A U.K.-based clean energy company has devised an inexpensive, energy efficient and environmentally friendly energy storage solution that uses pumped-hydro technology in conjunction with a denser flow of liquid to manufacture energy.

According to RheEnergise, its High-Density (HD) Hydro technology could be used on hillsides throughout the U.K., offering the country’s energy system a new source of underground hydro-powered energy storage.

In lieu of water, RheEnergise has created a fluid called R-19, a substance that is 2.5 times denser than water and that offers more than double the energy than current low-density hydropower systems operating throughout Europe, the Scottish Highlands and Wales.

The process includes the pumping of non-corrosive R-19 uphill between storage tanks during low energy demand scenarios and their associated low prices. In the event that energy demand increases, the R-19 is released downhill, traveling through turbines to produce electricity and supplying power to the grid.

RheEnergise chief executive Stephen Crosher said: “Energy storage, like our HD Hydro system, will enable the increased deployment of wind and solar generation to achieve the energy transition [as] renewables, being intermittent, require flexible, efficient, and low-cost storage solutions.

“Flexible technologies like HD Hydro will form part of the U.K.’s smart electricity grid, supporting the integration of more low-carbon power, heat and transport technologies, which BEIS [the Department for Business, Energy and Industrial Strategy] estimates could save the U.K. energy system up to £40bn by 2050.”

The RheEnergise HD Hydro system solution reportedly operates underneath smaller hills instead of mountains — which is contrary to traditional pumped-hydro energy storage — requiring vertical elevations of just 100 m or less to both store and release energy.

According to RheEnergise, HD Hydro associated projects could include anywhere from 5 MW to 100 MW of power, can be connected to existing grid infrastructure and could work in concert with other renewable energy projects.

While currently conducting its first crowdfunding campaign via the Crowdcube platform to fund the construction of a proposed 500 kW test rig at Cumbernauld, in Scotland’s Central Belt, RheEnergise also plans to have its first operational commercial system in 2024 and roughly 100 more systems operating within the next 10 years.