A new, longer-duration, grid-scale battery storage technology under development is getting a big financial boost. Xcel Energy is partnering with Form Energy, an energy storage technology company, to build a 10-megawatt commercial iron-air battery demonstration project at the soon-to-be shuttered Comanche power plant site near Pueblo.

A commitment of $10 million in grant funding from Breakthrough Energy Catalyst to Xcel Energy to support the test project was announced Monday. Xcel Energy plans to use the federal Inflation Reduction Act to lower development costs even more.

Form Energy officials said its iron-air batteries could deliver cost competitive electricity for as long as 100 hours. The batteries will allow Xcel Energy to integrate more low-cost, renewable energy into its system and maintain the reliability of the grid as it retires all of its coal plants by 2030, according to a press release from Xcel.

“Innovative long-duration energy storage technologies are crucial to achieving 100% carbon-free electricity,” said Bob Frenzel, chairman, president, and CEO of Xcel Energy in the release. “This Catalyst grant will accelerate adoption of this promising new technology, which allows us to provide higher percentages of renewable energy while still providing affordable electric service to our customers.”

Founded by Bill Gates, 13 companies – including General Motors, Microsoft, BlackRock, Citi Bank and American Airlines – have provided more than $1 billion in direct capital contributions to Breakthrough Energy, a platform that funds and invests in emerging climate technologies.

“By investing in clean energy storage solutions, Xcel Energy is laying the groundwork for a net-zero future that’s affordable and keeps the lights on regardless of the weather, and these projects will help accelerate our journey there,” said Mario Fernandez, head of Breakthrough Energy Catalyst, in the release.

Form’s technology uses rusting iron in a chemical process that releases electrons to generate electricity, providing electricity storage that can be regenerated. Form has developed the technology into what it says will be a utility-scale solution to the intermittency of power generated by wind turbines and solar panels.

Most utility-scale battery technologies on the market can only provide four-to-six hours of energy storage at full rated power. While this is adequate for some circumstances, recent severe weather events – ranging from heat waves to cold snaps to thousand-year rains – have hampered the electric grid.

Weather-dependent generating resources are by nature intermittent – and that’s not good for a power grid, which requires stable energy every day all year long.

Form Energy’s promotional materials said the battery bank footprint uses about half an acre of land per megawatt and higher density configurations could provide more than 3 megawatts per acre. To replace the 1,365 megawatts capacity of the three Comanche generating units, Units 1, 2 and 3, would require 682 acres of batteries at half acre per megawatt or 455 acres at three acres per megawatt.

Jaramillo said its system will be able to store energy at less than 1/10th the cost of lithium-ion battery technology and could be online by 2025.