SSE’s 50MW battery storage asset at Salisbury in Wiltshire, England, which entered commercial operation in April 2024. Picture credit: SSE Renewables.
Grid-scale project in County Offaly could power over 115,000 Irish homes for up to two hours at a time
SSE has acquired the project development rights for a 120MW/240MWh grid-scale battery energy storage system (BESS) project in Ireland’s Midlands from UK-based renewable energy company Low Carbon which, if approved for final delivery, could be constructed and operational by the end of decade.
The purchase marks another step forward for SSE Renewables, the renewable energy business of FTSE-listed SSE plc, as it continues to grow its battery storage development portfolio on the island of Ireland.
Under the deal SSE Renewables has acquired the consented Thornsberry BESS project in County Offaly from Grid Systems Services Limited, a developer of grid-scale battery storage projects in Ireland owned by Low Carbon.
Thornsberry is on a secured greenfield site in the townlands of Derrynagall and Ballydaly near Tullamore with planning consent for a grid-scale BESS. It has a grid connection offer to connect 120MW of import/export capacity to Ireland’s national grid via an adjacent existing 110kV substation.
The proposed battery system would be capable of storing up to 240MWh of energy for flexible dispatch at times of peak demand. When called upon, Thornsberry would be capable of providing back-up energy to the equivalent of over 115,000 Irish homes for up to two hours at a time*, while also delivering essential balancing services to Ireland’s energy system.
Subject to a final investment decision by SSE Renewables, the project could enter construction and be operational by the end of the decade. The project would be expected to provide a boost to the supply chain and job creation in County Offaly and the wider Midlands during delivery. It would also support the delivery of local authority essential services in Offaly through the payment of development contributions and commercial rates.
The addition of the Thornsberry project grows the company’s secured battery pipeline in Ireland to 300MW, as part of a wider 1.8GW pipeline across Ireland and the UK.
"Acquiring the consented Thornsberry project in County Offaly is another great step forward in our plans to grow SSE Renewables’ battery storage development portfolio in Ireland. The addition of this grid-scale project can make an important contribution to the delivery of SSE’s fully funded five-year Net Zero Acceleration Programme, while also advancing the diversity of the technologies in our portfolio.
Heather Donald Director of Onshore Wind, Solar and Battery – UK and Ireland, SSE Renewables
The Midlands has a long and proud tradition of supporting Ireland’s energy security. With the development of new onshore wind, solar and battery projects such as Thornsberry, the region can continue to play a significant role in delivering homegrown energy for Irish consumers while decarbonising the country’s power system. In doing so, we can help ensure vital energy projects can deliver positive social and economic benefits to County Offaly and the wider Midlands."
Low Carbon, which began developing the Thornsberry project in 2018, was one of the first movers to develop, build and operate battery storage and solar in the Irish renewables market having provided approximately 20% of the country’s operational storage capacity.
"We are delighted to collaborate with SSE on this project, which underscores Low Carbon’s leading position in the Irish storage market. Furthermore, this announcement demonstrates our expertise of delivering high-quality investable assets to the market, meanwhile playing an important role in supporting our future growth as we aim to build 20GW of new renewable energy.
Roy Bedlow Founder and Chief Executive of Low Carbon
Increasing renewable energy capacity is just one part of the answer as we look to accelerate the energy transition. Battery storage is as of equal importance, providing a complete energy solution to power homes and businesses round the clock, whilst helping the grid to become greener."
Battery storage technology is a key net zero enabler as part of a diversified portfolio of energy technologies because of its ability to hold and release energy when most needed. Batteries work by storing energy when output from natural sources such as wind is high, and then releasing it as required at times of peak energy demand. They are fast responding and will play an increasingly important role in Ireland’s energy mix as carbon-based generation is phased out and replaced by renewables.
Thornsberry is the latest project to join SSE Renewables’ growing battery storage development portfolio on the island of Ireland. In May 2024, the company announced the acquisition of the 100MW/200MWh Derrymeen project at Dungannon in Northern Ireland, which is targeting delivery at the end of 2026, subject to a final investment decision. The company is also developing an 80MW battery project at Tawnaghamore, County Mayo, and a 100MW future prospect battery project at Tarbert, County Kerry.
In Great Britain, the company has brought its first 50MW battery asset into operations at Salisbury in Wiltshire. In Yorkshire, the company is constructing a 150MW battery project at Ferrybridge (due to complete in the first half of next year), as well as a second 150MW project at Fiddlers Ferry and a 320MW battery project at Monk Fryston.
Advisers on the transaction were KPMG (Corporate Finance) and Addleshaw Goddard (Ireland) LLP (Legal) for Grid Systems Services Limited, and A&L Goodbody for SSE Renewables (Legal).
* Quoted 115,757 homes supplied for 2 hours, based on an 120MW (240MWh) battery against assumed average daytime (08:00-20:00) hourly use of 1.03kWh at a typical home (based on Typical Domestic Annual Consumption, 4,200 kWh per household, Commission for the Regulation of Utilities).