The ESB has rejected calls for a 32-mile overhead power line through Co Galway to be put underground, despite this week's ruling against a similar development in Co Donegal.
A spokesman said it would cost between seven and 20 times the project's £30 million budget to switch to an underground link. Underground cabling would also have serious implications for detecting and addressing power failures.
Planning permission for the Portumna-Athenry power line was granted in February, but members of the local authority hope to get the decision revoked following fresh concerns over health implications.
However, in its ruling on the Donegal case, An Bord Pleanala found there was no increased risk of contracting cancer due to electro-magnetic fields generated by overhead power lines.
The ESB spokesman said it was more difficult to detect power failures on underground lines, and areas could be left without power for weeks or months.
"The whole idea of this development is to strengthen the power system in Galway and to make the area more attractive to high-tech investors," the spokesman added.