Ireland's electricity transmission system operator, EirGrid, has completed its 2026 marine and coastal survey campaign for the Powering Up Offshore – South Coast programme, aimed at developing the electricity infrastructure required to integrate offshore renewable energy generation from the country's south coast into the national grid.

Building on the survey programme carried out in 2025, the latest campaign involved nearly 70,000 hours of work covering 2,337 kilometres of maritime area, with investigations focused on marine, coastal and environmental conditions.

The collected data will support ongoing engineering, environmental and planning assessments of infrastructure options for connecting the Tonn Nua maritime area, which forms part of the Irish Government's South Coast Designated Maritime Area Plan for Offshore Renewable Energy (SC-DMAP).

Infrastructure to connect 900 MW of offshore renewable energy

The Powering Up Offshore – South Coast programme involves developing the infrastructure needed to transport electricity generated in the Tonn Nua maritime area to Ireland's national electricity grid.

Once developed, the project is expected to facilitate the connection of approximately 900 MW of offshore renewable energy, enough to supply almost one million homes, according to EirGrid.

The 2026 surveys will help assess seabed and coastal conditions and identify potential options for subsea cables, offshore substations and other grid connection infrastructure.

The findings will inform subsequent engineering, environmental assessment and project planning activities.

Public consultation open until 8 December

The completion of the survey campaign coincides with an ongoing 12-week public consultation through which EirGrid is seeking feedback on emerging infrastructure options for connecting Tonn Nua to the national electricity grid.

The consultation will remain open until 8 December 2026 and covers potential connection infrastructure in Cork and Wexford, along Ireland's southern and southeastern coasts.

The options under consideration include potential landfall locations, offshore cable corridors, offshore substations, grid connection points and onshore transmission cable routes.

Feedback from local communities, landowners, fisheries representatives and other marine users will help inform the selection and assessment of infrastructure options during the next stage of development.

EirGrid advances offshore grid connection planning

Adam Cronin, Head of Offshore – South Coast at EirGrid, said the completion of the surveys will provide information to improve understanding of marine and coastal conditions and support the development of infrastructure options needed to connect offshore renewable energy to the national grid.

He also acknowledged the involvement of local communities, fisheries representatives and other marine users, whose cooperation helped the survey teams complete the campaign.

EirGrid has encouraged stakeholders to participate in the ongoing consultation and review the proposed infrastructure options.

The transmission system operator explained that the survey findings, together with feedback received during the consultation, will inform the next stages of infrastructure development associated with the Tonn Nua maritime area.

With the completion of its 2026 survey campaign, the Powering Up Offshore – South Coast programme continues progressing through the planning and assessment stages required to connect future offshore wind generation to Ireland's electricity system.