idaho Power ended its participation in coal-fired operations at North Valmy unit 1 in December 2019 and unit 2 in December 2025; EIA’s owner file still lists its half of both.

Purchased power is not split by fuel in the report. From 2007 to 2022 it was split between contracts with small producers under federal law, mostly wind, solar and geothermal projects in Idaho, and other purchases. The series since 1998 is on Idaho Power power supply by source, where the latest year is 2025 at 20,395 GWh.

EIA’s figures are for the State of Idaho: every plant inside it, every retail customer in it, and the net flow across its border. Idaho Power’s figures are for one utility whose territory is southern Idaho and a corner of eastern Oregon, and whose purchases include power generated inside Idaho by producers it does not own.

Rocky Mountain Power, the northern cooperatives and the wholesale market fall in the difference between the two.

The average prices are EIA’s Form 861 retail revenue over retail sales. In 2024 Idaho’s residential price was 11.52¢/kWh, lower than every state except North Dakota; the all-sector price was 9.51¢/kWh. The national averages were 16.48¢/kWh and 12.94¢/kWh.

Among the six states that border Idaho, the residential price ran from Washington at 11.90¢/kWh to Nevada at 15.00¢/kWh.

On the bill, the same file gives revenue per residential customer: an average of $109 a month in Idaho in 2024 against $142 nationally, for 11,326 kWh a year per Idaho customer against 10,359 kWh. Idaho households use more electricity than the national average and pay less for it.

Businesses paid 9.17¢/kWh and industrial customers 7.69¢/kWh in 2024. The bill series is on Idaho electricity prices.

In 1990 an Idaho household paid 4.87¢/kWh against 7.83¢/kWh nationally, 62.2% of the national figure; in 2024 the ratio was 69.9%.

The five states with the lowest residential prices in 2024, with the share of each state’s own use that its dams generated that year:

The comparison for every state is on Idaho electricity prices.

The state average covers every utility. EIA’s sales file by utility gives each one’s own average residential price for 2025, with its customer count; by year, the same figures are on Idaho electricity rates by utility.

Source: EIA, Retail Sales and Price of Electricity by State (EIA-861).

In Idaho Power’s table the hydropower row has ranged from 5,347 GWh in 2022 to 11,135 GWh in 1998, and the purchased power row from 2,401 GWh in 2010 to 7,178 GWh in 2022.

The annual report does not price the purchases. It says its power cost adjustment mechanisms, in the report’s words, mitigate in large part the earnings impacts of volatile fuel and power costs; a cost kept out of earnings is recovered in rates.

EIA publishes no state-to-state flow table, so the origin of the rest of the net 8,348 GWh is not in any file on this site. Three parts of it have no published Idaho figure.

Rocky Mountain Power, a PacifiCorp division, serves eastern Idaho from a six-state system. Its plants include the other two thirds of Jim Bridger, and coal and gas plants in Utah and Wyoming. PacifiCorp’s address on Form EIA-860 is Portland, so its plants fall outside the ownership rule above, and its 10-K reports for the whole system rather than for Idaho.

Utilities and cooperatives in northern Idaho buy federal hydropower marketed by the Bonneville Power Administration from dams on the Columbia and Snake. And Idaho Power’s purchased power has no fuel attached to it in any filing.

A utility’s average price is its revenue over its sales, not its rate schedule. The tariff a customer is billed on, with its service charge and seasonal tiers, is set by the Public Utilities Commission, and it is not in any EIA file.