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November 2025
Bridging Nations: powering homes across the UK and Ireland
MaresConnect, a 750 MW electricity interconnector project, on track to power 570,000 homes across the UK & Ireland
The project designed to link the power markets of Ireland and Great Britain, building a cleaner, more resilient energy future for both nations. The project will span approximately 245 kilometres, combining subsea and underground cables that connect the Maynooth substation near Dublin with the Bodelwyddan substation in Denbighshire, Wales.
The interconnector’s primary goal is to enable the bi-directional flow of electricity, enhancing grid stability and unlocking greater integration of renewable energy sources across the Irish Sea. By facilitating efficient power exchange, MaresConnect is set to play a pivotal role in accelerating the energy transition across the region.
Strategic Significance: A Win-Win for Ireland and the UK
For Ireland, MaresConnect represents a key step towards becoming a net exporter of renewable energy, especially offshore wind power. With Ireland’s relatively small domestic electricity market, interconnection is essential to maximise the use of abundant renewable resources, allowing excess clean energy to reach wider markets.
For the UK, the project enhances energy security and supports European energy integration objectives aligned with the European Green Deal. MaresConnect strengthens cross-border cooperation and resilience while helping both countries meet ambitious 2030 climate and net-zero goals.
How MaresConnect Works: Weather, Wind, and Power Flow
The demand for interconnector capacity across the Irish Sea is shaped significantly by weather patterns, particularly Atlantic depressions sweeping northeast across Ireland. During periods of strong wind generation, wholesale electricity prices in Ireland tend to drop as renewable energy displaces more expensive sources. This results in power flowing from Ireland to Great Britain for roughly four to six hours.
As the weather system moves towards Great Britain, the flow reverses, highlighting the dynamic and mutually beneficial nature of this interconnection. This flexibility not only supports grid stability but also drives economic and environmental gains by optimising renewable energy utilisation.
Project development and timeline
MaresConnect is being developed by MaresConnect Limited, a special purpose vehicle jointly owned by Foresight Energy Infrastructure Partners and Etchea Energy Nominees Limited. The project has secured a crucial grid connection at National Grid’s Bodelwyddan substation and is currently progressing through procurement and onshore survey phases.
Given the scale and complexity, MaresConnect’s journey from concept to operation involves detailed technical design, securing permits, and extensive stakeholder engagement. Construction is planned to begin at the end of 2026, with commercial operations expected by 2029.
Regulatory backing and European recognition
Strong regulatory support on both sides of the Irish Sea underscore the project’s significance. Positive assessments from the UK’s Ofgem and Ireland’s Commission for Regulation of Utilities (CRU) reflect growing recognition of the critical role private investment plays in achieving net-zero goals.
MaresConnect was also designated as a key project in the European Network of Transmission System Operators for Electricity’s (ENTSO-E) Ten-Year Network Development Plan 2022 (TYNDP), highlighting its critical role in the continent’s energy infrastructure landscape.
Economic and Environmental Impact
Strategic Investment in Europe’s Clean Energy Future
FEIP’s investment in MaresConnect exemplifies a forward-thinking approach to sustainable infrastructure development. By bridging Ireland and Great Britain through enhanced grid interconnection, this project not only strengthens energy security and market efficiency but also accelerates the broader European energy transition.
MaresConnect is more than just an interconnector - it's a critical link driving the transition to a cleaner, more integrated energy future for both nations.
FEIP targets projects that address key bottlenecks in the energy transition, such as grid infrastructure and long-duration energy storage, to enhance energy security and accelerate the shift to net zero