In partnership with the University of Greenwich and the University of Exeter, UK-based RheEnergise has secured a grant of £1 million ($1.2 million), funded through the Net Zero Innovation Portfolio (NZIP) as part of the UK Government’s Energy Entrepreneurs Fund (EEF).

The government grant will fund work to identify and test waste materials (such as tailings) that could be used in the high-density fluid (HDF) that is integral to RheEnergise’s grid-scale High-Density Hydro® energy storage system, which RheEnergies says is an environmentally-benign alternative to water.

RheEnergise’s long duration storage system is low-cost and energy efficient, the company states. The fluid used in the system is two-and-a-half times denser than water (similar in viscosity to cream) and is therefore able to provide two-and-a-half times the power and two-and-a-half times the energy when compared with conventional low-density hydro-power systems that rely on water and operate in the Scottish Highlands, Wales and across Europe. It means that RheEnergise can deploy its long duration energy storage system beneath the surface of hills rather than mountains, so opening up massive commercial opportunities in the UK, Europe and further afield. There is very real potential for RheEnergise’s storage system to be deployed in operating mines and quarries, the company says.

The research project, funded by the UK Department for Energy Security & Net Zero, wants to identify suitable minerals and waste streams that can be recycled into the high-density fluid which can be locally sourced and are lower cost, rather than having to rely on minerals imported from overseas.

Stephen Crosher, Chief Executive of RheEnergise, says: “The opportunities presented by the EEF grant are phenomenal. We are delighted to be able to lead and partner with two outstanding universities – Greenwich and Exeter. The project has the potential to solve three huge questions that affect people daily and globally: those of climate change mitigation, delivering firm power supply from renewables and how to use waste from other industries for new purposes, creating truly circular economies.

“The government grant, from the Department for Energy Security & Net Zero, will help us to cut the operating cost of our hydro energy storage system, whilst increasing its sustainability. By using locally sourced waste materials, we can lower the costs of our projects, reduce carbon emissions from transportation and processing and create a new circular economy where none currently exists.

“Working with colleagues from Greenwich and Exeter Universities, our research team will be closely examining waste and tailings from various sources but in particular from mines and quarries. There is also the potential that operating mines and quarries, which by their very nature have high elevations and are high energy users, could use our energy storage system.”

Later this year, RheEnergise will start work on building a 250 kW/1 MWh (four hours) demonstrator of its High-Density Hydro energy storage system at a site near Plymouth, UK, and is planning to have its first 5 MW grid-scale project in commercial operation within the next 3-5 years.