Idaho Power headquarters in downtown Boise. (Brad Carlson/Capital Press file)

Idaho Power officials expect peak demand to grow by nearly 45% over the next 20 years, with over half the gain coming in the next five years, according to the Integrated Resource Plan that the Boise-based utility filed with state regulators.

Utility commissions in Idaho and Oregon are expected to set a schedule for public review and comment on the plan, updated every two years.

Growth continues to be driven by increases in population and a broad range of commercial and industrial expansion, according to an Idaho Power news release.

The preferred portfolio focuses on least-cost and reliability-enhancing generation and transmission projects with an eye toward further reducing wildfire risk.

The plan also highlights the need for more transmission line infrastructure — specifically the Boardman to Hemingway and Southwest Intertie projects designed to enable the company to import energy when demand is high, according to the release.

The average number of metered customers is expected to increase by just over one-third from nearly 648,000 as of December 2024 to 867,000 in 2045, according to an executive summary of the plan.

The long-range plan calls for adding 1,445 megawatts of solar, 885 MW of battery storage, 700 MW of wind, 611 MW in coal-to-gas conversions and 550 MW of new gas as well as 344 MW of energy efficiency and 20 MW of incremental demand response.

The company’s demand response programs are designed to incentivize customers to use less energy during periods of peak demand.

Idaho Power added 460 megawatts of new solar between 2022 and 2025, and the company forecasts more than 500 MW of contracted solar and 600 MW of contracted wind power to come online over the next few years, spokesman Brad Bowlin said.

Among agriculture customers, the growth of on-site generation has been fairly slow over the last few years, he said.

“The size of solar systems used by irrigators is quite a bit larger when compared to a residential system, but the contribution to the system at peak times is muted because most of the energy generated by those systems is being used by the customer and not fed back to the grid,” Bowlin said.

Irrigation demand — which now makes up about 20% of system peak demand in the summer — is expected to grow 0.6% a year on average through the plan’s 20-year forecast period, he said.

“Not only is the ag sector one of our most important customer groups, they are a key to our demand response programs,” which help delay the need for new resources and “play an important role in the IRP and our long-term planning,” Bowlin said.

Energy used for Irrigation represents more than 80% of the company’s total demand response portfolio.

Idaho Power’s Irrigation Peak Rewards program has about 2,700 irrigation service points enrolled, representing about 272 MW of demand reduction capacity — more than 90% of the total generating capacity of our largest gas-fired plant” at Langley Gulch in southwest Idaho, he said.

As for wildfires, a plan adjustment increases the likelihood that certain transmission facilities will be out of service — thus impacting annual capacity starting next summer — given the recent prevalence of fires and an increase in de-energizing transmission lines when encroachment occurs, according to an appendix.

Plan detail:

https://tinyurl.com/Idaho-Power-plan