A defiant Energy Secretary Steven Chu today defended the decisions his agency made relating to the failed Solyndra solar energy company and repeatedly refused to apologize for the half-billion-dollar loss to taxpayers as a result of the controversial loan guarantee.

Chu told members of the House Energy and Commerce Committee this morning that every decision about the loan guarantee was "made only on the merits" and that political considerations "played no role" in the process.

And when Chu was asked if he should lose his job over Solyndra, the Energy secretary said the subject had not come up in his discussions with President Obama.

Chu's testimony irked panel Chairman Fred Upton (R-Mich.), who has been overseeing an eight-month probe of DOE's loan to the now-bankrupt California solar energy company.

After reviewing 186,000 pages of DOE documents, sitting through five hearings about Solyndra and reviewing interviews with more than a half-dozen other Obama administration officials, Upton this morning said "the number of red flags about Solyndra that were raised along the way -- many from within DOE -- and either ignored or minimized by senior officials is astonishing."

Upton and his fellow GOP lawmakers believe the Solyndra debacle resulted from a perfect storm of incompetent management by DOE, questionable legal decisions made to keep the company afloat and pressure from White House officials who were interested in helping political cronies who also happened to be Solyndra investors.

"At every opportunity, Solyndra and DOE officials, including you, Mr. Secretary, publicly assured the American people that Solyndra was on track and would eventually thrive, right up until the time that Solyndra declared bankruptcy," Upton said.

Chu testified that every decision was left to career staffers who always had the best interests of the taxpayer in mind.

Upton finally asked Chu who should apologize for the more than half-billion dollars in taxpayer money that is expected to be lost as a result of Solyndra.

Chu declined to make such an apology.

"It is extremely unfortunate what has happened, but if you go back to the time to decisions that were being made, was there incompetence? ... Was there any influence of a political nature? I would have to say no," Chu said.

Chu added that Solyndra's demise was not based on anything DOE could have planned for. After DOE awarded its loan guarantee to the company, he said, "the bottom fell out" of the solar market as a result of increased production of solar panels from China and a shrinking market in Europe.

"Fundamentally, this company and several others got caught in a very, very bad tsunami," Chu said.

As Chu sought to fend off repeated accusations that politics played a role in the Solyndra deal, Oversight and Investigations Subcommittee ranking member Diana DeGette (D-Colo.) framed the GOP investigative efforts as a political "three-ring circus."

Multiple Democratic members chided Upton for his outrage over the DOE loan program after The Washington Post today uncovered a new DOE document showing that Upton joined members of the Michigan delegation in December of 2009 to lobby for a solar energy project in their state. That loan to United Solar Ovonics was never approved by DOE.

"I don't support the way Chairman Stearns and Chairman Upton has been running this investigation," said committee ranking member Henry Waxman. "They criticize you for awarding loan guarantees at the same time they were seeking awards for solar energy projects in their districts."

Waxman said the focus of the committee investigation should not be on scoring political points but on how best to make a transition from fossil fuels to a clean energy economy.

But "the agenda of congressional Republicans is clear: Do everything possible to maintain our addiction to fossil fuels and cripple clean energy companies," Waxman said.