Plans for a pumped storage scheme in Gwynedd, Wales, have taken a major step forward with news that developer SPH has been granted planning permission for an underground grid connection for the Glyn Rhonwy facility.

The decision by Gwynedd Council’s planning committee means SPH can feed power generated by the 99.9MW, 700MWh facility into the North Wales electricity grid via a buried cable, overcoming any fears by opponents of the scheme that pylons would be used.

“For us it’s a case of delivering on what we always said we would do,” said SPH managing director Dave Holmes. “The approval by the council of our chosen connection route finally puts the issue to bed.”

The cable will be buried in a narrow trench, primarily in the verges of the road network, with the surface reinstated as cable laying progresses along the route. At Afon Rhythallt the cable will be carried within the road bridge if a structural survey shows it is suitable, or taken several metres under the river bed by the technique of horizontal directional drilling. Laying of the cable is expected to take around 12 months.

The Glyn Rhonwy scheme already has planning permission at an output of 49.9MW, but a decision to install higher output underground turbines meant SPH had to re-apply for permission to build the scheme, even though other key design details remain unaltered. Examination of the revised scheme by the UK Planning Inspectorate closed at the beginning of September and a final decision will be made by the UK Secretary of State by early March 2017.

“In the meantime we are continuing to make progress,” said Holmes. “We’re working on the few remaining outstanding consents, fine-tuning the construction timetable and liaising with potential equipment and services suppliers so that we are poised to move to financial close and into the build phase.”

SPH has said that the scheme will bring a £100m+ investment to Gwynedd. The three- to four-year-long construction of the facility is expected to create a substantial regional economic uplift with hundreds of construction workers needing to be housed and fed locally. When operational, the site will support up to 30 skilled full-time jobs, along with work for regional contractors and suppliers, all of which will last for the lifetime of the facility of 125 years or more.

Cllr Mandy Williams-Davies, Gwynedd Council Cabinet Member (Economy) said: “The granting of planning permission for an underground grid connection is a positive development for this important scheme. From the outset, the developers have consistently proposed an underground connection to the grid, and we welcome the fact that the scheme is progressing on this basis.”

SPH was created by QBC to take the Glyn Rhonwy scheme forward to construction and operation. The scheme was designed in consultation with Gwynedd Council, Cadw, Countryside Council for Wales, Natural Resources Wales and AECOM.