Drax Group, a 3,400-employee clean energy company, has the Scottish government's go-ahead to build out a 500-million-pound (roughly $630 million) "water battery."
The underground pumped storage hydro plant could be a game changer for housing renewable energy in Scotland. It's also part of a plan to strengthen the UK's power grid, officials said in a project summary.
"Hydropower has real potential to play a greater role in our transition to net zero, and to help ensure a resilient and secure electricity supply across the U.K.," Scotland's First Minister Humza Yousaf said in the Drax report.
The project, which is still in early development stages, leverages the power of the wind, water, and gravity to make and store energy. The system could also be used to store solar power.
Water batteries include two reservoirs, with one positioned above the other. When renewable energy sources (in Scotland's case, wind turbines) are producing more power than needed, the extra juice pumps the water into the top reservoir. And, thanks to the power of gravity, the stored water is kept as "charged" energy.
When the grid needs a boost, the water in the top reservoir can be released to the bottom one, turning a turbine and creating electricity, per the U.S. Department of Energy's description of the process. The Scotland project will use a reversible turbine to move the water between reservoirs.
Water batteries are an effective way to solve renewable energy's notable storage conundrum, providing a reliable alternative to lithium-ion batteries, which are costly and difficult to mine.
"These plants play a critical role in stabilizing the electricity system, helping to balance supply and demand through storing excess power from the national grid," Drax CEO Will Gardiner said in the company's report.
The 600-megawatt plant will be located at the "Hollow Mountain" of Cruachan Power Station, in a scenic, mountainous area with a long history of hydropower. The new, underground hydro-storage project would bring the site's overall power capacity to more than a gigawatt, Drax officials claim.
To put that into perspective, a gigawatt is equal to the power of about 1.3 million horses. Around the house, a gigawatt represents the power needed for 100 million LED lights, according to the U.S. Office of Energy Efficiency & Renewable Energy.
This office also has a list of benefits Scotland should realize as part of this unique project. The U.S. has 18 states using water batteries, with more on the way. They are ready for service during periods of heavy usage, like during heat waves. The systems are highly efficient, at 70-80%.
In Scotland, Drax and government officials are still working out the market details to bring this project online. However, they are planning for the water to be flowing by 2030, employing nearly 1,000 people and helping to power Scotland and its neighbors more cleanly.
"The Scottish Government will continue to urge the U.K. government to provide an appropriate market mechanism for hydropower," Yousaf said in the Drax report.
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