(Adds details on earnings)
Aug 2 (Reuters) - Duke Energy Corp reported a lower-than-expected quarterly profit as the U.S. utility failed to keep a lid on its operating expenses.
The company's total operating expenses rose 11 percent to $4.67 billion in the second quarter, as it spent more on the fuel used in electricity generation.
Duke, valued at nearly $57 billion, has been expanding its business through acquisitions and investment in renewable energy and power generation stations for electric vehicles.
Operating revenue from the company's electric utilities unit, which accounts for the bulk of Duke's overall business, rose to $5.22 billion from $5.16 billion.
The net income attributable to Duke fell to $500 million, or 71 cents per share, in the second quarter ended June 30, from $686 million, or 98 cents per share, a year earlier. (bit.ly/2O6R49I)
Excluding items, the company earned 93 cents per share, missing analysts' average estimate of $1.03 per share, according to Thomson Reuters I/B/E/S.
Total operating revenue rose to $5.64 billion from $5.56 billion.
Shares of the company were marginally down in thin premarket trading. (Reporting by Anirban Paul in Bengaluru; Editing by Maju Samuel)