The Solar Power Expert Blog

Solar Efficiency Records Rise as Prices Promise to Fall

by GuestPoster - March 3rd, 2012.
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Solar panels grow more efficient with each passing year. Spurred by private and government sponsored research, efficiency records in thin film solar modules fell at least three times in the past year. Competing technologies spark this race to converting sunlight into electricity, which currently hovers at about 17.4% efficiency. CIGS (Copper, Indium, Gallium, Selenid) is a photovoltaic process preferred by European manufacturers, while Americans have devoted their time on perfecting a Cadmium-Telluride (CdTe) based technology. Both technologies are competing with the currently available polycrystalline silicone (Si) wafers and are closing the efficiency gap.

Thin film solar cells will greatly reduce the cost of solar power installations because of their reduced weight, decreasing transportation and structural framing costs. The manufacture of CIGS and CdTe wafers is far less than their silicone counterparts but factories have been turning out silicone wafers since the early 1970’s while thin film cells are barely toddlers. More than 90% of the Photovoltaic market is Si due to the availability and better solar conversion efficiencies (24.7%), though thin film is making significant inroads due to its increases in efficiency and lower cost of installation.

First Solar set a thin film solar cell efficiency record with its CdTe photovoltaic panel at 17.3%. Cadmium-Telluride cells have been in experimental laboratories since the 1950’s. The perfect match of protons in terms of conversion to electricity has made this technology exceptionally promising. The drawbacks have been the commercial use of cadmium, which is extremely toxic, and the rarity of Tellurium. Tellurium mostly comes as a by product of copper, lead and gold mining. Half of the Tellurium used in the United States came from China. Cadmium is abundant, usually mined as a byproduct of Zinc and therefore has not gone through the cost shifts associated with silicon. Cadmium-Telluride is less toxic than elemental cadmium, but great care must be taken in the handling of these cells. There is even discussion on whether cadmium gases would be released into the atmosphere from large industrial CdTe panels built in the desert.

CIGS panels use a much lower level of cadmium in the form of cadmium-sulfide and some models use zinc instead. Like CdTe, CIGS solar panels show a greater resistance to heat than traditional silicon and are simpler to manufacture since no silicon crystals must be grown, eliminating multiple steps in production. The cost of producing CIGS solar panels continues to fall due to research into coating materials which increase cell sensitivity without adding manufacturing complexity.

According to the latest solar energy news, progression in efficiency and integration of thin film solar technology into wider solar arrays could produce a generation of photovoltaic panels under $1.00/W from it’s current average of about $2.00/W making solar energy not only affordable but on par with conventional power generating systems. The future of solar is the efficiency of today.

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