
On a flat piece of land in west Dublin, 96 black container-like structures sit in perfectly straight rows.
A persistent hum is the only indicator of the electronic equipment packed inside.
Each cube is a battery storage unit, full of tiny lithium-ion batteries, just like the ones you find in your cell phone.
The large boxes are surrounded by transformers, inverters and other equipment.
Together, the units provide 30MW of electricity storage – enough to power 30,000 homes for up to two hours – for the grid.
The facility, which is almost complete and ready for use, belongs to ESB.
It is one of a number of companies, including Iberdrola, RWE and Statkraft, which already have or are developing more than a dozen such plants around the country.
The companies claim that these facilities will form a crucial link in the chain that will ultimately result in Ireland moving its electricity generation capacity to fossil fuel-free renewable energy sources.

“As we increase the level of wind penetration and solar penetration on the system, we need to make sure the system is stable and we need to make sure we manage some of the intermittency associated with renewables,” said David Farrell, Head of Onshore Asset Development at ESB.
“A battery like this does just that. It provides frequency response to any variation in frequency and even if you have load swings in the system. That’s really important for grid stability.”
“It also provides a form of reserve capacity, so in the event of a capacity shortage in the system, this can provide, in this case, 30MW for two hours. And on top of that, it also provides the ability to store electricity when there is excess electricity on the system, it can be stored every now and then at peak demand or when there is a shortage it can be released into the system.”
Energy storage is not new to Ireland – the 300MW pumped hydro station at Turlough Hill in Wicklow has been in operation for almost 50 years.
But to store enough power to run the country for just one day, we would need 60 Turlough Hills.
So if we’re going to get rid of all the fossil fuels that our electricity is currently stored in and become entirely dependent on the sometimes unreliable renewables, we’re going to need a lot more long-term sustainable energy storage options.
Larger battery storage facilities are an option and here plans are being developed for devices that can store many hours of power when the wind stops blowing or the clouds cover the sun.
ESB is currently installing the world’s largest flywheel in Moneypoint as part of a new Synchronous Compensator which will help smooth grid imbalances.
Other technologies are also in the pipeline, but ultimately experts believe that green hydrogen will be the solution in the medium to long term.
“It means making electricity from water and renewable electricity,” says Professor Hannah Daly, from the Department of Engineering at University College Cork.
“When there is an abundance of renewable energy sources, we use the electricity to split the water molecule into hydrogen and oxygen and then we use that hydrogen as a way to store energy when we need it.”
“It can then go on to make transport fuels, to heat our homes and district heating.”
Of course, no new technology is completely green.
So what about the environmental impact of these new solutions, like huge battery storage facilities?
“No mining is environmentally friendly and lithium and other valuable minerals used in batteries and other energy storage technologies are not perfect,” Professor Daly said.
“But the impacts of these things pale in comparison to the impacts of drilling for fossil fuels, refining them, transporting them and then burning them. So we have to keep it in context.”
Although full of potential, the energy storage sector here is still very much in its infancy with around 500 MW of combined capacity already delivered, growing to 800 MW next year.
But last year energy experts Baringa estimated that to meet the 80% renewable energy target by 2030 in Ireland and Northern Ireland, 1,700MW of battery storage would be needed across the island.
About 60 more projects with a combined capacity of 2,500 MW are underway, and the industry is confident of meeting its 2030 targets.
But it also says it needs policy and investment support from the government to make it happen.
“We have no government targets for energy storage,” says Bobby Smith, director of Energy Storage Ireland.
“And that’s needed to send that signal and drive investment forward for the industry. There are certain policies right now that could be upgraded or better implemented to facilitate energy storage. Especially around the ability of energy storage to get connections to the grid because there’s a huge bottleneck right now now.”
“And the ability of storage to participate fairly in the market.”
That’s because the market here has been designed for fossil fuel generators, Smith said, making it difficult to bring new assets into the market.
“We’re going to have to, we’re going to upgrade our systems. And it’s up to stakeholders like Eirgrid, stakeholders like the CRU, to develop policies that better integrate energy storage.”
It seems that if Ireland gets its energy storage deployment right, the opportunity could be huge.
The EU estimates that 435 GW of capacity will be needed across the Union by 2050.
Ireland has huge potential for renewable energy, making it well suited to generate and store power for export.
This could potentially spark a whole new cleaner, greener energy industry here.
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