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)
November 16, 2006
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.