Using Reflective Dishes to Raise Solar Potential
by Jeremy Elton Jacquot, Los Angeles on 08.30.07
Once primarily the key component for chipmakers, silicon has rapidly become a hot commodity in the burgeoning market for renewable energy with rising demand for solar panels prompting a drastic decline in its global supply. This had spurred a worldwide search for alternatives to the precious element as scientists and businessmen race to anticipate further growth in the solar market over the coming years. A team of researchers at Israel's Ben Gurion University, led by David Faiman, believe they may just have found a viable alternative in gallium arsenide.
Though more expensive than silicon, gallium arsenide is also more efficient when used in a reflective dish. "The dish could be put in a sunny backyard and generate most of the home's utility needs. The costs per watt are comparable to that of a conventional power plant, but without fuel," said Faiman, a professor of physics at the university. This follows an earlier recommendation by analysts at Jefferies, an investment bank, that concluded that while gallium arsenide was still too expensive to use, it could be coupled with mirrors to reduce costs.
The reflector designed by Faiman and his colleagues would collect and intensify sunlight a thousand times over, they claim. The resulting concentrated light would be directed at solar panels — which would convert it into energy with twice the efficiency of conventional panels.
Faiman is working with a start-up company, Zenith Solar, to develop a home solar energy system that would use a 107.6 sq. ft. reflector dish. They plan on unveiling a prototype by the end of 2008. He estimates that a similar energy system built on 4.6 sq. mi. in Israel's Negev desert could generate as much as 1,000 MW of electricity, or close to 10% of the country's energy needs.
Others, however, are less sanguine about the potential for gallium arsenide to fill the vacuum in the solar market. George Crabtree, the director of materials science at the DOE's Argonne National Library, cautioned that the technology has yet to prove itself in areas like total cost competitiveness and system integration. "It is likely to take several more years before the other aspects of CSP (concentrated solar power) technology are sufficiently developed and proven ready for deployment. CSP technology is like digital audio ten years ago," he concluded. He argued that solar energy derived from silicon in the sunny regions of Italy and the U.S. would be able to compete on a cost- and efficiency-basis within 5 years.
Cheaper solar energy can't come fast enough as far as we're concerned.
Via ::Planet Ark: Reflective Mirrors Seen Raising Solar Potential (news website)
See also: ::Solar Cell Innovation: Silicon Nanoparticles Improve Performance, ::Solar Panel Tracks the Sun, Uses less Silicon
Gallium arsenide as a replacement for silicon? Efficient, yes, but how can you dispose of gallium and arsenic in a "green" manner - silicon can be recycled and isn't nearly as toxic to produce.
You are very correct!
Wow.
1 mile2 is equal to 2,165,559.92 M2.
–so for this article we see at total of 9,961,576 M2 of collector area to put out 1,000 MW worth of daylight electrical power. That yields about 100 watts per M2 if my math is correct.
Since my old science teacher taught me that with 100% solar energy collection efficiency for electrical generation, we could have about 1.4KW per M2/hour in space, we would see about 1.0 KW M2/hour on the ground (plus or minus clouds, pollution, etc) – so 10% efficiency yields about 100 W/M2 . So far, the system in the story looks pretty good from a cost/watt basis.
A salt pond has a lower capital cost but a higher maintenance demand and only has an upper Carnot-cycle extractable efficiency of 15% -- at best. Other solar collection methods trade a much higher price for more conversion efficiency.
The panels could be mounted some distance above ground and the shady area underneath used for agribiz purposes, thereby reducing the capital cost for the land. Another big plus would be the cooling fluid for the solar cells could be used for absorption cooling, with more Agribiz applications – making it even more dual use.
My point? Why don’t we see Shell, BP or other “energy giants” not only doing this work, but putting it to use NOW? Nevada and Arizona have compatible climate and open areas - lets get cracking!.