PLANS have been unveiled to transform Britain’s largest conventional hydro power plant into a new pumped hydro storage facility.
SSE Renewables is behind the proposals which were announced during a visit by Scotland’s first minister, Humza Yousaf, to Sloy Power Station on the banks of Loch Lomond.
The visit marked the 80th anniversary of the 1943 Hydro Electric Development (Scotland) Act, which brought hydro-electric power to the Scottish Glens eight decades ago. Now SSE Renewables has announced plans to convert the existing conventional 152.5MW Sloy Hydro power station to pumped storage.
SSE Renewables explained that, as Britain transitions to a net zero power system, the development of additional pumped hydro storage projects will be crucial for energy security back-up and for balancing a renewables-led energy system during periods when the wind doesn’t blow and the sun doesn’t shine.
Subject to final design, the converted Sloy scheme would be capable of delivering up to 25GWh of long-duration electricity storage capacity. At the flick of a switch, the converted Sloy scheme could provide ‘firm, flexible’ renewable energy for up to 160 hours non-stop, enough to power around 90,000 homes for up to one week.
Over the coming months, SSE Renewables will refine its project design to convert the Sloy plant from conventional hydro power to pumped hydro storage technology ahead of a period of public consultation later this year. Subject to the scoping opinion, it’s expected a planning application could be submitted to the Scottish Government by late 2023 or early 2024.
Subject to a positive consenting outcome and the prevailing policy environment, SSE hopes to make a final investment decision on Sloy in late 2025, and to fully adapt and commission the new pumped storage scheme by 2028.
If approved for delivery, the project would require investment totalling the high tens of millions of pounds and would contribute to SSE’s Net Zero Acceleration Programme, or NZAP, which commits to investing around £7 million a day on critical low-carbon infrastructure needed in the net zero transition.
SSE’s decision to announce plans for additional new pumped hydro storage capacity at its existing Sloy Power Station comes as the leading low-carbon energy infrastructure company awaits the UK Government’s decision on how it intends to support the deployment of long-duration electricity storage, as set out in last year’s British Energy Security Strategy.
Humza Yousaf said, “Scotland has vast natural resources which have helped us to become world leaders in renewable energy. Facilities like the Sloy Power Station continue to play a significant role in energy supply, providing flexible services to the grid and help to ensure a continued, resilient and secure electricity supply, by helping to balance our intermittent renewable electricity generation.
“Hydro power was the country’s original source of renewable energy and it has the potential to play a significantly greater role in the transition to net zero – both on a small-scale in co-operation with local communities and on a larger scale, to help to ensure a continued resilient and secure electricity supply.
“We continue to call for the UK Government to provide an appropriate market mechanism for hydro power and other long duration energy storage technologies, to ensure this potential is fully realised.”
Finlay McCutcheon, director of onshore Europe at SSE Renewables, added, “We’re delighted to announce new redevelopment plans for our landmark Sloy Power Station, especially as we mark the 80th anniversary of Hydro Power’s contribution to homegrown power supply in Scotland and Britain.
“In converting our existing Sloy conventional hydro power plant to a pumped hydro storage facility, we can provide the additional large-scale, long-duration electricity storage we need as part of the country’s future energy mix. With up to 25GWh of storage capacity, the scheme would be capable of powering 90,000 homes for an entire week, so bolstering our energy security and providing the balancing flexibility we need in a renewables-led energy system.
“The development of pumping capability at Sloy also complements our development plans for our other pumped hydro storage project at Coire Glas. Taken together and if approved for delivery, Coire Glas and Sloy can treble Britain’s current flexible electricity storage capacity. That’s why it’s crucial the UK Government urgently confirms its intention on exactly how they will help facilitate the deployment of pumped hydro storage projects as part of our future energy mix.”
