Rubber bullets at solar shoot-out

In the world of silicon photovoltaics, the silicon panel we know today is king. But will it be tomorrow, in the face of ever-evolving solar technologies?

That was the question probed in a web seminar yesterday by the Cleantech Group. Speakers representing silicon photovoltaics, thin film and concentration technologies squared off, contrasting the futures of their technologies and fielding questions from an audience of 206 investors, solar installers and other industry influencers.

Moderator Dallas Kachan, acting editor of the Cleantech Group, questioned the long term sustainability of silicon panels' current technologies and price points.

"While nobody thinks the solar PV panel as we know it today will go away, a number of technical and economic decisions need to be made by the industry. The silicon PV panel is at a crossroads. It won’t be used in some applications it’s been used in in the past," he suggested.

SolarWorld, a vertically-integrated maker of traditional silicon-based products, agreed PV panels needed to evolve. The company pointed to active research into technologies such as edge defined film-fed growth, string ribbon, silicon sheet from powder and ribbon growth on substrate—all of which were aimed at making silicon go farther.

Today's PV panel will stay relevant versus other technologies, argued SolarWorld, because all elements of its cost equation continue to fall.

"We're currently at about 50% of the cost we were in 2002. Silicon plays one role in that, but it's becoming less and less. We're optimizing every element: silicon, wafer, cells and modules," said Terry Jester, director of engineering and operations for SolarWorld Industries America.

Jester noted SolarWorld was reducing wafer thickness and the waste between wafers, and making the wafers larger.

The economic premise of thin film is based on the fact that it’s supposed to be cheaper per watt. But, as noted in the seminar, some installers report they're having to install twice as much of it to get the same efficiency as a silicon module system, and the extra labor undermines its promise of lower costs.

Mike Gering, president of Global Solar, a vendor of thin film solar material, countered that the CIGS (copper indium gallium di-selenide) technology his company's film is based on, after years of development, finally stands to deliver on thin film's cost promise.

"Our efficiencies are already about 75% of silicon technologies, which have 20 years in the market already, and we're still increasing. Our material and production costs are lower, and our prices are becoming more competitive," he said.

The three solar camps were reluctant to mix it up publicly.

Gering characterized the solar market as big enough, and growing, to support all vendors' different technology approaches.

The best illustration of brotherly co-opetition between the presenters came from NuEdison, the vendor representing solar concentration.

"We don't see ourselves as an either/or," said Joe Lichy, President and CEO of NuEdison. "We see our concentrator technology moving all solar vendors forward, helping them achieve more aggressive cost reduction goals."

NuEdison is pursue 5x-range optical concentration modules that do not require any tracking. "We get more efficiency out of traditional silicon," Lichy said. "When you get to a concentration factor of more than 5, however, there's no cost benefit from going beyond that until you get into 100x concentration or so, but then you require moving parts."

Attendees had pointed questions, some probing the role the silicon shortage has been having on supply and prices. One attendee specifically asked why panel prices were falling when there’s still apparently a silicon shortage, and wondered whether companies upstream have just been padding their margins.

SolarWorld's Jester took the question, and maintained vendors were just responding to market pressures.

The event was sponsored by SolarWorld, Global Solar Energy and NuEdison, with support from Fat Spaniel Technologies and Fronius.

To access an archive of the event, click here.

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