It plans to build a 102-mile link costing £2.8bn to connect the proposed Moorside nuclear power station in Cumbria to the electricity network.
The electricity distributor has shelved plans for pylons in the Lake District and will now construct a £450m underground line running for 14.5 miles through the entire western section of the Lake District National Park.
This could see the existing lines there being removed completely, leaving this part of the park free of pylons for the first time in 50 years.
The network operator has also proposed building a 13-mile tunnel under Morecambe Bay to avoid the southern part of the park at a cost of £1.2bn, and replacing the low voltage line around Hadrian’s Wall with underground cables.
It said many of the existing lower voltage lines, owned by Electricity North West, which run around the west coast of Cumbria could be replaced with higher voltage lines using fewer, taller pylons.
It is estimated that around £1.9bn will be spent putting sections of the connection out of sight – over 50% of the cost of the total project.
Consultation on the proposals starts at the end of this week and nearly 90,000 newsletters have been mailed to homes and businesses along to route to explain how people can take part.
If approved, construction will start on the new connection in 2019, so it is finished and ready to export the electricity Moorside will generate by 2024.
Robert Powell, Project Manager said: “Balancing the impact of the project on the landscape against its cost has involved making some difficult choices as the cost of building a connection is ultimately passed on to energy bill payers.
“We believe the proposal we are going to consult on over the coming months strikes the best balance. Our consultation will now give people a chance to have their say on the fine detail of the project.”