An ‘iron-air’ battery has been developed in the US that can store electricity from wind or solar power stations for days at a time, slowly discharging it to the grid.
Scientists say it will tackle climate change by reducing the need for fossil fuel power plants, according to technology startup Form Energy, from Massachusetts, US.
The Iron-Air battery is a ‘new class of cost-effective, multi-day energy storage system,’ that can feed electricity for 100 hours at 1/10th the cost of lithium-Ion, the ‘holy grail’ in terms of renewable energy technology.
It is made using iron, one of the most common elements on Earth, and works by breathing in oxygen, converting iron to rust, and turning rust back to iron.
As it takes in the oxygen and converts the iron back and forth it is charging and discharging the battery, a process that keeps the energy stored for a longer period.
The batteries are too heavy for use in electric cars, according to the firm, who say they are designed to meet the challenge of keeping a constant power supply.
If development continues at pace, Form Energy hope the first batteries will be working to supply the grid by 2025.
This will solve one of the most elusive problems facing renewable energy, that is how to cheaply store large amounts of electricity and supply it to power grids when the sun isn’t shining for solar panels or wind isn’t blowing for turbines.
Solar and wind resources are the lowest marginal cost sources of electricity in most of the world, but they don’t provide a constant supply like fossil fuel power plants.
The electric grid now faces a challenge in how to manage this variability in supply without sacrificing energy reliability or affordability.
Form Energy claim their new battery system is the solution to this growing problem.
Mateo Jaramillo, CEO and Co-founder of Form Energy, said they conducted a broad review of all available technologies and ended up reinvented the iron-air battery.
This was done to ‘optimise it for multi-day energy storage for the electric grid.’
The firm says the battery they are developing will allow countries to fully retire thermal assets like coal and natural gas power plants.
‘With this technology, we are tackling the biggest barrier to deep decarbonization: making renewable energy available when and where it’s needed, even during multiple days of extreme weather or grid outages,’ said Jaramillo.
It will also be cheaper, the firm said. A lithium-iron battery cell uses nickel, cobalt, lithium and manganese minerals that cost up to $80 per kilowatt-hour of storage.
Using iron, Form hopes to get that to less than $6 per kw/hour in terms of mineral costs for each cell, and packing them into a full battery system will still keep the cost to less than $20 per kilowatt hour of energy storage.
This is the price point that experts say renewables will finally be able to replace traditional fossil-fuel power plants.
Investors in the firm include Breakthrough Energy Ventures, a climate investment fund backed by Bill Gates, Jeff Bezos and others. They’ve also taken funding from steelmaking giant ArcelorMittal, a world leading iron-ore producer.