ORESS Tonn Nua Offshore Wind Auction

The Minister for Climate Energy and the Environment, Darragh O'Brien TD, announced the final result of the Tonn Nua Offshore Wind Auction on December 9, 2025. Following the provisional result announcement on November 26th, Helvic Head Offshore Wind DAC is now confirmed as the auction winner with an offer price of €98.719 per megawatt hour. Helvic Head is a joint venture partnership between ESB and Denmark-based renewable energy developer Ørsted. Subject to compliance with the auction terms and conditions, contracts will be signed in the coming months.

This price compares very favourably to recent offshore energy auctions in other jurisdictions and to the price secured in Ireland's recent onshore RESS 5 onshore wind and solar auction. The price is also significantly below the average wholesale electricity price in Ireland to date in 2025 of €114 per megawatt hour.

The Tonn Nua project will be located off the coast of Waterford within Area A of the South Coast Designated Maritime Area Plan. Tonn Nua is one of four maritime sites within the South Coast DMAP identified for future offshore wind development. The project will have a target installed renewable capacity of 900 MW, enough to power almost 1 million homes. It will save 1.8 million tonnes of CO2 emissions each year after its construction, making a sizable contribution to Ireland's wider climate and renewable electricity targets.

Government is working towards the next planned auction for Area B in the South Coast DMAP. Work with EirGrid to develop grid connection options for the site, named ‘Lí Ban’, is already at an advanced stage, and the Minister is making arrangements for geophysical, metocean and other surveys to inform this auction.

Background

Government published the Terms and Conditions of Ireland's second offshore wind auction (Tonn Nua) under the Offshore Renewable Electricity Support Scheme (ORESS) on 31 October 2024. The Terms and Conditions set the framework for a competitive auction to take place in the second half of 2025 to select a single winner of ORESS two-way CFD support for a 900 MW offshore wind farm to be developed in the first site of the South Coast DMAP. Publication of the Terms and Conditions followed a year long process of engagement with stakeholders involving two consultations and several technical workshops.

An updated version of the Terms and Conditions (Ver 1.1) was published on 27 May 2025.

The qualification phase of the Tonn Nua Auction opened in Q3 2025, with the bidding phase in Q4 2025.

The Tonn Nua project will contribute 900 MW towards our Climate Action Plan targets of 5 GW installed offshore wind capacity and will save 1.87 million tonnes of CO2 annually over its anticipated 30+ years of operation.