FAQ

Tonn Nua is a planned fixed-bottom offshore wind project within the South Coast Designated Maritime Area Plan (SC-DMAP), with an expected capacity of approximately 900MW.

The SC-DMAP is Ireland’s first statutory marine spatial plan prepared by the State that identifies specific sea areas off Ireland’s south coast suitable for fixed bottom offshore wind. It was formally made in October 2024 and is a statutory plan under the Maritime Area Planning (MAP) Act 2021. Further information can be seen here: The South Coast Designated Maritime Area Plan for Offshore Renewable Energy (SC-DMAP).

Tonn Nua is being developed by a Joint Venture (JV) partnership between ESB and Ørsted.ESB is the leading Irish utility and Ørsted is the national Danish utility, both with significant experience in developing offshore wind projects. A dedicated team has been established in Ireland to develop the project. The grid transmission infrastructure for the project is being developed and built by EirGrid.

The JV partnership between ESB and Ørsted was selected through a competitive auction process under Ireland’s Offshore Renewable Energy Support Scheme (ORESS) in December 2025. The JV partnership secured the right to develop the site by submitting the most competitive bid price at 98.72 €/MWh.

Tonn Nua is located off the coast of Co. Waterford and is situated between 12 - 20km from shore. In total, the site area is 306 km². A map of the area is here: MAC-Map-MAC240057.pdf.

The Tonn Nua site was identified through the South Coast Designated Maritime Area Plan (SC-DMAP) which was ratified by the government in 2024. The process to select the site was done in consultation with key stakeholders. The SC-DMAP identified four offshore sites with Tonn Nua being the first of these sites to be developed. The process for choosing the site and the data used can be viewed here: The South Coast Designated Maritime Area Plan for Offshore Renewable Energy (SC-DMAP).

For fixed-bottom offshore wind, water depth is a key constraint because foundations, installation vessels, and construction methods have depth limits. Along Ireland’s south and west coasts, water depth increases quickly, so suitable fixed-bottom areas can be closer to shore than in some other regions in the UK and Europe.

At Tonn Nua, water depths are approximately 48–69m (average ~57m); while fixed-bottom technology is advancing, deeper-water solutions and the vessels to install them are not yet widely available at commercial scale. Currently the deepest offshore wind project for fixed turbines in the world is in max water depths of 58m. Typically the cost of these projects increases with increased water depths.

Tonn Nua is being progressed in response to the Government’s commitment to have 5GW of offshore projects in development by 2030 and to decarbonise Ireland’s energy system. When operational, it is expected that Tonn Nua will offset around 1.8 million tonnes of CO₂ emissions per year.

Tonn Nua will connect directly to the Irish grid and is expected to make a substantial contribution to national electricity needs for homes and businesses. By increasing the supply of renewable electricity generated in Ireland, the project can support energy security and emissions reduction goals.

Through ORESS, the project is expected to receive a long-term support arrangement that provides greater price certainty for electricity over the contract term. This can help reduce exposure to short-term volatility driven by fossil-fuel price shocks. The project has guaranteed a fixed market price for this electricity for the next 20 years. This price is fixed at 98.972 €/MWh. This is significantly lower than the current market price. For context, 2025 wholesale electricity in Ireland averaged 113.83 €/MWh.

In addition, a report published by the Southeast Energy Agency in March 2026 has confirmed that the development of the project will bring considerable economic benefits to the Southeast region. The report estimated that the development of all four sites will generate between €1.7 billion and €2.2 billion in additional Gross Value Added (GVA) for the wider South region. See here for further details: South East Positioned for Major Economic Boost from Offshore Renewable Energy - South East Energy Agency.

The project is expected to support regional employment and investment over its lifetime, alongside the delivery of renewable electricity. It will also provide a significant community benefit fund of circa €120 million (€6 million per annum over 20 years). As per requirements under the Offshore Renewable Energy Support Scheme (ORESS) contract, this investment will be managed independently and will go directly to local community initiatives.

The electricity generated will feed directly into Ireland’s national grid via the grid connection assets being progressed by our delivery partners EirGrid. This means the project will support Ireland’s renewable electricity and decarbonisation targets and contribute to national energy security.

The project timeline is governed by the Terms and Conditions of the contract signed with the Department of Climate, Energy and the Environment (DCEE) under the Offshore Renewable Energy Support Scheme (ORESS).

The project now moves towards obtaining the relevant consents and licences for surveys and construction, as well as undertaking significant stakeholder engagement, environmental assessment and design. Depending on these factors the project’s current planned timeline for operation is 2034. This timeline is also subject to the delivery of the transmission infrastructure by EirGrid.

The project has been awarded a Maritime Area Consent (MAC) by MARA. This provides the leasehold conditions for the site for 50 years and allows the project to progress to planning submission. The project has also applied to MARA for a Maritime Usage Licence (MUL). This will provide the license to carry out surveys which will inform the site design and environmental assessments required for the planning application to be submitted to An Coimisiún Pleanála.

The Tonn Nua team will be progressing the project through all the necessary surveys to inform an Environmental Impact Assessment and an Appropriate Assessment which are both required as part of the planning process. These surveys and assessments will take a number of years to complete and will help shape the project design and procurement steps towards delivery.

Offshore wind projects typically require several survey campaigns to understand seabed conditions, site environment, offshore weather and sea states. Together, these datasets support project design, safe construction, and the Environmental Impact Assessment (EIA) and Appropriate Assessment (AA). These surveys tend to take a number of years to complete and fall into the following categories:

• Geophysical surveys map the seabed to identify seafloor features and potential hazards (e.g., boulders, shipwrecks) and to help optimise turbine locations and cable routes.
• Geotechnical surveys investigate soil and rock properties (e.g., through boreholes or coring) and help to inform turbine foundations and cable burial design.
• Metocean surveys measure wind, waves and currents conditions to support optimum design of the site and inform safe working conditions.
• Environmental surveys establish baseline knowledge of species and habitats on site eg marine mammals, birds, fish, seabed habitats etc.

The surveys are carried out in conjunction with requirements in the relevant license (in this case a Maritime Usage Licence). As part of the application process for the license, the planned surveys are subject to assessments by MARA to ensure that activities will not have significant impact on the environment or species dependent on the area. The license conditions also dictate requirements with respect to notice of survey activity to other marine users.

Surveys will be planned and communicated in advance with marine users to minimise disruption and establish co-existence. Information on survey programmes and any associated arrangements will be shared via Marine Notices and published online. Engagement with fishing representatives and fishermen on the register is underway.

Please see link here to relevant license application: MUL250019 - MARA - Maritime Area Regulatory Authority.

We recognise the importance of fisheries to Ireland and its coastal communities. Fisheries impacts will be assessed through surveys and formal assessment during consenting. The project is developing a Fisheries Management and Mitigation Strategy informed by fisheries data and stakeholder input, to avoid, minimise, and manage impacts - particularly for sensitive fisheries.

The final number of turbines will depend on factors such as seabed conditions and the turbine sizes available to the market at the time of construction. Based on current turbine technology (15MW) this could be around 60 turbines, with fewer required if higher-capacity turbines are used.

The final turbine size has not yet been confirmed. Modern offshore wind turbines are typically around 250–280 metres tall to the tip of the blade (measured from sea level).

Offshore wind turbines will be visible from the shore, but the extent of the visibility will vary depending on distance, weather, light conditions and viewpoint.

Visual impacts will be assessed as part of the Environmental Impact Assessment and consenting process. The public and other stakeholders will be consulted on this, including through the sharing of photomontages or other visualisations, to support feedback. Design options and mitigation measures to help reduce impacts will be considered in advance of planning submission.

The project will be consulting with public and key stakeholders throughout the development stage (i.e. 2026-2029). The project will be running consultation events locally to engage directly. You are also welcome to contact the stakeholder team at any point using the details found on the ‘contact us’ page.

For offshore wind projects to be delivered, developing an early supply chain is a priority. We are working closely with relevant Government departments (e.g. Department of Enterprise, Trade and Employment) and agencies (Enterprise Ireland and IDA) to develop appropriate local supply chain expertise within Ireland to support delivery of this project. Please contact us via details on the ‘contact us’ page if you are part of the supply chain and wish to register your services with us.