Xcel Energy is partnering with Form Energy, an energy storage technology company, to build two 10-megawatt iron-air battery demonstration projects: one at the soon-to-be shuttered Comanche power plant site near Pueblo and another at the likewise retiring Sherburne County Generating Station in Becker, Minn.
At a meeting in Pueblo on Thursday, Xcel Energy, Form Energy, and the Department of Energy Office of Clean Energy Demonstrations announced $4.3 million for planning, permitting, and other development before the construction of the projects begin. In May, Breakthrough Energy Catalyst announced a commitment of $10 million to Xcel Energy to support the test project.
Form Energy says its iron-air batteries can deliver cost-competitive electricity for as long as 100 hours. According to a news release from Xcel Energy, the batteries will allow Xcel Energy to integrate more low-cost, renewable energy into its system and maintain the grid’s reliability as it retires its coal plants.
Weather-dependent generating resources are, by nature, intermittent, and that’s not good for a power grid, which requires stable energy throughout the day and year.
“An unavoidable feature of renewable energy like solar and wind, is that it is intermittent, meaning that the sun doesn’t shine 24 hours a day and the wind doesn’t always blow,” said Margaret Larson of the OCED. “While shorter duration is currently being installed to support today’s level of renewable energy generation, longer duration is needed as more renewables are deployed on the grid and is a critical component of our strategy to increase renewable energy and enhance grid reliability.”
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 intermittent 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 – from heat waves to cold snaps to thousand-year rains – have hampered the electric grid.
Form Energy 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 1,365MW capacity of the three Comanche generating units, Units 1, 2, and 3 would require 682 acres of batteries at half an acre per MW or 455 acres at three per MW.
Form Energy representatives told The Denver Gazette that its battery system requires one-tenth of the space of solar power for an equal amount of electricity.
Xcel said the groundbreaking will happen at the beginning of 2025, and the project is expected to be in service by the third quarter of 2026.
Xcel is holding a virtual open house using Microsoft Teams in early December.