Tonn Nua offshore wind project awarded to Ørsted and ESB in major Irish energy auction

Ørsted and Electricity Supply Board (ESB) have secured provisional rights to develop the 900 megawatt (MW) Tonn Nua offshore wind project off the coast of County Waterford, following a successful bid under the Irish government’s latest offshore wind auction. The announcement, made by the Department of Climate, Energy and the Environment, signals the outcome of Ireland’s second competitive tender under the Offshore Renewable Electricity Support Scheme (ORESS), focused exclusively on the Tonn Nua site.

Spanning 306 square kilometres in Irish waters, the Tonn Nua location was the only site made available under this round of ORESS. The Ørsted–ESB joint venture will now advance the fixed-bottom offshore wind project, supported by a 20-year partially indexed contract for difference (CfD) that provides price certainty and opens the door to grid connection and seabed lease approvals.

The Tonn Nua offshore wind project is expected to reach final investment decision by 2031, with first power targeted for the mid-2030s. If brought to completion, Tonn Nua would represent a significant contribution to Ireland’s net-zero targets and its ambition to establish a robust domestic offshore wind industry.

How the contract for difference structure supports long-term revenue visibility and investor confidence

The Ørsted and ESB joint venture secured a two-way CfD priced at EUR 98.719 per megawatt-hour. This partially indexed CfD will span 20 years starting from the project’s commercial operation date, which is expected to fall around the mid-2030s. The longstop date for operational commencement, as set out in the auction terms, is 1 January 2037.

The contract ensures price predictability and a bankable revenue stream for developers, which is expected to ease financing hurdles for the sizable capital expenditure typically involved in offshore wind infrastructure. Ireland’s transmission system operator, EirGrid, will be responsible for constructing the onshore and offshore substations of the Tonn Nua offshore wind project as well as the export cables, reinforcing the state-led planning model that now governs offshore renewables in the country.

This approach reduces interface risk for private developers and marks a departure from earlier developer-led planning frameworks, which were often bottlenecked by permitting and grid uncertainties.

What the Ørsted–ESB joint venture reveals about Ireland’s offshore wind pipeline potential

The Tonn Nua offshore wind project is the first auctioned site to emerge from the 50:50 partnership between Danish renewables major Ørsted and Ireland’s Electricity Supply Board. Formed in 2023, the joint venture is designed to co-develop a pipeline of offshore wind projects off the Irish coast, aligning Ørsted’s international project development expertise with ESB’s deep local knowledge and utility experience.

Alana Kühne, Ørsted’s Head of Region Europe Development, stated that the consortium welcomes the Irish government’s continued support for offshore wind, and affirmed the project’s strategic importance to ensuring a green, secure, and affordable energy supply for Ireland in the decades ahead. She indicated that the Tonn Nua site remains in an early stage of maturity and will be subjected to the joint venture’s internal stage-gate process before reaching final investment decision.

Jim Dollard, Executive Director for Generation & Trading at ESB, said the outcome provides a clear path toward delivering a project with strong energy security and pricing benefits for Irish consumers. He described the win as a meaningful milestone in Ireland’s decarbonisation journey and an example of how collaborative partnerships can accelerate climate-aligned infrastructure.

What regulatory and development milestones must be met before Tonn Nua offshore wind project proceeds to construction

Although Ørsted and ESB have secured rights under the auction, the Tonn Nua site must still pass through several regulatory gates before it can enter construction. The next major steps involve securing Maritime Area Consent (MAC) and a Marine Usage Licence from the Irish Maritime Area Regulatory Authority (MARA). These approvals are essential for undertaking marine surveys, environmental assessments, and developing the full planning application.

The Tonn Nua offshore wind project is being developed under Ireland’s revised planning framework, which aims to de-risk early-stage development by designating suitable sites and streamlining the permitting process. The state-led regime is also intended to standardise environmental baselines and reduce project-by-project variability in assessments.

As one of Ireland’s priority offshore wind zones, Tonn Nua is expected to become a test case for the execution speed and clarity of the new regime. Market observers will closely monitor whether the project’s progression timelines align with the government’s broader ambition of deploying 5 GW of offshore wind by 2030 and significantly more thereafter.

Why the Tonn Nua offshore wind project award could signal broader investor momentum for Irish offshore wind

Institutional investors and infrastructure funds tracking Ireland’s energy transition have noted the significance of the Tonn Nua auction. Securing a winning bid in a highly focused, single-site auction suggests that Ørsted and ESB were confident in both the policy environment and the commercial viability of the project at the awarded strike price.

Analysts suggest that the move reflects growing institutional belief in Ireland’s maturing offshore wind market, which is benefiting from cross-party policy support, transparent auction frameworks, and strong long-term power demand from both residential and commercial consumers.

While the Tonn Nua offshore wind project is still years away from construction, the award is expected to serve as a bellwether for subsequent auctions, including floating wind pilot projects and additional fixed-bottom sites. The outcome also increases confidence in Ireland’s ability to run efficient, state-led offshore wind tenders that can attract world-class developers and unlock multi-gigawatt investment pipelines.

Why the Tonn Nua offshore wind project site represents more than just a single project for Ørsted and ESB

Beyond its 900 MW capacity, the Tonn Nua project sets a precedent for future joint development frameworks in the Irish energy market. It demonstrates the viability of 50:50 partnerships between international and domestic players under state-led auction mechanisms, which may become the default structure for delivering Ireland’s offshore wind targets.

As both governments and private sector players look to scale investment into clean energy infrastructure across Europe, projects like Tonn Nua offer a replicable model that balances public oversight with private execution expertise. The project is also likely to stimulate regional supply chain development in County Waterford and along Ireland’s southeast coast, potentially anchoring future offshore wind services, fabrication, and logistics hubs.

With the CfD secured, grid obligations handled by EirGrid, and a credible consortium in place, the Tonn Nua offshore wind project has cleared its first major hurdle. Whether it can maintain that momentum through regulatory approvals and final investment decision will depend on multiple variables, including policy continuity, permitting timelines, and evolving construction economics.

What are the key takeaways from the Ørsted–ESB Tonn Nua offshore wind project award?

• Ørsted and ESB have provisionally secured rights to develop a 900 MW offshore wind farm at the Tonn Nua site off County Waterford.

• The award was made under Ireland’s ORESS Tonn Nua auction, with a 20-year CfD priced at EUR 98.719/MWh.

• The Tonn Nua offshore wind project is expected to achieve FID around 2031 and deliver first power by the mid-2030s.

• Grid connections and transmission infrastructure will be developed by EirGrid under Ireland’s state-led model.

• Regulatory next steps include securing Maritime Area Consent and a Marine Usage Licence from MARA.

• The Tonn Nua offshore wind project award is the first project advanced under the Ørsted–ESB 50/50 joint venture, formed in 2023.

• Investors are likely to view the award as a positive indicator for Ireland’s offshore wind execution capacity.