Some alternative-energy developers that could gain millions in federal energy loan guarantees under the stimulus program may have shaky finances, according to financial filings and outside reviews. However, executives defend their start-ups’ strength and potential, while a U.S. Energy Dept. official is confident the feds’ investment will be repaid.

Solar energy developer Solyndra, Fremont, Calif., which received a $535-million DOE guarantee last year, has not showed a profit since its 2005 founding and was reviewed negatively last month by accountant Pricewaterhouse Coopers, which questioned its future. Tyngsboro, Mass.-based Beacon Power, which has a conditional $43-million guarantee to build a 20-MW energy-storage plant in upstate New York, faces delisting from the NASDAQ exchange by September if its share price does not rise above $1.

Solyndra CEO Chris Gronet claims the tight credit market has hindered the firm’s ability to raise the private equity required by the loan program, which gave it an extra six months to do so, and that the audit’s issues are typical for start-ups. A Beacon spokesman says the firm is optimistic it will get its loan “in a matter of weeks.”

Matt Rogers, a DOE official who oversees its loan guarantee program, defends the funding for untested and unprofitable firms. “Each of these firms is following a relatively traditional pattern for start-ups and how they move from investment to profitability over a finite amount of time,” he says, adding that revenue and cash flow are more critical predictors of loan repayment than profits.