The top of a large steel vat gently swings open, and a slab of silicon, cut into pieces the size of large bricks, is lifted onto a conveyor belt. On a mezzanine above the warehouse-style floor of the factory in Frederick, Bill Good is monitoring the six-foot furnaces that melt the silicon that goes into bricks, which are later sliced into wafers and turned into solar panels in a building next door.

Good, 53, used to work in a landscaping business, but like many people around the country he has found work in the alternative-energy industry. After two years, he said, "I could retire here."

That's the sort of job certainty many workers would envy. Growth in the solar, wind power and biofuel sectors has been fast and promises to be enduring. Last Thursday, BP PLC's solar division announced a $70 million plan to double the capacity of the Frederick factory and hire 70 more people.