Solar cell breakthrough: 40% efficiency achieved

If that silly Hummer O2 concept vehicle we just saw didn't sate your appetite for environmental friendliness, try this on for size: researchers at Boeing-Spectrolab have just succeeded in building a multi-junction solar cell that achieves an incredible 40.7% efficiency, or -- to the best of our knowledge -- about twice that of the reigning champ in this space. To put this Department of Energy-backed breakthrough in perspective, it was less than two months ago that Silicon Valley-based SunPower announced a 22% efficient cell, and even that model was claimed to produce 50% more power over a given space than previous iterations. In case you're unfamiliar with multi-junction cells -- no shame in that game -- they can best be described as being composed of several layers, with each slice capturing only a portion of the solar spectrum; this method of optical concentration is what has allowed cells to surpass the 12% to 18% efficiency barrier faced by most traditional modules. In conclusion, while this is certainly an encouraging development, we remain somewhat skeptical about its potential for real-world implementation: once Big Oil gets wind of this new tech, it will likely "disappear" just as quickly as that guy who invented a car that runs on water, man.

[Via Slashdot]

[AussieBob @ Mar 27th 2008 5:08PM]

Spectrolab PV cells are being used in sun tracking Parabolic Sunlight concentrators by an Australian R & D company. They operate at up to 36% efficiency in Melbourne summer sunlight in controlled testing over an extended period of time. Spectrolab make ½ a dozen different types of cells and I'm not sure which one is being used by this company. This company has developed their own inverter and storage cells and wind power generators, and they hold patents on all items. These are approaching commercial production with licenses having been sold internationaly already. hey are expecting to sign with

[Grant @ Aug 15th 2008 12:34PM]

"Concentrated sunlight" means exactly what it sounds like- sunlight is concentrated to a greater-than-typical intensity via the use of mirrors or lenses. This is done for multiple reasons. The most important ones:

1. With proper heatsinking (cooling), a given size of solar panel may be used to capture the light from a MUCH greater area, thus reducing the resources needed, per unit area, to capture & convert the sun's energy into usable electricity. However, one must factor in the cost (financially AND environmentally- resource & pollution-wise) of the mirrors/prisms/lenses necessary for the system. Otherwise, an overall comparison to 1-sun-intensity panels becomes impossible, or at best, inaccurate and misleading.

2. Solar cells' efficiency is NOT LINEAR!!! Specifically, if you were to, say, double the intensity of sunlight incident on pretty much any type of solar panel, you will NOT get double the power output- you actually get MORE than double. This is of CRUCIAL importance in understanding why solar-concentrator PV systems are such a good idea, among the other reasons listed- in summary, they are feasibility of higher-quality panel usage and less resources necessary for, and pollution generate by, the PV-panel production process.

3. Solar cells, depending on the material(s) used for the active layer(s) as well as their quality (number & type of defects in the semicon crystal lattice), have intrinsic loss factors. By concentrating sunlight and making possible much greater effective-energy-capture-area-per-panel-area, it also becomes economically feasible to use higher-quality cells. For example, a few % efficiency increase @ 2X the panel cost for a 1-sun-intensity panel is UTTERLY impractical, whereas the same proposition for a panel onto which is concentrated HUNDREDS of suns IS practical, since the ABSOLUTE increase in power-per-unit-area for this type of system (concentrated, high-quality cells/panels) may turn out to be several times the TOTAL output of a 1-sun-intensity panel. In other words, the cost of the panel itself is much smaller in comparison to the system overall, AND any % efficiency gains are multiplied by a much greater amount per-unit-area-of-panel. Sooo, using high-quality cells becomes a lot more feasible when they are more efficiently utilized with solar concentrators.

Finally, a point of clarification: No offense Engadget, but you need to do some homework before posting about & discussing things you don't understand so well. Specifically, this part of the blurb: "In case you're unfamiliar with multi-junction cells -- no shame in that game -- they can best be described as being composed of several layers, with each slice capturing only a portion of the solar spectrum; this method of optical concentration is what has allowed cells to surpass the 12% to 18% efficiency barrier faced by most traditional modules."
--The first part is spot-on; multi-junction cells DO have multiple layers, each successive layer having a lesser bandgap, meaning that it has a lower photon-threshold-energy (PV panels do not generate ANY power from photons below this level, but any energy ABOVE the threshold is wasted as heat- this is mostly why multi-junction panels are a lot more efficient than monojunction ones). So hooray for pointing that out. But the second part is EXTREMELY misleading & actually that's the reason I decided to post to this fossil in the first place. Specifically, "...this method of optical concentration is what has allowed cells to surpass the 12% to 18%..." is utterly untrue. Multi-junction panels are NOT a means of optical concentration. They are a means of more efficiently harnessing a broader band of wavelengths of incident light. Optical concentration is simply concentrating (increasing the intensity of) incident sunlight, usually by focusing paneled or parabolic mirrors onto a relatively small area of PV panel.

For disambiguation's sake, I will try to summarize these panels' differing operating principles cleary & succinctly: They are multi-junction panels which ALSO utilize solar concentration. By employing multiple junctions, efficiency is greatly increased, but so is cost. However, as stated above, properly concentrating sunlight onto a given panel will ALSO increase its efficiency- NOT JUST TOTAL POWER OUTPUT. To give you all an idea of the approximate quantitative enhancements:
1: Going from single-jcn to multi-jcn panels- typical, production, available-today-panels, at an intensity of 1 sun (normal, daylight intensity), will increase efficiency from roughly 12-16% to somewhere in the 20-35% range.
2. Going from single-jcn to multi-jcn panels- THE EXACT SAME panels as in #1, employing a heatsink & solar concentrator device such that a few hundred suns are incident on the panels (EXTREMELY high intensity), efficiency goes from approx. 15-22% for single-jcn and ~28-40% for the multi-jcn flavor.
***These values may be somewhat out-of-date or slightly inaccurate as I am going from memory, but I believe them to be "close enough" and the error, if any, being fairly small. That said, feel free to correct/enhance what I've said. In fact, I encourage you to do so!

Sorry for this post being so lengthy, but I feel there is a lot of incomplete and/or inaccurate info regarding solar panels out there. Hopefully this will clear up the picture for at least some of you. If you've read this far, thanks for bearing with me.
Copyright 2008, myself. Please do NOT copy, reproduce, or distribute any part of this in any way without my explicit permission, exception being to quote/reply in this thread, as it is prohibited by law. Chances are I will say yes, but I'd very much like to know what your intended use is prior to doing so. Thanks!

[J @ Jan 27th 2009 5:24PM]

Hey Grant, insightful comment. Thanks for coming back and posting it. I'd like to ask you a few other questions about CPV - you can reach me at http://www.nullstream.com

[Tad @ Aug 15th 2008 4:11PM]

How many here advocating for solar are running it already? Anyone? How is it working out for you? If not, what would be your trip point to pony up the $25,000 - $50,000 (varies highly I know) to outfit your house? An acquaintance of mine just spent $50,000+ on solar for his brand new ultra efficient house (in sunny Tucson, AZ) and assuming no panel degradation (which will happen I presume) and assuming he doesn't have to replace his batteries (which I presume he will) and without any other repairs or maintenance (which there will likely be), he tells me he assumes a break even point in 20 - 25 years... although some rough math on my part makes that seem longer than is likely by some few years. I love 'big energy' (especially I just had to go a few days w/o power due to a storm and got to enjoy being powerless) but would certainly like to not pay for electricity... who wouldn't?

[mike burchfield @ Jan 7th 2009 12:11AM]

cood you sind me A picturic on the broking solarcell and how much think you

[Pete @ Dec 6th 2006 3:42PM]

If we could get these on our homes for reasonable prices with payoff ranges under 5 years we could start selling electricity to the local utilities and make some cashola.

[James Sonne @ Dec 6th 2006 5:16PM]

With this level of solar efficiency, we could supply the entire world's energy needs by covering a region the size of L.A.
Why do we still burn things? I'm so confused.

[Gil @ Dec 6th 2006 5:25PM]

Because it's cheaper.


Hell we could blanket parts of Sahara. I calculated the costs to cover the entire desert in a previous comment but they were incredible. Small regions however are possible.

As a plus we'll also have a gigantic mirror that we can use to attack things in space. The Death Earth... we'll have to make sure we don't leave any cooling vents open :)

[noni @ Dec 6th 2006 4:52PM]

Boeing is in the solar power game now? Since when has there been sun in Seattle?

[Lita @ Dec 6th 2006 5:18PM]

Spectrolab is in Southern California. Related to Boeing's sattelite works (used to be part of Hughes, I think). Plenty of sun in Cali. Boeing's not even based in Seattle anymore, dude. They're all about Chicago now.

[par @ Dec 6th 2006 3:59PM]

Countries with lots of sun should use this as much as possible. House roofs should be made out of this. What are people/governments waiting for? The savings would be enormous in the long term.

[Matt @ Dec 6th 2006 4:04PM]

Well, to start I would imagine that they are waiting for an actual product. Just because something worked in a laboratory doesn't mean you can all of the sudden stroll on down to your local Walmart and pick one up.

While a 40% efficiency rate is a tremendous breakthrough, there are probably still a lot of problems to solve. For instance, how much does it cost to manufacture one? Doubling the energy output doesn't help a hole lot if it costs 3 times as much to make one.

[uetani @ Dec 6th 2006 4:59PM]

Not necessarily true. What if the resources consumed to create the material are high and the lifetime of the material is short? Unless the total life cycle of the product results in a lower consumption of resources over its competitors the product is fun from a technology standpoint but has no place in general use.

[Samuel McConnell @ Dec 6th 2006 4:39PM]

If these really are 40% efficient, then there may not BE utilities to sell the electricity back to for long.

[Craig @ Dec 6th 2006 4:07PM]

Any idea how much these things will cost?
Oh, by the way, the highest efficiency until now was 30% (it's in the linked article ^^)

[Alcaron @ Dec 6th 2006 4:13PM]

"In conclusion, while this is certainly an encouraging development, we remain somewhat skeptical about its potential for real-world implementation: once Big Oil gets wind of this new tech, it will likely "disappear" just as quickly as that guy who invented a car that runs on water, man."

Translation:

"In conclusion...we would like to make some stuff up."

[Crazylink @ Dec 6th 2006 5:09PM]

He didn't make that up. It's a common phrase that Steven from that 70's show says when he's high.

[mike @ Jun 17th 2007 2:27AM]

its an old twilight zone show about a man who invented a car that runs on water.. look it up

[James @ Dec 6th 2006 4:28PM]

I think NASA would just use it for the satellites and space probes. It'll be a while before this technology trickles down to the consumer level.

[rkguy @ Dec 6th 2006 10:03PM]

Hey, its good to see someone thinking about lifecycle analyses.

Earlier solar panels produced a net loss (0.1%) in energy when looking at the fuel used to mine the oars, the cost of fabrication, transportation, lifetime, and efficiency.

Hopefully we'll have a real winner on our hands this time around, always keeping in mind the process from development to decommissioning

[Ian Jardine @ Dec 6th 2006 5:49PM]

One Question:

What time to market?

[Larry @ Dec 6th 2006 5:42PM]

And in another two months you will see similar results with RSL, also working on full spectrum plus CIGS technology. Big oil isn't big enough to stop what is happening in photovoltaics. Soon, the downstramers will be talking about "Big PV". The big story is what this technology will do for the developing world, but they are a secondary target.
Hang on. This is going to be a fun ride.

[Vince D @ Dec 6th 2006 5:51PM]

Easy guys.

Simple economics will drive the dynamics of this. If the cells can be produced economically, AND widespread production is feasible, AND the efficiency works out in practice, AND they are adopted on a large scale, the very first thing that will happen: the price of electricity generated by fossil and nuclear will drop. Dunno what this will do to the payback period.

Bottom line - let the PV cells be produced. If they make economic sense, people will buy them, the price of electricity will drop, along with greenhouse gases. If they don't make economic sense, they will fail, or be supplaned by a different technology. Under NO circumstances should government get involved.

[oxfdblue @ Dec 6th 2006 4:50PM]

This is great. Want to see it in widespread use...let's get Al Gore to run for President.

PS- It may not be anywhere close to 40% efficient, but the technology is out there to turn most glass surfaces into solar electric generators. A small company called XSunX has developed a product called PowerGlass, a solar energy film that would be placed in between layers of glass. Imagine all the glass towers in this world as one giant solar energy collector?

[Z @ Dec 6th 2006 4:51PM]

I want these for home. Anything to make it as green as possible.

[Paul @ Dec 6th 2006 4:55PM]

Um, you may need utility companies for the cloudy days.

[Sean @ Dec 6th 2006 6:48PM]

Triple junction, high efficiency cells are typically very expensive and pretty much only cost efficient when used in satellites (Boeing has aerospace and military divisions).

- Sean Wachob

[disciple83 @ Dec 6th 2006 5:26PM]

the fun thing about that solar energy storage is that the energy can pretty much go anywhere once it has been converted, including batteries. Cloudy days aren't as big a problem as you would think. I am sure as the technology develops to make the collection process more efficient, the technology to increase storage capacity and efficiency will also develop. One day, we will actually be able to run a house or office building on pure solar, even during the cloudy days. (Maybe a nuclear backup unit will be more convenient then as well.)

[macgyver1 @ Dec 6th 2006 6:37PM]

I sure someone KEEPS THIS AFLOAT. Big Ol' will sure drive down prices to keep these things out of our hands. I hate greed...

[Gil @ Dec 6th 2006 5:33PM]

I just realised that this invention brings Solar to roughly the same efficiency level as Coal burning!!!

From wikipedia:
When coal is used for electricity generation, it is usually pulverized and then burned in a furnace with a boiler. The furnace heat converts boiler water to steam, which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process has been improved over time. "Standard" steam turbines have topped out with about 35–40% thermodynamic efficiency for the entire process, but the emergence of supercritical turbines running at extremely high temperatures and pressures has led to efficiencies of 46%, with further increases in temperature and pressure offering potential for even higher efficiencies

[Matt @ Dec 6th 2006 9:29PM]

you trust wiki? i waste time screwing with their articles

[Craig @ Dec 8th 2006 11:52AM]

HAHAHA that has nothing to do with pv cell efficiency... with pvs, the efficiency is the percentage of photons that knock electrons loose (thus generating electricity. Not thermodynamic efficiency... You just can't compare...

[Simon @ Jul 16th 2007 7:43PM]

There are certain other advantages to not burning coal!

[Nobuyuki Idei @ Dec 6th 2006 6:34PM]

Indeed.

[disciple83 @ Dec 6th 2006 6:04PM]

In theory, with America's free market, the government isn't involved. But chances are, with the promise of freedom from war-causing demands for oil, not to mention the decrease in spending alone for the wars and the oil, I have a feeling the government will not want to put a hindrance on something like this. With the technology being developed in the US, it would also give us an edge over foreign nations in the tech market, allowing for a change of pace outside of computer operating systems.

[Vince D @ Dec 6th 2006 6:09PM]

Government involvement would be the worst thing possible, because it tends to fix technology at an early stage and preserve it forever, killing innovation. Let technology and the free market work, and soon we might see 60% efficiency, let government get involved and we will be stuck at 40% for all eternity.

And the bit about it decreasing the propensity of government to start wars - that's a joke, right?

[John @ Dec 6th 2006 6:22PM]

Just for all of you that didn't do your research, these are concentrator cells, which are vastly different than your run of the mill Si solar cell (the 22% efficient ones) and operate at 200 to 400 suns. Also Spectrolab just broke their old record of 39%, which just occured last year. So, I laugh at all your excitement and the revolution this new cell is going to bring.

[Nobuyuki Idei @ Dec 6th 2006 6:30PM]

Get some buckets of green paint then.

[darshanmathew @ Dec 6th 2006 6:36PM]

solar power?
it produces DC electricity.
its not easy to convert all appliances from AC240V or AC110V to work with DC.

also solarpanels can be personal home or maybe just the neighbourhood. cos DC doesnt travel far. without gr8 losses. Lossless transmission: its the reason why AC was invented.

congrats to the guys who developed the efficient solarCells. just hold on to it tight. cos some venture capitalist will come along promising a bright future for the entire world. and once he takes over you'll find out he is owned by an oil company and he can sit on the idea and stifle development of the project as long as they want. viva OPECartel.

[Freetolio @ Dec 7th 2006 7:28PM]

AC transmission is not a lossless process by any stretch of the imagination. That's why you can stand under high voltage lines at night and light up a fluorescent bulb by positioning it vertically.

[Chris @ Dec 7th 2006 1:52PM]

Most of those devices convert that AC back to DC before actual use.

[fredouil @ Dec 7th 2006 1:58AM]

without government involvement nothing is really possible when it come to energy since it require huge investments and long-term view, private companies lack of both, they can not finance with cheap loans like those that State have access to.

the third world infrastructure in US and UK is good indication about what non-government planning can do ;-).

[fredouil @ Dec 7th 2006 1:58AM]

without government involvement nothing is really possible when it come to energy since it require huge investments and long-term view, private companies lack of both, they can not finance with cheap loans like those that State have access to.

the third world infrastructure in US and UK is good indication about what non-government planning can do ;-).

[fredouil @ Dec 7th 2006 1:58AM]

without government involvement nothing is really possible when it come to energy since it require huge investments and long-term view, private companies lack of both, they can not finance with cheap loans like those that State have access to.

the third world infrastructure in US and UK is good indication about what non-government planning can do ;-).

[Vince Daliessio @ Dec 6th 2006 10:24PM]

Baloney. Electricity in the US (and in the UK, I surmise) has been a government-regulated monopoly almost from the start. There were numerous cities where competition thrived (see Baltimore MD) in the early days before government, at the behest of the electric monopolists, put a stop to it.

The primary reason innovation is at a crawl in electric generation is this government-protected monopoly. Solar is a welcome antidote, but the fundamentals of the system have to change first.

[nikster @ Dec 6th 2006 7:03PM]

About Big Oil, You should know that BP renamed itself "Beyond Petroleum" which pretty much says it all. Oil is on a time-line. While there's lots of oil in the ground, it becomes economically unfeasible once it costs a barrel of oil to get a barrel of oil out of the ground, and it will become too expensive for most practical applications long before that time.

40% efficiency is awesome!! Solar is already very efficient for heating water, basically all you need is some black piping. Thermal pumps also have come a long way, and there are now many zero energy houses built in Europe - without a lot of sun. The same thing would be WAY easier in California or any of the more sunny states in the U.S.

In addition, using solar power to cool down buildings should be a natural, since the solar cell already absorbs a percentage of the sun's energy.. if anything solar + thermal pump cooling in hot countries should be a lot easier than using the same thing for heating in cold countries...

[Vortex @ Dec 6th 2006 7:39PM]

> I want these for home. Anything to make it as green as possible.

I believe that the goal of a solar cell is to be as black as possible. :P

[Steve @ Dec 6th 2006 9:23PM]

It's kind of funny... because if (like people are suggesting) we were to have everyone put them on their roof, then the demand for electricity would go down... and selling your "extra" wouldn't be worth it.

[Kevin K @ Dec 6th 2006 8:51PM]

This is great news!

Any word on availablity? Demand is here, with double the power of previous toting panels, this oens a sure hit!

Visa?

[Luke @ Dec 6th 2006 9:18PM]

Almost had another good article without a BS slant at the end. Here, I'll help you guys out and ship you a load of tin-foil.