British startup plans to turn hills into enormous batteries

British startup plans to turn hills into enormous batteries
RheEnergise High-Density Hydro simple diagram. Credit: RheEnergise

Hundreds of hills across the UK could be used to provide the UK’s energy system with a new long-life source of underground hydro-powered energy storage.

A team of British engineers from the startup, called RheEnergise, has invented a low-cost, energy-efficient, and environmentally-benign energy storage solution – High-Density Hydro – that utilizes the gravity of hills. The system utilized one of the oldest forms of energy storage, hydropower plant that pump water up mountains when energy is cheap, and then release it when needed to spin turbines and generate more electricity.

While the huge dam needed for hydropower plants can take a decade or even longer, the new system can be built on relatively small hills, making it feasible in a larger range of areas. The HD Hydro system has less impact on the environment and will be faster to build and easier to maintain, and therefore lower cost.

Instead of using water, the High-Density Hydro system uses a special fluid, called High-Density Fluid R-19, that is 2½ times denser than water. This means it can store the same amount of energy as water on a smaller hill. It can provide 2½ the power and energy when compared to a conventional low-density hydropower system.

The liquid is pumped uphill between storage tanks that are buried underground. The storage tanks are connected by underground pipes, meaning a RheEnergise HD Hydro system can operate beneath small hills rather than mountains. It requires 2½ less vertical elevation. It, therefore, means that there are many more sites suitable for RheEnergise projects – in the UK and across the world.

The startup claims that this breakthrough could allow around 700 sites across the country to play host to their high-intensity hydro projects, which in theory could create a total of 7GW of energy storage to help the UK use more renewable electricity.

We offer a neat, low-cost, zero-carbon, and scalable solution to meet the energy storage needs of this country and across the world,” said Stephen Crosher, Chief Executive of RheEnergise. “Energy storage, like our HD Hydro system, will enable the increased deployment of wind and solar generation to achieve the energy transition; renewables, being intermittent, requires flexible, efficient, and low-cost storage solutions. Our HD Hydro system offers exactly that. We all know that HD TV is much better than conventional TV, it’s the same with HD Hydro, much better, in fact, 2½ times better.

The technology has the potential to give the many abandoned mines in the north of the United Kingdom a renewable energy-focused new lease of life. According to Fast Company, the startup recently mapped out 9,500 sites in the UK with hills that are ideal for accommodating the technology. RheEnergise is currently undertaking its first successful crowdfunding campaign to fund the next phase of its work. They said the technology could be months away from being installed in one of the sites they have pinpointed.