Long-lasting grid batteries – why iron-based batteries may be key to decarbonisation

While development of renewable energy sources, and how the energy produced may be distributed over our national grids, is advancing at a rapid rate, one problem still remains – what happens to our energy production from renewable sources when the sun sets and the wind stops blowing?

One obvious solution would be to use a large energy storage means (e.g. batteries) to help even out energy production when supplies from renewable are low, with such storage mean storing excess energy during times of high production. To provide power for large populous areas or even entire countries, the scale of any such such storage means needs to be huge, and distribution networks set up for varying energy provision between renewable sources and storage batteries. Ultimately though, being able to store energy from renewable sources for hours or even days at a time, and then being able to distribute said energy in times of low supply would be a huge step forward in the use of clean power.

It is proposed that new types of iron-based batteries might be up to the task.

Oregon-based ESS, who has been investigating national grid storage and supply style batteries, whose batteries can store energy for between 4 and 12 hours, has recently launched its first grid-scale projects. Additionally, Massachusetts-based Form Energy has also recently developed batteries that store power for up to 100 hours. Its first installation will be a one-megawatt pilot plant in Minnesota, slated to be completed this year.

Interestingly, both companies rely on batteries that use iron, one of the most abundant materials on the planet. This means that their offerings could eventually be cheaper than other grid storage candidates, like lithium-ion and vanadium flow batteries. Form Energy further believes that its batteries could ultimately cost just $20 (approx. £16) per kilowatt-hour, lower than even optimistic projections for lithium-ion batteries in the next several decades.

While many challenges of iron based batteries still need to be addressed, such as the fact iron batteries typically have low efficiency, meaning a good fraction of the energy that’s put into them can’t be recovered, and unwanted side reactions can also degrade them over time, if such iron-based batteries can be deployed widely, at a low enough cost, they could provide a huge step forward in powering more of the world with renewable energy.