Xcel Energy’s iron air battery in Becker will ‘hopefully’ cost $20 million, deliver 0.45% of the coal plant’s power output
Yesterday I attended the Midwest Reliability Organization’s Hybrid Reliability meeting in St. Paul, Minnesota. One of the presenters was from Form Energy, a battery startup focused on building low-cost, iron-air batteries that can last for 100 hours, compared to the typical four-hour duration for lithium-ion batteries.
Form’s iron-air batteries have been touted by wind and solar advocates as a solution for the inconvenient fact that these energy sources often fail to show up for work for extended periods of time, and lithium-ion batteries are not only unable to bridge these long intermittency gaps due to their short duration, but they are also prohibitively expensive.
The longer duration of iron-air batteries is likely why, in January of 2023, Xcel Energy announced they would be partnering with Form Energy to deploy a ten-megawatt (MW) battery that could provide the grid with 1,000-megawatt hours (MWh) of energy at the Sherburne County Generating Station in Becker.
A Star Tribune report from January noted that Xcel Energy did not disclose the costs of the battery, but I was able to ask the Form spokesperson what the project would cost. He included several caveats about needing to conduct site-specific engineering work, but he said the company hoped to get the costs down to $20 per kilowatt hour, or $20,000 per MWh at the project.
That price point would mean that the battery in Becker would cost $20 million.
Form’s 100-hour batteries are interesting because they last a long time, but they do not deliver much power to the grid at any one time. In other words, they can supply a small amount of power for a very long time.
For comparison, the Sherburne County Generating Station (Sherco) is a coal-fired power plant that can generate up to 2,238 MW of power per hour if it is operating at full capacity. This means the Form battery will only be able to supply the grid with 0.45 percent of the power provided by the coal plant when it is up and running.
In a statement, Xcel said that Form’s battery “will strengthen the grid against normal day-to-day, week-to-week, and season-to-season weather variability, in addition to extreme weather events, including severe winter storms and polar vortex events.” Maybe, but at what cost?
Replacing the power output potential of Sherco with Form batteries would require 224 ten-MW battery facilities, each costing $20 million, bringing the cost to $4.47 billion. That is just the capital cost of the battery. It doesn’t include the government approved-profits Xcel Energy would make by building it or the cost of building the wind turbines and solar panels needed to charge the batteries in the first place.
Form hopes to cut the cost of its batteries in half compared to the estimated cost of the Becker project, but even at that cost, the electricity provided by the battery will be much more expensive than continuing to run the coal plants at Becker for the foreseeable future. Minnesota lawmakers and utilities are gambling with grid reliability by mandating unreliable wind and solar technologies and hoping that unproven batteries will save the day in the future.