The Idaho Public Utilities Commission (IPUC) recently gave the company the green light to build the projects, ruling that they are in the public interest. Despite recent price impacts due to global supply chain disruptions, the cost for large-scale batteries has dropped significantly in recent years while their capacity has increased. Combining batteries with solar enables the batteries to continue delivering energy to the grid when solar production drops off while customer demand remains high.
Those peak periods, typically hot summer afternoons and evenings when irrigation pumps and air conditioners increase the demand for electricity, are what drives the need for new resources.
Battery energy storage systems are designed to discharge their capacity over a four-hour period. For example, a 40-MW battery can deliver 160 megawatt-hours (40 MW X 4 hours). That’s enough to power more than 5,000 homes during those peak demand periods.
“These battery projects are an example of how we are using new technology to make sure our customers have reliable power while we adapt to the continued growth on our system,” said Mitch Colburn, Vice President of Planning, Engineering and Construction. “These systems — along with the solar projects coming online and future resources identified by our long-range plan — will also move us closer to our goal of providing 100% clean energy by 2045.”
The state’s largest solar farm, the 120-MW Jackpot Solar project south of Twin Falls, began delivering electricity to Idaho Power in December. On Feb. 17, the company submitted plans to the IPUC for a second solar project in the same area. The 100-MW Franklin Solar project will be built by the same developer — Duke Energy Sustainable Solutions — that built the Jackpot facility.
Franklin will also include a 60-MW four-hour duration battery energy storage system owned and operated by Idaho Power. Pending approval by the IPUC, the Franklin project is scheduled to come online in 2024.
Jackpot and Franklin Solar are independent power producers that will sell their energy to Idaho Power. The battery systems will be company-owned and operated, giving Idaho Power the flexibility to store energy when it’s most economical and deliver it to the grid when customers need it most.
The company anticipates needing even more energy and capacity in 2025 and beyond and is currently analyzing proposals for projects that would come online in 2025 and in the process of soliciting proposals to meet resource needs in 2026 and 2027. These resources would potentially be in addition to the 500-kilovolt Boardman to Hemingway transmission line that the company plans to have online in 2026, providing additional import-export capacity to the Pacific Northwest.