National Grid is funding an independent study into the costs of different technologies used to transmit power.
The Institute of Engineering and Technology is also examining the best applications of underground cables, under sea cables and pylons.
National Grid wants to build overhead pylons from Avonmouth in Bristol to Hinkley Point in west Somerset.
Campaign group No Moor Pylons, which is against the plans, has welcomed the study.
The energy company wants to install the pylons to link a new power station that will be built near the existing plant at Hinkley Point with Avonmouth.
The company is due to announce its preferred route out of two possibilities in Spring 2011.
Those against the idea want the 400,000 power lines to be buried beneath the ground or laid under the sea.
National Grid said buried power lines would be prohibitively expensive.
Paul Hipwell, chairman of No Moor Pylons, said: "We have maintained all along that National Grids cost estimates for undersea transmission were totally unrealistic.
"We are delighted that at last, after months of campaigning, independent experts will now be brought in to examine the costs.
"It is a real result for Somerset people."
A National Grid spokesman said it would "take account of the independent report as and when it comes out".
The company hopes the project will be in place by 2016.