Pressure has intensified on fossil fuel companies to curb emissions as investors threaten to withhold funds and public awareness of climate change grows.

BP on Wednesday said it planned deep cuts to its emissions by 2050.

Offshore installations at BP's Eastern Trough Area Project (ETAP), Shell's Shearwater and Total's Elgin-Franklin in the British sector of the North Sea could be connected via a 300-kilometres-long subsea cable, BP's letter said.

"Electrification of these platforms offers significant socio-economic benefits by significantly reducing emissions," BP said in a letter to the ministry seen by Reuters.

It said it had already submitted an application to connect to the Norwegian grid, asking the ministry's officials to meet to discuss the project further.

Norway, which has generated huge wealth by exporting fossil fuel, generates its own electricity almost entirely from renewable sources, such as hydro and wind power.

A number of oil platforms on the Norwegian continental shelf have already been connected to the grid, with more projects expected.

But the requests to electrify foreign oil platforms, replacing fossil fuel energy with carbon-free power, are unprecedented, the ministry said, adding it had yet to make a decision.

"Applications to build interconnections to supply petroleum installations abroad are not something the energy authorities have considered or decided on yet," a ministry spokesman said in an email to Reuters.

The installations would require 100-200 megawatts (MW) in power capacity, which could be provided by a subsea cable starting from 2023, with investments estimated in a range of 7 billion to 9 billion crowns ($760-977 million), BP said.

Shell had no immediate comment and Total could not immediately be reached for comment.

Norwegian news website E24 was the first media outlet to report on BP's letter.

By Nerijus Adomaitis