By Bob Haavind, Editorial Director, Solid State Technology

While many potentially disruptive photovoltaic (PV) technologies are taking shape in laboratories, commercialization is often stalled by a lack of suitable tools for production. Vendors setting up production lines tend to make do with whatever process equipment is available, which keeps even mainstream production from being optimal. The bottom line: emerging solar industry needs help from equipment makers — or else PV companies will be forced to develop their own production tools to get new technologies into the market, charged Lawrence Kazmerski, director of the National Center for Photovoltaics, Golden, CO, at a SEMICON West panel on solar technology.

“Equipment is a huge issue,” Kazmerski said, “It’s Neanderthal compared to semiconductors.”

Germany and Japan are far ahead of the rest of the world in developing solar energy, together accounting for 70% of the world’s PV industry, with the US a distant third at 11%, indicated David Hockschild of PV Now, a California solar industry advocacy group. Of the top ten companies in the industry, including Sharp, Kyocera, Shell, and BP, none are from the US, he added.

California is by far the leading solar market in the US, accounting for 71% compared to 2.5% for New York in second place, followed by a few other states like Arizona and North Carolina. Yet the potential for this technology is huge in the United States, according to Hockschild, because it receives far more solar energy than countries such as Japan, China, and others.

San Francisco is so anxious to get away from conventional power plants, he explained, that a $100 million solar bond issue in 2001 won by 73% of the vote. One of the first projects at Moscone (where the SEMICON West show is held) involved several energy-saving measures along with a $3 million solar panel installation.

“The light bulbs were essentially heaters that emitted a little light,” Hockschild said, so new lamps were installed that not only are more energy-efficient, but also boosted light levels by 30%. The $7 million investment at Moscone will be paid back in eight years, he added.

Every time the solar industry doubles, costs go down about 20%, Hockschild estimates. He rattled off an array of successful showcase projects around the world, including rows of homes in the Netherlands with solar-integrated skylights and the “Carlisle House” in Massachusetts which feeds power back to the grid. He agreed that the US trails several other countries in developing and using alternative energy systems, but he cited efforts to push US efforts. Congress passed a 30% tax credit for solar installations, for example, and six states plus Washington, DC, now have solar set-asides.

There was “unanticipated euphoria” when a budget of $148 million was announced to back a Solar America Initiative this year, according to Kazmerski of the National Renewable Energy Laboratory — but Congress keeps chipping away at the program, which is now down to $139 million. Development efforts are built around a Solar Roadmap, with R&D focused on “closing the gaps,” both in technology and commercialization. He expects the nation will have 5-10GW of solar power installed by 2015, with California alone aiming for 2GW by 2016.

Still, these efforts pale in comparison to Japan and Germany. Kazmerski explained that in Japan, each home with solar power is paid 63 cents/kWh — more than it would cost for power from the grid. As a result, he added, some Japanese actually build systems on their neighbors’ roofs to take advantage of the subsidy. Japan hopes that its aggressive support will mean that by 2050 solar power will supply half of the nation’s electricity.

Germany’s program uses no federal money — instead, every user of grid electricity pays an extra incremental fee to support the cost of solar installations, Hockschild explained. The utilities thus provide a pool to pay back these costs over a 10-year period, and the electric companies also provide credits for solar-generated electricity fed back into the grid.

Photovoltaic technology is steadily evolving, according to Kazmerski. There are many exotic cells under development, but 95% of the solar panels installed so far use crystalline silicon — in fact, in 2005 over half of the world’s silicon wafer production went into solar energy production, he explained. The initial cells from Bell Labs in 1953 had less than 1% efficiency, but even so, by November of the following year the first modules were installed. Since then, he said, some 1.7GW of solar energy has been sold.

Three companies now make crystalline silicon PV cells with over 20% efficiency, according to Kazmerski. The most efficient silicon cells from SunPower have a surface roughed into tiny pyramids to bounce light around and they have anti-reflective coatings to capture more energy from the light. Efficiencies of 28%-29% can be achieved with more exotic materials, such as cadmium telluride and copper indium selenide, he said, and five companies in the Bay area alone have been set up to commercialize these technologies.

On space missions, gallium arsenide has displaced silicon, and concentrators enable efficiencies up to 39%. Soon, according to Kazmerski, multijuntion concentrator solar cells, with different materials tuned to varying parts of the sun’s spectrum, will push efficiencies over 40%. Originally, it was thought that large fields of solar panels would generate electricity to be distributed to nearby communities, but the localized power generation approach, with panels on rooftops, now leads the way instead. But the rising efficiencies of concentrator technologies, and the much higher cost of fossil fuels, may lead to more centralized power generation as well, particularly in highly sunlit areas such as Southern California, New Mexico and Arizona.

Down the road ten years and beyond, Kazmerski envisions disruptive technologies pushing photovoltaic efficiencies up to 50%, 60%, or even 70%. “But that may be 30 years away,” he cautioned. — B.H.


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