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HelioVolt's No-Silicon Solar Technology -- The Future of Building-Integrated Photovoltaics?

GREENBUILD-- Interview with John Langdon of HelioVolt, a maker of solar power products that use no silicon. He talks about the applications of the company's photovoltaics for commercial buildings, and the economics of designing solar into a structure. Hear what's now and what's next from this innovative renewable energy company, with a prediction for the future of solar technologies. (podcast)

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Music by Chris Keister

Related in the EnergyBlog:
"Solar Innovators HelioVolt, SunPower, Stellaris Honored for Innovations" (regarding a WSJ article)

HelioVolt Corporation is preparing to build a manufacturing facility to make their rooftop solar panels that use no silicon. In this podcast we speak with HelioVolt executive John Langdon during the Greenbuild Conference and Expo 2006. Here's a brief summary of what he told us:

What's next in solar from HelioVolt?

HelioVolt's initial products will be traditional solar modules for existing buildings. The company plans eventually to produce complete systems for commercial rooftop modules, architectural glass and solar curtain wall products -- all without using silicon.

How are solar cells made without silicon?

Most of the PV market today is based on crystalline silicon. The widely reported shortage of silicon feedstock, Langdon says, is hindering the growth of the solar market.

HelioVolt's products don't use silicon; instead they use copper indium gallium selenide (CIGS), a compound semiconductor. With a very thin layer -- about the thickness of a human hair -- it's about 1/100th as thick as conventional cells, CIGS absorbs the same amount of light, says Langdon.

HelioVolt's technology involves printing the CIGS substance onto glass, metal, or plastic. High-volume printing is expected to bring the manufacturing cost down. Langdon believes at least half the solar market will be based on thin-film technology, eventually.

What is the payback period for thin film solar modules?

In many locations, such as Japan, photovoltaic systems are economic without subsidies because the cost of electricity is relatively high. As the cost of photovoltaics comes down, or the cost of electricity goes up, solar energy will cost less than fossil-generated electricity, Langdon predicts.

Rather than payback, businesses should think about the monthly cash flow related to energy costs, Langdon suggests. For many businesses, the long-term cost per kWh is more important than initial cost. Austin Energy has a green power program with a ten-year fixed cost per kWh, and it sells more green power than any other utility, says Langdon.


Langdon must be grooming for politics by the way he deftly avoided the payback issue. From his response, I gather that there is no cost improvement!

Mr. Langdon doesn't directly answer my question about payback. He does discuss economics more in the podcast than I quoted in the article.

In the podcast he says that long-term cost predictability is more important than short-term payback period, especially for commercial energy users.

This system depends on the high price of electricity. This man has faith in our inability to replace fossils with anything economically viable, market-forced, rather than RPS-forced. I think, however, he's going to be unpleasantly surprised.

I'm doing a project for school on solar technology. Do you think it would be possible to send me some information on the process? Thank you.

I am very interrested to develope your product in Australia as I have all building industry ready to buy.
How many MW can you grant me? I also have started to buy for my french solar plants we have currently 10MW under permit to start construction from march 2009 next year.
We have all the land and permit and the final process can not go any faster.
I only want CIGS modules and as today only fews manufacturer are able to deliver very little; it is a good timing for my programm .
I look for a reliable manufacturer I hope you can keep few MW.
Thank you very much for your reply.
I have a Technicien and partner who will go to visit your factory if you believe that you can deliver some quantity for my company in france.
B. Regards.