San Jose, California - Solar energy advocate Sam Clarkson could not believe his eyes.
For years he had been attending solar energy meetings in the US, always running in to the same group of solar evangelists, a few dozen companies and a fair smattering of hippies.
But at Solar 2006, the solar industry's largest-ever expo in the US, things looked very different. The expo opened on Tuesday at the San Jose Convention Center in the epicenter of Silicon Valley. It attracted some 170 companies and 6000 participants - five times as many as last year.
As the bright California sun shone down on executives in business suits striding purposefully into the building, Clarkson was filled with optimism.
'For twenty years I've believed that the solar revolution is just around the corner,' he joked. 'Now we've finally turned the corner.'
His prognosis was not just the starry-eyed assessment of a committed environmental activist. Across the high tech region, the buzz is growing that alternative energy could be Silicon Valley's biggest money-spinner since the birth of the Internet.
'With the nation's biggest annual solar gathering coming to San Jose this week, an unmistakable message is being sent,' said the San Jose Mercury news, the high tech region's leading newspaper. 'California - and, more specifically, Silicon Valley - is one of the hottest solar markets in the world.'
As if to prove the point, even Google, the company that more than any other symbolizes the current mood of the high-tech region, jumped head first into the melee.
On the opening day of the conference, it announced plans for a huge solar power facility at the new corporate headquarters it bought last year for 319 million dollars.
The ambitious project will require installing more than 9,200 solar panels at the 'Googleplex'.
Once they're in place next spring, the solar panels are expected to produce about 1.6 megawatts of electricity, or enough power to supply about 1,000 homes.
Then there is Indian-born Vinod Kholsa, often considered the world's top venture capitalist, who gave the keynote speech at the conference. He was followed Wednesday by California Governor Arnold Schwarzenegger.
Another top venture capitalist John Doerr also boosted the financial future of clean tech.
'We're seeing an alignment of the environmental interests, automakers, the agricultural industry, the security and energy- independence proponents, even the evangelicals,' he said. 'When did all those [interests] come together before?'
With supporters like that, it's no wonder that venture investments in clean technology companies are soaring. In the first six months of the year, 1.4 billion dollars were invested in start-ups developing green energy technologies - compared to 1.6 billion dollars for the whole of last year, according to industry tracking firm Clean Edge.
Silicon Valley is a natural fit for most of this money - given its concentration of tech workers, finance, sunshine and a political culture that supports the cause.
Earlier this year, Schwarzenegger passed a bill giving 3.2 billion dollars in subsidies to create 1 million solar-powered homes in the next decade. The law also mandated that any new large home developments must offer buyers a solar option.
'Now everybody's a potential user of solar energy, and that's made a substantial difference,' said Scott Ely, a solar energy contractor.
Solar 2006 showed that there is already plenty of choice to fulfill those burgeoning needs. Companies from Germany, Japan, India, Korea, Israel and the US rolled out solar technologies for every conceivable use - from giant collector farms that power whole towns and factories to a solar-powered golf cart, the Cruise Car.
New technologies are vastly improving the efficiency of solar panels, allowing companies to make them out of flexible material that can cover any surface. There are also new kinds of solar panels being integrated into roof tiles and windows.
Giving an added boost to the sector is tech equipment giant Applied Materials, the world's largest manufacturer of machines that manufacture silicon chips. Last year it branched out into equipment to make solar photovoltaic cells, which are also made of silicon. The company believes it will make PV cells cheaper and more efficient and predicts that by 2010 there will be at least 10 solar plants producing 1,000 megawatts each a year - roughly the equivalent of a coal or nuclear power plant.
He's not the only one predicting huge growth for solar energy.
'I never thought I'd be happy to be among so many suits,' said the pony-tailed solar advocate Clarkson, looking at the participants at the solar conference. 'With all the money men jumping in, I know that solar energy is for real.'
© 2006 dpa - Deutsche Presse-Agentur 
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