Iron Flow Batteries

Wendell Berry had some strict definitions of when to consider something an improvement. Some of which, such as the definition that the improvement should be as small as or smaller than the previous version, are largely subjective and depend on the type of product. But in general Berry has good principles, most of which are satisfied when applying them to a new form of battery known as the “iron flow battery”.

Why we need better batteries:
The company ESS (located in Wilsonville, Oregon) is building flow batteries the size of shipping containers that have the capacity to provide energy to 34 houses for up to 12 hours. In this case, bigger is better, because with an increasing amount of energy coming from renewable sources such as solar and wind energy, we need to be able to store more energy for extended periods of time to make the energy available for people when it is needed. Lithium-ion grid-connected batteries no longer suffice, only being able to store energy for around four hours.

How it works:
The flow battery is made of iron, salt, and water, which are easily accessible non-toxic natural resources. They work by positively and negatively charging cells in large liquid electrolyte tanks. The electrolytes are iron salts, and in each cell there are two that are separated by a membrane.

In comparison:
Iron flow batteries are expected to last for at least 20 years, with no limit on how many times it is charged. This is a huge step up from lithium-ion batteries which have a shelf-life limited to a few years. An alternative energy storage method to batteries is hydro-electric storage, in which water gets pumped to a higher elevation and let back down again, but terrain can affect that, and it requires building quite a bit of infrastructure. The flow battery can get large, but not as large as hydroelectric storage systems, and it doesn’t rely on terrain.

Sources:

https://www.technologyreview.com/2022/02/23/1046365/grid-storage-iron-batteries-technology/