Xcel Energy to add iron-air battery system to store electricity in Becker

A sign marks an entrance to the Sherburne County Generating Plant.
A sign marks an entrance to the Sherburne County Generating Plant, known as Sherco. Plant owner Xcel Energy announced plans to install an iron-air battery storage system at the site of the plant, which will be retired by 2030.
Kirsti Marohn | MPR News

Xcel Energy plans to add a battery storage system at the site of its Sherco coal-fired power plant in central Minnesota.

Xcel is partnering with Form Energy, a Massachusetts company, to install iron-air battery systems at two of its retiring coal plants: in Becker, Minn., and Pueblo, Colo. The systems are able to store energy for 100 hours, longer than a typical lithium battery.

The Minneapolis-based utility says the technology will allow it to add more renewable energy to its system and maintain reliability, as it retires the coal plants in the coming years and transitions to cleaner electricity.

Strengthening the grid

Xcel hopes to have both systems online as early as 2025, subject to approval by state regulators.

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The utility plans to retire all three coal-burning units at the Sherco plant by 2030. Last fall, state regulators approved Xcel’s plan to build a 460-megawatt solar project in Becker that will be fully operational by late 2025.

In a news release, Bob Frenzel, Xcel's president and CEO, said the battery storage will strengthen the grid against extreme weather events and polar vortexes.

Xcel has pledged to deliver carbon-free electricity by 2050. Bills moving through the Minnesota Legislature would require utilities to reach that goal by 2040.

Great River Energy also is planning to install an iron-air battery pilot project in Cambridge this year.