48 n CLEAN ENERGY July/August 2025 www.drivesncontrols.com Record-breaking tidal turbine sets stage for commercialisation For more than six years, a 1.5MW tidal power turbine has been operating continuously in the turbulent waters of Scotland's Pentland Firth, without needing any unplanned or disruptive maintenance. This is a world record for tidal turbine performance and reliability, and means that the subsea device could be a forerunner of utility-scale tidal power schemes around the world. The 1.5MW turbine is part of a 6MW pilot array being operated by MeyGen, which is part of Edinburgh-headquartered and Singaporean-owned SAE Renewables (previously known as Simec Atlantis Energy). It is currently the world’s biggest tidal stream facility. Plans have been announced to add a further 59MW of capacity to the Pentland Firth array, with future phases potentially expanding this to 398MW, creating the world's first commercial-scale tidal stream power array. Tidal power is one of the most predictable forms of renewable energy. It complements unpredictable solar and wind power sources. With the cost of tidal power falling, it is predicted to become cost-competitive with nuclear energy by 2035. The global tidal energy market, which was worth $1.3bn in 2023, could reach an estimated $8.1bn within seven years. The UK – a world leader in the technology – is currently aiming to deploy 1GW of tidal stream technologies by 2035, enough to power around 829,000 homes. By 2050, the sector is predicted to be contributing up to £17bn and 15,000 jobs to the UK economy. The Pentland Firth turbines are being supplied by Bristol-based Proteus Marine Renewables. Late last year, Proteus signed a Memorandum of Understanding with SKF and GE Vernova’s power conversion business. The MoU sets out a framework for an alliance to supply tidal turbine systems to developers of commercial, multi-megawatt tidal stream projects. The partners are focusing initially on supplying at least 59MW of capacity to MeyGen for its Scottish site. “The successful operation and performance of our existing turbines have proven the reliability of this technology and its potential as a predictable source of renewable energy,” says Fraser Johnson, operations and maintenance manager for the MeyGen tidal array. “We are excited to collaborate with Proteus Marine Renewables, with the support of SKF, as we progress from a pilot project to full commercial deployment.” Proteus will be responsible for the system design, assembly, installation, commissioning of the turbines, as well as supplying speciality components and offshore services. GE Vernova will provide the electrical systems, from the generators to the grid. And SKF Marine – which provided the bearings for the original Pentland Firth turbine – will supply plugand-play 3MW powertrains for the future turbines. A key challenge for tidal stream energy is designing turbines that can operate reliably in harsh underwater conditions for extended periods. Using condition-based maintenance, tidal power plants should be able to operate for several years between overhauls. Proteus and SKF say that this has already been achieved with the MeyGen array that was commissioned in 2017. It has been in continuous operation since 2018, demonstrating the long-term reliability needed for tidal stream power to become a commercial reality. For more than a decade, SKF has been supporting the specification, development and supply of bearings and seals for tidal turbines. This includes the main rotor A subsea tidal turbine operating off Scotland since 2018 has demonstrated the long-term viability of the technology. It could lead to commercial arrays producing predictable renewable power at competitive costs. It could also open up a new market for mechanical, electrical and control technologies.
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