There's something incongruous about experts from normally cloudy Germany coming to California, the land of eternal sunshine, to teach the locals about how to harness solar power.

But that's was happening this week in San Francisco, where organizers of the world's largest solar exhibition, Germany's intersolar, launched an American version of their confab amid

predictions of a massive solar boom in the ailing US economy.

Conference chairman Professor Eicke Weber, director of the Fraunhofer Institute for Solar Energy Systems, insists that it makes perfect sense for Germans to bring their solar accumen to the Golden State.

Americans are already beginning to cut back on their driving habits

As soaring fuel costs combine with rapidly changing public perceptions about the dangers of climate change, the US embrace of solar power is at a tipping point, he predicts. Soon, the US will follow the massive investments already made in Europe in renewable energy, where thanks to strong government support the solar industry is years ahead of its American counterpart.

"Before, our only argument was the environment, but now with oil at $140 (88 euros) a barrel, I think the much stronger argument will be the pocketbook," he said. "That's why I think solar energy will have a great future in the United States."

No backing from Bush

One indication of the gulf that separates the two continents is the size of their solar exhibitions. The German Intersolar has been growing at some 30 percent a year. The recent Munich expo attracted more than 1,000 exhibitors and 50,000 attendees from 140 countries.

In contrast, the San Francisco Intersolar has only 200 exhibitors and 12,000 attendees.

The major reason for the difference is the scope of government support, or the lack of it in the United States. Under President George W. Bush, a former oil company executive, the federal government until recently denied the science of climate change. Vice President Dick Cheney famously dismissed conservation as a meaningless personal virtue.

Though the US does offer homeowners a one-time, $2,000 federal tax credit for the installation of photo-voltaic systems that convert solar energy into electricity, Weber argued that it needed a

so-called feed-in tariff to really allow the sector to take off. Such a tariff offers energy producers a guaranteed price for energy that they feed into the grid from renewable sources, and was the key stimulus in boosting the European solar sector.

But there are many other factors in play.

The next big thing?

For instance, it's no coincidence that the conference is taking place in San Francisco. The city is the northern anchor of Silicon Valley, where an ever-increasing pool of venture capital and a growing number of start-ups are chasing the solar dream.

SunPower Corp. CEO Thomas Warner next to the solar panels on the roof of the SunPower building in San Jose

Many are already predicting a solar boom, akin to the dot-com boom that accompanied the rise of the Internet. Some start-ups like NanoSolar and Solyndra are already valued at more than $1 billion before they've ever made a profit, reflecting the huge growth potential that Wall Street sees in the solar field.

The comparisons to California's tech industry do not end there. Solar-cell production is a close cousin to the production of computer chips, and there is a constant exchange of personnel, techniques and equipment between the two sectors.

"Each time we double the volume of production, the cost goes down by 20 percent," Weber said. "At the end of the day, it will be the least expensive energy of all. We just need a little help to ignite the revolution."

Dan Martin, who heads SemiCon West, a trade association of semiconductor manufacturers, believes the same dynamic -- that dramatically reduced the price of computer chips while simultaneously increasing their power -- will also characterize the solar voltaics sector.

"We are going to change the world," he said. "I've seen it happen before, and it will happen again."