SSE’s £100 million investment advances a massive hydro project that would quadruple the UK’s ability to store energy for extended periods.

The projected 92-meter-tall dam and two reservoirs at Coire Glas in the Highlands would be the largest hydroelectric project in Britain in the past four decades.

In 2020, the Scottish government authorized the 1.5 GW pumped storage facility.

However, the energy company SSE requires assurances from the British government before approving the project. The Department for Energy Security & Net Zero is “committed to supporting the low carbon hydro sector, including hydro storage,” according to a spokeswoman. Perth-based The £1.5 billion plan, according to SSE, would help combat climate change and increase energy security in the UK.

The Coire Glas concept is straightforward. It involves two reservoirs at various elevations in the Great Glen, a geological fissure that cuts through Scotland from Inverness to Fort William.

When electricity is abundant and inexpensive, water would be pumped 500 meters uphill for storage in an upper reservoir with a capacity of 11,000 Olympic-sized swimming pools.

When supply is low and costs are high, the water would be released and used to create energy by spinning four turbines far down on the borders of Loch Lochy before pouring into the lower reservoir.

Coire Glas could assist in easing the transition from oil, gas, and coal to renewable energy sources such as wind and solar by storing electricity generated during windy or sunny weather for use on cold, calm, or dark days. SSE’s head of onshore renewables, Finlay McCutcheon, stated, “We believe it could play an enormous role in enabling a decarbonized energy system.”

Professor at Strathclyde University, Keith Bell, stated: “the proposed scheme would help with another policy objective: reducing the UK’s reliance on imported gas.” Prof. Bell noted caution: “We need much more energy storage capacity to eliminate fossil fuels… probably 10 to 50 times greater than Coire Glas’s capacity.”

It would be the largest hydro system in the United Kingdom since the “Electric Mountain” project was finished at Dinorwig in Snowdonia in 1984 and one of the greatest engineering projects ever undertaken in the Highlands, producing up to 500 construction jobs at its peak.

After First Minister Nicola Sturgeon expressed concern about fresh North Sea drilling in the context of achieving Scotland’s goal of net zero greenhouse gas emissions by 2045, the pace of the energy transition has been a topic of discussion in the current campaign for the SNP leadership.

Mr. McCutcheon of SSE stressed that the UK government should support the strategic development of hydro capacity.

During an “energy crisis” in the UK and Europe this winter, he stated that the company’s current assets were “absolutely crucial” for keeping the lights on.

Mr. McCutcheon stated that despite the mild weather, “our existing pumped storage has never been used so intensively.”

The only other pumped storage facility in Scotland, run by Drax Group, is contained within a massive artificial cavern within Ben Cruachan on the Argyll shore of Loch Awe. With the development of a new underground power plant, the North Yorkshire-based company wants to more than double the production capacity of its facility, Hollow Mountain, to more than 1GW.

But both Drax and SSE have been hesitant to proceed without Whitehall assurances.

Mr. McCutcheon indicated that SSE needed clarification on how the UK government will assist projects like Coire Glas.

Last year, this was a crucial component of their energy security policy, but we need to see how it will work in practice. He continued, “There is no need for subsidies, but the investments are enormous.”

SSE desires a commitment to a revenue stabilization mechanism and additional assurances regarding how the regulated energy market would reward zero-carbon power generation. Prof. Bell of Strathclyde University said the Climate Change Committee had published a report this month requesting greater transparency from ministers.

The Department of Energy and Net Zero spokeswoman acknowledged that hydro would be “crucial in delivering greater energy security and independence and our net zero goals.”

“By 2030, we will support up to 480,000 well-compensated green jobs and leverage up to £100 billion in private investment in low-carbon technologies, including storage.” They noted that this would increase our energy security and ensure that our wholesale electricity rates are among the lowest in Europe.

SSE anticipates making a final investment decision in 2019. If implemented, completion is anticipated in 2031.

Coire Glas, when operational, could reach full generating capacity in less than 60 seconds, allowing for rapid flexibility in the event of a power outage elsewhere on the national grid.

Alternately, at a more sustainable level of operation, Coire Glas could power three million homes for up to twenty-four hours. The announced £100 million expenditure by the FTSE 100 corporation would be used for exploratory work, including constructing a four-meter-wide tunnel about one kilometer into the hillside to investigate the location’s geology.

The investment in Coire Glas coincides with the 80th anniversary of the Hydroelectric Development (Scotland) Act of 1943, which nationalized the industry and led to the construction of over 50 dams. Tom Johnston, a visionary Labour politician, was the main force behind the expansion that brought power and jobs to the glens, drastically enhancing the quality of life in rural Scotland in the postwar years.

It’s incredible how this old technology is now required anew, but for different reasons.

Historically, pumped hydro schemes were indispensable when everyone required electricity at once. Thirty million viewers witnessed Dirty Den serving his wife Angie with divorce papers on the Christmas Day episode of EastEnders in 1986. Most wanted a cup of tea to relax when the credits rolled. All those kettles generated an enormous demand for electricity, at which point our pumped hydro plants opened their sluice gates.

This occurs less frequently now due to changing TV viewing habits, and this type of technology will address supply peaks and valleys rather than demand fluctuations.

In 15 years, when we are nestled into bed on a windy night, it will give a place for the excess energy to be stored for use when we awaken.