The 139-acre project is expected to be completed and energized by the fourth quarter of 2010, DEGS said.
DEGS said the deal includes a 30-year power purchase agreement to sell all of the output from the solar farm and associated renewable energy credits to San Antonio-based CPS Energy.
In October last year, Duke Energy had agreed to develop commercial solar power projects in the United States with ENN Group, a private Chinese energy company.
The Blue Wing project is the first commercial solar power project Duke Energy will own and operate. The company, however, currently owns and operates 733 megawatts of commercial wind power generation.
Duke Energy shares closed at $16.55 Friday on the New York Stock Exchange.
(Reporting by Adveith Nair in Bangalore; Editing by Anil D'Silva)