UPDATE 1-Energy Future warns delay would kill Oncor sale to Buffett

(Adds Moelis banker comments, paragraphs 6-8)

WILMINGTON, Del., July 26 (Reuters) - Warren Buffett's Berkshire Hathaway Inc will walk away from its $9 billion acquisition of Oncor Electric Delivery Co if the deal is delayed, an attorney for the parent company of Texas' largest utility told a bankruptcy judge on Wednesday.

Energy Future Holdings Corp, the bankrupt owner of Oncor, disclosed Berkshire Hathaway's warning as the judge considers a request by the utility's biggest creditor, hedge fund Elliott Management Corp, to hold up the deal with Buffett so it can put together its own $9.3 billion bid for Oncor.

Berkshire Hathaway "may not go away forever, but they have told us and we have no reason to doubt them, that they will go away," Energy Future's lawyer Chad Husnick told U.S. Bankruptcy Court Judge Christopher Sontchi at a hearing in Wilmington, Delaware.

"They may come back but it's ... going to be for a lower price," Husnick added.

Berkshire Hathaway's deal for Oncor is due to be approved by a bankruptcy court on Aug. 10, but Elliott is asking for a delay of 35 to 40 days so it can put together financing for its own bid for the utility.

Roger Wood, a Moelis & Co investment banker representing Elliott, told the court that Elliott had secured $1.5 billion for its bid so far, significantly short of the $9.3 billion needed.

He said 10 other investors had expressed interest in joining Elliott in the bid. If all of them put in the amount they had indicated, Elliott would raise between $9.7 billion and $11.85 billion for the bid, he said. Some $3.7 billion of that investment interest came from a single investor in the form of proposed debt financing, Wood added.

While Wood did not name the investors, he cited their interest to argue that Elliott needs more time to secure financing for the bid. If Elliott's request for a delay is granted, Berkshire has the right to end its deal, according to court papers.

Energy Future filed bankruptcy three years ago, and two earlier deals for Oncor fell apart after facing regulatory hurdles.

(Reporting by Jessica DiNapoli in Wilmington, Delaware; Additional reporting by David French in New York; Editing by Lisa Shumaker and Dave Gregorio)