North-south underground electricity cable too expensive
An independent report on the north-south electricity interconnector has said it would be technically possible to use underground cables.
The reported added, however, that the increased cost would be enormous.
The interconnector is planned to link the electricity grids of Northern Ireland and the Republic of Ireland.
A report by three experts said using underground cables would see the cost of the project rise from 167m euros to 500m euros.
Some residents on the route along the Monaghan-Tyrone border are unhappy at the prospect of new pylons being built across the countryside.
The experts, from Sweden, Norway and Belgium, said the estimated costs were based on recent projects in Europe which dealt with similar terrains and conditions as the Irish project.
They also said that overhead cables could be made more attractive by spending more on new pylon designs rather than using the steel lattice towers which are currently proposed.
The report was commissioned by the Republic's energy minister Pat Rabbitte.
The business group Chambers Ireland said the underground cable option should now be ruled out.
Sean Murphy, Chambers Ireland deputy chief executive, said: "A north-south interconnector is vital for future energy needs for both Irish business and consumers.
"We need the interconnector to be completed as soon as possible to help in our efforts to contain electricity price rises now that oil and gas prices are rising.
"The report indicates that undergrounding the interconnector will cost taxpayers a minimum of 333m euros. This country cannot afford such gold-plating at this time."
A public planning inquiry into the Northern Ireland part of the project is due to begin in Armagh on 6 March.