Last Wednesday, Xcel Energy held an open house at the Monticello Community Center to discuss a plan for a battery storage facility on Xcel’s Sherco power plant site.  Representatives from Form Energy (who is manufacturing the batteries) and Argonne National Laboratory (who will measure, assess, and validate the project) were also on hand to discuss their respective goals and objectives.

The project is planned to be a ten year trial, and will test Form’s iron-air battery concept and its effectiveness at storing renewable energy for up to 100 hours.  The technology was first developed in the 1970’s through partnership between NASA, the Department of Energy and General Electric for outer space applications.

According to Xcel literature available at the event, the battery works through “reversible rusting: while discharging, the battery breathes in oxygen from the air and converts iron metal to rust; while charging, the application of an electrical current converts the rust back to iron and the battery breathes out oxygen.”

Xcel touted the safety of the system, stating that “the thermal runaway mechanisms that are a frequent cause of fires in lithium-ion batteries do not exist in Form’s technology.”

In addition, the batteries have been tested in California in temperatures as low as -40 degrees Celsius and as high as 50 degrees Celsius.

Xcel’s Hyde Weissenfluh spoke of the company’s receipt of a $70 million grant to develop this project, as well as one in Pueblo, Colorado.  He also cited $20 million received from a Bill Gates linked organization, as well as funding provisions derived from the Inflation Reduction Act legislation.  

Weissenfluh said that the impact of the project to ratepayers is unknown at this time, but is “something that can be built into the economic analysis” of the project.

Argonne’s participation in the project is part of the analysis that will determine the overall economic impact of the test site, with plans to model its effect on changes in community patterns.

Other factors in Argonne’s analysis will include workforce development trends, as well as the project’s compliance with the Justice40 Initiative, which was part of President Biden’s environmental executive order signed just days into his presidency.

Groundbreaking for the construction is expected to begin in October, with operation commencing during the fourth quarter of 2025 or early 2026.  The project will occupy about 8 total acres of land at Sherco’s current site, with about 5 acres used for the battery equipment. It will contain 256 enclosures, each measuring 40 feet long, by 8.5 feet wide and about 9 feet tall.  Each will be filled with the battery technology and will weigh about 150,000 pounds when fully loaded with the electrolyte solution needed for the storage to work properly.

Job statistics shared at the meeting indicated about 15-20 positions in electrical and mechanical fields during the construction phase, with a peak of 80-100 jobs during the enclosure deployment months.  Ongoing, the site will be mostly operated remotely, with some annual maintenance requirements that would translate into a .5 full-time equivalent position.

At the end of the 10 year trial, possibilities could include an extension of the project, or a full decommissioning of the site.  Newer technologies could also be deployed to keep some of the infrastructure in place and extend its life.  Form energy officials noted that many of the enclosure’s contents would be recyclable.