By Arno Schuetze, Christoph Steitz and Stefano Berra

FRANKFURT/LONDON (Reuters) - Canada's Enbridge <ENB.TO> and Australia's Macquarie <MQG.AX> are vying for a 49.9 percent stake in EnBW's <EBKG.DE> 2 billion euro ($2.2 bln) offshore wind park project Hohe See, three people familiar with the deal told Reuters.

EnBW, Germany's third-largest utility, is asking for final bids by the end of this month, the sources said. One of them said that Enbridge was seen as the frontrunner in the auction.

With a planned capacity of 500 megawatt (MW), Hohe See is one of Europe's largest offshore wind park projects and would be EnBW's biggest park to date, as the group aims to increase the share of renewables in its generation mix to more than 40 percent by 2020 from 19 percent in 2012.

Most upfront financing for offshore wind parks usually comes from utilities, but the price tag of at least a billion euros apiece means that outside money is crucial. Hohe See alone is expected to swallow investments of up to 2 billion euros.

EnBW, Macquarie and Enbridge declined to comment.

Enbridge and Macquarie have emerged as keen investors in Europe's energy infrastructure sector, which is seeing heavy M&A activity as pension funds and energy groups seek the steady returns big wind parks offer.

"The sector is really taking off now. Investors realize they can manage the risks," one of the sources said, also pointing to China Three Gorges' [CYTGP.UL] deal last month to purchase German offshore wind park Meerwind from Blackstone <BX.N>.

Enbridge late last year took a 24.9 percent stake in Rampion, a 1.9 billion euro offshore wind project owned by Germany's largest utility E.ON <EONGn.DE>, while Macquarie is already a stakeholder in EnBW's Baltic II park and RWE's <RWEG.DE> Galloper project.

Hohe See, which will be located in the North Sea around 100 kilometers west of the German island of Heligoland, will produce about 2,000 gigawatt hours of electricity a year, enough to power about 560,000 homes, and save 1.5 million tonnes of CO2.

($1 = 0.8977 euros)

(Additional reporting by Nia Williams in Calgary and John Tilak in Toronto; Editing by Edward Taylor and Susan Fenton)