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Science New Solar Cells Top 40% Efficiency
Brandon Hill (Blog) - December 7, 2006 11:22 AM
Print E-mail del.icio.us 46 comment(s) - last by TheLiberalTrut.. on Dec 11 at 5:57 AM
US DOE helps fund advanced solar technology

Solar cell technology has always shown promise as a source of renewable energy but relatively low efficiency levels and high costs have kept it out of the mainstream energy market. The United States Department of Energy (DOE) has announced that with the help of government funding, Boeing-Spectrolab has demonstrated a concentrator solar cell with a record-breaking 40.7% efficiency rating.

With concentrator solar cells, sunlight is intensified with the use of an optical concentrator. This allows for more electricity to be extracted out of each solar cell. Also employed are multi-junction solar cell structures which allow more of the solar spectrum to be captured by using multiple layers per cell. Each layer in a cell is then able to capture a segment of sunlight allowing for more efficient electricity production.

“Reaching this milestone heralds a great achievement for the Department of Energy and for solar energy engineering worldwide. We are eager to see this accomplishment translate into the marketplace as soon as possible, which has the potential to help reduce our nation’s reliance on imported oil and increase our energy security,” said Assistant Secretary Karsner.

With this new technology, the DOE is projecting that installation costs for these types of solar cells would drop to $3 per watt with electricity costing 8 to 10 cents per kWh. The long-term goal is to have solar energy technology installed in as many as two million American homes providing power at 5 to 10 cents per kWh by the year 2015.

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This is great news!
By Spartan Niner on 12/7/2006 11:32:54 AM , Rating: 5
To put this into perspective many conventional combustion engines are around 25%-33% efficient in converting chemical energy (gas/petrol) into mechanical energy/electrical energy. Having a 40%+ efficient solar cell panel/array that generates electricity at 8-10c/KWH would make it competitive or even better than conventionally generated electricity, depending on where you live. The cost of running DC projects just may drop a bit in the future :P




RE: This is great news!
By Spartan Niner on 12/7/2006 11:35:45 AM , Rating: 2
From the orig. article:

quote:
... nationwide acceptance of clean solar energy technologies by 2015. By then, it is intended that America will have enough solar energy systems installed to provide power to one to two million homes, at a cost of 5 to 10 cents per kilowatt/hour...


Okay, 8c a KWH would make many people happy, at 5c a KWH you have no excuse not to build a folding farm ;)


RE: This is great news!
By ADDAvenger on 12/7/2006 12:04:08 PM , Rating: 2
Any idea what it used to cost per KWh, and/or the efficiency of other cells? I once looked into solar power, maybe two years ago? But anyway, it would've taken something like forty years for the panels to pay for themselves (not literally, but through a reduced electric bill), and that was with the $40,000 system. Maybe I just wasn't looking in the right place..


RE: This is great news!
By ADDAvenger on 12/7/2006 12:08:13 PM , Rating: 2
Nevermind, just clicked the link in the article.

quote:
Almost all of today’s solar cell modules do not concentrate sunlight but use only what the sun produces naturally, what researchers call “one sun insolation,” which achieves an efficiency of 12 to 18 percent.


That's pretty awesome, in a year when this becomes mainstream we'll be able to buy solar panels that pay for themselves in twenty years. (and that's in a small town in Missouri that gets its power from a non-profit co-op, no telling what this'll do for you guys out in CA)


RE: This is great news!
By TheLiberalTruth on 12/11/2006 5:55:09 AM , Rating: 2
Unless, of course, you live in a state where 99% of the electricity consumed is generated from coal. There's, of course, the cost of the electricity (which, incidentally, is more than what my parents pay for electricity generated by a nuclear plant), and then there's the heavy cost to the environment in the form of acid mine drainage, acid rain, particulate emissions, carbon dioxide, etc, etc, etc, etc, etc.......


RE: This is great news!
By TheLiberalTruth on 12/11/2006 5:57:47 AM , Rating: 2
Hit the wrong reply link, that was supposed to be a reply to ariafrost.


RE: This is great news!
By masher2 (blog) on 12/7/2006 12:45:29 PM , Rating: 2
> " 8-10c/KWH would make it competitive or even better than conventionally generated electricity..."

I strongly suspect that figure is arrived at by dividing the product installation cost and expected lifespan by the nominal output. That means it's an ideal figure, practically attainable only in a desert location at a relatively low latitude. Furthermore, the requirement for a solar concentrator (at 1000 suns, no less), pretty much means this is going to be useful for utilities only, not private citizens...even if they did live in the Arizona desert.




RE: This is great news!
By TomZ on 12/7/2006 12:58:43 PM , Rating: 3
So, in summary, 20-40 years breakeven, which is long enough that the average American will not consider its purchase. Sad.


RE: This is great news!
By Dfere on 12/7/2006 2:33:36 PM , Rating: 2
Most people do not own a home for 40 years anymore.

I wonder if this is a case where possibly government interaction in the marketplace would be justified? Subsidies and such?


RE: This is great news!
By masher2 (blog) on 12/7/2006 2:52:00 PM , Rating: 2
This is aimed at commercial installations primarily, not home rooftop collectors. As such, they only need to improve the lifetime of the cells somewhat, bring economies to scale to bear on manufacturing costs, and solar power may well be viable.


RE: This is great news!
By CSMR on 12/7/2006 9:20:35 PM , Rating: 2
There are already subsidies in many places including some US states. The justifications would be to encourage the industry, which should help research and generate publicity.


RE: This is great news!
By CSMR on 12/7/2006 9:18:50 PM , Rating: 2
With a long term bond rate of 1.055 you need a factor of just under 20 for economic feasability, assuming that a few things are constant (output, energy costs) and no risk.


RE: This is great news!
By greenandgoldenergy on 12/7/06, Rating: -1
RE: This is great news!
By Seer on 12/7/2006 5:13:17 PM , Rating: 2
Advertisement, needs deleting


SLI?
By Christobevii3 on 12/7/2006 11:28:56 AM , Rating: 5
Maybe now I can afford to power two gtx8800's




RE: SLI?
By jmn2519 on 12/7/2006 11:50:21 AM , Rating: 2
Yeah now you will just need to sell surplus electricity back to the grid to PAY for your two gtx8800's.


RE: SLI?
By ADDAvenger on 12/7/2006 11:59:20 AM , Rating: 2
Take a look in anandtech's forums, either general hardware or graphics, and you'll find that power requirements are nowhere near the doom and gloom KW predictions.

You can most likely SLi GTXs with a sweet 550W PSU. It's not the wattage, but how many amps the 12v rails are rated for. (I'm pretty sure it's the 12v rails anyway, like I said, take a look yourself)


RE: SLI?
By ZoZo on 12/7/2006 1:51:24 PM , Rating: 2
p(Watts) = u(Volts) * i(Amperes), so with u constant at 12V, more Watts = proportionately more Amperes.
Therefore it is the wattage.


RE: SLI?
By ADDAvenger on 12/7/2006 1:56:46 PM , Rating: 2
...

It's not the total wattage of the PSU that matters, but the wattage of the rails that run the graphics card(s).


RE: SLI?
By masteraleph on 12/7/2006 2:16:13 PM , Rating: 2
quote:
p(Watts) = u(Volts) * i(Amperes), so with u constant at 12V, more Watts = proportionately more Amperes.


True. But the point is that if you use a PSU that puts a lot more power on the 12V lines and not much on the others, then you don't need something with a high wattage rating/power useage. You could make a 1Kw PSU that wouldn't power an SLI system, or a 550w one that would, depending on how the power is distributed.


RE: SLI?
By Oregonian2 on 12/7/2006 2:23:40 PM , Rating: 2
PC power supplies put out multiple voltages and modern ones have more than one +12 output (currently the most important one because it is used for the on-board regulators that produce the "core" voltages that consume most of the power (and powers the hard drive motors)). So a new supply could cut back on the over-all power rating but still be capable of putting out more current where it's important (+12). The new ones do away completely with one of the negative voltage outputs. In any case it's only a rating, a 300W load will take only 300W whether the power supply is rated 500W or 1000W. Just a better operating MTBF on the latter (probably).


Preaching Fusion
By TimberJon on 12/7/2006 1:32:08 PM , Rating: 2
Power may drop to that price after fusion reactor power hits the grid.

Hopefully in the future (2040+), we will be able to have a commercialized reactor installed in our home, eliminating the need for real-time monitoring of the city or national grid and using software clients to monitor power status on an individual level instead. No blackouts, no overloads. More power to high-powered manufacturing facilities, and possibly a wirelessly-powered transportation grid.

Im still waiting for Wallscreens.




RE: Preaching Fusion
By ADDAvenger on 12/7/2006 1:44:30 PM , Rating: 2
Commercialized reactor? Even if that becomes feasible (from safety as well as economic standpoints), Western civilization is waaaaaay too afraid of even the word reactor; there is no way in the world that people would allow this, especially in their own homes.

I like the thought, but there's entirely too much FUD out there.


RE: Preaching Fusion
By ZoZo on 12/7/2006 1:58:11 PM , Rating: 2
Too much Back to the Future will do that to you.

We'll be lucky if by 2040 we have more than one operating and profitable (in terms of energy output) fusion power plant in the world.
Unless cold fusion really does exist, there's no way we'll get 100 million °C of plasma contained in something that fits in a household. At least not in this century, or even this millenium.


RE: Preaching Fusion
By Oregonian2 on 12/7/2006 2:27:47 PM , Rating: 3
Just need some Tachyon rays in combination with di-lithium crystals to contain the anti-matter over next to the water heater in the garage.


RE: Preaching Fusion
By cocoviper on 12/7/2006 3:43:28 PM , Rating: 2
You do realize that a viable fusion reactor has been "about 30-50 years away" for about the last 50 years right?

There is not anything in recent nuclear engineering developments that suggests you will see controlled fusion producing an energy surplus in your lifetime. At least nothing more promising than the same level of promise in the 1950s...


RE: Preaching Fusion
By s12033722 on 12/7/2006 5:14:35 PM , Rating: 3
Are you aware that the JET experimental reactor has achieved a ratio of .7 output power to 1 input power, and the JT-60 reactor has achieved plasma conditions which would have achieved 1.25 output to input if it was using a deuterium/tritium mix as fuel instead of straight deuterium? Are you further aware that the ITER reactor which is just beginning construction should produce at least a ratio of 5:1 output to input?

http://www.iter.org/pdfs/ITER_Design_Phase.pdf

There have been significant advances made.


RE: Preaching Fusion
By ghost101 on 12/8/2006 1:00:53 PM , Rating: 2
When you say input, you dont mean all the power in the system but the input that needs to be given externally to the process. Right?

Otherwise it just sounds like another perpetual motion fantasy.


RE: Preaching Fusion
By masher2 (blog) on 12/8/2006 1:35:29 PM , Rating: 1
The "input" is the electrical power used to drive the fusion reaction; the "output" is the total power produced by the reaction process.

We've been able to produce fusion since the 1950s, but obviously if you're consuming more energy than you're getting out, its not much of a solution for power generation.


WOW!
By therealnickdanger on 12/7/2006 12:03:15 PM , Rating: 2
quote:
costs for these types of solar cells would drop to $3 per wall

LOL, that would be incredible!

It really is amazing how quickly this technology is adavancing. I plan on taking advantage of solar energy in my next home. Assuming a $3/Watt efficiency, I calculated it would cost ~$25,000 to equip my home with enough PV to power my current needs +20%. By default, the online calculator assumes $9/Watt efficiency, so it is much pricier. By the time I'm ready to buy, it will probably be cheaper...




RE: WOW!
By Sureshot324 on 12/7/2006 4:26:19 PM , Rating: 2
Another thing that would encourage solar power in homes, and I think a few states are already doing this, is to require the power companies so let you sell excess power back to them. Whenever your solar powers are generating more power than you need, they're making you money. When they're making less, you still have the power grid to back you up.

This eliminates the need for batteries, because the entire power grid is your battery. Also you don't need to drop 40k at once on a solar system. You can increase the amount of panels gradually.


RE: WOW!
By lemonadesoda on 12/7/2006 6:11:34 PM , Rating: 2
The cost of "connecting" and metering when selling electricity to the grid is much too expensive for a consumer/single home. It only makes sense when you have a medium/large solar farm.

In fact, just the equipment needed to transform the DC to the appropriate AC three phase would probably consume all of the little trickle of electricity you get from home roof panels.

So there'd be nothing left to sell, and probably about $50,000 of additional equipment in addition to the cost of the cells.

More problems:

1./ The typical half-life of a solar cell is around 15-20 years. No commerical solar farm is designed to operate on the same panels for >20 years. It just isnt feasible. They need to be replaced.

2./ The new 40% efficiency ration is actually achieved using lens tricks, essentially taking a larger area of light and concentrating it onto the cell. Unfortunately, this technique also shortens the life of the cell, albeit, by not as much as the gain in efficiency.


RE: WOW!
By masher2 (blog) on 12/7/2006 6:48:00 PM , Rating: 3
> "The new 40% efficiency ration is actually achieved using lens tricks, essentially taking a larger area of light and concentrating it onto the cell..."

The concentrators aren't a "trick". The efficiency is calculated against the amount of light energy impacting the concentrator itself, not the cell. So if a concentrator focuses 100x the light on a cell, that cell has to produce 100x the power to equal the same efficiency ratio.

The concentrators are useful for two reasons. Firstly, in the above scenerio, the cell would actually produce *more* than 100x the power, due to the higher flux allowing the secondary junctions to be more efficient. Secondly, concentrators are much cheaper per sq. meter than the cells themselves. Focusing the light gives a substantial cost advantage.




Is this really increasing efficiency?
By OxBow on 12/7/2006 12:42:09 PM , Rating: 2
The article lists that it's using concentrators and layering to get more energy out of each cell. While obviously this is a big improvement, it's not really increasing the conversion rate, but rather the amount of light collected and light collectors. The wafers themselves are still generating at their normal rate, they just have layers of them.

It's great that they've done this, but just goes to show how little the DOE has invested before into solar power over the years.




By Chudilo on 12/7/2006 12:53:06 PM , Rating: 3
You're not going to want to set up a concentrator on your roof. It would look pretty odd.

What you CAN do is, next time you need to redo your roof use the Photo-Voltaic shingles.
It's more money per shingle , but you get a better shingle which will serve as a shingle and as a solar panel.

By the time you'll have to replace the roof again, it would pay for itself and more.

That seems like a clever thing to do.


By masher2 (blog) on 12/7/2006 12:53:30 PM , Rating: 3
> "it's not really increasing the conversion rate, but rather the amount of light collected and light collectors...The wafers themselves are still generating at their normal rate."

Actually, the cell efficiency has been improved. Each layer of the cell is optimized for specific wavelengths of light, increasing the overall efficiency. The increase in overall flux from the concentrator is factored into the efficiency calculation.



Silicon, yes?
By gdillon on 12/7/2006 2:16:19 PM , Rating: 2
Those numbers really are pretty amazing, but it's important to think about the economy of the project as a whole. This is probably a crystallized silicon product -- global reserves of silicon are really tight. Most PV manufacturers are sold out of product until 2008. Incredible efficiency aside, if you can't make enough product, it's not worth that much.

I'm banking (literally, I hope the damn shares come back up soon) on CIGS thin-film technology. Not quite production capacity, yet, but it doesn't use silicon and has the potential to be much cheaper to produce. Much less efficient at this development stage, but when it's solar and you can put a farm in New Mexico where nobody's looking, you just make it twice as big and, presto, cost per watt decreases.

Buy shares of DSTI, please. My bank account (and the environment!) will thank you. :)

~g




RE: Silicon, yes?
By masher2 (blog) on 12/7/2006 2:28:16 PM , Rating: 1
> "This is probably a crystallized silicon product..."

No, crystalline silicon based cells are limited to around 25% maximum efficiency. These are multijunction cells, comprised of multiple materials, each optimized for a specific range of wavelengths. I didn't see in the article what specifically they were using for this cell, but its typically gallium, indium, arsenic, antimony, and the phosphides of the above.


RE: Silicon, yes?
By therealnickdanger on 12/7/2006 2:48:24 PM , Rating: 2
They are using gallium arsenide cells.


RE: Silicon, yes?
By masher2 (blog) on 12/7/2006 2:54:47 PM , Rating: 1
I'm sure they're using more than just gallium arsenide...you can't get a 30%+ efficiency with just a single material.


RE: Silicon, yes?
By gdillon on 12/7/2006 3:31:36 PM , Rating: 2
Ok, you're right, I looked up some stuff about gallium arsenide cells and they don't use silicon and they are thin film. Looks like they've been used most often on satellites and such. Wikipedia says they're maaad expensive, too: "They are also some of the most expensive cells per unit area (up to US$40/cm²)." The article linked from DailyTech suggests that this might become a really cheap price per watt solution, but I think that's "forward thinking" at the very least. It's the difference between producing some crazy efficient cells and creating a worthwhile product you could stick to your roof, power an airship, or use in a farm in the desert.

~g


Home use: water heating
By bobsmith1492 on 12/7/2006 10:32:53 PM , Rating: 2
For everyone that's talking about putting cells on your home, look into water heating systems instead. My school's engineering department put up a house here in town (LEED-certified, by the way! :P ) that uses hot-water heating panels.

They can be used to both generate hot water (apparently they'll keep water at 120 degrees on a cloudy, 20 degree Michigan day!) and also possibly to heat your home (only useful if you live in temperate zones).

Think of the efficiency gains: By using electric solar panels, you are converting solar power to DC electricity (40.7% max), DC to AC (maybe 90%+), transfering over mains lines to whatever is drawing the power (say 95+%), then converting through, say, an electric heater to useful heat energy (100%). That comes to less than 35% assuming you're using the latest and greatest (and not yet available) solar cells specified here - plus, they'll likely not work at all in an overcast Michigan winter.

So, on the other hand, with a hot-water heating system, I don't know the efficiency, but it's a lot easier to capture thermal energy from radiation than create electrical energy. By capturing heat and skipping all the in-between steps, you're much better off - and the panels are cheaper!

So, think about that if you live in any sort of temperate area. If you're in the south-west-southwest areas, maybe electrical panels are the way to go. Look into it! This is not an ad, by the way... just the rantings of a student who really enjoyed his thermodynamics class. :P




RE: Home use: water heating
By bigbrent88 on 12/9/2006 5:50:05 PM , Rating: 2
Actually I just looked at an old 1996 Pop Sci talking about solar shingles and roofing. They used an example where power generating cells can also heat water. Using the airspace behind cells to keep them cool, the hot air is diverted from the roof vent to an air-water exchanger which inturn heats the water. So you get extra efficiency from the same cells.


By PAPutzback on 12/7/2006 4:27:53 PM , Rating: 1
I could swear I read it here at DailyTech.




er ok boys
By ElJefe69 on 12/11/2006 5:34:30 AM , Rating: 1
My charge per hour is a hell of a lot more than that. I would get my money back in less than 8 years. I live outside of NYC. I would stab your mom in the head to get 10 cents per hour. I get like 40+.

plus...

no pollution. um. thats worth no cost benefit in the moral sense, but cheaper makes it even better.




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