A House GOP report capping a probe of the Obama administration’s backing for Solyndra calls the solar firm’s collapse a “cautionary tale” of political pressures and misguided policy leading to the loss of about a half-billion taxpayer dollars.

House Energy and Commerce Committee Republicans on Thursday released a report on their investigation of Solyndra, the solar panel-maker that struggled after receiving a $535 million Energy Department loan guarantee in 2009 and went belly-up last year.

{mosads}“Solyndra is a prime example of the perils that come when the Federal government plays investor, tries to keep a company and industry afloat with subsidies and attempts to pick the winners and losers in a particular marketplace. Policy and political pressures inevitably come into play to the detriment of taxpayers, as it did with Solyndra,” states the 154-page report available here.

The 18-month investigation, which included subpoenas and reviews of internal administration documents, has unfolded alongside frequent political attacks against White House green energy initiatives from the Republican National Committee, Mitt Romney and GOP lawmakers.

The report includes findings that a White House budget analyst warned in January 2011 that the federal government may have recovered more money by liquidating the struggling company than allowing the Energy Department (DOE) to proceed with a controversial early-2011 restructuring of the deal.

A second White House Office of Management and Budget analyst noted in an email at the time that “DOE is likely to be very sensitive about optics if it should default,” because Solyndra was the first loan guarantee granted under the Energy Department loan program.

However, the lengthy report does not provide specific evidence to back up GOP allegations aired over past months that administration officials provided the Solyndra loan as payback for campaign donations.

Republicans have pointed frequently to the role of George Kaiser, a campaign donation bundler for President Obama, whose foundation was a major investor in Solyndra.

The report notes, for instance, that “the White House Chief of Staff’s office and others in the White House were aware that Mr. Kaiser, a bundler for President Obama’s 2008 campaign, was the primary investor in Solyndra.”

Nonetheless, Republicans have not shown that the loan was granted as a result of political favoritism, despite repeated campaign-trail claims that the administration steered loans to Solyndra and other green-energy projects on the basis of political donations.

White House spokesman Eric Schultz attacked the Solyndra probe in a statement Thursday.

“This is month eighteen of this Congressional investigation and everything disclosed in the 215,000 pages of documents, 14 committee staff briefings, 5 Congressional hearings, 72,000 pages from Solyndra investors, and Committee interview with George Kaiser, affirms what we said on day one: this was a merit based decision made by the Department of Energy. As Republicans won’t answer how much investigation has cost taxpayers, we believe they should instead be focused on legislation to creating jobs and grow the economy,” he said.

Overall, the report catalogs information that has emerged during the probe that White House officials were keenly aware of the optics of the loan and were eager to complete the deal to tout Solyndra as a sign of a green energy economy. It notes internal administration concerns about the viability of the company that Obama and other senior officials personally promoted.

It says the Energy Department “ignored numerous warning signs regarding Solyndra’s finances” and “pushed forward with the guarantee despite these warnings because of the Obama Administration’s desire to use the Solyndra guarantee to highlight its stimulus.”

Solyndra won the loan guarantee under a stimulus-law addition to the underlying loan guarantee program, which was first authorized in 2005 through a bipartisan effort.

“Solyndra should serve as a cautionary tale on how political pressures and an Administration’s desire to create political events to highlight its policies can result in poor decision-making,” the report states.

Republicans in particular have taken aim at the early 2011 restructuring that put private investors — who agreed to provide another $75 million in capital to the struggling company — ahead of taxpayers for repayment if the company collapsed.

The House Energy and Commerce Committee on Wednesday approved GOP legislation that would prevent such “subordination” of taxpayers’ interests in other loan agreements, among other aspects of the bill that sets new restrictions on the loan guarantee program.

Republicans have alleged the terms of the Solyndra deal were a violation of the 2005 law that created the loan program, but the Energy Department says it vetted the restructuring with attorneys and that it was allowable.

They have portrayed the loan restructuring as a last-ditch attempt to save the company and protect taxpayers’ investments.

A senior House Democrat attacked the report Thursday.

“The Solyndra investigation hasn’t uncovered a scandal, but instead has created a symbol for Republicans to appease their fossil-fuel fundraisers and eliminate competition for oil, coal and nuclear energy,” said Rep. Ed Markey (D-Mass.), a senior member of the House Energy and Commerce Committee.

— Updated at 12:40 p.m.