Semiconductor companies are rushing into the solar power business faster than a Pentium-driven computer, promising to turn a niche form of renewable energy into a mass-market product.

Since May, computer powerhouses Intel (INTC), IBM (IBM) and National Semiconductor (NSM) have barreled into solar energy, joining hundreds of fellow technology mainstays. Virtually every chipmaker is weighing a solar play, says Rhone Resch, head of the Solar Energy Industries Association.

"We have a classic Silicon Valley land rush," says T.J. Rodgers, CEO of Cypress Semiconductor (CY), which owns 56% of SunPower.

Drawing the stalwarts is solar's 40% annual growth, says Gartner analyst Jim Hines. The 50-year-old chip business is expanding only about 5% annually after years of torrid growth.

Like the computer chip, solar cells use silicon or another semiconducter as a basic part. By replicating the chip industry's high-volume automated manufacturing, tech companies can deliver solar at prices competitive with grid power faster than the industry's current 2010-15 target, he says. Among the entrants:

•IBM. The computer giant in May unveiled a breakthrough concentrated photovoltaic (CPV) system that magnifies sunlight to 10 times the energy from today's CPV units, cutting the number of solar panels needed. A liquid metal absorbs heat so the semiconductor doesn't melt, technology IBM developed to cool high-power computer chips. IBM last month announced a new technique for thin-film solar — which uses 1% of the semiconductor in standard panels — to cut costs and boost efficiency. IBM says it will license both technologies.

•Intel. The No. 1 chipmaker this month said it's investing $38 million in German solar panel maker Sulfurcell. That followed the June spinoff of its own fledgling solar unit.

•National Semiconductor. The chip giant last month said its new technology can boost energy output in solar panels by minimizing losses from shade. It drew from its expertise in power management in cellphones. Executive Ralph Muenster wants to make passive solar systems "smarter."

Some techies are already on a path to solar riches. Applied Materials' machines turn out giant glass panels for thin-film solar makers, shaving production and set-up costs. It used the same devices to cut flat-panel TV costs. By 2010, 25% of revenue will come from solar, chief technology officer Mark Pinto says.

Cypress has automated SunPower's previously outdated factories. It's now churning out 300,000 solar panels a quarter, up from hundreds, and solar comprises 50% of Cypress' sales. "We just showed them how to make millions of them cheap," Rodgers says.