Idaho Power has formally requested regulatory approval to construct two new natural gas-fired power plants in southern Idaho, citing a surge in electricity demand that is outpacing the utility's current generation capacity. The move comes as the company faces projected capacity shortfalls of 236 megawatts in 2029 and 352 megawatts in 2030, according to filings with the Idaho Public Utilities Commission.
The utility is seeking certificates of public convenience and necessity for the South Hills Power Plant in Twin Falls County, which would add up to 222 megawatts, and the Peregrine facility in Elmore County, capable of generating 430 megawatts. South Hills is slated to begin commercial operations by June 1, 2029, while Peregrine is targeted for June 1, 2030. These projects are not part of a rate case, and Idaho Power has indicated that cost recovery will be addressed in a separate future filing.
Jared L. Ellsworth, Idaho Power's head of transmission, distribution, and resource planning, noted in a commission filing that the utility's latest resource review identified capacity deficits of 236 MW in 2029 and 352 MW in 2030, assuming other contracted resources and the Bennett Mountain gas expansion come online as scheduled. Ellsworth stated that bringing South Hills and Peregrine online would reduce the 2029 deficit to 98 MW and create a 125 MW surplus in 2030, though he cautioned that the surplus does not equate to excess power for sale. “A delay of resource procurements in 2029 will only exacerbate the capacity deficiencies,” he wrote.
The utility conducted an all-source procurement process that attracted 83 proposals, including solar, wind, battery storage, solar-plus-battery, and a single gas plant bid. Eric Hackett, who leads projects and resource development at Idaho Power, said the two gas plants were selected as the “least-cost, least-risk” options to bridge the capacity gap. Adam Richins, executive vice president and COO, told regulators that the company is experiencing “load growth across multiple customer sectors” amid higher costs, tight supply chains, permitting hurdles, and limited system capacity.
Idaho Power’s push for new gas generation comes as part of a broader transition away from coal, with increasing reliance on hydro, solar, wind, batteries, transmission, and natural gas. Brad Bowlin, a company spokesperson, said the utility is seeing “continued rapid growth” and emphasized that gas plants can start up quickly, while renewable sources are used first. The company’s 2025 resource plan projects peak demand will climb nearly 45%, or 1,700 megawatts, over the next 20 years, with about 1,000 megawatts of that growth occurring in just five years. Mitch Colburn, vice president of planning, engineering, and construction, said the utility is seeking resources that provide steady energy “at the lowest cost over the long term.”
The Idaho Public Utilities Commission has set a written comment period ending July 31, with Idaho Power required to respond by August 14. If no protests are filed, the commission may rule without a hearing, but it retains the authority to schedule one if comments warrant. The commission has already granted intervenor status to several parties, including the Idaho Irrigation Pumpers Association, Micron Technology, the Northwest Energy Coalition, and Renewable Northwest, ensuring that large customers and clean-energy groups will have a voice in the proceedings. The financial impact on customers remains unclear, as Idaho Power did not propose a rate increase in this filing, and Bowlin stated there is no estimate yet of potential bill effects.
IDACORP, the parent company of Idaho Power, noted that the South Hills and Peregrine case is still pending. The company recently received approval for the Bennett Mountain gas expansion, which will add 167 megawatts, and is also constructing the Boardman-to-Hemingway transmission line, a 300-mile project with PacifiCorp to help meet future resource needs.