IN Brief:
- EirGrid has unveiled a major offshore substation package for the Tonn Nua area on Ireland’s south coast.
- The programme is designed to connect around 900 MW of offshore wind through new offshore and onshore transmission infrastructure.
- Procurement activity is now advancing alongside marine planning and route development as offshore grid delivery becomes more structured.
EirGrid has unveiled the offshore substation package for its Powering Up Offshore – South Coast programme, bringing a central part of Ireland’s first major plan-led offshore grid development into clearer procurement focus.
The package relates to Tonn Nua, the first area within the South Coast Designated Maritime Area Plan to move forward for offshore wind development. EirGrid’s published material sets out a broader transmission programme intended to connect around 900 MW of offshore wind generation to the Irish grid through a combination of offshore and onshore infrastructure.
Trade reporting has described the substation package as covering the design, fabrication, installation, and commissioning of offshore substations and associated high-voltage equipment. EirGrid’s project documentation shows how those elements fit into the wider programme: offshore substation platforms in Maritime Area A, offshore transmission cables to landfall, new onshore substations, underground onshore cable routes, and loop-in connections to the existing transmission network.
That infrastructure is now becoming the practical backbone of Ireland’s offshore wind ambitions. National targets and designated maritime areas establish the framework for development, but transmission architecture determines how quickly generation can move from planned capacity into operational supply. Offshore substations, export systems, landing points, and onshore reinforcements sit at the centre of that transition.
Tonn Nua is the first plan-led site to advance under Ireland’s new offshore structure, following approval of the South Coast DMAP and the selection of the ESB-Ørsted joint venture for the wind farm itself. The transmission package shows how the delivery model is being divided between generation development and system integration, with EirGrid responsible for the network assets required to bring power ashore and into the wider grid.
Across Europe, this stage of delivery has become one of the most demanding. HV equipment, subsea cables, offshore platforms, fabrication slots, and specialist installation capacity are all under pressure as multiple countries pursue parallel build-out programmes. Developers and system operators are therefore under increasing pressure to define scope early and give the market clearer signals around sequencing and technical requirements.
Ireland is entering that environment while building much of its offshore transmission capability at scale for the first time. That increases the importance of package definition and procurement clarity. A well-structured substation package gives suppliers a clearer view of the engineering scope and helps separate what sits within the wind farm from what belongs to the regulated transmission programme.
The wider project architecture also shows how interdependent offshore grid delivery has become. Offshore substations have to align with cable routes, marine planning, landfall decisions, onshore substation design, and the constraints of the existing transmission system. Delay in one part of the chain can affect the rest. That is why procurement milestones for substations carry more weight than their formal title might suggest.
Ireland’s offshore programme is moving from concept and planning into a phase where equipment, interfaces, and delivery capacity begin to set the pace. The Tonn Nua package is an early marker of that shift, and of the scale of transmission work now required to turn offshore targets into operating infrastructure.
Project detail is available on EirGrid’s Powering Up Offshore South Coast page.