The policy, a Plaid Cymru manifesto pledge before May's Senedd election, would prohibit large steel lattice pylons for new lines up to 132 kilovolts. Instead, ministers favour undergrounding electricity circuits, arguing this could "reduce the visual impact of electricity infrastructure, helping to protect landscapes and local amenity". They also said buried cables could be less vulnerable to severe weather and could reduce the potential impact on birds and other wildlife.
The consultation document acknowledges that undergrounding is "generally considered more expensive to install and maintain" and could create construction impacts during installation. The policy would allow wooden poles or "equivalent, less intrusive infrastructure" to support overhead cables where certain planning tests are met.
Green Gen Cymru, the company behind plans for three major power line routes connecting onshore wind farms with the wider grid, has previously said undergrounding its cables would cost on average 4.5 times more than running them overhead, adding about £500m to the Towy Usk project between Carmarthenshire and Powys. The company recently unveiled a "slim and compact" 22 metre pylon designed "with the Welsh landscape in mind", after groups representing hundreds of landowners took the company to court in 2025.
Welsh Energy Minister Adam Price said new grid infrastructure was needed, but it needed to be "sensitively designed to minimise impacts on the environment and the communities that host them, while offering the maximum benefits for Wales".
The Welsh Conservatives welcomed the consultation. Environment spokesperson Andrew RT Davies said communities "should not have to accept eyesores across our beautiful natural landscapes, which must be conserved". The consultation runs until 15 January 2027.