NEW YORK, Nov 7 (Reuters) - Texas-based energy company Vistra on Tuesday posted lower third-quarter net income, driven by higher unrealized hedging losses that offset increased electricity output to help meet record demand during the hot summer.

Vistra said in an earnings release that net income stood at $502 million in the three months ended Sept. 30, compared to $678 million a year earlier.

The company said within the Texas region hotter-than-usual temperatures had kept power prices higher than it had expected.

As of end of the third quarter, Vistra had hedged approximately 90% of its expected generation volumes on average for the balance of 2023 through 2025, its earnings release showed.

The company raised and narrowed its outlook for 2023 ongoing operations-adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) to $3.95 billion-$4.1 billion from $3.6 billion-$4 billion previously.

CEO Jim Burke said in a statement the group remained focused on "producing strong, stable earnings", returning capital to shareholders, maintaining balance sheet strength, and supporting the clean-energy transition.

The company was working to close its $3.43 billion acquisition of Energy Harbor, announced in March, "in the fourth quarter", he added.

In addition to a retail business, Energy Harbor operates nuclear power plants in Ohio and Pennsylvania. (Reporting by Nicole Jao in New York; Additional reporting by Scott DiSavino in New York; Editing by Jan Harvey)