Siemens to modernize the HVDC link between Northern Ireland and Scotland

June 18, 2020

  • Siemens will upgrade control and protection system of Moyle Interconnector
  • Refurbishment increases security of supply, improves integration of renewable energy and enhances provision of ancillary services


Siemens Gas and Power (Siemens Energy) has been awarded the project to refurbish the Moyle Interconnector, a high-voltage direct-current (HVDC) link between Ballycronan More in County Antrim, Northern Ireland, and Auchencrosh, Scotland. Owned and operated by Mutual Energy, the Moyle Interconnector control and protection system is almost 20 years old and is being modernized to enhance its operation. The refurbishment of the 500-megawatt interconnector will increase the security and reliability of the power supply to consumers in the United Kingdom. The project to upgrade the technology originally installed by Siemens in 2001 is now underway and the refurbishment is scheduled to be completed in September 2022. 

HVDC converter station in Ballycronan More, Northern Ireland.

HVDC refurbishments are complex projects, as the optimal scope needs to be identified and all remaining interfaces clarified. With the help of constructive and detailed discussions between Mutual Energy and Siemens, a common understanding was established and the scope defined as; the detailed design, manufacturing, factory testing, installation, and commissioning of the control and protection system (including the replacement of auxiliary supplies, valve base electronics, and the measurement system), and the supply of a control training simulator.

The refurbishment of the interconnector will address the demands of the evolving electricity networks in both Great Britain and Northern Ireland. In particular, the upgrade improves the dynamic performance of the interconnector, enabling Mutual Energy to offer enhanced ancillary services. These will provide a valuable range of options to the System Operators as they seek the continued reliable and efficient management of the networks, whilst accommodating more variable renewable generation. Additionally, by introducing an overload capability, the upgraded Moyle Interconnector will have greater operational flexibility.

Speaking about the upgrade, Paddy Larkin, Chief Executive of Mutual Energy, said; “With almost 20 years in operation, the Moyle Interconnector has been a vital energy asset and we’re pleased to further enhance its operations and functionality. The new system will allow us to adapt to evolving security standards and changing grid conditions – best serving the needs of our customers and Northern Ireland’s energy requirements. It was crucial for us to ensure downtime during works was minimized so as to not impact operations, and we’re pleased to have a partner that can honor that requirement. Siemens’ diligence and collaborative approach make them a reliable and trusted partner and we look forward to their expert team safely delivering this project.”

“With its enhanced control features, the HVDC Classic system will be perfectly equipped for the future to more effectively meet the energy market’s demands”, says Hauke Jürgensen, Head of Large Transmission Solutions at Siemens Energy. “The upgraded system will provide more operational stability to weaker AC grids and will operate in a wider range of AC grid system conditions. In the future, more energy – mainly produced by renewables – can be transmitted from Scotland to Northern Ireland and vice versa.”

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Siemens Energy Media Relations Team

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Siemens Gas and Power GmbH & Co. KG is the global energy business of the Siemens group, which has been working with its customers on solutions for the evolving demands of industry and society for more than 150 years. With planned stock listing, Siemens’ energy business will operate independently as Siemens Energy in the future. It will offer broad expertise across the entire energy value chain, along with a comprehensive portfolio for utilities, independent power producers, transmission system operators, the oil and gas industry, and other energy-intensive industries. With its products, solutions, systems, and services, Siemens Energy will address the extraction, processing, and transport of oil and gas as well as power and heat generation in central and distributed thermal power plants, and power transmission and technologies for the energy transformation, including storage and sector-coupling solutions. The majority stake in Siemens Gamesa Renewable Energy will round out its future-oriented portfolio. With its commitment to leading the way in decarbonization of the global energy system, Siemens Energy will be a partner of choice for companies, governments, and customers on their path to a more sustainable future. With around 90,000 employees worldwide, Siemens Energy will help shape the energy systems of today and tomorrow.