Idaho Power has signed a 20-year contract for an 82 MW battery. Most US battery contracts are signed with a developer that owns the project. Idaho Power signed this one with Prevalon Energy, the Mitsubishi Power Americas company whose equipment the battery is built from.
Key takeaways
- Prevalon Energy, a Mitsubishi Power Americas company, signed an agreement with Idaho Power on 29 March 2024 for an 82 MW, four-hour battery energy storage system with up to 328 MWh of output, together with a long-term service agreement covering maintenance and remote monitoring.
- Enerdatics records the Prevalon and Idaho Power battery agreement as a 20-year onsite contract of the grid services agreement type, with no tariff disclosed.
- The Idaho Power battery will use Prevalon's Battery Energy Storage Platform, a complete AC system including battery enclosures, inverters, transformers and an energy management system.
- Idaho Power plans to integrate more than 5,000 MW of wind and solar energy over the next 20 years, and the 82 MW Prevalon battery is designed to support grid resiliency and supply during peak demand.
- Enerdatics records 84 battery offtake contracts in the United States announced between January 2023 and June 2025, of which five are onsite and two carry a disclosed tariff.
What has Idaho Power actually contracted for?
Capacity it can call on at peak, from a battery it does not have to design. The system is rated at 82 MW with four hours of duration, which means it can deliver its full output for four hours before it is empty. That gives 328 MWh, enough to cover an evening peak after solar output falls away.
The contract has two layers. The first is the agreement for the battery itself, which Enerdatics records as a 20-year grid services agreement. A grid services agreement pays for what a battery does for the network, such as storing and releasing energy on instruction, rather than for a fixed volume of generated power. The second layer is a long-term service agreement under which Prevalon maintains and remotely monitors the system.
The technology is Prevalon's own. Its Battery Energy Storage Platform is a complete AC system, meaning the battery enclosures, inverters, transformers and energy management software arrive as one package rather than being assembled from different suppliers.
Why does it matter who is on the other side of the contract?
Because the counterparty determines who carries the performance risk. In most US battery contracts in Leap, the supplier is a developer or independent power producer that owns the project and buys its equipment from a manufacturer. If the battery underperforms, the developer answers to the buyer and then looks to its own equipment supplier.
Here the equipment company sits directly opposite the utility. Prevalon describes itself as a global leader in battery storage, with more than 30 projects and 3 GWh of utility-scale systems deployed. Its name is on both the hardware and the 20-year contract, and on the service agreement that keeps the hardware running. That removes one link from the chain between the cells and the customer.
Enerdatics records the contract as onsite. That is rare in US battery offtake. Of the 84 contracts in Leap from January 2023 to June 2025, five are onsite. The rest are offsite arrangements in which the utility or buyer contracts for output from a project elsewhere on the grid.
How does this fit Idaho Power's wider buying?
It was the first of three. Enerdatics records nine power contracts with Idaho Power as offtaker, three of them for batteries. After the 82 MW agreement in March 2024, Prevalon signed a second contract with Idaho Power in January 2025, this time for a 200 MW battery. In the same month Clenera signed a 20-year agreement for the 100 MW Crimson Orchard battery, alongside a separate 120 MW solar contract for the same site.
That means Prevalon is the counterparty on 282 MW of the 382 MW of battery capacity Idaho Power has contracted in Leap, or about three quarters. For a utility, repeating a supplier reduces integration and operating risk across a growing fleet. For Prevalon, it turns a single equipment sale into a long-term position on the Idaho grid.
The batteries sit alongside a growing solar book. Idaho Power is a named offtaker, with Meta, on the solar projects at Pleasant Valley, and has contracted solar output from developers including Duke Energy. Idaho Power's stated plan is to bring more than 5,000 MW of wind and solar onto its system over 20 years, and storage is how that output gets moved into the evening.
Enerdatics records 84 battery offtake contracts in the United States between January 2023 and June 2025. Half of them, 42, are in the CAISO market in California. Of the 66 with a disclosed term, 30 run for 20 years or more, so the length of the Idaho Power agreement is standard. What is not standard is everything else. Idaho Power operates outside an organised wholesale market, which Leap classifies as Independent. The contract is onsite. And only two of the 84 contracts carry a disclosed tariff, so the price Idaho Power is paying cannot be benchmarked at all.
What does the deal signal for US utility battery procurement?
It shows that a utility outside the organised markets can buy storage on different terms from a California buyer. In CAISO, most of the battery contracts in Leap are resource adequacy or tolling agreements with independent developers, and the buyer pays for capacity that someone else owns and operates. Idaho Power has instead contracted directly with the equipment supplier and kept service under the same counterparty.
The four-hour, 20-year shape matches what developers have been signing elsewhere. Strata's Scatter Wash battery in Arizona, for example, carries a 20-year tolling agreement with Arizona Public Service for a four-hour system. The difference in Idaho is who holds the contract, not what the contract covers.
The open question is price. Neither Prevalon contract with Idaho Power discloses a tariff, and nor do almost any of the other US battery contracts in Leap. Until one does, the market can see who is buying storage and for how long, but not what it costs.
Frequently asked questions
What did Prevalon Energy sign with Idaho Power? Prevalon Energy signed an agreement with Idaho Power on 29 March 2024 for an 82 MW, four-hour battery storage system with up to 328 MWh of output, plus a long-term service agreement for maintenance and remote monitoring.
How long is the Idaho Power battery contract with Prevalon? Enerdatics records the agreement as a 20-year grid services agreement. The tariff was not disclosed.
How many battery contracts has Idaho Power signed? Enerdatics records three battery contracts with Idaho Power: two with Prevalon Energy, for 82 MW and 200 MW, and one with Clenera for the 100 MW Crimson Orchard battery.
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