Slashdot Mirror
New Solar Panel Design Traps More Light
GoSun wrote in with an article about new solar panels that opens, "Sunlight has never really caught fire as a power source, mostly because generating electricity with solar cells is more expensive and less efficient than some conventional sources.
But a new solar panel unveiled this month by the Georgia Tech Research Institute hopes to brighten the future of the energy source." The new panels are able to produce sixty times the current of traditional models.
you don't want it bright, if it reflects light that's unused energy!
you want a dim future
60 times the current, at 1/60th of the voltage. They're working hard to achieve the next milestone which is 100 times the current (at 1/100th voltage) before Xmas ... in space.
Sunlight has never really caught fire as a power source
Well, I always saw that as a good thing, I don't know about everyone else here...
This is non-news. Multi-layered cells have been talked about forever, and haven't they all previously run into similar issues?
If you can get low $/watts with low efficiency that would be OK. Tile your house with the stuff, use it as the external covering for buildings.
That is one of the major problems with PV showcases like the Australian solar race. they push efficiency more than $/watts which is my the winning cars cost hundreds of thousands of dollars.
Engineering is the art of compromise.
Yawn. Posting about how a supposed innovation is actually several years old has been done before. Didn't we just read a post titled *yawn* yesterday?
It's power that matters, not current.
The best solar cells today get about 13 watts / square foot. The toatl power available on a sunny day with near perpendicular light is 130-140 watts. So efficiency is near 10%. The best a new design can do is about 10-11 fold increase, not 60.
Besides the bad pun... you obviously have never used magnifying glasses on poor helpless insects...
There was a Monty Python episode where they were comparing penguin brains to human brains. They found that if the penguin were scaled up to human size, its brain was still smaller than a human brain. But -- and this is the important part -- it's larger than it was before!
You're talking about two different types of measurements for solar cells.
The statement "60x the current" has almost no relation to the maximum theoretical conversion of sunlight efficiency. It completely leaves out the voltage problems inherrant in these 3d designs. The total output measured in watts or VA would be somehwat more comparable to your "20 percent efficient".
Learn some math before you post.
) Human Kind Vs Human Creation
) It'd be interesting to see how many humans would survive to serve us.
I'm tempted to say "Cripes, This Again," because it comes up in almost every discussion about solar cells.
Instead I'll say: That may have been true once, but it isn't any more. It will become less and less true with time, as learning economies and economies of scale come into effect.
Electric power delivered to me at home is about $0.10/kwHr. Solar panels are about $5/w for the panel or a bit less. Grid tie inverters are a bit under $1/w (at least in the low kilowatts range). It's a bit pricier if you want batteries and completely off-grid, but I'll assume a simple grid tie system designed to reduce your utility bill.
That means your solar panel needs to produce 60,000 wHr of electricity per watt to pay for itself, ie it needs to operate for 60k sunny hours. That's about 25 years or so, in a reasonably sunny mid-latitude climate. That's about the life of the solar panel.
Now, that only sort of answers how green they are. In terms of carbon budget, they probably come out ahead -- not all the cost of the solar panel pays for the energy to make it, there are other costs as well. In terms of total pollution, I don't really know -- there are some nasty chemicals involved, but I think the silicon industry in general is pretty good about disposal (I don't know details off hand, sorry). I don't think there are any subsidies on the manufacturing, just tax credits and such when you buy them, so I think I've fully accounted the costs.
So, overall, I'd guess they're marginally greener than the alternatives. Solar panel prices are falling rapidly, which means they're getting greener to make (at least if we assume manufacturing techniques aren't getting messier). I'd guess they start to come out clearly ahead in the next couple years.
If we had so many wind turbines that we were collecting enough power to run the world, would that not have some effect on the global wind patterns?
No. There is simply more power in the Earth's wind than we could harvest. Or, if you please, the current annual input of power into the atmosphere is greater than the total energy cost of human civilization, by a few orders of magnitude.
Remember: every single watt of solar power that reaches the ground winds up in the atmosphere as heat, the foundation of wind.
Also solar power cools the Earth's surface. Solar farms are envisioned as acres and acres of panels in the desert. That would turn a very hot spot into a very cold spot, changing the currents there, and thus affecting overall temperature distribution (ie, the wind).
If, and ONLY if, the solar panels were not only almost perfectly efficient, but also sucked energy from heat in the atmosphere.
Same sort of thing goes for tidal energy. If you collect enough, you are going to affect life in the ocean.
Tides are powered by the moon's gravity, bub. Sure you'll have an effect, but the tides are already affecting the moon's rotation.
There just ain't no free ride.
Depends on what you means as "free." Sure, the soup kitchen needs someone to pay for the soup, but the bums getting a hot meal get to enjoy someone else's largesse. Most of the power sources available to humanity work like that, including photovoltalic solar, fission, and hydroelectric.
But it doesn't matter to me that some hydro-electric plant far from my house is making power at $0.02 per kWh, what matters to my economic reality is that my local power company charges just over $0.08 for the first dozen kWh delivered each day and then has a sliding scale that goes up to $0.36 kWh for increased amounts of power.
Before I installed solar panels a high percentage of my power was costing me that top rate. So the relevent economic calculation for me is the cost to install my panels divided by the expected number of kWh that they will generate across their lifetime. This number comes out at about $0.16 per kWh. So I'm better than breaking even now, and assuming that energy prices continue to rise, I'll do even better in years to come.
The final kicker in the equation is that I've switched to a time-of-use tariff so across the summer the power company will credit me with $0.209 for excess power that I generate in peak hours (between 1pm and 7pm), and $0.112 for partial-peak (10am-1pm + 7pm-9pm).
If I'd taken the capital that I used to install the panels and invested it instead, I'd have to maintain a >19% annual pre-tax rate of return to beat the panels. Possible, but extremely unlikely (especially with my stock-picking track record!).
Why isn't this tagged "itsatrap"???
Agent K: A *person* is smart. People are dumb, stupid, panicky animals, and you know it.
Now all we need is something that can trap more girls and well be set!
"When life gives you lemons, don't make lemonade. Make life take the lemons back!" -- Cave Johnson
It's like a third grader's book report... Why don't we just get the water from the well... from GTRI's site
When Mark Pinto of Applied Materials spoke at Stanford in EE380 two weeks ago, he said that the current energy payback time on their solar panels is two years, and they're trying to get that down to six months. Some of the fab steps borrowed from semiconductor processing, where the areas aren't so large, can be improved.
Hey, if you have solar panels on your roof, how often to you have to wash them? Do they develop a film that reduces their efficiency?
Computers are useless. They can only give you answers.
-- Pablo Picasso
Current solar cells are ~20% efficient... you can't do better then 100% obviously.
Nobody claimed they produced 60 X the power. In DC circuits Volts X Amps = Watts. 60 times the current does not equal 60 times the power if the voltage is not the same. The article is very clear, the voltage is way down. They make no power claims. It's even implied that the voltage is near zero. These panels may be less effecient than the curent generation. They are working on raising the voltage. Good luck and I hope they come out with some power figures soon.
The truth shall set you free!
The power convesion ratio is not really that important in itself. The only really important measure is $/watt.
Right, and the only thing that matters with hard drives is $/GB ratio? People don't size systems based purely on $ figures; required output weighs into the equation heavily, since systems usually pay themselves back pretty fast. It doesn't matter when you have a whole hillside or roof, but otherwise, size is important, and the more efficient a panel, (duh), the smaller. That matters for space availability and wind loads.
For example, it's not practical to put solar panels on the roof of a UPS truck; you could cover the entire roof, and even on a sunny day, you probably still wouldn't be able to supply enough energy to keep it going on a day's worth of deliveries. Increasing the efficiency matters here. Likewise for say, putting a solar panel on the back of a cell phone.
The other arena this helps in? Wind loads. If you have a residential system with several panels on a tracking frame, if the panels can be half the size, that means a cheaper frame and tracking system, and less of an eyesore in your back yard. Or, alternatively, twice as much power from the same frame.
What really matters is retail availability. I've been reading about advances in solar panel technology for years, and it's dripping into the consumer market like molasses. Why? Well, for one thing, oil companies are snapping up solar intellectual property and companies like crazy...
Please help metamoderate.
This is one of those grand myths that the public just can't shake. Photovoltaic's have a very good energy return on investment (EROI).
The energy payback peroid for various PV cell types are:
Crystal Silicon: 3.3 years
Multicrystal Si: 0.8 years
CIS: 0.4 years
To put that is perspective of EROI:
Photovoltaics (Si): 60:1 - 10:1 (based on above)
Wind: 60:1
Coal(US average): 9:1
Nuclear (light water): 4:1
Oil (mid-east): 10:1 - 30:1
Oil (US): 3:1 or less
And that is keeping in mind that the lifespan of PV is calculated at 30 years, an arbitrary number picked to equalize it with the life of a coal or nuclear power plant, however are panel warranties are 20-30 years alone. There is no reason to believe that the average lifespan of a PV panel won't be 40-60 years or more.
Spectrolab has cells that are over 40% efficient. See here for more details.
JSL
Where's the news in a half finished project that doesn't deliver any benefits (so far) on existing technologies? Who was the fool that got suckered into producing an infomercial?
t m
This is news: http://www.abc.net.au/catalyst/stories/s1865651.h
Sliver cell solar technology. This was on Australian TV in March. Generating the same amount of power using a fraction of the silicon required today. Brilliant.
Why doesn't Perry think referring to cream cheese as cow fudge is funny?
I have yet to post this, but it was all I could think of,
You must be new here.
Paying taxes to buy civilization is like paying a hooker to buy love.
Actually, this approach is a different one to the multi-layered aproach you are probably referring to.
Said multi-layered approaches use multiple pn junctions with differing band-gaps, all on top of one another. This allows them to capture a broader spectrum of incoming light energies, thus increasing efficiency.
The approach referred to in this article is attacking a different problem - using a 3-D 'nano-tower' construction for the pn junctions in order to minimise the reflection of light, thus capturing more of it and therfore being more efficient.
While I'll agree that even this idea for such nano-cells has been around for a little while, it is still in very early stages of development, and has a long way to go. It is encouraging to see apparent evidence that the concept does work, however!
Almost. The laws of thermodynamics dictate that you will never get more energy out of a system than you are putting in. The measurement that we're interested in is not the thermodynamic efficiency, but the "thermoeconomic" efficiency. ThermoEconomic Efficiency is the ratio of the cost of the energy in to the value of the energy out.
The 4KW heat pump you mention is only providing 10KW because it is sucking the extra 6+KW from the ground. The key is that you don't pay for that 6KW of ground energy, but you do get value from it. So, thermoeconomically the heat pump is running at 250% (10KW/4KW), but thermodynamically it is running at less than 100% (10KW/(4KW+6KW+friction)
When our name is on the back of your car, we're behind you all the way!