By Nneka Nwogwugwu
A team of engineers have developed a system that adapts one of the oldest forms of energy storage, hydropower, to store and release electricity from gentle slopes rather than requiring steep dam walls and mountains.
The engineers discovered that hundreds of hills across the UK could be transformed into renewable energy “batteries” through a pioneering hydropower system embedded underground.
According to them, the discovery could unlock hundreds of potential hydropower sites across the UK, which would be quicker and cheaper to build than traditional hydropower dams and also lead to fewer negative environmental impacts.
RheEnergise, the company who innovated the project, said the project would pump the dense fluid up a hill with a height of 200 metres, at times of low electricity demand. It would be held in an underground storage tank larger than an Olympic-size swimming pool.
The company which released a recent report on Energy storage on its Twitter handle, also stated that the hillside projects would mimic the UK’s traditional hydropower plants by using surplus electricity to pump water uphill and later releasing the water back down the hill through turbines to generate electricity when needed.
The chief executive of RheEnergise, Stephen Crosher said its high-intensity hydro projects could be built in one to two years, quicker than traditional hydropower projects, which take between five to 10 years to construct and require high levels of financing. He hopes to build the first plant in mid-2023 and has begun crowdfunding the cash to pay for the pilot.
“But the ‘high-intensity’ hydro projects use a mineral-rich fluid, which has more than two and a half times the density of water, to create the same amount of electricity from slopes which are less than half as high.
“Then when extra electricity is required, the fluid would be allowed to flow back down the hill, over generating turbines, to effectively return the electricity used by its pumps earlier in the day back to the grid,” Crosher noted.
RheEnergise 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.
The UK is expected to need around 13GW of flexible clean energy generation and storage to help balance the electricity grid by the end of the decade, according to a report by Aurora Energy Research.
“RheEnergise would begin building projects of about 10MW at disused mines and quarries, but it could also locate the projects near wind and solar farms and bury the system in hillsides to reduce their visual impact,” he said.