Massive new “reversible rusting” batteries could help Ireland’s electricity grid shift away from fossil fuels

Sitting at a table in a conference room near-ish Grand Canal Docks recently, Paul Blount explained why his company wants to install a massive new battery in Donegal.

The short answer is: to sop up wind energy when there’s extra, save it until there’s a need for more electricity and then feed it back into the grid.

What takes a bit more explanation, and a bit of PowerPoint, is what this new type of battery is, and the role it could play in helping Ireland get rid of gas-fired power plants and building a grid powered almost entirely by wind and solar – which wax and wane with the weather, and don’t emit carbon to worsen climate change.

The battery is produced by a US company called Form Energy, and, importantly, its main ingredients are very common and cheap – iron and air – nothing fancy and hard to get like the lithium used in the dominant battery technology.

And the company, co-founded in 2017 by an MIT professor and an ex-Tesla exec, says these batteries can store energy for longer than other such batteries: up to four days – “at system costs competitive with legacy power plants”, rather than just a couple hours.

If these batteries work as advertised, if the science and the economics are right, they could lead to a leap forward in decarbonising electricity grids around the world, say the customers buying them.

Announcing in December the planned construction of a Form Energy battery in Mendocino County, the chair of the California Energy Commission called it “transformational for California’s energy mix”.

When Great River Energy broke ground on their Form Energy storage project in Minnesota last month, Great River called it “a significant leap in energy technology”.

Now Ireland is set to be the first country outside the US to try out Form Energy’s iron-air batteries, a company spokesperson said.

The company where Blount works, FuturEnergy Ireland, a joint venture between commercial semi-states ESB and Coillte, is planning to install one at a substation near Buncrana, in Co. Donegal. With – all going well – more to follow at other sites.

“It’s not a complete slam dunk, guaranteed to succeed and will definitely be game changing – but from our perspective, it looks extremely promising,” Blount says. “The idea would be to kind of roll it out of scale from 2028 to 2035”, he said.

To make these new long-duration energy storage systems work economically, Blount says, FuturEnergy is pushing the government for policy changes.

What to do with extra power?

Coillte, a state-owned forestry company, has loads of land. ESB is in the energy business.

Their joint venture, FuturEnergy Ireland, builds wind farms, mostly. But there are times when they produce more power than anyone around them can use right then – so it’s wasted.

“If we just keep building wind in certain locations, eventually you’re wasting so much of it because the transmission really can’t carry it,” Blount said.

One option would be to send the power produced by on-shore wind farms in the south and west of Ireland to some place where it’s needed, probably Dublin.

But the obstacles to getting planning for that kind of project, which runs across very long strips of land, are daunting, Blount says.

“I would say look at the North-South Interconnector project,” he said. “That is 25 years in the works and still not built.”

Getting planning to store the energy near where it’s produced until there’s a need for it, seems more realistic, he says.

“The number of battery projects that have been built start to finish in kind of five, seven years is – it’s not easy, but it’s a lot easier than 200 kilometers of a large overhead powerline,” he said.

Choosing a storage technology

There are a lot of different storage technologies to pick from.

There’s “pumped storage” like at Turlough Hill, in Co. Wicklow, where excess electricity is used to pump water to a reservoir at the top of the hill – and when that power’s needed back in the grid, the water runs down the hill through a turbine to turn that energy into electricity.

Another way to power is by using it to make hydrogen, storing that in, say, gas canisters, and using that as fuel later. ESB and Bus Eireann have tried that out.

There are also thermal storage technologies, like using electricity to heat up a giant rock, or pool of water, or pile of salt to save that energy for later.

And then there’s batteries. Short-duration, long-duration, lithium-ion, iron-air.

“We’ve looked at other technologies [besides Form Energy’s batteries], like we’ve looked at thermal storage technologies, we’ve looked a little bit of hydrogen as well,” Blount said. “We’ve looked at thermal, chemical, electrochemical and some mechanical as well.”

But one Friday or Saturday night Blount was watching a YouTube video about Form Energy’s iron-air battery.

“By Monday morning, I was emailing the company, and by that Thursday, I think I was talking to one of the co-founders,” he said.

Blount then worked with FuturEnergy’s procurement team on a broader more public search, to make sure Form was the right technology – getting in touch with members of the Long Duration Energy Storage Council to talk about their technologies.

“We had a bit of dialog with all the providers, and we kind of got down to maybe three potential candidates, and then Form were, I would say, by a good distance, the leading one,” Blount said.

“We’ve seen enough that we’re taking the first baby steps towards delivering the first projects in Ireland,” he said.

Will it work?

The details of Form Energy’s technology are both complicated and secret, but basically it’s “a reversible rusting process”, Blount says. It all happens inside shipping containers, he says.

“When iron rusts, there’s electrons emitted as part of that”, which can be fed back into the grid, Blount says. Taking electricity out of the grid and feeding it into the containers reverses the rusting process.

“Ultimately, it is containers in a field”, he says, and a bit safer than lithium-ion batteries which could possibly short-circuit, leading to a fire, although this is very rare. And the containers can be linked together to make bigger and bigger batteries.

People are often sceptical of companies that come along and claim to be the next big thing. But big companies are buying into Form Energy’s promise.

FuturEnergy – and the California Energy Commission, Great River Energy, and others – are hopeful that Form Energy’s storage technology will work for them. So is Xcel Energy, a US utility that is planning Form Energy batteries in Minnesota and Colorado.

These early projects will “provide evidence on whether the chemistry works or not and reveal information on how much land these projects need”, says Fei Wang, co-founder of the Green Collective, which provides open-source intelligence on electrical grids and offers tools to assess clean energy assets’ performance in Ireland.

“A big advantage of lithium ion batteries is the low requirements of land and hence the relative ease of construction,” Wang said. “Cheaper batteries like iron-air will require more land, but we don’t know exactly how much more.”

Beyond the questions of how well the chemistry works, and how much land these batteries will require, there’s also the question of how to make the economics work. The fundamentals are good, says Wang.

“When Form Energy announced its iron-air chemistry, the industry was elated, as these are two of the cheapest and most abundant raw materials, a stark contrast to lithium and other rare earths that are needed in current short-duration batteries,” she said.

“The costs of iron-air batteries should be much cheaper than other types and consequently make larger deployments with more capacity/energy bankable,” she said.

A spokesperson for Form Energy said that “Form is targeting an all-in installed cost of USD20/kWh, or around a tenth of lithium-ion batteries, at scale.”

Now comes the challenge, for the companies that hope to build and run these storage systems, of building them at a reasonable cost – and getting as many streams of revenue as possible from them.

The economics of these early Form Energy storage projects in California, Minnesota and Colorado are being helped by government grants. Blount says FuturEnergy is hoping for grant help for its first project, too – the one in Donegal.

“We’re calling it kind of a small-scale commercial demonstration site, because, you know, 10 megawatts, 100 hours, which is 1 gigawatt hour of energy capacity, for what we’re looking at, that’s quite small scale,” he said.

“But it’s half the energy capacity of Turlough Hill,” he says. Which is “by a distance the largest storage project in Ireland”.

Can this project go ahead under current government policies and market structures?

“With this particular project, we have made an application for granted funding to the European Union Innovation Fund,” he said. “If that doesn’t work, we’ll pursue our sources.

To make the other, bigger Form Energy batteries that FuturEnergy plans to build – “four to even up to eight times the energy capacity” of this one – more economically viable, FuturEnergy is looking for policy changes from the government, Blount says.

Stacking revenue streams

There are a few ways the operator of a Form Energy battery could make money from these batteries, Blount says.

First, buying electricity when there’s excess and it’s cheap, storing it until there’s a shortage and prices are higher, and then selling it.

“There’s a very complicated story there in terms of upgrades that are required to EirGrid’s systems to allow us to do that properly,” he said. “But that’s coming. I would say, look, but by 2026, or 2027, I think that’ll be there.”

Second, selling “system services” to EirGrid. There are already big batteries online in Dublin that do this – absorbing electricity for shorter periods and discharging it into the grid in a flash when needed.

Third, selling capacity on the “capacity market”. “It’s a market designed to procure enough megawatts to make sure that we can meet peak demand,” Blount says. “So you can get up to 10-year contracts.”

Fourth, the creation of a new series of “bulk energy time shifting auctions”, where companies that offer long-duration storage services could compete for long-term contracts to provide them. He likens these to the existing Renewable Electricity Support Scheme auctions.

Underlying all of these potential revenue streams is the ability of the battery to both take electricity out of the grid, and put electricity into it. Most players do one or the other: power plants usually just produce it; homes and businesses usually just consume it.

There’s a charge for putting electricity into the grid, and another charge for taking it out – this money’s used to help maintain and improve the grid.

At the moment, battery operators have to pay both fees at different times. Blount says they shouldn’t have to.

Batteries are really in a way neither generators nor consumers but actually part of the grid itself, so they shouldn’t have to pay transmission fees to help maintain and improve the grid, he says. “We’re saying, at a minimum, it should be zero,” Blount says.

Some combination of those revenue streams, and cutting the transmission charges, could make building big iron-air batteries to help further decarbonise Ireland’s economically viable.

“If we can get grant aid funding for a first kind of small commercial demonstration site [in Donegal] from some source, we could potentially build a business case from the energy market, the capacity market and the system service market, but we probably need some level of reform to the network charging,” he said.

Lobbying

Both Form Energy and FuturEnergy have been lobbying the government on this new storage technology, according to the Register of Lobbying.

Blount met with Green Party TD Eamon Ryan, minister at the Department of Environment, Climate and Communications, and Paul Kenny, a special advisor, last October and November, according to the lobbying register.

They talked about an emerging long-duration energy storage technology, with the intended result being “Support for LDES technology innovations”, the filing says.

The government has since then published, in August, an Energy Storage Policy Framework.

“They’ve said within that document, the latest stage by which they need to have an auction for this type of, generally, this kind of large energy capacity technology, is the end of 2028,” Blount said. “For us that’s probably enough for now to keep going, but we will be monitoring each of the steps.”

There’s also talks going on about the issue of transmission charges, Blount said. “There is work ongoing in terms of network charging reform, but it’s not clear to me yet where that’s going to land,” he said.

In another filing, published in August, Form Energy says its representative, Cillian Totterdell, met with the same special advisor, Paul Kenny. They were “Discussing energy storage policy, including long duration energy storage policy”,  the filing says.

What policy changes was Form Energy looking for, and was it looking for any subsidies, to help make its technology economically viable in Ireland?

“There’s a diversity of charges and levies which shape investment and operations beyond the signals of the wholesale electricity market,” a Form Energy spokesperson said.

There’s the transmission charges, “which indeed we see could be better aligned with the value provided by storage”. “There’s an understanding of this issue and EirGrid is seeking to update the system.”

He also pointed to the government’s Energy Storage Policy Framework, published last month. Which he said, “acknowledges the important role of long-duration energy storage (LDES), and the need to put in place mechanisms to deliver it to the system”.

“Acknowledging the future role of LDES [long-duration energy storage], the Government and CRU [Commission for Regulation of Utilities] have tasked EirGrid with putting in place measures to ensure the Irish electric system has the assets it needs deployed,” he said.

“Form is engaged with this work, primarily along with our wider sector through Energy Storage Ireland,” he said.

A spokesperson for the Department of Climate, Environment and Communications said the goal of Ryan meeting with Form Energy was for “the Minister and his officials to stay in touch with energy stakeholders and inform themselves on technology advances in this fast moving sector”.

“Form simply presented their new technology, and the investments they were making in the US,” the spokesperson said. “They had no request for the Minister or the Department. The Minister updated them on the progress towards the now adopted and published ‘Electricity Storage Policy Framework’.”

Electricity storage is a “highly important” technology, the spokesperson said. “Its role will increase as the technology available become more effective and cheaper and it will allow us to make ever greater use of renewable electricity sources by balancing supply and demand,” he said.

“The Government approach to storage is strictly technology and provider neutral,” he said.

CORRECTION: This article was updated at 6.29pm on 18 Sept. 2024 to reflect that while a lithium-ion battery catching fire is possible, it is unlikely.