Why is ESB building giant batteries in the city?

Out in an industrial area between Inchicore and Ballyfermot, rows of big black electrical appliances sit in a grid on concrete pads, surrounded by gravel, behind two high fences.

This is ESB’s Kylemore Way battery energy storage system (BESS), which is in its “final stages of testing and will soon be in full commercial operation”, according to a company spokesperson.

It is one of a growing number of battery systems that companies are building and plugging into the electrical grid across the country.

Also in Dublin, there’s a big one planned for an ESB site on Poolbeg peninsula, which in 2021 the company and its partner Fluence described as “the largest by energy capacity signed in the EU”.

All these batteries will help the country’s electrical grid cope better with the variability of the amount of power fed into it by wind farms and solar panels, which rises and falls dramatically depending on the weather.

But much more needs to be done to prepare the country’s electrical system for the large increase in renewable energy planned for the next few years, says David Newbery, director of Cambridge University’s Energy Policy Research Group.

Otherwise, these additions will have rapidly diminishing returns, said Newbery, as part of his talk last Wednesday “Electricity in Ireland: Transition and the Energy Crisis”, organised by the Institute for International and European Affairs and the ESB.

This is “an underappreciated consequence of a high renewable electricity penetration”, he said. “Ireland is probably at the forefront of facing this compared to the rest of Europe.”

On a path to generating extra

As nations across the globe scramble to limit the pace of climate change, and the damage it will do, Ireland has set ambitious targets for cutting the amount of electricity it generates with fossil fuels, and replacing that with electricity from wind and the sun.

In 2005, 7.2 percent of the electricity people used in Ireland came from renewables, and by 2021 that had increased to 36.4 per cent. By 2030, the plan is to more than double that so that 80 percent of Ireland’s electricity comes from renewable sources.

In his talk on Wednesday, Newbery called the targets of 50 percent renewables by 2025 and 80 percent by 2030, “very challenging”.

Most of that increase is supposed to come from new wind farms built in the seas offshore.

There are at least two of these planned for the Dublin area: the Dublin Array, about 10km offshore Dalkey and Bray; and the Codling Wind Park, 13–22km offshore Co. Wicklow, between Greystones and Wicklow town, connecting to the grid in Poolbeg.

At the moment, no more than 75 percent of demand for the electricity that people in Ireland use at a point in time can come from renewables, Newbery said. The grid just can’t handle more than that, he says.

So when the wind is blowing hard, sometimes there’s more renewable electricity than the grid can take, Newbwery said.

It’s not uncommon for Eirgrid, the overseers of the country’s electricity wires, to tell wind farms they have to switch off, or “dispatch down”.

As the share of electricity Ireland’s getting from wind farms increases in the coming years, the periods when the wind is blowing hard and generating more power than the grid can take will become more frequent.

The more “surplus” power is generated but wasted, the higher the cost of delivering electricity, Newbery said. And the higher the cost of cutting carbon emissions, too, which is the goal of the shift to renewables, he says.

To avoid these effects, Ireland needs to find ways to avoid wasting renewable energy, Newbery said.

Options to avoid wasting power

There are several ways for Ireland to avoid wasting (or “curtailing”) renewable energy, Newbery said in his talk last Wednesday.

First, it needs to fine-tune the grid further to be able to handle a higher share of renewables, he said.

“If we do nothing by 2026 and keep in particular the limits on wind at 75 percent then a very substantial amount and a large fraction of the time will be curtailed,” he said.

By 2030 with 80 percent renewables that limit has to be raised to 95 percent “if we’re going to avoid quite serious problems”, he said.

“Some very clever management and electronics will be needed to raise the target to the ambitious 2030 level of 95 percent,” he said.

Second, Ireland is planning to build a massive extension cord, basically, to France – the Celtic Interconnector – coming ashore in Youghal, Co. Cork, so it can import electricity when it doesn’t have enough, and export when it has too much.

This is in addition to two other existing interconnectors: the East-West from Rush, Co. Dublin, to Wales and the Moyle from Islandmagee, Co. Antrim, to Scotland.

Selling the electricity to customers in Great Britain or Brittany is another way to keep from wasting it.

Sometimes, though, the wind will be blowing just as hard over there – so they won’t need Ireland’s excess renewable electricity, Newbery said.

Third, there’s the batteries, like the ones in Inchicore and Poolbeg.

“The good news is that batteries are now cheaper than a few years ago,” Newbery said by email on Saturday.

These can both store some extra electricity until it’s needed, and also be used to keep the grid in tune and happy, so to speak – countering some of the effects of the variability of wind energy flowing into it.

“We believe that fast-acting battery storage plants, like our 75MW project at Poolbeg in Dublin, will play a crucial role in supporting grid stability and delivering more renewables such as onshore wind, offshore wind and solar on Ireland’s electricity system,” said an ESB spokesperson.

ESB will deliver 300 megawatts of battery capacity within the next two years at sites including Poolbeg, Inchicore and South Wall in Dublin, the spokesperson said. The first of its major battery plants was opened at Aghada Generating Station in Co. Cork last year, he said.

There is a limit to all these efforts to take better advantage of Ireland’s renewable power generation, though.

And as Ireland approaches it the cost of reducing its carbon emissions by squeezing more carbon-savings out of its electricity system will rise quite sharply, Newbery said.

“You can rapidly reach the point where the cost of reducing carbon dioxide by adding more renewable electricity may be much higher than reducing carbon dioxide emissions elsewhere in the economy,” he said.

Indeed, there is certainly a point where the benefit of adding more and more renewable electricity to the system begins to get very small, says Muireann Lynch, a senior research officer at the Economic and Social Research Institute (ESRI).

“This is true of any technology, right? There’s an optimal level of every technology and it depends on everything else within the system,” she says.

There’s a bigger picture too, Lynch says, when it comes to reducing carbon emissions from Ireland’s energy consumption.

Only 22 percent of the energy people and companies in Ireland use is in the form of electricity, according to the Sustainable Energy Authority of Ireland (SEAI)’s “Energy in Ireland” report for 2022.

Fifty-two percent is used as oil, and 17 percent as gas, the report says.

“So, you know, we could magic away every single tonne of CO2 from electricity tomorrow, and we’d still have a big problem on the transport and heating side,” she says.