By Jason Deign
Gaelectric’s Larne project funding approval this month has focused attention on European efforts to develop large-scale storage technologies that could rival pumped hydro.
Dublin, Ireland-based Gaelectric was granted €90m in European Union backing for a compressed air energy storage (CAES) project due to be built in Larne, east Antrim, on the Northern Irish coast.
The funding came on top of €15m in previous grants, the BBC reported. The Larne CAES project, due for completion around 2022, is a European project of common interest that will generate up to 330MW of power for up to six hours.
Being developed in association with Dresser-Rand, it will store compressed air in two caverns located in salt deposits below ground. When needed, the air would be re-heated using natural gas and, on expansion, drive a turbine.
The plant’s compressors will also provide up to 250MW of demand response to mop up excess wind capacity on the Northern Irish grid, which only has limited connections to electricity networks on Ireland and Great Britain.
Storage caverns required for CAES
“The storage caverns required for the CAES station will be developed in the Permian Halite Member at a nominal depth of 1,500m with a thickness of approximately 200m,” explains an environmental statement for the plant.
“The proposed project will not only boost economic activity and employment locally but it would also act as a positive signal for further investment in Northern Ireland and even greater economic activity and employment.”
Besides boosting the economic prospects for the region, the funding announcement is a fillip for CAES, which is seeing a revival after the world’s last and only second plant came online in 1991, and for large-scale storage overall.
Gaelectric, for example, is pursuing two other CAES projects, one in the northwest of England “with local partners” and one in the Netherlands with AkzoNobel.
And as recently reported in Energy Storage Report, RWE of Germany and ALACAES of Switzerland are developing a technology called “advanced-adiabatic CAES,” which preserves compression heat for greater efficiency.
“Cheaper than pumped hydro”
UK developer Storelectric is meanwhile studying CAES plants that could have a levelised cost of storage of GBP£68 per megawatt-hour, said to be “cheaper than pumped hydro.”
The company claims to be mulling three CAES technologies: an adiabatic model, one that uses methane to re-heat the air, and one that uses hydrogen.
It is unclear how close Storelectric might be to getting projects off the ground, with chief technology officer Mark Howitt this year hinting that UK regulation may be a stumbling block for the company.
And they are not the only developers looking to create energy storage plants that could potentially achieve gigawatt-hour capacities at roughly the same cost as pumped hydro.
A gravity storage concept
In Germany, for example, Heindl Energy is looking at a gravity storage concept whereby water is pumped into a tank capped by a heavy rock mass.
It is “a concept with which unprecedentedly large quantities of power can be stored for a long time of 6-14 hours, and can be made available again,” says Heindl Energy on its website.
The company predicts it could build an 8GWh plant at a cost of USD$200 per kilowatt-hour of capacity, and that the project could have a lifespan of at least 60 years.
UK start-up EscoVale Consultancy Services is working on a similar concept, which it calls Ground-Breaking Energy Storage (GBES) and which “aims to meet or beat” pumped hydro commercial and performance benchmarks.
GBES plants might typically have a capacity of 2GW and 20GWh, EscoVale says.
Energy conversion structure
Elsewhere, Danish inventor Jan Olsen has patented “an energy storage system comprising a reservoir, a load and an energy conversion structure.”
In addition, a few years ago Subhydro, of Norway, was touting a kind of inverse pumped-hydro technology using concrete air tanks at up to 800m below water.
To be fair, most of these schemes are still very much at the drawing board stage. But Gaelectric’s cash injection shows Europe may be willing to place bets on relatively novel technologies.
And with investigators such as Dr Björn Peters warning that pumped hydro, or something very much like it, is the only way Europe can get anywhere close to a 100% renewable energy system, that’s a bet policy makers may need to make.
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