Dinorwig pumped hydro station gets cable upgrade

Built in the 1970s, Dinorwig sits inside the mountain Elidir Fawr in Snowdonia national park in Gwynedd, north Wales. The pumped hydro facility can deliver a maximum power of 1,728MW and has a storage capacity of around 9.1GWh.

The Dinorwig to Pentir project is replacing cables from the power plant to National Grid’s 400kV Pentir substation, around 12km away. The first new circuit, comprising three 12.2km cables each made from 14 sections joined together and weighing an estimated 1,500 tonnes, has been installed under sections of the A4086 and A4244, in nearby fields and inside Dinorwig. The project was carried out by engineers from National Grid and contractors Morgan Sindall Infrastructure and Siemens Energy

Each new circuit takes a different route from the original cables, allowing the existing connection to remain in service while the upgrades take place. According to the project partners, the scheme will help futureproof vital infrastructure carrying clean electricity from the ENGIE-owned Dinorwig power station, known locally as ‘Electric Mountain’.