OptiSolar Inc. (OptiSolar) has laid off nearly 300 people, about half its staff. The company has also stopped the construction of a manufacturing plant because it could not secure the funding it needed to expand. OptiSolar had eliminated 185 positions at its Hayward, California headquarters and an additional 105 jobs in Sacramento, the location of a planned manufacturing plant.

Last year, OptiSolar when secured a deal to build a 550-megawatt solar power plant in Central California for utility PG&E Corp., said its contract would not be affected by the move because construction was not scheduled to commence until 2010.

It’s on hold until we are able to attract financial support, OptiSolar spokesman Alan Bernheimer said, adding that the company was applying for loan guarantees from the U.S. Department of Energy.

The financial crisis and tight credit markets have put expansion of the high-flying renewable energy industry on hold in recent weeks, though many firms are encouraged by US President-elect Barack Obama’s pledge to double alternative energy production in three years as part of a plan to stimulate economic activity.

We’d like to take the Obama administration at their word, Bernheimer said. We’re sort of the poster child for what they’re talking about — renewable energy, green jobs and U.S.-based high-tech manufacturing.

Once it is finished, the Sacramento plant will be capable of generating in excess of 600 MW of OptiSolar’s thin film solar panels a year and is expected to employ about 1,000 people, Bernheimer said.

Until that plant is able to commence production, the company is relying on a smaller manufacturing facility in Hayward to fulfill its current commitments to customers.