Grid Stability
Welsh Power is at the forefront of the newly developing grid stability market in the UK having been awarded 7 grid stability projects across the three National Energy System Operator (NESO) pathfinder tenders:
- Pathfinder Phase 1: Rassau Project
- Pathfinder Phase 2: Scottish Projects (Gretna, Rothienorman, Thurso and Neilston)
- Pathfinder Phase 3: Sellindge Project and Cilfynydd Project
Welsh Power, along with its partner Quinbrook Infrastructure Partners, a specialist investment manager focused exclusively on renewables, storage and grid support infrastructure, continues to develop and operate cutting edge synchronous condenser projects to provide inertia and contribute short circuit level to strengthen the UK grid.
Pathfinder Phase 1: Rassau Project
An early entrant into the newly developing GB grid stability market, in 2019 Welsh Power developed a synchronous condenser and flywheel project at Rassau in South Wales for participating in the first NESO (then National Grid ESO) pathfinder tender.
In early 2020, Rassau was awarded a pathfinder contract to provide stability services to NESO. The facility, which was designed and constructed by Siemens Energy, provides inertia to strengthen the grid, short circuit power to ensure its reliable operation and reactive power for voltage control.
Partnering with Quinbrook Infrastructure Partners on this ground-breaking project for Wales and the UK, Welsh Power managed the construction, which completed in February 2022.
“The facility can provide approximately one per cent of the inertia needed to operate the grid safely - with zero emissions.”
The facility is now operational and under Welsh Power’s management. The facility stabilizes the operation of the grid providing inertia which has traditionally been provided by fossil fuelled power plants which in turn will allow a higher percentage of renewable electricity to contribute to the GB generation mix reducing its carbon intensity.
“The innovative technology solution at Rassau is the first of many such facilities needed to manage grid stability as we transition to net zero. Welsh Power’s partnership with Quinbrook allows us to play an exciting role in the development of this market and I am proud of the whole team effort needed to deliver this groundbreaking project from concept to operation in two years.” Alastair Fraser, Welsh Power Chairman.
Pathfinder Phase 2
From 2020, Welsh Power developed a portfolio of four projects in Scotland, namely; Gretna, Rothienorman, Neilston and Thurso in readiness for participating in the NESO’s Pathfinder Phase 2 tender process.
In February 2022, Welsh Power, along with its partner Quinbrook were awarded four projects in NESO’s Pathfinder Phase 2 procurement process securing over half of the £323m contract value awarded by NESO. Construction works began late 2022/early 2023 under Welsh Power’s management.
Alastair Fraser of Welsh Power commented, “Success in the Pathfinder 2 tender validates the two years of hard work that our teams at Welsh Power, Quinbrook and our extended network of partners have invested to bring these nationally important developments to the point where we are ready to start construction. We consider these innovative projects an essential step towards building an effective zero carbon electricity network in Great Britain. Through the partnership with Quinbrook, Welsh Power is able to continue to build its expertise in developing these exciting new projects.”
The Rothienorman site in North East Scotland entered commercial operation in December 2024; the first of the ten Pathfinder 2 sites to reach this milestone and the second grid stability project under Welsh Power’s management to commence operations.
Construction at Rothienorman commenced in February 2023, with the key equipment supplied by Siemens Energy.
Rothienorman is contracted to provide 1,357MVA of short circuit level and 470MWs of inertia. The Scottish portfolio will further stabilize the operation of the power grid which in turn will allow for more renewable energy to be used on the network.
Matthew Tucker, Welsh Power’s CEO commented “We are delighted to have brought the first project awarded a contract under NESO’s Pathfinder 2 tender into commercial operation. The Rothienorman grid stability site provides much needed short circuit contribution to the electricity grid in the north of Scotland, an area of significant renewable energy generation. The team at Welsh Power together with our partners at Quinbrook and Siemens have overcome myriad challenges to deliver a high-quality installation that will serve to stabilise the GB energy system for decades to come.”
Gretna, Thurso and Neilston continue under construction and are expected to become operational imminently.
Pathfinder Phase 3
In November 2022, Welsh Power, again partnering with Quinbrook were awarded two contracts in Phase 3 of National Grid ESO’s Stability Pathfinder programme. The Pathfinder programme aims to deliver investments in nationally critical transmission infrastructure which is essential to delivering a net zero future.
Welsh Power and Quinbrook had been working on these two new projects since early 2021 when suitable site locations were identified at key points on the GB transmission system.he projects located at Sellindge in Kent and Cilfynydd in South Wales are estimated to deliver savings to customers of £3.5 billion over their initial 10 years of operations. Larger than Welsh Power’s projects awarded contracts in Pathfinder phases 1 and 2 they will provide nearly 50% of all the inertia contracted under the Phase 3 Pathfinder programme as well as contributing some 17% of the tendered short circuit requirements. The services the plant will provide will help NESO achieve its ambition to operate the GB electricity system using only renewable energy sources and without the need for fossil fuels.
Our success in Pathfinder Phase 3 follows on from our success in Pathfinder Phase 1 and Pathfinder Phase 2 and reinforces Welsh Power’s position as the UK’s leading independent provider of grid stability services.
The projects are significant infrastructure investments and will create high quality jobs not just during construction but for the long term. The projects are currently under construction being managed by Welsh Power.