Snowdonia Pumped Hydro (SPH) is set to begin construction of a £160m grid-scale electricity storage facility as early as next year.
The development follows receipt of planning permission for the energy storage scheme from the UK Government.
The government has granted permission to transform two abandoned slate quarries at Glyn Rhonwy near Llanberis in North Wales into water reservoirs to help store approximately 700MWhs of energy.
SPH's managing director Dave Holmes said: “We see the grant of permission for our Glyn Rhonwy scheme as highly significant, signalling a real change that will enable the UK to meet carbon reduction targets while keeping electricity supply secure and prices for consumers under control.”
The power stored would be sufficient enough to provide electricity to 200,000 UK households for seven hours every day over a projected operational lifetime of 125 years or more.
Holmes added: “Glyn Rhonwy can be expected to deliver around 32 million MWh over its lifetime. An equivalent 700MWh Lithium-ion installation would deliver just 2.1million MWh before needing its batteries replacing.
“This means electricity delivered by pumped hydro is twenty times cheaper per MWh than Lithium-ion batteries over its lifetime and carries less environmental baggage.”
The SPH electricity storage facility will use excess energy generated from power plants, such as from wind and solar sources, to pump water through an underground tunnel from the lower to the upper reservoir.
When lack of sufficient wind or sun reduces generation, or when fossil fuel generators fail to start, the water will flow back down the underground tunnel and spin a turbine to regenerate stored energy at a power output of 99.9MW.