Battery storage – a key pillar of enabling a net zero carbon emissions future

Renewables are at the heart of the vision we have for Ireland’s future energy system. By harnessing the natural power of wind, solar and hydro, we can generate carbon-free electricity and gain independence from volatile global fossil-fuel markets. But the variable character of these power sources raises an obvious question: how can we ensure a stable supply of electricity even when the wind doesn’t blow or the sun doesn’t shine?

One answer lies in battery energy storage systems (BESS). This technology makes it possible to store energy from renewable sources and release it when power is needed most, helping to balance out supply and demand on the electricity network.

As part of our drive to reach net-zero carbon emissions throughout our operations by 2040, we have been ramping up investment in BESS facilities across the country. Our first large-scale installation in Aghada, Cork, went live in 2022, followed by a 75MW facility at Dublin’s Poolbeg Energy Hub, Dublin in February 2024. Now, a second phase of BESS launched at Aghada in November has added a further 150MW of fast-response storage to Ireland’s electricity network.

Delivering flexibility to support renewable power

BESS are made up of three main components:

The battery itself, which captures and stores energy from sources like wind farms or solar panels.
A power conversion system, which allows the energy stored in the battery to be released back to the electricity network as and when needed.
To help manage this, smart digital technologies are increasingly being used to help coordinate the best times to charge and discharge the batteries.

These systems add a new kind of flexibility to how energy is managed on the network, something that is increasingly essential as ever more renewables come on stream. There are times when renewable power sources like wind farms generate more energy than is needed for electricity demand at a given moment. BESS facilities can absorb this excess power and then rapidly release it at a time when it’s needed, with response times of just 120 milliseconds. By maximising the use of clean power sources like wind and solar, this technology is already playing a valuable role on our journey to net zero – while also strengthening the security of Ireland’s energy supply.

A vital element of our future net-zero system

With the launch of the new Aghada facility, ESB’s total BESS capacity now stands at over 300MW – enough to power around 200,000 homes, making our portfolio one of the largest in Europe. We are investing up to €300m in the technology but are still just at the beginning of this journey: as part of our pathway to net zero, we plan to have multiples of our current battery storage, together with hydrogen storage, in place by 2040.

BESS and other forms of storage are a key pillar in Ireland’s future electricity system, together with renewables and the back-up generation that is currently provided by natural gas, and will be replaced by non-fossil fuels over time. A number of the BESS facilities currently in development are part of hybrid projects, which will see storage installed alongside existing solar and wind farms. By facilitating the integration of a growing volume of renewable energy on the grid to meet Ireland’s climate targets, BESS will be a critical technology on the path to eliminating carbon from our energy system while maintaining security of supply.

Read more about ESB’s Net Zero Pathway here, and find out how our work in this area relates to our broader Sustainability Leadership Plan here.