The first of three new sets of power cables connecting Dinorwig hydroelectric power station in north Wales to the transmission network has been energised.
Engineers from National Grid, and contractors Morgan Sindall Infrastructure and Siemens Energy, reached the key milestone as part of the Dinorwig to Pentir project to replace cables originally installed in the 1970s, and which are now coming to the end of their operational life.
Dinorwig power station is owned and operated by First Hydro, a company which is 75% owned by Engie.
Since autumn 2021, National Grid has been upgrading the 12 km connection between its 400kV Dinorwig substation – which sits inside the same mountain as the power station, transmitting its electricity to the grid – and its 400 kV Pentir substation.
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.
Each new circuit takes a different route from the original cables, ensuring the existing connection can remain in service and continue transmitting vital clean power from Dinorwig while the upgrades take place.
Alongside installing the new underground electricity cables, National Grid is also making good progress on major upgrades to its Dinorwig substation.
Phil Rose, National Grid’s Lead Project Manager for the Dinorwig to Pentir cable replacement project, said: “Completing the first of our three connections marks a really significant milestone in this crucial project to futureproof the infrastructure carrying clean power from Electric Mountain.
“It’s also a fantastic achievement for the team despite some very difficult conditions, with extremely hard rock and unprecedented rainfall challenging our progress at times.
“We appreciate the cooperation and understanding of the local community whilst the work takes place, and want to thank everyone locally for their continued patience while this essential work progresses.”
Peter Kirk, Managing Director, Energy at Morgan Sindall Infrastructure, said: “Energising circuit 3 at Dinorwig-Pentir creates a more resilient power network for the UK.
“This improvement will enable the network to better handle sudden changes in power demand and unexpected outages, and also supports the UK’s net zero carbon goals by providing vital infrastructure needed for renewable energy sources.”