Road to Renewables: EirGrid’s roadmap for clean energy integration

Ireland is focused on achieving its climate and energy goals of becoming carbon neutral by 2050, with an interim target of reducing emissions by 51 per cent by 2030 compared to the 2018 emission levels. It intends to achieve these targets through the Climate Action Plan 2023 published in December 2022 under the Climate Action and Low Car­bon Development (Amendment) Act, 2021, to implement economy-wide carbon budgets and sectoral emissions ceilings. Northern Ireland, which is part of the UK, also aims to achieve carbon ne­u­­trality by 2050. Both Ireland and Nor­thern Ireland, whose electricity systems and markets have been integrated since 2007, aim to deliver up to 80 per cent ge­ne­ration from renewable energy sources by 2030, an increase from their previous goal of 70 per cent.

Ireland has achieved significant strides in the renewables sector. The integrated power system of Ireland and Northern Ireland, overseen by the Irish transmission system operators EirGrid and SONI Limited (part of the EirGrid Group), has effectively managed up to 75 per cent of variable renewable generation (referred to as system non-synchronous penetration or SNSP) since April 2022. This made Ireland the first in the world to reach this milestone, overcoming major technical challenges associated with integrating el­ectricity from wind farms and solar fa­rms, as well as interconnectors linking to other countries. The aim is to reach 95 per cent SNSP by 2030 to achieve the country’s renewable goals.  This requires over 22 GW of renewable energy sources capacity addition, inclu­ding 5.5 GW of onshore wind, 5 GW of offshore wind, 8.4 GW of solar and ap­proximately 3 GW of storage capacity by 2030. This ambition must be achieved while ensuring the re­liability, resilience and affordability of the electricity system.

Against this backdrop, EirGrid and SONI, operators of the integrated Single Electricity Market (SEM) for Ireland and Northern Ireland, published the “Shap­ing Our Electricity Future Roadmap Version 1.1” in July 2023. This is a revised version of the plan initially published in November 2021, outlining the network, market and operational changes requir­ed to establish a power system with an 80 per cent renewable energy sources share by 2030. The EirGrid Group plans to invest Euro 3.4 billion across the country by 2030, including an additional Euro 236 million under the latest plan.

Power Line presents the key drivers, future plans for network, system operations and electricity markets for meeting the new renewable ambitions…

Key drivers

The key driver for investments in the grid is its need for accommodating a significantly higher volume of power from the upcoming renewable capacity to meet demand centres. By 2030, electricity de­ma­nd is expected to substantially inc­rease to 56 TWh across the island, up fr­om around 40 TWh in 2021. This is due to the increasing utilisation of electricity for transport and heating, as well as demand from power-intensive users such as pharmaceutical plants, high-tech manufacturing operations and data centres.

On the supply side, there are plans to in­tegrate substantial amounts of wind and solar into the grid. Specifically, the country intends to incorporate 5 GW of offshore wind capacity by 2030, in addition to 2 GW for hydrogen production. This initiative is being supported by the De­part­ment of Environment, Climate and Communications’ (DECC) Renew­able Electricity Support Scheme (renewable energy sources), with EirGrid conducting the auctions. In June 2023, EirGrid announced the final results of the Rene­wable Energy Sources 1 auction, selecting four offshore wind projects aggregating 3,074 MW (from the six qualified projects). These projects have the capacity to deliver 12 TWh of electricity annually, with the largest among the projects being the 1.3 GW Codling Wind Park. The auction yielded highly competitive prices, averaging Euro 86.05 per MWh, which is claimed to be one of the lowest prices paid by an emerging offshore wind market. By comparison, Ireland’s average wholesale electricity price over the past 12 months exceeded Euro 200 per MWh. This marks Phase I of the co­untry’s offshore wind development. In April 2023, DECC published the Phase II framework and policy for transitioning towards a more enduring and long-term offshore regime. EirGrid will launch the first Renewable Energy Sources 2 auction under this phase by the end of 2023, with a focus on achieving the 2030 offshore wind goal. Notably, EirGrid will construct offshore transmission infrastructure for Renewable Ener­gy Sources 2, including offshore substations and submarine cables connecting these substations to the onshore grid. Further, the latest policy proposes that future offshore wind projects will connect to offshore substations, to be desig­ned and built by EirGrid, which will be a first for the company. However, successful participants in any subsequent auctions (af­ter Renewable Energy Sources 2) may be required to develop all offshore transmission assets, including offshore substations, which will subsequently be transferred to EirGrid.

In addition, beyond Phase II and the 5 GW goal, the government is committed to pursuing Phase III, which targets an initial 2 GW of floating offshore wind in­s­tallation off the south and west coasts and may include projects available for green hydrogen production. DECC in­tends to launch the Phase III policy, alo­ng with a longer-term regime for offsho­re renewable energy, in the first quarter of 2024.

By 2030, all thermal capacity using coal, peat and oil as primary fuel will be dec­ommissioned, along with other ageing thermal plants. These are expected to be replaced by new gas-based generation, LDES, new interconnection capacity and demand-side units. The country pla­ns to incorporate 2.75 GW of new LDES over the next eight years in addition to the 150 MW of short-duration storage. Storage capacity will be utilised for reserve provision and capacity adequacy to assist with congestion management, which helps in managing surplus renewable generation while minimising the amount of renewable energy sources generation to achie­ve the government’s target.

Network plans

EirGrid, with a transmission line length of approximately 9,500 km (excluding the Dublin 110 kV network and other 110 kV circuits considered as part of the distribution system), plays a key role in transmitting the planned capacity. As of March 2023, it had approximately 362 projects in various stages of development in its network delivery portfolio. Several of these projects are essential for reinforcing the network infrastructure.

Further, the latest plan has added 19 network projects (including three in Nor­thern Ireland) and four large-scale renewable hubs. The hubs serve as a me­a­ns to connect renewable energy so­ur­ces projects to specific parts of the grid that have spare capacity. Additio­nally, as part of its strategy to optimise the use of existing network infrastructure and leverage innovative technologies for managing network congestion and maximising capacity, EirGrid plans to deploy dynamic line rating (DLR) and power flow controllers (PFCs). In fact, 10 of the 16 newly added projects in Ireland are new technology projects based on DLR and PFCs, while the remaining pertain to the upgradation of the existing grid. In Northern Ireland, two projects invol­ve upgrades to existing circuits and the third pertains to the construction of a new substation.

Renewable hubs and grid reinforcement

High voltage renewable hub substations are proposed to be strategically located to facilitate the connection of significant quantities of new renewable generation in nearby areas. This approach aims to prevent multiple smaller-scale connections to the 110 kV grid, as well as reducing additional congestion on the network. The latest roadmap has identified four new hubs, with three in the Mid­lands and one in the southeast region. These consist of a 400 kV renewable hub collector substation looped into the 400 kV Oldstreet – Woodland circuit; a 220 kV substation looped into the Maynooth – Shannonbridge circuit; and two 220 kV hubs each connected to the Maynooth substation and Great Island substation (in the southeast).

Given the numerous upcoming onshore renewable energy projects in the Mid­lan­ds, EirGrid is upgrading its existing network via uprating and refurbishment projects to enhance the capacity of the existing underlying 110 kV network. In the northeast, several uprates and DLR projects have been identified, while in the southeast, the application of flexible network technologies besides the rene­w­able hub has been identified.

Regarding the ongoing grid development to facilitate renewable energy so­ur­ces connections in the west and nor­th­west, EirGrid is developing the 60 km, 110 kV CP0816 North Connacht project, marking the country’s first long underground cable circuit. It runs from the Moy substation in Ballina County, Mayo, to the Tonroe substation in Balla­g­had­e­r­reen County, Roscommon, and is desig­ned to accommodate the upcoming renewable generation connections in North Mayo. In Cork, several station up­grades and line refurbishments, in addition to the planned interconnector connection with France (Celtic Inter­con­­nector), are under way to ensure supply security and maintain the necessary levels of reliability and flexibility.


The 400 kV link between Ireland and Northern Ireland (second North South In­terconnector), spanning 138 km to co­nnect Meath in Ireland to Tyrone in No­rthern Ireland, will increase the tra­n­sfer capacity between the two countries and improve supply security. This project is expected to be fully operational by 2026.

Ireland is preparing to connect to the European Union (EU) via the 700 MW Celtic interconnector with France. This involves a 575 km high voltage direct current (HVDC) subsea connection that will link the coast of Cork with the Ceinture Dorée (Gold Belt) coast in Brit­tany in France. The cable will pass west of the Isles of Scilly, UK, creating a direct link between the French and Irish markets and boosting renewable energy so­urces integration. This project is set to be completed in 2027.

Further, private players are building interconnectors to connect the Great Britain (GB) electricity market (England, Northern Ireland, Scotland and Wales) to SEM. MaresConnect plans to develop a 750 MW HVDC multipurpose interconnector from Dublin in Ireland to Bo­delwyddan and Denbighshire in Wales, UK, by 2030. This interconnector will al­so integrate upcoming offshore wind projects into the grid. Recently, TI LirIC Limited proposed a 700 MW HVDC interconnection to connect the Kilroot substation in Northern Island to Sco­t­land, UK, by 2029.

Offshore wind integration

To facilitate offshore wind integration, EirGrid has commenced work on identifying and developing offshore connection platforms for the Renewable Energy Sources 2 auction. This approach will “future-proof” these platforms, enabling EirGrid to potentially connect much higher volumes of offshore wind in the future when the onshore grid is robust enough to absorb this capacity.


By 2030, EirGrid plans to invest Euro 3,396 million in Ireland and Euro 326 million in Northern Ireland. Of the Euro 236 million earmarked for investment in the revised roadmap, Euro 169 million will be allocated towards uprating existing circuits, Euro 19 million to PFC and DLRs and the remaining Euro 48 million for the new substation in Northern Ireland.

Electricity markets

The roadmap categorises the key chan­ges required for market design evolution to efficiently achieve the renewable ambition into two pillars. Under the first pillar, it is necessary to align markets wi­th the two-part operational challenges posed by the trading of large renewable energy sources volumes. The first part involves replacing the technical capabilities offered by conventional plants with a balanced portfolio of alternative technologies such as renewable energy sour­ces, demand-side resources, storage and new support technologies. The second part pertains to the emerging technical and operational limitations as the power system transitions to high renewable energy sources levels.

Under the second pillar, there is a re­quirement for trading arrangements to facilitate the integration of SEM into the GB and EU markets. Brexit has separated the SEM and GB markets from the European day-ahead market, resulting in the absence of day-ahead trading on the SEM-GB border. The pre-existing (interim) intra-day arrangements bet­ween SEM and GB remain operational, enabling trading across the two interconnectors. Trading arrangements for full SEM integration will involve aligning market structures with the EU legislation, optimising interconnection usage and facilitating effective export and im­port of large volumes of renewable energy sources.

Challenges and the way forward

To comply with government renewable energy policies in Ireland and Northern Ireland, it is necessary to accommodate the unprecedented penetration of variable renewable energy sources while minimising curtailment levels. This will require a significant evolution in power system operation, as well as necessitating EirGrid and SONI to address unique challenges. Achieving the 2030 renewable energy sources target will require a seismic shift in approach due to the sc­ale of the undertaking coupled with significant challenges such as deliverability, technical scarcities and economic considerations.