UPDATE 1-NRG Energy targets asset sales of up to $4 bln

(Adds details, background)

July 12 (Reuters) - NRG Energy Inc said it was targeting asset sales of up to $4 billion as part of an agreement with activist investors Elliott Management and Bluescape Energy Partners to cut costs and reduce debt.

Shares of the largest independent U.S. power producer were up 11 percent at $18.15 in premarket trading on Wednesday.

As part of the deal reached in February with Elliott and private equity firm Bluescape, NRG agreed to set up a five-member committee to look into cost-cutting, asset sales, capital allocation and broader strategic initiatives.

NRG said on Wednesday the three-year program, which would help reduce debt by $13 billion, included the divestiture of between $2.5 billion to $4 billion of assets.

The company's debt fair value was $18.6 billion and carrying value was $19.4 billion, as of Dec. 31.

The plan would include sale of 50-100 percent of the company's interest in NRG Yield Inc and the unit's renewables platform, the company said. 1/8nBw3yG4X2a

All stated objectives have transparent and achievable targets, Jeff Rosenbaum, portfolio manager at Elliott Management, said in the company's statement.

Cheap natural gas flowing from shale fields has brought down electricity prices in recent years, squeezing margins for wholesale power generation companies.

Elliott and Bluescape together have an 8.2 percent stake in the company, according to Thomson Reuters data.

(Reporting by John Benny in Bengaluru; Editing by Arun Koyyur and Sriraj Kalluvila)