600 MW LDES facility with green hydrogen electolyzer proposed in Ireland

Irish developer Net Zero Energy is planning to build a large-scale long-duration energy storage (LDES) plant worth around €2 billion in County Carlow, in the east of the country.

The project, dubbed Rathrush Green Energy Park, will store surplus generated energy from off-site, non-dispatchable renewables sources such as wind and solar. This excess energy will be used to power an electrolyzer that splits water into hydrogen and oxygen. The hydrogen is stored on-site in underground rock caverns to be converted into electricity using a hydrogen-fired gas generator. The green electricity can then be deployed on demand to the national grid at the nearby 220 kV Kellis substation. Water supply will come from the nearby Tullow Waste Water Treatment Plant.

“By making available 600MW of renewable energy at the flick of a switch to a grid which, at the time of project delivery, will peak at around 7,000MW, Rathrush Green Energy Park provides significant, secure and green long duration storage for the Irish grid,” Net Zero Energy’s chairman Tim Cowhig said.

Net Zero Energy opened a public consultation phase for the project on 9 June. The developer’s CEO, Peter Harte, wrote in a LinkedIn post announcing the opening of the consultation that “a handful more LDES projects of this scale”, combined with Ireland’s abundant renewables would give the country an electricity system “that is 100% free of volatile and insecure fossil gas imports.”

“The Rathrush Green Energy Park will be able to meet 10% of Ireland’s peak demand, and store 30x more energy than Turlough Hill,” Harte wrote, referring to the ESB’s pumped-storage hydroelectricity plant that can generate up to 292 MW of electricity at times of peak demand.

The project will also be a considerable asset to Ireland’s small, but growing LDES market. Other LDES projects under development in Ireland include the 1 GWh Ballynahone iron-air energy storage facility being developed in the northwest of the country by FuturEnergy and Form Energy.

The Net Zero Energy team’s priority for the next few months is to work with the local community around the Rathrush, Rathoe and Tullow areas in County Carlow. Harte wrote that the company has enlisted a dedicated community liaison officer and team on the ground, and it has briefed the Carlow local authorities and local residents and businesses near the project site. A community benefit fund will be set up to contribute to local sports clubs and voluntary organizations.

Net Zero Energy is a County Cork-based developer. It claims the Rathrush development will save up to 180,000 tonnes of carbon dioxide emissions annually, equivalent to removing 40,000 cars.

The project is classified as a Strategic Infrastructure Development and will be subject to approval by the national planning board, An Coimisiún Pleanála, following the community engagement process. If planning is granted, the project will then be put forward for a licence to operate from the Environmental Protection Agency.