SLOW action from the UK Government is “preventing” essential Scottish renewables projects from moving forward, Humza Yousaf has said in a letter to the Prime Minister.

The SNP leader told Rishi Sunak that the lack of a market mechanism to support the growth of pumped-storage hydro meant that projects which had already secured planning permission had stalled.

Yousaf called for change as he said that pumped-hydro storage is the only major form of renewable energy generation which is not currently eligible for UK Government support.

READ MORE: Scottish renewable power 'utterly wasted' as wind farms paid to shut down

The First Minister’s intervention comes after a report commissioned by Scottish Renewables and published earlier in May identified six “shovel-ready” pumped-storage hydro projects across the country.

The report said the projects could deliver almost 15,000 jobs and generate up to £5.8 billion for the UK economy by 2035, if the UK Government would “deliver the measures it has promised to enable investment in large-scale, long-duration energy storage”.

Pumped-storage hydro power uses excess electricity generated during times of high supply and low demand to move water from a low elevation to a higher one.

Later, if the wind is not blowing or sun not shining, then the water can be released to flow back down to a lower elevation, turning a turbine and generating electricity as it goes.

Such projects are seen as essential to a stable renewable energy network as they can help compensate for the variable output from sources such as solar and wind.

Currently, instead of the excess power generated by Scottish renewables projects being stored for future use, wind farms are paid millions of pounds to shut down and not provide energy to a National Grid which cannot cope.

In 2020 and 2021, a total of £806 million in such “curtailment costs” was paid to wind farms. A total of 82% of that was paid out to generators north of the Border.

In his letter to Prime Minister Sunak, Yousaf said: “While additional deployment of renewables will play an important role in lessening dependence on fossil fuels for electricity generation, large-scale, long-duration energy storage is also absolutely critical to achieving our collective goals.

READ MORE: Richard Murphy: The way to win independence? Removing people’s worries over money

“It can help to integrate and maximise our significant renewable electricity generating capacity, ensure security of supply and manage constraints across the grid.

“With this in mind, I am calling on the UK Government to support the development of long-duration energy storage (including pumped hydro storage) through an appropriate market support mechanism.”

The UK currently has four pumped-storage hydro facilities, which were all commissioned between 1963 and 1984. They have a combined capacity of 2.8GW.

The six “shovel-ready” Scottish projects identified by the May report could more than double this capacity to 7.7GW.

The National: Map showing the approximate locations of the six 'shovel-ready' pumped-storage hydro projects slated for ScotlandMap showing the approximate locations of the six 'shovel-ready' pumped-storage hydro projects slated for Scotland (Image: Google/NQ)

A market system which provided a minimum guarantee of revenue would allow several such projects which have already secured planning permission to go ahead, the First Minister argued.

He also said that the UK Government should accelerate the consenting process for large grid projects.

Yousaf’s letter went on: “A UK Government consultation in 2022 identified pumped hydro storage as the most well-established large-scale, long-duration electricity storage technology in the UK.

“It also committed to develop appropriate policy to support investment and ensure the deployment of sufficient large-scale, long-duration energy storage to balance the overall electricity system by 2024.

“I am concerned that slow action in this area is dampening investor confidence and preventing projects that are essential to the joint goals of our governments from coming forward.”

READ MORE: 'Mind-boggling' UK Government silence as Scottish renewables industry urges action

Tory ministers Andrew Bowie and John Lamont have both come under fire in recent weeks for their apparent “ignorance” of pumped-storage hydro.

Despite the technology dating back decades, Lamont referred to it as “new” in the Commons, while Bowie suggested hydro was “nascent” at a Scottish Parliament committee meeting.

Bowie further told that hearing of the Holyrood Net Zero Committee in late April: “Discussions are on-going right now between officials at the Department for Energy Security and Net Zero and Treasury colleagues as to how best we can create a framework to deliver hydro technology to market.

“The discussions are at an early stage, and I do not foresee that any announcement will be made in the immediate future, but they are under way.”

The Economic Impact of Pumped Storage Hydro report commissioned by Scottish Renewables was jointly funded by Buccleuch, Drax, Foresight Group, Intelligent Land Investments (ILI) Group, and SSE Renewables. Those firms all have pumped-storage hydro projects in Scotland that they are keen to break ground on.

The National:

The first project slated to come online is ILI’s Red John, which is planned for the northern end of Loch Ness. It should be running by 2027.

The final project identified in the report is also ILI’s. At Balliemeanoch in Argyll and Bute, it is slated to come online in 2034.

SNP MP Philippa Whitford, who raised the issue of pumped-storage hydro with Lamont in the Commons last week, previously told The National: “The UK Government’s not invested enough in energy infrastructure or this, which is energy security. That’s what I don’t understand. If you don’t start now then the dates about when they’re expected to come onstream just won’t be happening.”

The UK Government has been approached for comment.