The project off the northeast coast of England is expected to become the world's largest offshore wind farm, helping the companies achieve their climate targets.

Eni's investment in the development was for a combined 405 million pounds, the companies said on Friday.

"Entering the offshore wind market in Northern Europe is a great opportunity to gain further skills in the sector thanks to the collaboration with two of the industry's leading companies," Eni chief executive Claudio Descalzi said.

Along with many other oil majors Eni plans to massively increase its renewable power generation to reduce its reliance on fossil fuels and meet internal climate targets. It plans to have more than 55 gigawatts of renewable capacity by 2050, up from less than 1 GW in 2019.

Eni has already formed a joint venture with Norway's HitecVision to take part in an offshore wind power tender in Norway next year.

SSE and Equinor said they would each realise 200 million pounds from the Dogger Bank sale, which is expected to be completed in early 2021 subject to regulatory and lender approvals, while still holding a combined 80% stake.

"Once again, we have demonstrated Equinor's ability to create value from renewables projects," Paal Eitrheim, the company's head of New Energy Solutions, said.

Equinor also sold a 50% stake in two U.S. wind farms to BP in September, booking a $1 billion profit.

The deal with Eni covers the first two parts of the Dogger Bank development, which were given the go-ahead last week and will add a combined 2.4 gigawatt of capacity, with completion scheduled in 2023 and 2024 respectively.

Equinor and SSE retain 50% stakes in phase C, which is still in the planning stages and could add a further 1.2 gigawatt in 2026, at which time Dogger Bank would produce enough electricity to supply 5% of British demand, equivalent to six million homes.

Britain is already the world's largest offshore wind market and is aiming for 40 GW of capacity by 2030, up from 10 GW now.

(Reporting by Nerijus Adomaitis in Oslo, Susanna Twidale in London and Stephen Jewkes in Milan; Writing by Terje Solsvik; Editing by Susan Fenton, Elaine Hardcastle and Alexander Smith)

By Nerijus Adomaitis and Stephen Jewkes