Portland General Electric (PGE) has energised 475MW of battery energy storage to boost grid reliability and keep costs low for customers in the US state of Oregon.

The three new utility-scale battery energy storage systems add more than 1.9 gigawatt hours (GWh) of dispatchable capacity, bolstering the electricity supply for the Portland metro area.

Collectively, these installations will power 300,000 homes for up to four hours during peak demand.

The lithium-ion energy storage systems are situated at key substations in North Portland, Troutdale and Hillsboro. They are designed to optimise the balance between electricity production with consumption more effectively, alleviating pressure on the grid.

The integration of battery storage technology not only diminishes its dependence on costly short-term electricity purchases but also contributes to stabilising energy costs and mitigating price fluctuations for consumers.

These systems also facilitate the incorporation of renewable energy sources, such as wind and solar.

Two of the newly operational facilities were developed by Eolian, as part of PGE's 2021 All-Source Request for Proposals (RFP) process.

Located in North Portland, the 200MW Seaside facility was delivered to PGE by Eolian under a fixed-cost build-to-transfer agreement. Commercial operations were started in July 2025.

The Sundial, a 200MW facility in Troutdale, was developed by Eolian and will be operated under a 20-year storage capacity agreement by NextEra Energy Resources. It began operations in December 2024.

The third facility, Constable, is a 75MW installation owned by PGE in Hillsboro, constructed under an engineering, procurement and construction (EPC) agreement with Mortenson that reached commercial operation in December 2024.

PGE also completed its Coffee Creek battery storage system near Wilsonville in 2024, bringing its total large-scale battery storage capacity up to 492MW.

In December, the company made a power purchase agreement (PPA) with Avangrid to procure electricity from the Tower solar project, in Portland, Oregon, which has a capacity of 120 megawatts alternating current (166 megawatts direct current).