Lower fuel costs to reduce bills for Idaho customers of Rocky Mountain Power

BOISE, Idaho — Rocky Mountain Power’s costs for fuel and wholesale electricity decreased in 2025, producing a modest decrease in customer bills for the coming year. As part of an annual review of these costs, the company requested an average 0.6% decrease for Idaho residential customers. A typical residential customer using 836 kilowatt-hours per month would see a decrease of $0.61 per month on their electricity bill. The company proposes the decrease to take effect June 1, 2025, subject to review by the Idaho Public Utilities Commission.

“The company is working hard to maintain our position as a low-cost energy provider,” said Tim Solomon, director, Commercial Accounts and Community Relations for Rocky Mountain Power. “The annual adjustment process makes sure Rocky Mountain Power customers always pay a fair price for the energy they need. A winter 2025 survey of prices nationally shows a typical residential electric bill in Idaho at $119 per month, while the national average is $179.” For details, visit Residential customer price comparison

The annual energy cost adjustment mechanism is designed to track the difference between the company’s actual expenses for fuel and electricity purchased from the wholesale market, against the amount being collected from customers through current rates. The costs are tracked in a separate account called the Energy Cost Adjustment Mechanism and adjusted each year. If costs are higher than the level included in base rates, a surcharge is applied to customer bills as a separate line item. If costs are lower, a credit is applied.

Testimony supporting the company’s application shows fuel supply constraints and price volatility in previous years stabilized in 2025, resulting in more normal output from low-cost thermal generating plants. Lower natural gas costs, together with lower wholesale market prices, moderated the cost of supplying electric service to Idaho customers in 2025.

Pending commission approval, the changes would take effect June 1, 2026, with the following impact on each rate schedule:

Residential Schedule 1 – 0.6% decrease

Residential Schedule 36 – 0.6% decrease

General Service Schedule 6 – 0.7% decrease

General Service Schedule 9 – 0.8% decrease

Irrigation Service Schedule 10 – 0.5% decrease

General Service Schedule 23 – 0.7% decrease

General Service Schedule 35 – 0.7% decrease

Public Street Lighting – 0.2% decrease

Tariff Contract 400 – 1.1% decrease

The public will have an opportunity to comment on the proposal as the commission studies the company’s request. The commission must approve the proposed changes before they can take effect. A copy of the company’s application is available for public review on the commission’s website, www.puc.idaho.gov, under Case No. PAC-E-26-05. Customers may also subscribe to the commission’s RSS feed to receive periodic updates via email. The request is required to be available at the company’s offices in Rexburg, Preston, Shelley and Montpelier, although the company urges customers to visit our website at rockymountainpower.net/rates.