SunPower , an U.S. manufacturer of solar panels, reported an unexpected net loss for the first quarter, hit by the credit crisis and the difficult economic conditions, the company said Thursday.

SunPower's net loss was $2.5 million, or 6 cents per share in the first three months of the year. A year ago, the company had a profit of $14.7 million or 15 cents per share in the same period.

The first quarter of 2009 was the most challenging quarter we've seen since SunPower went public in 2005, said Tom Werner, SunPower's CEO in a statement.

Currently, the government is giving funding for renewable energy companies, including solar and wind, however it is forecasted that an increase in costs of materials may prove difficult for some firms.

SunPower also cut its 2009 earnings forecast to $1.25 to $1.75 a share on revenue of $1.3 billion to $1.7 billion.