Minnesota utility co-op sees big battery as piece of grid reliability puzzle

Great River Energy, a distribution and transmission cooperative, has partnered with a Massachusetts startup on a long-duration energy storage pilot project that it hopes will help buffer its grid from extreme cold and heat impacts.

By Frank Jossi, Energy News Network

The utility cooperative partnering with Form Energy on its first “iron air” battery project sees the long-duration energy storage technology as a potential buffer for its grid during extreme cold snaps like 2019’s polar vortex.

Great River Energy, a Minnesota generation and transmission cooperative that serves 28 member utilities, had been in discussions with the Massachusetts startup company for several years before committing to the pilot project, according to Jon Brekke, its vice president and chief power supply officer.

“We’re interested in pursuing long-duration storage because it gives us reliability advantages over traditional lithium-ion batteries,” Brekke said. “We can look at a 10-day weather forecast, and if we see that the weather is going to get very cold seven or eight days out, we can make sure that the battery is charged up.”

Wind speeds tend to decrease during extremely cold temperatures. Meanwhile, turbine components can become brittle or stop working as temperatures plunge into the double-digits below zero. Those factors caused Upper Midwest wind generation to drop off two winters ago during a prolonged polar vortex. (Coal and gas plants also experienced outages.)

The stakes for wintertime grid reliability will increase as more homes and buildings transition to electric heat, but long-duration energy storage could also help utilities manage the grid during scorching hot weather that is also becoming more common in Minnesota due to climate change.

Form Energy’s “iron air” battery. Credit: Form Energy / Courtesy

Form Energy’s “iron air” batteries store energy for as long as 100 hours or more, offering Great River Energy another tool to deliver electricity during challenging weather events.

Members approved the pilot as a power supply resource that will be owned and operated by the generation and transmission utility. Brekke did not reveal the cost of the project but characterized it as “small” and not involving a significant investment risk. If the pilot meets expectations, Great River Energy may make the battery a significant part of its power resources. 

Form Energy has raised $367 million so far from investors. It’s among a handful of new long-duration battery companies in a field that could experience explosive growth as more utilities work toward higher clean energy goals. Great River Energy plans to generate 50% from renewable energy by 2030 and saw Form Energy as having a solution that may fit its needs.

Nearly all utilities today use lithium-ion energy storage solutions that discharge backup electricity over four hours. Form Energy’s technology is based on iron and uses electrochemistry to make reversible rust iron. The battery discharges energy while breathing in oxygen and creating rust. During charging, the electric current converts rust back to iron and breathes out oxygen.

Ted Wiley, Form Energy’s co-founder, explained that hundreds of washing machine-sized batteries are chained together to form a 1-megawatt power block. The technology uses relatively cheap and plentiful iron instead to store electricity at a tenth the price of lithium-ion batteries — a key to Great River Energy’s interest in the project.

“We saw the vision here of having ultra-cheap, long-duration storage, and we found a fit with Form Energy,” Brekke said.

Great River Energy’s deal with Form Energy could grow to as many as 300 megawatts in the future if the technology works, Brekke said. Beyond serving the utility during cold weather spells, Great River Energy sees the Form Energy batteries as a market hedge and potential economic development engine for Minnesota’s iron ore industry.

Battery storage represents 12% of projects in the queue of the MidContinent Independent System Operator (MISO). In Minnesota, three small community battery storage projects funded by a state program are being installed now, joining several other small pilots built in the last five years.

Connexus Energy, a cooperative serving several Twin Cities suburbs, began running a 30-megawatt solar-storage project in 2019 that was, at the time, one of the largest in the region. Clean Grid Alliance Executive Director Beth Soholt said that as power companies transition to more weather-dependent generation sources such as wind and solar, the need for storage grows.

Long-duration storage will help utilities deal with “extreme heatwaves or cold snaps and the crazy weather patterns we’re seeing” due to global warming, she said. However, most storage applications cannot mimic the power output of natural gas or coal plants during a weather crisis, Soholt said.

Long-duration batteries also allow utilities the flexibility to buy energy at low-cost times. Great River Energy will be able to buy energy overnight, when wind power is plentiful but demand is low, and deploy it “when the grid is stressed or in need of power supply,” Brekke said.

As Form Energy works to bring the battery technology to the market, the goal is to reach cost parity with thermal generation such as natural gas. 

The battery storage pilot project is expected to begin operation in 2023 next to two natural gas plants in Cambridge owned by Great River Energy. A future installation could happen in the state’s Iron Range.

“The other thing we like about Form is the connection to Minnesota with the iron air technology,” he said. “We’re just thrilled that this is using a product that is so important to Minnesota’s economy. And Minnesota can become a significant energy player should this technology prove to be successful.”

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