The head of Eirgrid has again insisted that it is not possible to put the North-South interconnector underground.
Fintan Slye says pylons are the only way to proceed with a vital piece of national infrastructure.
He says that putting the line underground would add around half a billion euros to the cost which he says cannot be justified to the public.
Slye told the Oireachtas Committee on Communications that he is committed to proceeding with the line as soon as possible.
"Our view is that the most appropriate solution for a North-South is an overhead line and the planning application, a draft of which is with An Bord Pleanala as we speak, is based upon an overhead line solution. It is stating that as our preferred option," said Slye.