The Energy Department’s senior staff has acknowledged in interviews the intense pressure from top Obama administration officials to rush stimulus spending out the door.

“We had to knock down some barriers standing in the way to get these projects funded,” Matthew C. Rogers, the Energy Department official overseeing the loan guarantee program, said in March 2009, just days before Solyndra got its provisional loan commitment. Mr. Rogers said Energy Secretary Steven Chu had been personally reviewing loan applications and urging faster action on them.

Two committees of Congress, the Department of Energy’s inspector general and the Department of Justice are now investigating what went wrong in the Solyndra case. In Washington, it has set in motion a highly partisan battle over the benefits or failings of Mr. Obama’s stimulus program.

Some Republican lawmakers have raised questions about political interference in the loan decision, pointing to the fact that George B. Kaiser, a billionaire from Tulsa, Okla., was a fund-raiser for Mr. Obama’s 2008 campaign and the backer of a foundation that is Solyndra’s leading investor. While he has met with top White House and administration officials multiple times, Mr. Kaiser and administration officials say they discussed issues related to his foundation, not Solyndra.

But during the period when Solyndra’s loan guarantee was under review and management by the Energy Department, the company spent nearly $1.8 million on Washington lobbyists, employing six firms with ties to members of Congress and officials of the Obama White House. None of the other three solar panel manufacturers that eventually got federal loan guarantees spent a dime on lobbyists.

Energy Department officials said the lobbying had no impact on their decisions. But Solyndra, which had been among 143 companies to express an interest in a loan guarantee and 16 that were asked to submit a formal application — ended up securing the first financial commitment. Solyndra’s loan guarantee was the highest of the four companies.

Tim Harris, the chief executive of Solopower, which got a $197 million loan guarantee last month to build solar panels in San Jose, Calif., said his company had never considered employing a Washington lobbyist to grease the application. “It was made clear to us early in the process that that was clearly verboten,” Mr. Harris said. “We were told that it was not only not helpful but it was not acceptable.”