A SCOTS company behind pumped storage hydro schemes has praised the latest figures for onshore wind power generation, but claimed a “green ceiling” on renewable generation will have to be addressed to ensure that net-zero targets are met.

The ILI Group said the latest figures for the first six months of this year showed Scotland generated enough electricity through onshore wind power to supply 4.47 million homes – double the number of households in Scotland.

It said the “exciting” figures showed onshore wind power in Scotland was helping the whole of the UK to hit its clean generation targets.

The Scottish Government has committed to reaching net-zero – the point at which the same volume of greenhouse gases is being emitted as is being absorbed through offsetting techniques such as forestry – by 2045.

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ILI Group’s CEO Mark Wilson said: “These new figures reflect the scale of delivery by Scottish onshore wind, and will increase as new developments go ahead.

“However, they can also be misleading since there is currently a ‘green ceiling’ to the amount of renewable generation that the power network can accommodate.

“As new renewable generation goes online and older coal, gas and nuclear plants contribute less, this leaves us increasingly dependent on intermittent renewable power that cannot be scheduled to meet demand or lack of it, to fill this gap.

“The missing link is energy storage on a scale that was unimaginable only 10 years ago.”

Wilson added: “Our own company’s 2GW of planned pumped storage hydro schemes in Scotland can go a long towards filling this gap and along with hydrogen and battery technologies will help ensure the transition to net-zero electricity generation.

“They will offset millions of tons of CO2 emissions and will also bring billions of pounds of investment to Scotland; creating hundreds of new green jobs which, disappointingly, has not been the case so far with other renewable energy developments.”

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Pumped storage hydro schemes allow the National Grid to store energy that cannot be absorbed by consumers during times of peak wind or solar power generation.

This is done by using this spare energy to pump water from a lower reservoir to a top reservoir.

The water can then be held until times of higher demand for energy when it is released to the lower reservoir through turbines generating electricity like a conventional hydro plant.

Its advocates describe it as essentially “a giant water battery”.

Brian Wilson, a former UK energy minister, said system could give hydro power in Scotland a new lease of life.

He said: “It becomes a bit repetitive to hear about the numbers of homes powered by windfarms without any reference to security of supply and the means of ensuring it.

“That is now where there is huge potential for Scotland because of our natural assets.

“One way or another, there has to be back-up and therein lies the huge opportunity for UK industry.

“Pumped storage hydro – which provides 95% of storage around the world – is the obvious answer instead of over-relying on imports via interconnectors.

“Hydro power has served Scotland exceptionally well in the past and can do so for many years to come.

“This is an opportunity to give an established technology a new lease of life with huge potential benefits for the Scottish economy while at the same time helping to solve the inescapable challenges posed by the growth of renewables.”

ILI Group already has more than 2GW of pump storage hydro in the pipeline with its first 450MW development, Red John at Loch Ness, which is currently going through the planning stages.

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