Devon Hillside 'Battery' Powers 400 Homes With New Tech

A hillside outside Plymouth just became a giant battery, proving that one of the world's oldest power sources can work in places we never thought possible.

Engineers at RheEnergise have successfully fired up the UK's first "high-density" hydropower system, generating enough electricity to power 400 homes. The secret? A mineral-rich fluid that's more than two and a half times denser than water, meaning gentle slopes can do the work that once required towering dams and steep mountains.

Traditional hydropower plants pump water uphill when electricity is plentiful, then release it through turbines when the grid needs power. This new system works the same way, but the denser fluid creates equal power from slopes less than half as high. That opens up thousands of potential sites across the UK and around the globe.

Chief Executive Stephen Crosher says the demonstration project consistently hit its target of 500 kilowatts, giving the team confidence to scale up. The company is now in talks with developers in Italy, Poland, Spain, and North America to build the first commercial-scale projects within three years.

The timing couldn't be better. As wind and solar farms multiply across the UK, the grid increasingly needs ways to store extra power when the sun shines and wind blows, then release it during calm, cloudy periods. Without storage, grid operators sometimes pay renewable farms to shut down when they're producing too much electricity.

The UK government has committed over £69 million to develop long-duration storage solutions like this one. Officials believe technologies that can store clean energy for extended periods will reduce both carbon emissions and the cost of reaching net zero.

The Ripple Effect

This Devon hillside represents more than one successful project. By eliminating the need for mountains and massive infrastructure, high-density hydro could transform energy storage from a geography problem into a geography opportunity. Countries without dramatic elevation changes could finally harness hydropower's reliability.

The underground design also means faster, cheaper construction compared to traditional dams. Projects could be embedded into existing hillsides near cities and towns, bringing energy storage closer to where people actually use electricity.

Minister Patrick Vallance praised the innovation as essential for managing growing energy demand while transitioning to clean power. The technology gives grid operators a new tool for balancing renewable energy's natural fluctuations without falling back on fossil fuels.

RheEnergise expects to partner with major utilities throughout the 2030s as renewable energy becomes the dominant power source and long-duration storage becomes increasingly valuable. The Devon project proves the concept works, and now the race is on to scale it up worldwide.