Subscription Center
Aug 27, 2009 08:01 AM | 28
Here's a seemingly simple solar power fact*: the sun bathes Earth with enough energy in one hour (4.3 x 1020 joules) to more than fill all of humanity's present energy use in a year (4.1 x 1020 joules). So how to convert it? In the world of solar energy harvesting, there's a constant battle between cost and efficiency. On the one hand, complex and expensive triple-junction photovoltaic cells can turn more than 40 percent of the (specially concentrated) sunlight that falls on them into electricity. On the other, cheap, plastic solar cells under development convert less than 5 percent.
In between, ubiquitous photovoltaics—the multicrystalline silicon solar panels cropping up on rooftops across the country and, indeed, the world—struggle to balance the need for (relatively) easy manufacturing and low cost with technology to get the most electrons for your solar buck.
Yesterday, Spectrolab announced that its newest triple-junction solar cells had achieved the world record in efficiency, converting 41.6 percent of specially concentrated sunlight into electricity. All told, a tiny cell just 0.3174 square centimeters turned the sunlight equivalent of nearly 364 suns into 4.805 watts. That kind of efficiency is why 60 percent of satellites in orbit today bear earlier iterations of the technology; that's a total of roughly 640 kilowatts of Spectrolab cells circling Earth.
Those cells cost 40 cents per watt, according to the manufacturer—if you happen to have the sunlight equivalent of 500 suns streaming down while enjoying a temperature of 25 degrees Celsius. In reality, only specialized applications like satellites (and government contractors or agencies like NASA) can afford the technology.
More Earth-bound photovoltaics, like Suntech's Pluto line of multicrystalline cells, which boasts 17.2 percent efficiency converting one sun's light into electricity, or Suniva's ARTisun single silicon crystal cells that can convert 18.5 percent of the sunshine into electricity, cost more than $2 per watt. Installation roughly doubles that price.
Bringing the cost of just the photovoltaic cells down to about $1 per watt is the magic number solar manufacturers are aiming for, figuring that will make them cost-competitive with electricity produced by burning natural gas. Some manufacturers of thin film cells (less efficient but cheaper), such as First Solar, claim to have reached that mark, with efficiencies around 10 percent. Finding a way to further boost the ability to convert sunlight into electricity while also lowering costs to this level would herald the true dawn for solar power—something anticipated since photovoltaics were discovered.
Image: Germanium wafer courtesy of Spectrolab.
* This sentence was changed to correct my erroneous understanding of the definition of "factoid." Thanks MechaMunch
Tags:
alternative energy,
solar cells,
sunshine,
green power,
solar energy,
solar power,
solar panels,
photovoltaics,
energy,
renewable energy
More News Blog:
Next: Death of the directory: When was the last time you opened a phone book?
Previous: Check please: Can the din of a restaurant help Parkinson's patients with speech troubles?
See what we're tweeting about
BoraZ Why a Science Experiment Gone Bad Doesn't Make Me a Criminal http://t.co/1jWbYNgtqw BoraZ RT @jayrosen_nyu: Public television’s attempts to placate David Koch. http://t.co/Bpn8E6sH1W A devastating account ...
DrJudyStone And thank you for kind words and RTs on Lieberman post: @medskep @Claresy_Bear @LeighGTurner @kbellbarnett @scopedbylarry
Deadline: Jul 30 2013
Reward: $100,000 USD
The Seeker desires a method for producing pseudoephedrine products in such a way that it will be extremely difficult for clandestine che
Deadline: Jun 29 2013
Reward: $7,000 USD
The Seeker for this Challenge desires proposals for chemical methods that could rapidly degrade a dilute aqueous solution
Powered By: 
YES! Send me a free issue of Scientific American with no obligation to continue the subscription. If I like it, I will be billed for the one-year subscription.
28 Comments
Add Comment"Factoid" means fake fact, not small fact. Yeesh.
Reply | Report Abuse | Link to thisyou're right. and here i always thought a factoid was just kind of a "talking point." i'll make a change. thanks
Reply | Report Abuse | Link to thisok...this is the real world operation problem...this is an expensive triple junction InGaAs cell...and it is showing this high efficiency under 364 suns....but out there in the wild, there is only one sun, and that one is also changing its position constantly, so....the efficiency shown here has no real, practical and factual meaning....people in the solar cell business know that if theoritically modeled as a Carnot system, a single junction Si based solar cell at 6000* F has a max efficiency of 43.5%...but this can't be ever achieved... similarly this number is also not of any real use....it is really unfortunate that so much money goes into research...where as most of this money must go into deployment of the solar farms, and the improvement of the existing grid...look at what happened to the Pikin's sponsored wind farm....that would have been a good start...but just because of the primitive grid...the whole plan got scraped...big mistake and our loss....we all will regret this...as time passes on the cost of getting stuff and deploying it rises also...and soon it will overtake the benefits....then ...well won't we all say..."didn't i say so...!"
Reply | Report Abuse | Link to thisok...this is the real world operation problem...this is an expensive triple junction InGaAs cell...and it is showing this high efficiency under 364 suns....but out there in the wild, there is only one sun, and that one is also changing its position constantly, so....the efficiency shown here has no real, practical and factual meaning....people in the solar cell business know that if theoritically modeled as a Carnot system, a single junction Si based solar cell at 6000* F has a max efficiency of 43.5%...but this can't be ever achieved... similarly this number is also not of any real use....it is really unfortunate that so much money goes into research...where as most of this money must go into deployment of the solar farms, and the improvement of the existing grid...look at what happened to the Pikin's sponsored wind farm....that would have been a good start...but just because of the primitive grid...the whole plan got scraped...big mistake and our loss....we all will regret this...as time passes on the cost of getting stuff and deploying it rises also...and soon it will overtake the benefits....then ...well won't we all say..."didn't i say so...!"
Reply | Report Abuse | Link to this@supersaurabh: Firstly, the practical application of this cell is in a solar concentrator, not as a conventional solar panel. This reduces the cost as you only need a small amount of high-efficiency, high-cost material. Secondly, a photovoltaic cell is not a Carnot engine and it makes no sense to try to model it as such.
Reply | Report Abuse | Link to thisPractical application? There is no on-Earth practical application for a solar cell that requires both a high concentration of sunlight and a 25C working environment. Useful in the chill of space, not so much here on Earth.
Reply | Report Abuse | Link to thisI've leave as an exercise for the readers to calculate how many watts of cooling would be required to chill something that size to 25C in the glare of 364 suns. Any guess on what multiple of 4.805 watts that would be?
Is that a simple solar power fact? I don't know of anyone who could easily fathom the amount of sun that shines on the entire earth for an hour or the world's yearly use of energy. I recommend giving people stats they can use (small, but relevant) i.e. 1 square meter of sunlight is around 1000 watts (any person can remember this forever, even if it is not exact). Take a square meter of these panels and you have around 416 watts or about the energy to use 4 old 100 watt light bulbs (or whatever comparison you want but something people can relate to). Using numbers people can relate to will increase their understanding of the science (worked for me listening to Richard Muller's UC Berkley class called Physics for Future Presidents).
Reply | Report Abuse | Link to thisToo many people in the scientific community are skeptics (not that it hasn't always been that way!). Sure, these are small steps, but we can't forget what amazing technologies have been created by time, determination, and countless small steps. Personally, I congratulate the developers whose hard work has brought a bit closer to solving the biggest socio-political problem (as well as ecological problem) of our time-- energy consumption.
Reply | Report Abuse | Link to thisAs Setorius said, the practical application of these modified cells are not in traditional flat panel configurations, but in concentrators.
Reply | Report Abuse | Link to thisI have played around with concentrators and have maximized the efficiency of a set of ~14% panels by using a light-gathering plastic tubing (not glass fiber-optic) running the length of my gutters and using fiber lines (real glass fiber-optic)to rout it to the two panels next to my battery bank, Everything in my house except microwave and stove runs on 12V.
The two 12V marine batteries in my bank have never been unintentionally drained by normal usage (of one man). The system actually came from my sailboat and it was refit to my house.
Reply | Report Abuse | Link to thisThat being said, I would also point out that using high grade light filters (like ones used in astrophotography ) in the fiber lines would block out the spectrum's not utilized by the photovoltaic cell will significantly* lower the temperature of the photovoltaic; The highest grade filters for a 2" are a fraction of the cost of large cooling systems. Once combined with a cheap convection cooling system perhaps 25' C can be obtained cheaply. I don't have .40cent/Watt cells and my system runs hotter than 25'C but it's a cheap system for a hermit like myself and It runs my house.
In the end, in a four person household, the new spectrolab 41.6% cells and a decent concentrator setup could power a regular home (minus stove, microwave) without giant bulky arrays of panels on their roofs that cost a lot to maintain. I don't think this type of system would need the same cooling as the .40cent/ Watt cells, and would be slightly cheaper.
Initial system cost will be high, but low enough to be afforded my most homes.
Adding one last thing, my house and everything in it except dryer/micro/AC are from my boat (which I lived on for a long time sailing the world) and I run a minimalist home, never wasting water or leaving a light on. I run my TV,DVD/VCR, HAM radio,refrigerator, washing machine (not dryer), desktop computer, and CFT bulbs all off my 12V boat system. I draw from the grid only for dryer,Mic,AC...collectively insignificant since they only run for short periods.
Reply | Report Abuse | Link to thisSomeone help me out here. How much energy does it take to manufacture these inefficient technologies for mass consumption? Where does that energy come from? Will these wonderful solar technologies ever recover the amount of energy that they cost to produce? Just wondering.
Reply | Report Abuse | Link to thisRelatively little solar money goes toward this research. The bulk of research is spend on making earthbound solar more affordable.
Reply | Report Abuse | Link to thisIncidentally, CPV does make this exact technology viable for earthbound use in Utility scale operations. Not as good as solar thermal, but this is the kind of research that will bridge that gap. There are serious advantages of CPV over thermal-CSP if they could get it cost competitive, and it's getting closer and closer.
Relatively little solar money goes toward this research. The bulk of research is spend on making earthbound solar more affordable.
Reply | Report Abuse | Link to thisIncidentally, CPV does make this exact technology viable for earthbound use in Utility scale operations. Not as good as solar thermal, but this is the kind of research that will bridge that gap. There are serious advantages of CPV over thermal-CSP if they could get it cost competitive, and it's getting closer and closer.
Wow, that's service. Thanks!
Reply | Report Abuse | Link to thisWow, that's service. Nice article. Hope it's as efficient as early reports say.
Reply | Report Abuse | Link to thisFactoid? Quite appropriate usage given the original definition was "facts which have no existence before appearing in a magazine or newspaper".
Reply | Report Abuse | Link to thisIn common usage the relevance of a factoid is where it's expressed, rather than any inherent information, true or otherwise. Were it merely false, what would be the point of the word other than a lazy over-simplification?
Deckchairs on the titanic people .... the rate research increases the amount of power you can generate is dwarfed by the rate population is increasing .... we'll just go nuclear and fill the world with waste we can't even get rid of now ... then our grandkids with say "WTF were they thinking"
Reply | Report Abuse | Link to thisNatives of Northern Canada quietly build Super-insulated straw bale houses and just using this unimaginably crude technology live almost fuel free in the most arduous of climates, where winter temperatures reach and sustain 40 degrees Celsius below zero for weeks at a time! Imagine, if NASA's space age equations, and super insulation materials and technologies for space travel were applied to the average new American home! We quite likely can reduce the amount of energy we use, for air conditioning, heating, lighting and cooking, just by applying existing science and technology! But we don't! See the movie about the EV-! for why? Who Killed the Electric Car! Yankee Assholes!
Reply | Report Abuse | Link to thisThe following is a useful observation on how "factoid" is used:
Reply | Report Abuse | Link to this"[...] factoid originally referred to a piece of information that appears to be reliable or accurate, as from being repeated so often that people assume it is true. The word still has this meaning in standard usage. Seventy-three percent of the Usage Panel accepts it in the sentence It would be easy to condemn the book as a concession to the television age, as a McLuhanish melange of pictures and factoids which give the illusion of learning without the substance.�Factoid has since developed a second meaning, that of a brief, somewhat interesting fact, that might better have been called a factette. The Panelists have less enthusiasm for this usage, however, perhaps because they believe it to be confusing. Only 43 percent of the panel accepts it in Each issue of the magazine begins with a list of factoids, like how many pounds of hamburger were consumed in Texas last month. Many Panelists prefer terms such as statistics, trivia, useless facts, and just plain facts in this sentence." (New Heritages Dic, http://education.yahoo.com/reference/dictionary/entry/factoid
So it has two meanings. For me, the way David Biello uses it is now the primary meaning, and I'd prefer an alternative expression for the other meaning, like "fake fact" or "media 'fact'". Normally I'm a language pedant, but in the sense of a stickler for 'clean' meaning. Language changes, however, and I detest hypercorrectness where trivial details of archaic usage are turned into shibboleths to catch people out. Or new usages are invented to show off non-existent learning (like the use of 'virii' as the plural of 'virus').
Truthseeker1000... the biggest socio-political problem (as well as ecological problem) of our time-- energy consumption . The only problem I see with your conclusion is forgetting the amount of energy consumption is directly connected to the larger problem of population control. As long as no one is willing to step forward and show the courage to honestly deal with methods of controlling the planets birth rate, all other issues are insignificant by comparison. As long as the birth rate stays so far ahead of our ability to care for these new inhabitants of this world, things will only continue to get worse. We see the pictures of conditions in "third world" countries and all the pleas for help. Simply make birth control a condition of aid. In actualality the difference in conditions here in the U.S. is only in numbers. We have the same problems as the other parts of the world. The difference is in who we are concerned with first. Help out at home, then take on the rest of the world. If the U.S. had half its current population numbers think how much better the quality of life would be. Religion (socio) and greed and outright theft of our resources (political) were really interested we could make this part of the planet a true paradise. That is if we can afford the cost of putting at least part of our planet back together. Think Super-fund cleanup funds. The only thing cleaned was our wallets by the Government.
Reply | Report Abuse | Link to thisWhat amazes me is that those who's ego insists they make as many copies of themelves as possible never look ahead to see what they are passing on to those self images. Not as much as was once possible and less and less each time a birth is counted by our politico's
For the rest of those "third world" countries, what else is there to enertain the population after dark?
THIS DISH/MIRROR TO HEAT A STERLING ENGINE IS NUTS! It will work but need a large amount of maintenance, oil for the moving parts , cleaning and field maintenance to name a few. the tower collectors to create steam work well but share the same problems. (spend your money on current cells) take what we know works with NO MOVING PARTS; PV Cells and run with it. Easy maintenance...readily available, and costs are now at an all time low. My 2 cents. www.evergreensolarinstaller.com
Reply | Report Abuse | Link to thisJust one more thing,..(Salt Paste) 6-parts sodium nitrate to 4-parts Potassium nitrate, mix with brine paste to form a thermal battery, at well over 400 degr. F you make steam of any fluid that has a lower boiling point... combine the two of concentrated collectors on a fixed battery of this mix and you will hold the heat for days!!! a constant like that would yield a steady supply of energy in much the same way a PV system stores power in a battery for electricity. Go with what works! PS Yes the both mentioned chemical compounds are used in explosives but here they are in a stable form.
Reply | Report Abuse | Link to this"In the world of solar energy harvesting, there's a constant battle between cost and efficiency."
Reply | Report Abuse | Link to thisThis statement is false.
"Agua Luna" renewable energy for lighting up your home. All of us would have heard of "Agua Luna" solar power somewhere or the other. We have abundant energy from the sun that can be tapped up and used to provide electricity for our home sweet home. All you need are some "Agua Luna" solar panels, batteries and control systems and you are good to go. The initial setup might cost you a bit, but then that is it. "Agua Luna" - You are off the grid and power up your house with these solar panels. You are no longer tied down by those monthly electricity bills.
Reply | Report Abuse | Link to thishttp://www.agua-luna.com
http://twitter.com/americandollars
http://www.facebook.com/Agua.Luna.Fans
http://digg.com/environment/Agua_Luna_Review
http://www.free-press-release.com/news--http://agua-luna-how-to-build-wind-power-1265810855.html
http://www.prlog.org/10527104-agua-luna-how-to-build-wind-power.html
As solar energy continues to advance, <a href="http://www.sharpusa.com/SolarElectricity/SolarProducts.aspx">Solar Electricity</a> is becoming an even more obvious way to not only reduce the amount of environmental pollutants omitted into the atmosphere, as a result of more traditional methods of burning of coal to generate electricity, but as a way to cut down cost for electricity for consumers long term. I work with Sharp who offers free solar energy consultation and will even help you to determine the cost savings of going solar long term.
Reply | Report Abuse | Link to thisWow! Great info.
Reply | Report Abuse | Link to thisScientists have continuously been involved in various research oriented programs to devise such alternative strategies. They have come out with innovations that led to the development of solar panels resulting in other devices like solar cells, solar cookers, solar heaters, watches etc.The best thing about these solar panel cells is that you can make them on your own. We are here to help you out. The discovery of Albert Einstein has become so simple that it can be availed at home. It will not only save a lot of money but also will ensure a better and contended life.
Here the elaboration of working of solar cells has been done immensely well. I think the next step to this can be <a href="http://www.howtomakesolarpanel.biz/">how to make solar panel</a>! Hope people find out the ways to learn it too.
Wow! Great info.
Reply | Report Abuse | Link to thisScientists have continuously been involved in various research oriented programs to devise such alternative strategies. They have come out with innovations that led to the development of solar panels resulting in other devices like solar cells, solar cookers, solar heaters, watches etc.The best thing about these solar panel cells is that you can make them on your own. We are here to help you out. The discovery of Albert Einstein has become so simple that it can be availed at home. It will not only save a lot of money but also will ensure a better and contended life.
Here the elaboration of working of solar cells has been done immensely well. I think the next step to this can be <a href="http://www.howtomakesolarpanel.biz/">how to make solar panel</a>! Hope people find out the ways to learn it too.