5. ELECTRICITY AND RENEWABLES

Transmission

The transmission system comprises approximately 6 400 kilometres (km) of high-voltage overhead lines and underground cables, and over 200 substations. Electricity generated in power plants is transformed to higher voltage levels – 110, 220, 275 and 400 kV – and fed into the transmission system (see Figure 5.14). The Dublin area is an exception as the 100 kV lines and cables and some of the 220/110 kV transformer stations belong to the distribution system.

EirGrid is working on two extensions to the transmission system, both related to expected strong demand increase in the greater Dublin area. The West Dublin Project includes the installation of a 220/110 kV gas insulation switchgear substation that will connect to an existing 220 kV double circuit line. The project is responding to a significant increase in demand associated with the growth of multinational companies in a business park in western Dublin. It is scheduled for completion in 2019 and is sized to accommodate potential future demand growth.

The Kilkenny-Laois reinforcement project will resolve SoS problems resulting from strongly growing demand and projected growth. The project comprises a new 400/110 kV substation near Portlaoise (which will be connected to the existing 400 and 110 kV lines), a new 110/38 kV substation in Kilkenny and new 110 kV overhead lines that link with the new substation near Portlaoise. The project is scheduled for completion in 2021.

Focus area: Interconnectors

Existing interconnectors

Ireland’s geographical location causes challenges in interconnection with neighbouring countries. Ireland is exclusively connected to the United Kingdom through two electricity interconnectors that are also used for electricity trading. These are the 300 MW north– south interconnector, linking the electricity systems of Ireland and Northern Ireland, and the 500 MW east–west interconnector, connecting Ireland and Wales (United Kingdom). EirGrid owns and operates both interconnectors. Ireland is not meeting the indicative EU electricity interconnection target of at least 10% of installed capacity by 2020; its level of interconnection is 7.4%. Ireland will not have a direct electrical interconnection with the rest of the European Union when the United Kingdom leaves.

Interconnectors present benefits for the electricity markets such as improved SoS, diversification of electricity supply and increased flexibility for the integration of a high share of intermittent renewables. This is particularly important for a small system such as the Irish one. Ireland’s policy position on interconnection as outlined in the 2018 National Policy Statement on Electricity Interconnection (DCCAE, 2018a) emphasises the important role of interconnection in transition to a low-carbon energy future. It may have a variety of wide-ranging benefits to the Irish consumer, including lower long-term costs of electricity through connection to a larger market and diversity of electricity supply.

Ireland’s transmission network can safely absorb a level of renewable production generation of up to 42% of total electricity generated without affecting the SoS. Higher penetration levels, to which Ireland aspires, would require significant additional interconnection or energy storage. Further interconnections will be necessary.

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5. ELECTRICITY AND RENEWABLES

Figure 5.14 Map of electricity infrastructure

220 kV cable

110 kV cable HDVC cable

East-West interconnector

North

Atlantic

Ocean

Cork Area

km

050

This map is without prejudice to the status of or sovereignty over any territory, to the delimitation of international frontiers and boundaries, and to the name of any territory, city or area.

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5. ELECTRICITY AND RENEWABLES

Developing interconnectors in Ireland

Ireland is pursuing three new projects for interconnectors: the second North–South interconnector, the Greenlink interconnector and the Celtic interconnector. All three projects are on the third list of the EU projects of common interest that are considered of national priority and important infrastructure projects for Europe. Only the Celtic interconnector would ensure continuous market coupling with the European Union once the United Kingdom has exited the European Union (table 5.2).

The existing North–South interconnector is running at full capacity and creates a bottleneck in the SEM. The construction of a new 400 kV alternating-current/1 500 MW overhead-line North–South interconnector is planned to improve the security of electricity supply across the island of Ireland, and to improve grid capacity and reliability in Ireland and Northern Ireland. The increased capacity will also facilitate connection of additional renewable capacity to the grid and help reduce curtailments. This is important in Ireland’s commitment of 40% of electricity consumption from renewable resources by 2020.

Based on trading data since SEM has been in place in 2007, the electricity demand has been considerably higher than the current 300 MW capacity. There is a regular demand for cross-border transfer of more than 750 MW, with peak demand reaching 1 100 MW (SONI, 2016). The second North–South interconnector project has received planning permission in both jurisdictions, Ireland and Northern Ireland, but legal challenges to the planning consent have slowed progress. Construction is expected to begin in 2020, and the commissioning of the interconnector is planned for 2023.

The Greenlink project is a proposed 500 MW interconnector between Ireland and the United Kingdom. The proposed route runs from the Great Island substation, in Ireland, to the Pembroke substation, in Wales. Element Power, a private investor, promotes the project. The construction is planned to start in 2020, with the interconnector becoming operational in 2023. The CRU made an initial assessment of the Greenlink project in October 2018 and determined that it is in the public interest (CRU, 2018c). The CRU expects to undertake consultation in 2019 on the proposed regulatory regime to support Greenlink following the submission of sufficiently detailed financial and technical information from the Greenlink developer. The CRU is also closely liaising with the regulator for gas and electricity markets in Great Britain in the final project assessment process.

The Celtic interconnector is a proposed 700 MW connection between the south coast of Ireland and the north-west coast of France. EirGrid is developing this project in partnership with the French TSO. The length of the Celtic interconnector would be approximately 600 km, which is about three times longer than the existing East–West interconnector. The two TSOs lodged an investment request with the Irish and French regulatory authorities in September 2018. A decision is expected in March 2019. Construction is scheduled to commence in 2023 for completion in 2025-26.

The case for building the Celtic interconnector between Ireland and France is strengthened by the vote of the United Kingdom to leave the European Union. If built, this project will be the only direct electricity connection between Ireland and the EU electricity market. It could potentially benefit from higher funding through the Connecting Europe Facility than anticipated at the start of the project.

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