Skip to comments.Cheap, Superefficient Solar
Posted on 11/10/2006 11:33:50 AM PST by aculeus
Solar-power modules that concentrate the power of the sun are becoming more viable.
A worker arranges wafers that will be fabricated into superefficient solar cells. These cells could help dramatically reduce the cost of generating electricity from solar energy. (Credit: The Boeing Company) Technologies collectively known as concentrating photovoltaics are starting to enjoy their day in the sun, thanks to advances in solar cells, which absorb light and convert it into electricity, and the mirror- or lens-based concentrator systems that focus light on them. The technology could soon make solar power as cheap as electricity from the grid.
The idea of concentrating sunlight to reduce the size of solar cells--and therefore to cut costs--has been around for decades. But interest in the technology has picked up in the past year. Last month, Japanese electronics giant Sharp Corporation showed off its new system for focusing sunlight with a fresnel lens (like the one used in lighthouses) onto superefficient solar cells, which are about twice as efficient as conventional silicon cells. Other companies, such as SolFocus, based in Palo Alto, CA, and Energy Innovations, based in Pasadena, CA, are rolling out new concentrators. And the company that supplied the long-lived photovoltaic cells for the Mars rovers, Boeing subsidiary Spectrolab, based in Sylmar, CA, is supplying more than a million cells for concentrator projects, including one in Australia that will generate enough power for 3,500 homes.
The thinking behind concentrated solar power is simple. Because energy from the sun, although abundant, is diffuse, generating one gigawatt of power (the size of a typical utility-scale plant) using traditional photovoltaics requires a four-square-mile area of silicon, says Jerry Olson, a research scientist at the National Renewable Energy Laboratory, in Golden, CO. A concentrator system, he says, would replace most of the silicon with plastic or glass lenses or metal reflectors, requiring only as much semiconductor material as it would take to cover an area the size of a typical backyard. And because decreasing the amount of semiconductor needed makes it affordable to use much more efficient types of solar cells, the total footprint of the plant, including the reflectors or lenses, would be only two to two-and-a-half square miles. (This approach is distinct from concentrated thermal solar power, which concentrates the heat from the sun to power turbines or sterling engines.)
"I'd much rather make a few square miles of plastic lenses--it would cost me less--than a few square miles of silicon solar cells," Olson says. Today solar power is still more expensive than electricity from the grid, but concentrator technology has the potential to change this. Indeed, if manufacturers can meet the challenges of ramping up production and selling, distributing, and installing the systems, their prices could easily meet prices for electricity from the grid, says solar-industry analyst Michael Rogol, managing director of Photon Consulting, in Aachen, Germany.
But the approach has been difficult to implement. "It has not delivered on the promise, mostly because of the complexity of the systems," Rogol says. The goal is to engineer a concentrating system that focuses sunlight, that tracks the movement of the sun to keep the light on the small solar cell, and that can accommodate the high heat caused by concentrating the sun's power by 500 to700 times--and to make such a system easy to manufacture.
In the face of this complexity, many have decided to focus their research efforts on cutting the cost of traditional "flat-plate" systems. This is done through making them thinner, to decrease the amount of semiconductor needed, or through turning to cheaper, though less efficient, organic materials. But now several companies claim to have developed reliable systems that can be manufactured on a large scale. For example, SolFocus is making a system that combines the concentrators and cells in one sealed package by employing manufacturing techniques similar to those used to make automobile headlamps. This way they can easily be created in large quantities, according to the company's CEO, Gary Conley.
As for the use of superefficient solar cells, critics originally said that although the cells worked well in the lab, it would be unlikely that their high efficiencies could be maintained in large-scale manufacturing. Unlike conventional solar cells, which use only one type of semiconductor (silicon), these more efficient cells, called multijunction cells, are made from layers of three types of semiconductor. This approach is meant to overcome a major limitation of silicon: although it can absorb photons from most of the spectrum in sunlight, it does so inefficiently, converting into heat, rather than into electricity, most of the energy in high-energy photons from the blue and ultraviolet parts of the spectrum. The multijunction cells use three materials designed to efficiently convert light from different parts of the spectrum, the result being that much less is converted into heat and much more into electricity.
All of the materials must be carefully engineered to work with the other materials, and they have to be assembled under very clean, well-controlled conditions. So in the 1990s, when this type of cell was still experimental, people called it "a laboratory curiosity that could never be manufactured in large volume," Olson says. "Now Spectrolab on their production floor does better than we do in the lab. So it basically blew that myth out of the water."
Other factors that have limited the use of concentrated solar, such as aesthetic objections to mounting concentrator systems on suburban rooftops, may largely restrict applications to commercial buildings or arrays in the desert.
But the advances that have come about, along with growing demand for solar and a shortage of silicon feedstock, have made concentrated solar photovoltaics attractive.
"There's a lot of uncertainty in this area, where historically there's been a lot of hype that just hasn't been delivered," Rogol says. "The biggest news for me is that serious solar people, over the course of the last year, have made notable commitments to concentrators."
Copyright Technology Review 2006.
This sort of news scares the heck out of radical Islam. They know their window of opportunity to defeat the west is dependent on oil profits.
Bump for later gettin-off-the-grid reading.
It's not that efficient if it needs a much larger sized-are of concentrator to make the small chip work. In theory, almost any solar cell would do better with large concentrator focusing more sunlight on it.
I don't think Christopher Reeve (RIP) will be walking anytime soon.
You should see the tiny little ants go up in flames when I do this to them... Ouch!!!
And don't expect that if an answer is found, that it will be made available to the regular Joe for alternative energy. There's no money to be made that way.
A free energy source would cripple our economy as we know it.
If Christopher Reeve starts walking again, I'm getting the hell out of this country. The moon might be a good place to start.
Do you realize how many dead people got up last Tuesday to vote? The Donks will have Mr. Reeve fixed up in no time!
It seems to me that a system of reclined troughs which track the sun, and focus onto concentrating solar cells -- which are cooled by a liquid flowing from bottom to top, and then into a water system pre-heater, would combine enough efficiency to be of great interest to the homowner.
Especially this homeowner. Hmm, make a great camper, too.
you comment reminds me of this comic book series called "grendel" a few years back... Similar story with a race to energy tech. First one there has all the political power.
Is Larry Flynt dead, yet? If he isn't, then he will be walking soon.
All thanks to the Democrats.
science be praised.
I would bet he voted, though.
You'll need some solar cells.
Actually, solar dynamic power generation would probably work better up there. A good system was designed in the sixties.
But he probably voted on Tuesday.
Imagine what happens if this tech is advanced enough just to power a single family home with normal usage.
All of a sudden, every utility company looses every residential account.
Coal demand down, prices plunge then mining goes out.
Also consider the impact on all those who live in areas where sunlight is not a given. In areas with mega condo growth.
It has to be transitioned. However once this hits it will not just be the USA it will be ALL the world.
EU would be devastated, Russia would be wiped out.
The Islamic world would be pushed back into a dessert tribe mentality. Oh wait, they would not change.
Does this mean that they will soon have an overweight problem too?
I can tell you right now that as long as they think that way, they will never succeed. (Unless of course they are Muslims, and believe that:
Tabari I:236 When the sun rises upon its chariot from one of those springs it is accompanied by 360 angels with outspread wings . When Allah wishes to test the sun and the moon, showing His servants a sign and thereby getting them to obey, the sun tumbles from the chariot and falls into the deep end of that ocean. When Allah wants to increase the significance of the sign and frighten His servants severely, all of the sun falls and nothing of it remains in the chariot. That is a total eclipse of the sun. It is a misfortune for the sun.
But it will be very difficult to make the system work with Allah screwing around scaring people whenever he feels like it..
Thats because the Democraps already have him raised from teh dead and flying
No problem. Just pass Allah a note that Mohammed wants things a certain way. He'll cooperate.
Allah lets Mohammed have anything he wants.
I don't know if this is real or not, but a lot of buzz has been happening in the marine message boards about it.
On a boat, it's not about $ per square foot, it's all about power per square foot.
What kind of working fuild will be used to carry away the heat?
Be fun to see how these turn out for residentail use.
That is why, even if a (over)unity device is invented,(and near unity, very efficient ones probably have been) it will never be allowed exist. It would change the world completely.
The devistation would be unimaginable.
In most parts of the country, water with a non-toxic antifreeze could be used. You would need a closed loop system with heat transfer as shown in this diagram. There should be no contact with the domestic water. (If toxic antifreeze is used, a double buffer system is recommended.)
You could also use a number of oils as a transfer medium.
"A free energy source would cripple our economy as we know it."
I don't think anyone is going to be giving away free energy. The trick is to find something cheaper than fossil fuels.
While it may change the economy as we know it, I don't see it crippling the economy. It might slow down or you might even see a boost while everyone scrambles to build a new infrastructure to support the technology.
Boeing? Cool. It would be great to have a solar house. Hopefully similar breakthroughs will come soon, for battery technology--to date the weak link.
Honda will bring Hydrogen cars out, soon. And they won't wait for the massive "infrastructure" delivery system problems.
Honda, long maker of small portable generators, will introduce household size hydrogen converters. Buy a car and converter as a system.
Apparently hydrogen can be made from natural gas.Thinking broadly on such developments, both seem to encourage property and home ownership.
A personal solar generating system is unlikely to be so portable, as to allow a renter to carry it from apartment to apartment.
And I doubt an apartment owner could easily set up for multiple converters to hook up to natural gas lines.
In both cases, property owners are favored. One more set of reasons for investing in real estate.
Just what we need.
Hire the illegals to polish the lenses everyday.
Maybe they can make a machine like a lawn mower and they can ride on it and do the four acres.
Yeah, we'd have to put Kerry in the Oval Office for that to happen.
Sorry, Mr. Reeve.
They'll have to raise Reeve from the dead first. Tall order.
We don't burn oil to make electricity anymore.
I have no affiliation with this company.
Nice job in manufacturing.
In the future, for driving, the feds are going to need a sun tax. And for taking a break, a shade tax.
How is ongoing development of alternative energy technology dangerous and stupid?
Your family can face extinction, mine won't.
So the solar panels on my boat are going to kill my family?
Then you just aren't thinking hard enough. First, you wouldn't need "new infrastructure" for such a device. Over unity means just that. It creates more power than is required to set it in motion, whatever form of motion that may be.
You wouldn't be able to give excess away, because everyone will be able to produce their own power according to their own need once this discovery is learned by the masses. Imagine there is no longer any need for electricity. It is now freely abundant.
Energy drives our entire economy the whole world over. Industry will collapse and disappear overnight. Sure, there will still be some consumer industry, but nothing near the scale there is now, all of which is based on petroleum energy and by products, and the cost of producing energy itself.
A cheap clean, alternative renewable energy source would be devastating to our petroleum based industry we have today, and will cause quite a economic downturn and a very long period of adjustment. But it still wouldn't be free.
Completely free energy is another beast all together. We are way too overpopulated for such a thing to become available. You won't die in the cold, but good luck finding a job. They will be very hard to come by.
Sharp shows off its flat lens? Cognitive dissonance....
A free energy source would cripple our economy as we know it.
I'm afraid you are right. Attempts should still be made though.
Energy costs are a large part of the productivity of the american (or any other) worker. Productivity drives wages.
If the cost of energy went to zero -- wages and employment would go up and not down.
Oh yes we do.
OK, here's my idea.
Manufacture 10-ft dishes that resemble the home satellite receiver dishes of the early 80s. However, the surface would be a mirror.
These dishes would be balanced so that they are able to move and track the sun with very little power required.
At the focal ppoint of the dish, you would mount solar receptor capable of receiving/converting HIGH tempratures into voltage.
This voltage is used to crack the hydrogen out of water. They hydrogen is then used to power fuel cells.
What would they be producing?
What the heck ever happened to the spray on solar stuff that got some press a while back?
I've been hearing this kind of hype about solar cells for about 45 years now, so I don't believe a word of this one. And I did some reearch on photovoltaics......
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