Glyn Rhonwy Pumped Storage

The Glyn Rhonwy Pumped Storage scheme has been designed to bring new life to two dis-used slate quarries in the slopes of Cefn Du mountain in the Dyffryn Peris valley approximately 1.5km north west of Llanberis and 11km south east of the town of Caernarfon. The scheme will utilise two disused slate quarries; Glyn Rhonwy and Chwarel Fawr.

Changes to the Glyn Rhonwy scheme

The decision to apply for the change has been reached after talks with the Department of Energy and Climate Change, and with potential construction company partners. Britain’s energy needs have evolved since the scheme was designed and the government has included storage within the 2014 Electricity Market Reform Act with the aim of helping to ensure that Britain does not suffer blackouts.

The higher output will enable the Glyn Rhonwy facility to enable play a larger role in the new market, making it even more useful in balancing supply and demand as the percentage of renewables supplying power to the UK’s electricity grid continues to increase. The facility is expected to achieve carbon payback in around six months.

Is the revised scheme really going to look just the same?

Yes. Nothing above ground would change. For more information about how this is possible, please visit Glyn Rhonwy Scheme Features.

If nothing above ground will change, why is it necessary to apply again for planning permission?

The planning system treats a pumped storage scheme such as that at Glyn Rhowny in just the same way as a conventional power station – even though the two types of facilities are self-evidently very different.

Under current planning law installations under 50 MW in output are determined by the relevant local authority, while those with outputs larger than 50 MW are determined by the UK Planning Inspectorate. The development will constitute a Nationally Significant Infrastructure Project (NSIP) under the Planning Act 2008 and SPH must apply to the Secretary of State for Energy and Climate Change for a Development Consent Order (DCO).

With construction work due to begin at the site next year, the application to amend the output of the scheme is being made to the UK Planning Inspectorate.

Gwynedd Council, along with other local stakeholders that also gave their assent to the original scheme, will be the Planning Inspectorate’s primary consultees.