A TECHNOLOGY first used more than 100 years ago and which has been likened to a “huge, infinite battery” could help Scotland achieve its climate ambitions.

As renewable sources play an increasingly important part in our energy mix, the problem has been a shortage of storage for generated power, which has led to claims of wind-farm operators being paid millions of pounds to switch off turbines.

However, Mark Wilson, CEO of Intelligent Land Investments Group (ILI), said pumped storage hydro (PSH), where energy is stored as water, could solve the storage problem, as well as cutting carbon emissions.

PSH uses an upper and a lower reservoir. In daytime, water drops through tunnels to the lower level, driving hydro turbines to generate electricity. At night, cheap electricity is used to pump the water back to the higher level.

ILI is involved in three applications for PSH developments at Loch Ness, Loch Tay and Loch Awe. Wilson told the National: “It is a very simple process ... at time when energy would not get used and would go to waste, or when wind turbines have to be switched off and developers paid, the energy is used to pump the water back up to the top head pond to be used when necessary.

“It’s seen as a huge, infinite battery, but unlike a battery that loses efficiency when it is charged and recharged, that doesn’t happen.

“This is energy that you can get simply by hitting a button – you can’t do that with wind and solar.

“These projects will allow us to do that because the energy will be stored until it’s needed.”

The technology is being widely used globally, but Wilson said the UK was only now beginning to catch on.

“Each of these will cost approximately in excess of £500 million with a five-year lead time to build them, so that would answer why they haven’t been built. But with other sources being closed down through government policy they are now becoming essential. The three projects we’re building will offset carbon emissions by over a million tonnes per annum.

“There’s one in Switzerland that’s been going for over 100 years, one in Oban has been working for 50 years.

“So it’s a proven technology right on Scotland’s doorstep.”

Dr Richard Dixon, director of Friends of the Earth Scotland (FoES) said PSH was becoming increasingly important.

“Pumped storage is a vital asset for the electricity grid and is even more important today than in the past because it is so good at supporting renewables like wind power,” he said.

“The UK Government needs to recognise the potential for more low impact but high power pumped storage schemes in Scotland and ensure the structure of electricity payments is changed to support their construction.”

Scotland’s Energy Minister, Paul Wheelhouse, said: “Pumped Hydro Storage is a tried and tested technology that performs a vital role in providing both grid scale storage and in balancing demand and supply at peak times and can play an important ‘black start’ role in re-energising the grid following an outage.  

"Scotland’s Energy Strategy makes clear our view that Pumped Hydro Storage has a key role to play now and in the future in enhancing energy security, providing local jobs and helping integrate renewables on to the network. 

“Scotland’s existing Pumped Hydro Storage fleet makes up the vast majority of capacity within the UK, and is a highly complementary technology for Scotland’s growing renewable energy capacity, in enabling storage of energy that can be released to generate electricity at times when renewable energy output is high, but demand is low. 

“With further very significant capital projects proposed for development in Scotland, all that is missing is for UK Ministers to finally heed our repeated calls for a ‘route to market’ for pumped hydro that gives some price stability for investors and enables construction of consented projects, thereby significantly enhancing system security.”

Mark Ruskell, Scottish Greens climate and energy spokesperson, said: “Scotland has a proud history of hydro power and we should be exploring every option in our journey to build a carbon-neutral economy.

“Each application should of course be subject to assessment but there’s no doubt that we have the potential to use our natural resources and skilled workforce to capitalise on the renewable technology revolution.

“We need to see a transformation in the energy system and storage will be increasingly important as we substitute fossil fuels for renewables.”

Fabrice Leveque, from Scottish Renewables, added: “Scotland’s plentiful rainfall can dampen spirits, but it acts as one of the country’s best renewable energy resources, utilised by one of our most popular, well-established green energy technologies – hydro. Scotland’s landscape also has many suitable locations for large pumped storage hydro projects so it’s excellent to see such a strong pipeline on the horizon.”