* Buyers also taking on assumed liabilities of $1.3 bln
* Said to be biggest renewable energy generation deal ever
* Asian governments make big push to expand renewables use
* U.S.-based GIP raised record $15.8 billion fund this year (Recasts with details of the deal, buyers, quotes)
SINGAPORE, Oct 25 (Reuters) - U.S. fund Global Infrastructure Partners (GIP) has agreed to buy Equis Energy, Asia's largest independent renewable energy firm for $3.7 billion with partners including sovereign fund China Investment Corp, underscoring growing global interest in renewables investment.
Singapore-headquartered Equis is the largest renewable energy independent power producer in AsiaPacific, with over 180 assets comprising solar, wind and hydro generation spread across countries including Australia, Japan, India and the Philippines.
Equis' assets have installed capacity of more than 11 gigawatts. A big chunk of the assets are based in Japan.
"The transaction is the largest renewable energy generation acquisition in history and positions GIP as a dominant renewable energy developer in the key OECD growth markets of Australia and Japan, as well as across India and South-East Asia," Equis Pte Ltd and GIP said in a statement on Wednesday.
Moody's Investors Service said in September that renewables will become a central focus of national energy policies as more countries shift to renewable procurement through competitive auctions.
Reuters reported in July that Japanese trading firms, global pension funds, several companies and buyout firms were competing to buy Equis, at a time when many Asian governments are expanding the use of renewable power and its costs are falling.
"Government policies are supportive and encouraging of renewables. But just as important and if not more so, is that the cost curve of both wind and solar has come down massively," one person familiar with the Equis deal said on Wednesday.
"In most markets now, you don't need government subsidies to make it economically viable and that's always been the handbrake," said the person, who was not authorised to speak to the media on the matter.
The Public Sector Pension Investment Board, one of Canada's largest pension investment managers, is also part of the buying consortium, the statement showed.
This year has already seen CIC sign a big-money deal, after it agreed to buy European warehouse firm Logicor Ltd for nearly $14 billion.
"We are excited by the new investment in Equis Energy which is a strong fit with GIP's global renewable investment strategy," Adebayo Ogunlesi, GIP's chairman and managing partner, said in the statement.
New York-based GIP, which manages over $40 billion for its investors, has investments in Spain's Gas Natural, Port of Melbourne and Britain's Gatwick Airport.
GIP raised a record $15.8 billion in its third fund that closed in January. Another infrastructure investor, I Squared Capital, aims to raise as much as $6.5 billion in a new global fund.
During the Equis sale process, many bidders had formed consortia to divide up the portfolio as some were keen to only buy certain assets, and the total acquisition size was large.
The buyers are also taking on assumed liabilities of $1.3 billion.
Equis and GIP said they signed a binding deal for the sale of 100 percent of Equis Energy to GIP and co-investors. The transaction is expected to close in the first quarter of 2018.
Credit Suisse and JPMorgan were financial advisors to Equis Energy. Skadden, Arps, Slate, Meagher & Flom LLP acted as legal advisor while Clifford Chance advised GIP. (Reporting by Anshuman Daga; Editing by Edwina Gibbs and Christopher Cushing)