By: Teun Schröder
Energy group Xcel Energy says it has received the green light for the construction of an 'iron-air' battery with a capacity of 10 to 1,000 megawatts. The relatively cheap technique uses the oxidation of iron and is very suitable for power storage for several days.

The technology for this type of battery was developed by the start-up Form Energy and immediately attracted the attention of a number of well-known billionaires such as Bill Gates, Jeff Bezos and Richard Branson. Steel giant ArcelorMittal also showed interest. After successful pilots, the company can now scale up considerably in Minnesota.

Energy rusting out
The technique of an iron-air battery works as follows: the system uses the rust cycle of iron. When charging battery modules – about the size of a washing machine – electricity (ideally renewable) is used to convert rust or iron oxide into iron. Oxygen is released as a residual product. Discharging the batteries requires oxygen to be introduced into the system, which causes the iron to rust again. This releases energy.

The iron used for these types of batteries is relatively cheap and widely available. In addition, the battery, which uses water and air in addition to iron, is free of harmful substances.


Overcome bad weather
A disadvantage is that it takes a long time to charge and discharge an iron-air battery. What a lithium battery does in a few hours, this battery does in about four days. However, this disadvantage can be beneficial in certain situations. For example, the iron-air battery can store renewable energy from solar panels over a series of sunny days. If a period of rainy weather follows, an energy supplier can rely on the long discharge time.

Replacing coal with renewable
Form Energy is now approved for the first time to install a gigawatt-scale battery system at the Sherburne County Generation Station in Becker, Minnesota. Xcel Energy will start using the battery. The energy company still manages a few coal-fired power stations, but has been replacing these more and more with renewable energy sources in recent years. For example, the Sherco Solar solar park is currently being built at the power plant in Becker. With a capacity of 710 megawatts, this park should become one of the largest in the US.

Giant pasture
Form Energy's washing machine-like modules will be placed on an area of ​​2 hectares. That is a lot of space, if you compare it with the same storage capacity with lithium batteries. Nevertheless, the Form energy battery is considerably cheaper. According to the manufacturer, the modules last for years and the parts are fully recyclable. The 'levelised cost of storage', in fact the investment costs required to store 1 kilowatt hour, is therefore only 10 percent of that of lithium batteries.
Ready in 2025
“Multi-day battery storage has the potential to help us make better use of the renewable energy we generate,” said Bria Shea, responsible for regulatory policy at Xcel, in a press release. At the same time, we ensure that the grid remains reliable for our customers. “We look forward to connecting this system to our Sherco solar farm and learning more about the role it can play in our efforts to achieve 100 percent carbon-free electricity.”

Construction of the battery will begin next year. If all goes well, it will be online in 2025.


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82 w
Great innovation by gates and Bezos
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82 w
Wow, that sounds fascinating! It would be great if Gates and Bezos could team up to create a cheap and reliable rust battery that generates gigawatts. It would certainly be revolutionary in the renewable energy sector!
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82 w
The cost is low and the upside is really high on these
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82 w
Very innovative in deed