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Using a novel technology that adds multiple innovations to a very high-performance crystalline silicon solar cell platform, a consortium led by the University of Delaware (UD) has achieved a record-breaking combined solar cell efficiency of 42.8 percent. The current record of 40.7 percent was attained in December 2006 by Boeing's Spectrolab, Inc.
"The percentage is a record under any circumstance, but it's particularly noteworthy because it's at low concentration, approximately 20 times magnification. The low profile and lack of moving parts translates into portability, which means these devices easily could go on a laptop computer or a rooftop."
-- Allen Barnett, UD professor of electrical and computer engineering
The research was led by Allen Barnett, principal investigator and UD professor of electrical and computer engineering, and Christiana Honsberg, co-principal investigator and associate professor of electrical and computer engineering. The two direct the University's High Performance Solar Power Program and have been working to achieve the 50 percent efficiency goal set by the Defense Advanced Research Projects Agency (DARPA).
Barnett and Honsberg said that reaching the 42.8 percent mark is a significant advance in solar cell efficiency, particularly given the unique small and portable architecture being used by the consortium and the short time—21 months—in which it was developed.
Honsberg said the previous best of 40.7 percent efficiency was achieved with a high concentration device that requires sophisticated tracking optics and features a concentrating lens the size of a table and more than 30 centimeters, or about 1 foot, thick. The UD consortium's devices are potentially far thinner at less than 1 centimeter.
"This is a major step toward our goal of 50 percent efficiency," Barnett said. "The percentage is a record under any circumstance, but it's particularly noteworthy because it's at low concentration, approximately 20 times magnification. The low profile and lack of moving parts translates into portability, which means these devices easily could go on a laptop computer or a rooftop."
Honsberg said the advance of 2 percentage points is noteworthy in a field where gains of 0.2 percent are the norm and gains of 1 percent are seen as significant breakthroughs.
"This achievement is the direct result of the new architecture we developed under the DARPA program," Barnett and Honsberg said. "By integrating the optical design with the solar cell design, we have entered previously unoccupied design space leading to a new paradigm about how to make solar cells, how to use them, and what they can do."
In November 2005, the UD-led consortium received approximately $13 million in funding for the initial phases of the DARPA Very High Efficiency Solar Cell (VHESC) program to develop affordable portable solar cell battery chargers.
The highly efficient VHESC solar cell uses a novel lateral optical concentrating system that splits solar light into three different energy bins of high, medium and low, and directs them onto cells of various light sensitive materials to cover the solar spectrum. The system delivers variable concentrations to the different solar cell elements. The concentrator is stationary with a wide acceptance angle optical system that captures large amounts of light and eliminates the need for complicated tracking devices.
The VHESC would have immediate application in the high-technology military, which increasingly relies upon a variety of electronics for individual soldiers and the equipment that supports them. As well, it is hoped the solar cells will have a large number of commercial applications.
Today, the American soldier carries a pack that weighs nearly 100 pounds of which about 20 pounds are the three-day supply of batteries needed to power their gear. The DARPA program aims to dramatically reduce the battery logistics pipeline and provide the soldier with more power at reduced weight, thus improving mobility, survivability and the availability of advanced electronic technologies on the battlefield.
As a result of the consortium's technical performance, DARPA is initiating the next phase of the program by funding the newly formed DuPont-University of Delaware VHESC Consortium to transition the lab-scale work to an engineering and manufacturing prototype model. This three-year effort could be worth as much as $100 million, including industry cost-share.
During the first 21 months of the VHESC program, a diverse team of academia, government lab and industrial partners, led by UD, was focused on developing the technology basis for a new extremely high efficiency solar cell. The rapid success of that effort has enabled the present transition to a focus on prototype product development.
Barnett credits the early success of the program to the team approach taken to solving the problem. Partners in the initial phase included BP Solar, Blue Square Energy, Energy Focus, Emcore and SAIC. Key research contributors included the University of Delaware, National Renewable Energy Laboratory, Georgia Institute of Technology, Purdue University, University of Rochester, Massachusetts Institute of Technology, University of California Santa Barbara, Optical Research Associates and the Australian National University.
"What we've done," he said, "is create a virtual lab by having all of these companies, universities and national laboratories in the consortium. This has given us access to a broad range of capabilities in terms of expertise and equipment."
That approach is exemplified by the fact that the record-breaking system features three types of solar cells-one made by industry (Emcore), one by the National Renewable Energy Laboratory and one by UD.
"This is a solar cell that works," Barnett said, adding, "This technology has the potential to change the way electricity is generated throughout the world."
Barnett believes the 50 percent efficiency mark is just the beginning. "Our best inventions are in front of us," he said. "The consortium has been a super team, and has worked to develop new devices and architectures based on a breakthrough design paradigm."
The newly formed DuPont-University of Delaware VHESC consortium will be made up of industrial partners, national laboratories and universities. The consortium's goal is to create solar cells that operate at 50 percent in production, Barnett said. With the fresh funding and cooperative efforts of the DuPont-UD consortium, he said it is expected new high efficiency solar cells could be in production by 2010.
The real question is when are these incredible products gong to start hitting the shelves? 42% is great, when do we get to use it. Until these products are being installed, they are nearly irrelevant.
The solar industry has been promising alot for a very long time and never seems to get around to delivering these new miracle products for many years.
Fine lines:
"With the fresh funding and cooperative efforts of the DuPont-UD consortium . . ."
I have read 42.8 long time ago at: http://en.wikipedia.org/wiki/Solar_cell#Solar_cell_efficiency_factors .
Liquid cooled PV is out there and the concepts are actually simple. I think that the close marriage with liquid cooling and electricity adds just enough complexity to the arrangement that its penetration into the market place has been small. The idea though from an engineering perspective, IE solar thermal and solar electric being the "same" system is great from an efficiency point of view. The overall efficiency now can be 70+% and as the PV gets better the capacity generation from each form of power just shifts. Even cells at 50 and 60% efficiency would still benefit from a thermal pull off...
I think what is needed is some slick modularity and packaging... .....Bill
I agree with Eric as to keeping the focus of this forum to discussing and debating clean energy rather than divisive political bickering.
As for military funding, at least it is for a technology that will potentially save lives (reducing battery weight=greater mobility, portable systems=unmanned surveillance/detection) rather than weapons, right? And anyhow, perhaps the success of this program will only encourage funding for solar from other (more peaceful?) sources.
Anyhow, I think this will quiet any doubters of the program and I look forward to the press release of commercialization AND to when they announce the 50% efficient cell they've been promising.
Nie,
As a former "Moron Grunt" I am proud that you have the opportunity to express your opinion in the greatest country on earth. Rest assured that the vast majority of the US military are very highly motivated and deeply ethical. Do not the actions of a few mischaracterize the noble efforts of the many. yes the job is violent at times, but it is also very giving and idealistic the reaminder.
As far as looting and pillaging, I'm not sure what you are referring to. As far as i know we, th military or the US have not taken anything from Iraq in the form of Oil or payment for their liberation. We have left many our dead and vast amounts of our treasure for their betterment.
I wouod hope that we could focus future discussions inthis forum on the topic of clean energy and not pollute it with vile personal attacks on anyone. We should be able to keep this professional so that everyone will feel welcome to contribute. I hope that you will consider this...and by the way...it nice that we may see a peace dividend from DARPA's efforts...I hope we can agree on that.
I think his point was that "better killing" is once again the motivator for change. A sad reality for mankind. The military industrial complex which includes the oil companies and 95% of the money on the planet, as it exists today, was Eisenhower’s worst fear for America once we had "the bomb".
"Projects that will further alienate the Globe against us" H Nie. Are you serious? This project, if it works and can be mass produced, will help us become an energy independent nation. With cheap solar cells that are 50% efficient, we will be able to move away from an oil economy, thus protecting our national security and the environment. The US is one of the world's top polluters, if we went solar because of a militarily funded program, we would be a beacon of environmental stewardship for the rest of the world to follow. This project has the potential for great things. Just like the internet, which was helped along its early stages by the US military, this project can drastically improve the world.
I recently visited the Smithsonian Air and Space museum and took the time to really look at the first satelittes that were made to orbit the earth. If you look at them they have on their exterior the worst looking photovoltaics I have ever seen. Looked like something I put together in my shop.
In 1965 however, guess what? that was it!
I believe those cells were only 10% efficient. Here we are in 2007 with a near production model 43%, not bad. If we are lucky enough to go to an 80% efficient cell in the next 40 years we will have an entirely different world economy with energy basically provided free to everyone. Imagine that.
If 10% of our roof tops had any type of solar systems, our bills would be sooo sky high you could not believe it. The idea of dumping $20,000 (60 million homes times 10% equals 6 million x $20,000 equals $120 trillion dollars) on 10% of the homes in America is a scary thought. Since the rate of return on these systems is around 3%, the governent would have to subsidies the entire make work program. Only the real fringe of the enviromental movement will build systems that take over 30 years of electric bills to pay off.
We would not have to worry about roads, schools or hospitals, since we wouldn't have enough money left to pay for any of them. Remember the current solar power systems are glorified welfare programs. Solar has the distinction of being one of the least affordable renewable energies.
Wow, quite an array of opinion and commentary!
I am in agreement with the idea that some government body, be it the military or the Dept. of Energy, putting money into scientific research & industry that will develop alternative energy and technology for us, the consumer/ citizens.
We will have access to it soon.
Look at some of the many advances coming from govenment investment in military applications: computers (origins are targeting computation and code-breakers), night vision technology, GPS technology, Gore-tex, and even the chem-light! We will not be at war forever, though it may feel that way, and the budgets will be diverted into other hopefully very useful and environmentally friendly uses.
I am for PV and am willing to sacrifice myself (and my money) at the present level of efficiency. Perhaps there will be a company that would offer efficiency upgrades at a discount for their older customers? Hmm.
I'll also think that there is a very wide use for other approaches to solar light and energy: to produce Hydrogen for example, (solar tubes) replacing light bulbs to light our homes, thermal to heat (or preheat) our water, evaporation to distill our water, and Wind energy as a byproduct of solar heating of the earth.
Let's just say that 10% of all rooftops with present day PV efficiency would go a very long way to reducing our gas, coal and oil dependence, and PV @ 40-50+ percent efficiency on even more rooftops (of the future) could eliminate the need. [An aside - Power companies better get their act together and invest in offering PV units for their customers at little cost and reap the benefit as their installations produce as much capacity or more than that household or building needs - a surplus!]
Lastly, the by-products of the manufacture of any of the above technology could pollute, but one industry's byproduct is another industry's gold. Much can be recycled, and pollution averted.
Thanks for reading my ramble.
It's not about % eff, it's watts per $1. We have enough area for panels I run my home on a grid tied system and send extra back and help the power company and it's only 2.4 kw. I have room for 30K if I wanted.
It's also about efficiency like LED lights and energy star products. We have to start thinking and using the technology we have instead of wanting more power and higher efficiency per cell. We gave all we need, let's just use it.
Sunpower is 22% efficient by the way aqnd has a 25 year warrenty like most solar PV. A few space cells at 25% crach in the heat of earth.
Great news for solar cells and mankind; but let us pay homage to the source of the power. Hydrogen that great ball of sunshine that pops up over the horizon every morning without fail.
Putting H. "tHe friendly element" to work.
Mike H. founder HYDROGENHEADS
Obviously this is a technology advancement announcement , which is much different than commercial availability. However, this does not necessarily mean that these cells will never have commercial viability. If anything, the technology behind the cells can have significant commercial implication.
For example, no one produces PERL cells (record holders for crystalline silicon efficiency--http://www.pv.unsw.edu.au/links/products/purchase.asp) on a large-scale commercial basis. However, some of the technology used (texturing, back contacts, selective doping, etc.) ARE being used in commercially available high efficiency solar panels today. Similarly, I think the advances being done here will absolutely have commercial implication. For one, notice that these cells achieved 42% with only 20x concentration as opposed to the 500x (I think, someone correct me if I'm wrong) needed for the previous record holding Spectrolab cells. Obviously, there are some novel breakthroughs going on here. Nothing says that in a decade (or hopefully less), these technologies won't be implemented in publicly available products.
As a fledgling in the solar world, I don't remember when solar cells were only viable for space applications, but aren't we talking about similar things here? There's always time between advanced research and commercial application, so those promises of lowered costs and improved performance are manifesting themselves but at a delay.
Full Disclosure: I was an undergrad student of both Chris Honsberg and Allen Barnett, but was not involved with this particular program
(just another comment or two)
I forgot to indicate my work with AR coatings was in 1975. Subsequent research was initially on amorphous silicon solar cells but efficiencies were too low.
I performed semiconductor R&D for about 17 years on a variety of semiconductor materials at GE, Rockwell, McDonnell Douglas, and Northrop in addition to testing semiconductor devices at Hughes, and Boeing and am very happy at the achievements Al's group made.
(CONTINUED)
the efficiency of arrays was FAR LESS. I demonstrated that AR coated silicon cells [for Hughes to be used on their satellites (mounted on the outside of the satellite rather than on expandable 'panels' as is done today)] had a higher efficiency than did non-AR (anti-reflection) coated cells. Typical cell efficiency increased from about 7 to about 8 percent. The silicon cells were about one inch square.
I am excited about the improvements Al's group has accomplished. Heterstructures containing III-V , II-VI, and II-IV-VI layers should also significantly increase potential efficiency [III-V indicates the layer is made of materials from the third and the fifth columns of the periodic table.].
Like the GPS, Satellite photography (Fresnell lens technology), www2 and other truly significant improvements in technology, >40% terrestrial PV cells will never make it to the public because the military has a chokehold on all things technical. Illegal corporate spying has been around much longer than illegal civilian spying.
Industrial espionage has been a staple of the US (and others) government/military policies for decades. And with the NG, nuclear, utility cartel constantly looking over the shoulder of Congress, that won't change soon.
Pay attention to the national RPS legislation as a perfect example. Do you really think it will be allowed to pass? My money says no; hope I have to eat my words.
Jim Duncan
North Texas Renewable Energy
What these kind of articles never address is what would be the estimated (high volume) manufacturing cost of a panel with this kind of technology. That is really the key as to it's viability. If, for example, to get this kind of efficiency, you have to fill the thing with gold and have an ounce of plutonium embedded into the cell, it's never going to be produced.
My PV system runs on Sharp 175's that are 13.5% efficient, so 43% would be a miracle, but, as far as I'm concerned, not giving an estimated cost is the same as not being produced.
This gain in power and reduction in size is definitely good news.
And, I know this is not a political board, but I just have to point out to that while I agree with much of Eric Hansen's defence of the members of US military, Mark is wrong that the US (or, more specifically, the Bush/Cheney Admin) did not start the conflict in Iraq. There was no link between 9/11 and they knew it, but they went anyway (because mere facts don't seem to matter much to them). I don't blame any of that on the troops, but it is clearly the fault of this particular US Admin, which has a record of getting it wrong on most things, including energy policy and the environment, and then compounding its errors with completely incompetent planning and implementation. Unfortunately, good planning and implementation also require a grip on reality and something more than a cartoonish understanding of the world outside their immediate circle of cronies and yes-people; but, sadly, this is an adminstration that tries desperately to insulate itself from anybody other than cronies, sycophants and yes-people (or as they like to put it, people who "get it").
For those of us out there that are actually using PV technology for powering our homes, it would be great to see some cells put into the market place with efficiencies higher than 17%, let alone 20 or 42.8%! I keep reading about all these advancements in technology, yet it is still the old Sharp, 12.5% efficient modules that are running my fridge and turning on my lights.....two questions I would have - when are we going to see something that I can purchase and plug into my Outback system? and How much will it cost? We in the consumer world of PV technology are getting tired of vague promises....in the meantime, my Sharp modules keep putting out those amp-hours, and my kid can sleep well knowing she will have power for another day.
Tom
One other factor not mentioned is the energy used to manufacture these cells. Under normal conditions how long will it take for these cells to give back the energy it took to make them in the first place? The other concern not often mentioned is how much pollution, toxic waste, and water contamination was created in the manufacture of these cells.
Granted, all other things being equal a more efficient cell will be better in these aspects than a conventional cell. But I doubt all other things are equal.
Derek
This new mark is solar cell efficiency when made widely available via scale economics will be a boon to all in so many ways. There is one thing I noted in the many terrific, erudite posts that needs not stand unremarked:
Mark ~ "We" absolutely did "start this conflict."
As anyone in the PV industry knows 40+ % cell efficiency would be great.
I think it is irresponsable for these companies to come out with these press releases. Nothing of the sort will be avaliable in the next 50 years. they are grandstanding for research grants.
We were told 10 years ago Thin film was the next best and greatest thing to come along, not, It is still half as efficient as crystalline, and get this it costs twice as much.
Mark my words no one will see these Cells in modules as we are using today in residential & commercial installations in the next 20-30 years....
I would love to see it, just not going to happen in our lifetime.
The public reads this and will make their decission not to buy a solar system now, instead they will wait, and wait they will.
Just one mans opinion,
Aram
Then theres the one about the Monkey and the Orange.
It seems there was this Monkey that came across a jar one day and in the jar there was an Orange. Well, being the simple minded primate that it is all the Monkey knew to do was to put its hand in the jar, grab the Orange and pull it out. But wait! A crisis. The Monkey could not pull its hand out with the Orange in it. So no Orange. Obviously to us Human beings, being of a higher order of primate, the solutuion is simple. Turn the jar over and let the Orange fall out.
It would appear though, that we are not of a higher order in this regard, when it comes energy. In a sence, we keep putting our hand in the jar trying to pull the Orange out and of course it will not come out with our hand around it. So, whats the answer to our energy crisis? Is it deductive reasoning that leads us towards technology in this regard? Or perhaps this is just plain cheating? Taking a hammer and smashing the jar? How do we as a higher order of primate, get the "energy Orange" out of the jar? Could it be that the simple act of turning it off is the answer? After all, why did we invent the off button if arent going to use the damn thing?
Of all the descriptions used, concerning this article and its content, the most obvious description has been completely missed!
Insanity or mass hysteria. Take your pick.
I never get tired of writting this - For well over 7,000 years human beings more than survivied, we flourished, on the planet Earth without the need for all this energy we use today. The fact that we are here today is testimony to this self evident truth. It has only been within the last 100 t0 150 years that this madness for more and more energy has become a plight, not just on the human race but on the entire planet Earth.
Reminds me of that story, I dont recall its name or author, but its about this village and how all the people in that yillage died, ether by there own hand or by anothers, lusting after an evil witch. Believing with every fiber of there soul that they had to possess her. Of course they didnt know she was a witch until it was to late.
Dont get me wrong, I am not against enrgy in its vast array of utilizations. I am simply making an observation of the human races behaviour revolving around energy.
Let me spell it out for you. Y o u r a l l i n s a n e !
If you want to be energy independent as a nation, then simply turn it off. But you cant can you? There seems to be some sort of taboo making you believe that this action will make us weaker as a nation when compared to other nations. We have to produce. We have to consume. We have to multiply. We have to protect. In some ways this sounds like the actions of virus, a disease, spreding out leaving dead or dying tissue in its wake.
Its been said that, "Blessed are the meek, for they shall inherit the Earth." If this be true, I have to wonder, just what kind of wasteland will they inherit?
Well Jim Berry, solar energy may be expensive but we have got to start lessening our dependence on foreign oil so that we will have no excuses to get ourselves involved in messes like Iraq.
And by the way, the Us is behind the eight ball on all renewable forms of energy. Germany and Japan are very supportive of solar energy, dispite its cost. In fact, the citizens of Germany voted to increase their electric bills to help support. it.
How's that for collective consciousness?
I think that splitting and concentrating the solar spectrum is the way to go.
There are some patents on that specifically
http://www.pat2pdf.org/patents/pat6469241.pdf and
http://www.pat2pdf.org/patents/pat7206142.pdf
There
is
The tipping point I referred to above is the confluence of 1) widespread perceptions about global warming, 2) inevevitable taxes/caps on carbon emissions, 3)increased world-wide demand of all fuels and raw materials used in todays energy generation, 4) soon-to-be increased incentives from federal/state/local agencies to offset RE systems costs, and 5) significant improvements in raising the effeciency of concentrating PV. (Finally got back on track with the topic! ) The costs for fossil, and even nuclear fueled generation is about to dramatically increase---guarranteed.
But I, like many of you here, am disappointed that nothing seems to be happening outside of the lab. In fact, I believe that the industry may be infected with group think; where they misinterpret the goal to be the objective. It's the old 80/20 rule; they think they MUST get to 50% efficiency (and now they are only about 80% there.) They, and others will probably spend 80% of the entire federal/private grant money pursuing that last 20% efficiency, and it may take years. Here's the ahah moment: the real objective is to obtain cost effective renewable energy. Hello?? Guess what? You're there!! Continue experimenting, if you must, but get these damn things into production NOW. It's going to take time to perfect the manufacturing processes, and supply chain, but unless we get these things out of the lab, we will always be "about 18 months away". This is a golden opportunity to sieze the synergy developing around renewable energy, particularly solar, where the consumer is becoming more skeptical that we will ever deliver what we've been talking about for years.
There is a universal saying that "Those who wait for 100% of the answers before making a decision, will lose to their competition 100% of the time." Therefore, the benchmark is to pull the trigger whenever you reach about 80% certainty. Funny how that 80/20 rule applys to so many things. C'mon guys; pull the trigger!!
Well, I hate to be supportive of the work of the devil Thomas, but I have to take issue with your comments. You are welcomed to retreat back into the little house on the prarie, if you wish, but then plan on spending about 90% of your waking hours scrounging for food, fighting off predators, and wondering if you'll live through another winter, or drought. Technology is not our enemy; it facillitates our natural yearning for a lifestyle full of diverse experiences, and comfortable existence. And yes, ENERGY is a significant component of technological progress.
Have we gone too far? Perhaps. Some would suggest that modern lifestyles allow young and old to waste their time as couch potatoes, or avid gamers with no redeemable contributions to society---and technology/cheap energy has made that possible. Some might even question the value of this blog, where all this intellectual horsepower and critical thinking is not producing a single widget, or solving any problems. But I believe we have reached a tipping point, as my next post will explain.
About orders of magnitudes ...
Author: Jim Berry Date Posted: August 1, 2007 If 10% of our roof tops had any type of solar systems, our bills would be sooo sky high you could not believe it. The idea of dumping $20,000 (60 million homes times 10% equals 6 million x $20,000 equals $120 trillion dollars) on 10% of the homes in America is a scary thought.
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