The preferred site for a controversial electricity substation in Powys and the route for over 100 high voltage pylons will be unveiled later.
Opponents say the substation and the pylons, to service wind farms, will disfigure the countryside.
Two sites at Cefn Coch, near Llanfair Caereinion, and Abermule, near Newtown, have been earmarked for the substation.
