IT is “mind-boggling” that the UK Government has not delivered on its own promises to support the delivery of key renewables projects in Scotland – despite calls from the industry, the SNP has said.

It comes after a report commissioned by Scottish Renewables concluded that six “pumped-storage hydro” energy projects north of the Border could create 15,000 jobs and generate billions for the economy.

In the wake of the report, which was published on Thursday, the renewables body called on the Tory government to “urgently deliver the measures it has promised to enable investment in large-scale, long-duration energy storage so developers can deliver the existing pipeline of ‘shovel ready’ pumped-storage hydro projects”.

Pumped-storage hydro is a type of renewable energy that uses surplus created during times of high supply to fill in the gaps during times of low supply.

In a simple example, two reservoirs at varying elevations would be used. At times of energy surplus, excess is used to pump water up from the low ground.

When energy production is low, water is released to the bottom reservoir, turning a turbine as it goes to produce power and plug any gaps in the renewable system.

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 offshore wind.

However, the UK has just four pumped-storage hydro facilities, which were all commissioned between 1963 and 1984.

There are six new projects slated for Scotland, which could more than double the UK’s current pumped-storage hydro capacity from 2.8GW to 7.7GW.

The National:

Andrew MacNish Porter, policy manager for economics and markets at Scottish Renewables, said pumped-hydro storage was “an established and proven technology” that could deliver “socio-economic benefits to communities across the UK”.

But he went on: “However, an investment framework is needed to secure the massive capital investment required for these projects. We therefore urgently need the UK Government to clarify its support for pumped-storage hydro and deliver the required policy support to unlock the huge value these projects promise to deliver.”

SNP MSP Emma Harper told The National: "Scotland has vast renewable energy resources that can help us meet our world leading climate targets whilst becoming a powerhouse of green growth – and pumped-storage hydro must play a key part in meeting this ambition.

"It is mind-boggling that the Tory Westminster government continues to refuse to invest in sustainable energy projects across Scotland, like these projects that would more than double the UK’s pumped-storage hydro capacity, create almost 15,000 jobs, and generate up to £5.8 billion for the UK economy.

“Time and time again Scotland is being let down by nonsensical Westminster decisions that ignore our potential and our interests, proving beyond a doubt that only with the full powers of independence can so we make the most of Scotland's huge green energy potential."

And the Greens said the problems went far deeper than the Tory government’s refusal to engage with specific projects.

READ MORE: Six Scots renewables projects to deliver 15,000 jobs – if UK steps up, report says

Mark Ruskell MSP said: "At present, so many of the most important powers lie with a climate-wrecking UK Government that is doubling down on nuclear energy and planning for over 100 new oil and gas licences. It's not just about a failure to support specific projects, it's their entire approach to energy policy that needs to change.

"Over recent months we have made important progress in Scotland, but there is still far more to do, and time is not on our side.

"We have the potential and the skills to be a powerhouse of clean and green energy. We must seize the opportunity and break with the failed policies of the past and the damaging approach of fossil-fuel addicted governments like the UK."

The UK Government did not respond to The National’s request for comment.

The report, called The Economic Impact of Pumped Storage Hydro, was put together by BiGGAR Economics and commissioned by Scottish Renewables.