FREMONT, Calif.  A few years ago, Silicon Valley start-ups like Solyndra, Nanosolar and MiaSolé dreamed of transforming the economics of solar power by reinventing the technology used to make solar panels and deeply cutting the cost of production.

Founded by veterans of the Valley’s chip and hard-drive industries, these companies attracted billions of dollars in venture capital investment on the hope that their advanced “thin film” technology would make them the Intels and Apples of the global solar industry.

But as the companies finally begin mass production  Solyndra just flipped the switch on a $733 million factory here last month  they are finding that the economics of the industry have already been transformed, by the Chinese. Chinese manufacturers, heavily subsidized by their own government and relying on vast economies of scale, have helped send the price of conventional solar panels plunging and grabbed market share far more quickly than anyone anticipated.

As a result, the California companies, once so confident that they could outmaneuver the competition, are scrambling to retool their strategies and find niches in which they can thrive.