IN Brief:
- Energy Dome and Google have announced a 23MW / 200MWh CO2 Battery project in County Offaly, Ireland.
- The project has secured land, planning consent, grid connection, and a 10-year capacity contract from EirGrid.
- The system is expected online in 2028 and could be followed by a second 200MWh unit at the same site.
Energy Dome and Google have advanced a 23MW / 200MWh long-duration CO2 Battery project in County Offaly, Ireland, under the first bilateral commercial agreement between the two companies.
The project will be developed, owned, and operated by Energy Dome, with Google acting as offtaker. Commercial operation is expected in 2028. The system will be located near Rhode in the Irish Midlands, close to high-voltage infrastructure serving the Greater Dublin area.
Energy Dome’s CO2 Battery stores electricity by compressing and liquefying carbon dioxide in a closed-loop process. When electricity is required, the stored CO2 is evaporated and expanded through a turbine to generate power back to the grid. The architecture uses industrial components and avoids dependence on lithium-ion battery supply chains for the storage medium.
The Irish project has secured land, planning consent, and grid connection. It has also been awarded a 10-year capacity contract by EirGrid, adding a defined capacity-market revenue stream to the bilateral offtake structure. Energy Dome plans to develop a second 200MWh unit at the same location.
The site sits on brownfield land formerly associated with peat-fired generation, giving the project an added infrastructure dimension. Ireland’s Midlands have moved through a substantial energy transition as peat generation has declined, while renewable generation, grid constraints, and new electrical demand have moved further up the system agenda.
County Offaly is a practical location for long-duration storage because the surrounding area combines renewable generation, grid infrastructure, and constrained transfer capacity toward major demand centres. A storage system able to charge during periods of surplus generation and discharge during system stress can support both capacity adequacy and network utilisation.
Ireland’s electricity system is already operating under high renewable penetration, with wind providing a large share of generation during favourable conditions. That creates operational value for storage capable of shifting energy across longer periods than conventional short-duration batteries. The national target of 80% renewable electricity by 2030 increases the importance of storage assets that can support balancing, reduce curtailment, and provide dispatchable capacity.
The project also shows how corporate clean-power procurement is moving beyond simple annual matching. Large, continuous electrical loads need supply structures that can account for when power is produced, how it is delivered, and how system constraints affect real availability. A bilateral offtake linked to long-duration storage gives a more operational form to clean-power procurement than certificates or generation-only contracts.
Data-centre demand adds further pressure to that development path. Concentrated electrical loads require grid capacity, power quality, voltage stability, redundancy, and dispatchable supply arrangements. Work on voltage instability around data centres has already shown how digital infrastructure can expose weaknesses in local and regional power systems when load growth outpaces electrical reinforcement.
Long-duration storage does not remove the need for network investment, but it changes the operating options available to system operators and large energy users. Storage connected at an effective point on the network can absorb energy that would otherwise be constrained, release power during high-value periods, and support more efficient use of existing grid infrastructure.
The project also sits within a European storage market that is moving from headline capacity announcements toward deliverable assets with grid position, offtake arrangements, and construction pathways. A 2GWh Scottish storage project shows the scale now entering the UK market, while the Irish CO2 Battery adds a different technology route with an eight-hour operating profile.
Technology diversity is becoming more important as storage requirements broaden. Lithium-ion batteries have established a strong role in frequency response, short-duration balancing, and co-located renewable projects. Longer-duration requirements create openings for pumped hydro, compressed air, flow batteries, thermal storage, and CO2-based systems, each with different siting, efficiency, construction, and operational characteristics.
The County Offaly project has several of the components required for bankable infrastructure: a grid connection, planning consent, land, capacity-market support, and a named offtaker. Its remaining tests are engineering, procurement, construction, commissioning, and operation under real market and grid conditions.
By 2028, Ireland’s electricity system is expected to be carrying more renewable generation, more demand from digital infrastructure, and more need for flexible capacity. The Offaly CO2 Battery will enter that environment as a test of whether non-lithium long-duration storage can provide dependable grid service at commercial scale.
