Pumped hydro energy storage facility approved in North Wales

A Welsh company has been given the green light to develop the UK’s first grid-scale electricity storage facility in a generation.

Snowdonia Pumped Hydro (SPH) announced last week that it has received planning permission from the UK government to turn the quarries at Glyn Rhonwy near Llanberis in North Wales into water reservoirs that will store around 700 MWh of electricity. That’s enough to supply 200,000 homes with electricity for seven hours a day over a projected operational lifetime of 125 years or more.

The £160m project will use surplus electricity, for example from wind and solar sources, to pump water through an underground tunnel from the lower to the upper reservoir. The water is stored until the power is needed – at peak times to meet spikes in consumer demand, or when lack of wind or sunshine reduces renewable power output, or when fossil fuel generators fail to start.

The water then flows back down the tunnel, spinning a turbine in an underground chamber to regenerate the stored electricity at a power output of 99.9 MW.

There are currently four pumped hydro storage sites in the UK, the youngest of which was built more than 30 years ago.

But it’s thought that many more sites could be used. SPH has shown energy civil servants how the UK could build some 50 GWh of pumped hydro storage using unconventional sites like ex-industrial quarries, coastal locations and existing drinking water reservoirs.

“There are signs that the government is taking storage seriously,” commented SPH managing director Dave Holmes. “The National Infrastructure Commission last year urged swift action on storage, and a team inside the Department of Business, Energy and Industrial Strategy is looking urgently at how planning barriers and market disincentives to storage can be addressed. 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.”

Over 90% of the world’s electricity storage uses pumped hydro, according to SPH.

Explaining the benefits of pumped hydro over Lithium-ion batteries, Holmes said: “Glyn Rhonwy can be expected to deliver around 32 million MWh over its lifetime. An equivalent 700 MWh Lithium-ion installation would deliver just 2.1 million MWh before needing its batteries replacing. This means electricity delivered by pumped hydro is 20 times cheaper per MWh than Lithium-ion batteries over its lifetime, and carries less environmental baggage.”

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