The demand for solar energy is expanding rapidly, but one of the industry’s obstacles to even faster growth has always been the difficulty of getting enough silicon to make photovoltaic cells for solar panels.

This week, though, IBM announced a new potential source for much-needed silicon: waste silicon wafers used to make semiconductor chips for computers, mobile phones and other electronic devices. By erasing the layers of intellectual property that previously prevented those chips from being sold for other uses, IBM can now sell its scrap silicon wafers directly to companies that manufacture solar panels.

IBM and other companies in the industry use silicon wafers to imprint the patterns on semiconductor chips. Once scrapped, these product silicon wafers have typically been crushed and sent to landfills, or melted down for resale. That’s because the proprietary information encoded on the wafers has prevented them from being resold.

Using a process developed by engineer Eric White, though, IBM has found a way to erase the intellectual property from wafers so they can be reused or resold. IBM has introduced the process to turn old product wafers into monitor wafers to help manage the chip-manufacturing process. Wafers of either kind that reach the end of their lives can now be marketed to solar cell makers rather than being trashed.

IBM says up to 3.3 percent of the new silicon wafers made in the industry each day are currently scrapped. While that might not sound like much, when you consider that, worldwide, semiconductor manufacturers create 250,000 new wafers per day, the numbers start adding up. Using stats from the Semiconductor Industry Association, IBM estimates that could mean annual waste of up to three million silicon wafers — enough, according to IBM, to cover an area of 22.5 acres, or to provide solar power to 6,000 homes.

IBM says the new reclamation process helped it save more than a half-million dollars at its Burlingont, Vermont, facility last year; it expects to save nearly $1.5 million this year. It says it’s also getting ready to use the process at its plant in East Fishkill, New York, and will provide working details to others in the semiconductor-making industry.

ReneSola, one of China’s fastest-growing solar energy companies, has already begun to use the reclaimed silicon wafers to make its solar panels. And the IBM process recently won the National Pollution Prevention Roundtable’s "2007 Most Valuable Pollution Prevention Award."

Pretty big props for something that starts out so small.

Whether you’re shopping for an Earth-friendly ride or just interested in learning more about alternative transportation technology, consider checking out the second annual Alternative Car and Transportation Expo in California this week.

Now in its second year, the expo will run from 10 a.m. to 5:30 p.m. Friday, Oct. 19, and Saturday, Oct. 20. Featuring 100 different exhibitors, a slew of seminars, guest speakers and other attractions, the expo will be held at the Barker Center at the Santa Monica Air Center in Santa Monica, California. Admission is free.

Seminars during the expo will tackle such subjects as "Driving the Future: It’s Here Today," "The Likely Effects of Federal Climate Change Policy on the Development of Alternative Vehicles," "Getting Out of the Box, Moving With Our Feet," "Biodiesel Technology," "Hydrogen/Fuel Cell Technology" and "Monorails."

Expo attendees will also get a chance to take Sustainable Works’ Ecological Footprint Quiz, be able to use a free bicycle valet parking system, participate in a fuel cell "Ride and Drive" featuring the natural gas-powered 2008 Honda Civic GX NGV, and even buy one of the alternative-fuel vehicles on display during the show.

While some of the exhibitors are names that have already generated a lot of green buzz — like Segway — others might be less familiar, including:

• EcoLimo, which aims to become "the premier provider of fuel-efficient, chauffeured ground transportation service to businesses all over the world." With offices in Los Angeles, San Francisco and Washington, D.C., EcoLimo’s fleet includes the gasl/electric Lexus 400h hybrid, the biodiesel-fueled Mercedes E320 CDI and the compressed natural gas-powered Chevy Suburban.
• Gorilla Vehicles, a California-based company that sells electric tractors, ATVs and a one-person, standup electric utility vehicle it calls the Chimp.
• Oka Cars, a Russian maker of electric mini-cars, some of which are only for patrolling private parking lots and gates communities, others of which are licensed for travel on public streets.
• SSI-Racing, the California-based developer of the 2 SSIC, which it calls "the world’s fastest extreme street electric car." Still in the development stage, the 2 SSIC is designed to be a electric-powered replica of an American muscle car. SSI’s Website says the vehicle is going to be "uber-geeked to the max and get crazy good gas mileage."
• Vectrix, a 12-year-old U.S./European company that developed the Vectrix ZEV zero-emissions, electric-powered maxi-scooter. The company bills its invention as the "greenest ride in the world": with a built-in rechargeable battery, the Vectrix ZEV can go up to 62 miles per hour and can travel around 68 miles before needing a recharge. The scooter is already available through British Motor Car dealerships in California and retails for $11,000.