Jan. 20--Solar-industry executives paint a bright future for their industry, one where photovoltaic panels adorn roofs of homes and businesses and huge power plants capture the sun's rays to generate electricity. But the industry currently finds itself under cloudy skies and buffeted by threatening winds.

The solar tax credits approved late last year gave the industry a boost, and its leaders are hopeful for an even bigger boost by President Barack Obama, who has promised to promote clean technologies and energy alternatives to oil. But it's far from clear just how much help will come, and when.

Meanwhile, many once-promising solar companies struggle to maintain momentum against the strong head winds of the financial crisis. Feel-good headlines about well-funded startups and new jobs are giving way to grim announcements of factory delays and layoffs.

OptiSolar of Hayward announced this month it would lay off half of its 600 employees. The company, which has a contract to produce electricity for Pacific Gas & Electric, blamed its inability to get financing to expand a factory in Sacramento.

"We haven't been able to access the investment capital we were able to get earlier," said Alan Bernheimer, an OptiSolar spokesman. "It's a bitter pill."

The company has been retrofitting up to 1 million square feet of space at the old McClellan Air Force Base and was just starting to install manufacturing equipment there when the decision to halt

work was made. The result was 185 layoffs in Hayward and 105 in Sacramento. OptiSolar will continue manufacturing in Hayward, and it is shipping solar panels to Canada for a power plant under construction there. And it still plans to fulfill its PG&E contract, once the economy improves, Bernheimer said.

OptiSolar's pink slips could be a harbinger of bad news from other companies needing millions of dollars to finance the costs of building factories and huge power plants.

"These companies are going to be large consumers of capital," said Patrick Pohlen, an attorney who works in clean-tech financing at Latham & Watkins in San Francisco. And banks aren't lending right now.

"I liken the solar industry to the semiconductor industry 40 years ago," he said. "What a semiconductor company had to do was build a fab -- a factory -- to make a chip. That's kind of where solar companies are today. And the challenge is that to build a factory requires debt."

OptiSolar is just the latest solar company to come under threat by the bad economy:

--HelioVolt, a Texas maker of thin-film solar panels, opened a 122,000-square-foot factory in Austin three months ago.