Ørsted and ESB has been awarded provisional development rights for a 900 MW fixed-bottom offshore wind farm at the Tonn Nua site off the coast of County Waterford, Ireland. The award is under Ireland’s second wind auction in the Offshore Renewable Electricity Support Scheme (ORESS). Ireland’s offshore wind auction offered a 20-year partially indexed contract for difference (CfD) at a price of €98.72 per MWh. The price has also been called ‘competitive by international standards’, by Ireland’s authorities.
Project Overview
Tonn Nua offshore wind farm covers some 306 sq km in the South-Coast maritime zone. The zone is designated under the new spatial planning framework, and is the only site offered in Ireland’s second auction round. When complete, Tonn Nua offshore wind farm will supply up to 900 MW of renewable electricity, enough to power 800,000 to 1,000,000 homes in Ireland. The wind farm will also displace substantial CO2 emissions over its lifetime.
Tonn Nua Offshore Wind Project Factsheet
Developers: Ørsted and ESB 50/50 joint venture.
Site location: Off the coast of County Waterford, Irish South Coast. Tonn Nua (SC-DMAP zone) maritime site.
Site area: 306 sq km
Planned capacity: 900 MW
Contract: 20-year Contract-for-Difference (CfD) at €98.72/MWh strike price. Compare Dublin Array offshore wind farm weighted at an average €86.05/MWh.
Supply Impact: Power for 1 million households.
Transmission developer: EirGrid who will be responsible for export cable and substations.
Project Timeline
October 2024: Ireland makes official conditions for the ORESS Tonn Nua auction under the South Coast DMAP zone.
Q3-Q4 2025: Auction qualification and bidding process takes place under ORESS.
November 2025: Ørsted-ESB JV wins provisional rights to develop the 900 MW Tonn Nua site. Also secured a 20-year CfD at €98.72/MWh.
Late 2025 through 2026: Ørsted and ESB expected to apply for Maritime Area Consent (MAC) and Marine Usage Licence (MUL). Marine, environmental, and geotechnical surveys to begin once licenses are granted.
2027-2029: Further development spanning environmental impact assessments, baseline studies, seabed leasing, and grid-connection design with EirGrid expected to progress.
2031: Target year for FID.
Mid-2030s: Offshore construction and commissioning expected. First commercial power also expected.
January 2037: CfD date for commercial operations as set in the ORESS contract terms.
Ørsted and ESB Development Rights Win for Tonn Nua Offshore Wind Farm
Ørsted and ESB win for Tonn Nua offshore wind project development gives them the right to apply for a seabed lease and grid connection. The award also allows the offshore wind project move through Ireland’s consenting, environmental, and planning processes. Tonn Nua is however still in early development, with the Final investment decision (FID) targeted for in the next decade. After the FID is reached around 2031, first power from Tonn Nua is expected in the mid-2030s. This is however subject to permitting and clearance by the Ørsted-ESB JV.
The provisional award to Ørsted and ESB is not final. The JV will need to apply for a Maritime Area Consent and Marine Usage Licence from the national regulator. Detailed surveying and planning applications will then begin.
Tonn Nua Offshore Wind Farm Development Rights: The Bigger Picture
Ørsted-ESB development rights win for the Tonn Nua offshore wind farm in Ireland points toward the expansion of the country’s offshore wind capacity, and the diversification of its energy mix. The CfD strike price is also a mark-up that offshore wind in Ireland is becoming economically competitive compared to the U.S. and the UK. Competitiveness here can resonate in the sense of: climate measure, energy security, and as a risk-sharing hedge.
Ireland’s transmission system operator, EirGrid and Tonn Nua
The involvement of Ireland’s transmission system operator, EirGrid to build the export cables, and onshore and offshore substations as part of the project’s support framework further ‘secures’ Tonn Nua offshore wind farm. Securing grid connection has been a source of delay in many jurisdictions, and has even derailed some offshore wind developments like the 900 MW Borkum Riffgrund 3 in Germany.
