UPDATE 1-Denmark's Orsted lifts 2017 outlook after deal windfall

* Orsted agrees sale of stake in Irish Sea wind farm

* Deal to boost 2017 earnings (Adds context)

COPENHAGEN, Nov 1 (Reuters) - Danish energy group Orsted lifted its 2017 profit outlook after agreeing to sell a stake in what will be the world's biggest offshore wind farm for around 2 billion pounds ($2.65 billion).

Orsted, previously known as DONG Energy and the world's largest owner of offshore wind power, has a strategy of selling off large stakes in wind farms in order to invest the capital into new projects.

On Wednesday, it agreed to divest a 50 percent stake in the Walney Extension project off the coast of northern England in the Irish Sea to two leading Danish pension funds.

As a result, Orsted now expects 2017 earnings before interest, taxation, depreciation and amortization (EBITDA) of between 19 billion and 21 billion Danish crowns from a previous range of 17-19 billion. O

Orsted said third-quarter EBITDA of 1.76 billion crowns ($275 million) came in well below analyst expectations due to a delay in completing the sale of the Borkum Riffgrund 2 project because a supplier had to go through restructuring.

The company agreed to divest 50 percent of the project in the German North Sea in August, and some analysts had expected the proceeds to appear in the third-quarter results.

Orsted had been scheduled to report third-quarter earnings on Thursday but released the numbers a day early because the Walney Extension deal was ready to be announced.

Shares in the company, whose listing in Copenhagen was one of the biggest in 2016 globally, traded 0.3 percent higher at 1515 GMT. They are up around 45 percent since joining the stock exchange in June 2016.

The company's new name references Danish scientist Hans Christian Orsted. DONG stood for Danish Oil and Natural Gas. ($1 = 6.3958 Danish crowns) (Reporting by Stine Jacobsen; Editing by Jacob Gronholt-Pedersen and Keith Weir)