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Solar Cells Get Boost
An anonymous reader writes "Researchers from Los Alamos National Laboratory have tapped the efficiencies of nanotechnology to double solar cells' potential energy production. The key to the method is the use of lead selenium nanocrystals which can produce 2 electrons where 1 was produced before. Other optical applications can also benefit."
The article seems to imply that the technique would be applicable to existing materials, but also seems to imply that it has only been show to work for lead-selenium nanocrystals. So will the technique of using nanocrystals work with other materials? If not, will incorporating the lead-selenium nanocrystals in a matrix of conventional material, nanocrystal-sized or otherwise, generate two electrons/photon? And finally, does the cost of making the nanocrystals make the whole thing not cost effective, other perhaps in something like spacecraft, where every once saved is of tremendous worth?
If you can't beat them, embrace and extend them.
for every time I heard about cheaper, more efficient solar cell, I could buy a solar powered calculator. Which is just about all I've seen solar power be good for at the consumer level.
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Solar cells harness engergy by absorbing photons, which cause electrons in an atom (which are already there) to move to a higher energy state. This technique moves two electrons per photon, rather than one. The point I am making is simply that electrons are being moved, and not created. That would have amazingly different implications, as that would be creating matter from the energy in a single photon, which would only work with very high energy photons.
This is it folks, this is what we've been waiting for. As it is, solar panels are a pretty marginal energy source for most applications. We've all seen the specially built vehicles that are basicly a big solar panel on wheels (some of us (like me) have even built one). We've all seen the houses with the roof covered in solar panels and they still have to buy all whacky expensive 12v high efficiency appliances and forget about an electric drier. With solar cells like these, solar power just lept from impractical to practical. Make way for the days of solar powered PDAs and cell phones, cars, houses, buses, airplanes, you name it. This is the breakthrough that will lead the way. Unless it flops, of course.
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It contains lead! It contains selenium!!
(a preview of some enviro whacko's response)
BC
Earth is bad for the environment. It contains lethal amounts of lead, selenium. Dangerous amounts of dihydrogen oxide (which kills many thousands a year) have accumulated on its surface.
I usually see hundreds of responses for each topic posted. in the last 1/2 hr this topic has less than 15 responses. seems like people (incld /.ers) are least interested in solar power. no wonder abundant solar power is still not used in our cars.
It is indeed a shame that more interest in this technology doesn't exist. The lack of responses to this article is pretty disappointing, especially since I would think /.ers would be one of the main supporters. Doubling the output of cells is a definite improvement.
I remember reading somewhere (IIRC one of the Real Goods Source Books) that had the phrase similar to "Solar Panels will never become widely accepted until they are available from your local Home Depot." This definitely rings true. Aside from the solar powered walkway lights (total garbage), they have very little to offer there. Solar Cells need to be cheaper and more powerful if people are going to use them.
It's good to see that progress is being made, though, as this article describes. Perhaps one day it will indeed become practical to use solar panels. Until then, we're stuck with calculators.
From what I can tell there not manufacturing solar cells using "lead selenium nanocrystals" but rather they found a method of detecting "impact ionization" via the delay between the photon impact and electron emissions. They then tested several substances and discovered that lead selenium nanocrystals produced impact ionization on close to 100% of photon impacts.
So if you really want to know what's going on you need to discover how efferent lead selenium solar cell's are and what it takes to mass produce lead selenium nanocrystals in a cheep long lasting solar cell.
So it's a long way from producing 60+% efficient solar cells but it's still cool.
It's pretty good, but solar power will still be impractical. I can see solar powered cell phones and PDAs, but that's mostly due to advaces in making those devices low power and then converging with higher effeciency solar cells. Cars? no; houses? no, you STILL need those stupid batteries, and still won't have a dryer; buses? no; airplanes? no. All the vehicles require dense power like gasoline, deisel, or hydroden fuel cells, something, not the dilute stuff of solar cells.
However, the houses, you might be able to make a case. With the new cells, instead of an ultra high effiency house required, just a high effiency house required. So while you won't find the solar cells at home depot, you just might find all the high effiency appliances there.
If Mr. Edison had thought smarter he wouldn't sweat as much. --Nikola Tesla
Man, I have to stop there on the way home tonight to pick up more bits and pieces for the renovations we're making to our new house-- I *wish* I could just take a carload of solar shingles home with me, and plug them straight into some pre-existing standardized rooftop wiring grid.
It's currently a long-term win to buy panels, but it's too steep an up-front investment for most people. $20K with payback over decades is more than most people are willing to do. Perhaps the power companies could invest in people's rooftops, and charge the same rate for the power until they are paid off (plus a tidy profit).
until we can expect one of the big oil companies to obtain the patent to this and kill it like they have with the all the other dozens of promising recent solar and other clean energy technologies? I'm almost certain GW's boss Dick Cheney will find a way to make it happen, one way or another.
Renewable energy has made phenomenal leaps, but the storage restriction is the crux. Efficiency is great, and is a move in the right direction. What remanins is the development of efficient and economical storage devices. Imagine your car operating for a week on a one hour solar charge stored in a device the size of 4 D sized batteries.
I am me...I think
There's at least one user in California who got on a time-of-day net-metering rate program and installed a bunch of solar panels on his garage roof. His panels are cranking out watts during all of the high-rate hours (afternoon), and he gets credited at the retail rate. At night he charges his electric truck off the grid, and pays for those KWH at the off-peak rate. It's win/win; his panels pay for themselves, and the utility needs less peaking capacity.
Scientists restrict study to entire physical universe; creationist
If we get really lucky, this technology will work well at high light flux and high temperatures (~100 C). This would allow use of concentrating collectors and use of the waste heat for space heat and domestic hot water, multiplying the benefit of the collector and making the whole affair much more economical. Imagine a house that powers its own appliances, stores enough hot water for several days of hot showers and its own heating load, and on sunny days has plenty of juice left over to feed to electric cars. This house would be almost completely independent of fossil fuels and offset fuel use elsewhere, and I'll bet that we could build it now if cost was no object - if we can get 50% or even 40% efficient solar cells at $2/watt working at 100 C, we'll be there.
Scientists restrict study to entire physical universe; creationist
It's my understanding that amorphous cells degrade fastest, polycrystalline cells degrade more slowly, and single-crystal cells very slowly. The output curve levels off after a while; single-crystal panels will still be going at a large fraction of their rated output after 25 years unless you hit them with enough heat or moisture to damage them in some way, such as by degrading the interconnects.
Scientists restrict study to entire physical universe; creationist
If you want to fix the size of the nanocrystals, precipitate them using wet chemistry; nucleate a whole bunch of them all at once, and they will stop growing when the materials are depleted from the solution. Taking the suspension of nanocrystals and assembling them into a working device is another matter.
Scientists restrict study to entire physical universe; creationist
Scientists restrict study to entire physical universe; creationist
- Vast reduction in cost of electrical power
- reduction in demand for coal products to approx. 5% of current usage due to solar plants supplying grid (excess produced by nuclear);
- immense pressure to develop better batteries for use by cars;
- demand for tech to turn electrical power plus (whatever) ingredients into natural gas (cars powered by methane emit only CO2, not other nasty stuff, plus infrastructure there - existing cars can run on natural gas for $300 conversion kit);
- vast diminishment of political and economic wealth of many arab and persian) nations plus Russia, Venezuela, and some african countries;
- vast reduction in demand for hydro power in Northwest, hydro dams that are not useful for irrigation & flood control are torn down;
- home power kits still possible, but since 50% of cost of off-grid solar-cell electrical is electronics (not the cells), this isn't a major factor for most people;
Feel free to fill in your implications as replies, or refute these...-- Kevin J. Rice
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One person in California hardly qualifies as a "general consumer", but I appreciate the thought.
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The best planning can be done after the project completes.
Although it sounds fine, it really is a problem for the power companies; retail rates not only include generation costs, but the huge effort that goes on in transmission and load balancing. To be realistic, this sort of metering should be generation costs only.
One which never wears out. Compress air up to 300 or more atmospheres. It's much much cheaper to buy a pressure vessel than it is to buy batteries which hold an equivalent amount of energy and far far more efficient than electrolysis. Most useful for stationary purposes, generators etc due to the size and weight of the pressure vessel. (in fact you're using heat to store the energy)
P.S. Battery powered cars have been able to run for 250, 300 miles for a good 7 years or so with a battery life of around 100,000 miles. That's with NiMH batteries. With lithium ion or even better, lithium sulphur batteries they should be able to travel further than a petrol driven car. (Google for Solectria Sunrise and Solectria Force)
P.P.S. why do Americans call petroleum, gas? It's a liquid at ambient temperatures...
Government of the people, by corporate executives, for corporate profits.
Simple ignorance is forgivable and curable. Willful ignorance is contemptible.
I don't know what that means, and I don't want to know.
"immense pressure to develop better batteries for use by cars;"
The battery technology exists. It is simply expensive due to lack of manufacturing capacity.
The 80, 90 mile ranges you hear about for electic cars? Lead acid batteries. That's what... 200 year old technology?
NiMH, LiON, and even better LiS batteries are here, now, but are manufactured in quantities too small to make them feasable in a car. It's *purely* down to the manufacturing costs.
Government of the people, by corporate executives, for corporate profits.
Just because he doesn't fit the profile of the average consumer does not mean that he is not a general consumer; he doesn't have any billing arrangements that are not available to everyone else.
Scientists restrict study to entire physical universe; creationist
Besides, solar PV is such a small factor that we don't need to worry about these things for a while. When it grows to be 10% of peak grid generation it will be, but that time is years away and we have plenty of time to plan.
Scientists restrict study to entire physical universe; creationist
If you're aiming for 100C or above you could be generating steam. Pipe said steam through a turbine attached to a generator. You could build your own today for peanuts out of some mirrors and an old car or lorry turbocharger.
Couldn't comment on the efficiency of a home grown system, but utility solar thermal systems have been more efficient (30% or so) at producing electricity than photovoltaics for a long time now, must be decades.
Government of the people, by corporate executives, for corporate profits.
Canadian Tire doesn't sell 2x4s but they do sell other building supplies and tools apart from car stuff.
Go here and enter SOLAR as the keyword. (enter postal code: K1J 1J8)
I found this:
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View larger image
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Harness the sun's power to run small appliances (both AC and DC) such as TVs, lights, computers and to recharge your 12V DC batteries in your RV, boat or cottage. The 45-watt Cottage Solar Panel Kit is completely weather-resistant and works under all light conditions.
* Ideal for charging deep-cycle batteries and running small appliances
* ICP solar panels are completely weatherproof and can withstand 1/2" hailstones, up to 80C (176F) heat and can operate under 3" of snow (on sunny days)
* Works under all light conditions
* Kit includes three 15W solar panels
* Can run both AC and DC appliances
* Comes complete with 7A charge controller, ultra-bright fluorescent light and 140W DC to AC power inverter
* Includes 12V socket with 10' (3m) of wire, PVC frame, mounting hardware and battery clamps
* Manufacturer's limited 5-year warranty on power output
* Model No. 10058
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If fewer neanderthals would whine "if it's so good, why isn't everyone doing it", more people would do it. And we'd get further out of the doomed hole we've dug with our paleolithic energy economy.
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make install -not war
In New York we already get billed separately for generation and transmission (energy and its delivery). That lets them mark up each one separately, increasing the sum of the parts, and charge fees on each service. All in one convenient bill!
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make install -not war
The Sun dumps 1.3KW:m^2 on the Earth; about 1KW makes it through the atmosphere to the surface at "solar noon" (directly overhead, insolation perpindicular to the surface). Efficient transmission, like local consumption, efficient storage and transduction (like hydrolysis + fuelcells), and wide deployment (like every NYC rooftop, repeated nationwide) make solar collectors much more practical than our petro economy. We're hardly pumping oil in our garages for burning in our driers. With solar, we'll eventually dump a lot of that inefficient old hardware.
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make install -not war
You're the wacko: this nonsense spouts from *your* head. While you meanwhile probably don't even notice a factory spitting actual poison into your air, much less those which have been fixed to pollute less. Stop attacking environmentalists, and realize that you are one, like everyone else who lives in an environment.
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make install -not war
Extreme claims require extreme evidence: citations for these "sillier things" and toxic green manufacturing processes? Or just more FUD?
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make install -not war
How much energy is consumed by the thin-film solar cell manufacturing process, per square meter of produced cells? What is their efficiency curve over incident light wattage? How many years do they last? Ergo, what is the net energy production from their use? Many thermodynamic processes merely distribute energy costs to where they're not noticed, but still affect. If we burn oil and coal to manufacture a net-loss solar cell, we're digging ourselves deeper.
--
make install -not war
Why do Americans call petroleum gas?
Why does the rest of the world call gasoline petroleum?
Gas is short for gasoline, which is what we put in our cars (well, it used to be... now it is a mix of gasoline, ethanol and other crap). It's boiling point is well below that of water and evaporates rather quickly (gas fumes are much more explosive than liquid gas).
Petroleum is "a thick, flammable, yellow-to-black mixture of gaseous, liquid, and solid hydrocarbons that occurs naturally beneath the earth's surface, can be separated into fractions including natural gas, gasoline, naphtha, kerosene, fuel and lubricating oils, paraffin wax, and asphalt and is used as raw material for a wide variety of derivative products." (dictionary.com) It is also called crude oil.
What do you put in your tank? Gasoline or Petroleum? Us Americans use gas(oline) and it costs $2.50/gallon. If you Euros use petroleum maybe that is why it costs you $5.00/litre.
Hopefully, you were just joking and already knew why we call it gas. My point is that gasoline is NOT petroleum, but gasoline is closer to a gas at ambient temps than water.
Why do Euros call a trunk a boot? A trunk is where you store stuff, a boot is what you put on your feet. I store stuff in my trunk, but rarely put my feet in it.
IANAL, but I play one on
The big "oil" companies are major investors in new energy technologies, not to suppress but to turn them into profitable businesses. Thay are doing a lot of research on their own, and buying companies up as well. They all anticipate the growth of demand for alternative fuels, solar, and wind, and so forth. They are jockeying for position in that future marketplace.
I don't recall the number, but IIRC together these companies have invested multiple Billions of $ in advanced energy systems. This is not the sort of money one spends without expecting an equivalent return, eventually. They have been investing in these areas for a number of years, with the intent of making money, not suppression. They are also used to 'rolling the dice', taking multi-billion dollar risks for long term results.
These companies will without doubt be the ones that build the first big solar-thermal farms. Consider what size of company would be able to arrange investment for building, for example, a 100 square mile solar (or solar-thermal) grid in North Africa to feed electricy to that area and Europe. Big projects require big organizations, with experience in building big, complicated systems in the middle of nowhere.
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If you allowed for a four hour charge, you would only need a panel of 150 square meters, or the roof of a large garage.
"Solar power is not powerful enough to power a car".
THAT is the BEST tRoLL I've seen on /. today!
Way to go!
And your world is oh so Black & White, eh?
Reread your inane quote again, and the DO the math....
Not enough power, Indeed!
Anyway, I wanted to address this:
Perhaps you've heard of this amazing technology for storing electrical energy. It's called a "battery", and it's really quite remarkable. You can store energy in them and then carry them around with you to run electric devices a long way from the ultimate source of the energy. It also allows you to use the energy much faster than it was produced.The EPRI did a study which found that a typical small car would require roughly 340 watt-hours of electricity per mile. If you drive 30 miles a day, that would amount to 10.2 KWH/day. If you assume 6 effective hours of sunlight per day, you'd need 1.7 KW(peak) of production to produce it. If you have 1 KW/m^2 of sunlight and panels at 15% efficiency, that's a bit over 10 m^2; hardly a big deal, most apartment buildings have at least that much roof area per unit and detached homes typically have many times that. And yes, you dump the rooftop power into batteries rather than powering the car directly.
Scientists restrict study to entire physical universe; creationist
The subject line is the info
Scientists restrict study to entire physical universe; creationist
Facts are nice, but you don't need to be a rude ass about it.
I live in LA, which is great re: insolation but terrible re: commute distances; my office is 30 miles from my home and most people live 60-70 miles from their work. People commute into downtown Los Angeles all the way from Lancaster and beyond... 30 miles a day is not realistic. I don't think Los Angeles is the only city where long commutes are a reality, either.
I think you misread my intent as well; people ask all the time why we don't have solar powered cars, and the answer is it makes no sense to put solar panels on cars. The power you can generate from a car-sized solar panel array will extend the car battery range by maybe a few minutes over the course of a day.
re: storing excess power from a home PV panel into a battery bank, yes, that's great during the daytime but you're most likely to use it all up again in the evening. It is hard enough to build a house-sized system with enough power for all of the appliances in the house. It's even harder to build in excess capacity for something as power hungry as an electric car. If you're living totally off-grid, you're going to need more.
For example, the AC Propulsion T-zero is using 6800 18650 LiIon cells to give it a 300 mile driving range. That's a battery array of 100 in series by 68 in parallel, peak voltage of 420V and at 2AH/cell a total of 136AH or 57.1KWH total capacity. The Tzero is really light, this is only 190WH per mile. But let's assume a larger 4 seater and your 340WH/mile figure, with a commute round trip of 120 miles/day. That's 40.8KWH/day. For the 2-seater Tzero it's only 22.8KWH/day, which by your figures (6 hours, 15%) means 25m^2, or 45m^2 for the larger car.
-- *My* journal is more interesting than *yours*...
At current rates it makes no sense to try to power one's car 100% by solar electricity, but if you want to make the first 20 miles every day (or every trip) be sun-powered you could do that. Read the EPRI study link off this page (big download, long but informative read). If you did something as simple as putting solar panels over covered parking at workplaces (make covered parking a perk for EV or PIH drivers) you could get a substantial amount of range out of that. If the parking space is 9 feet wide by 17 feet long (roughly 14 square meters), you assume 1000 W/m^2 normal insolation at an angle that gives you 80% of that on a flat surface (probably pessimistic for LA) and 15% efficiency, I get 14 m^2 * 0.8 KW/m^2 * 6 hr * 0.15 ~= 10 KWH/day. At 340 WH/mile you'd get your 20 miles of battery range out of that plus some excess. If you postulate 50% conversion efficiency the production increases to 33.6 KWH/day, roughly 100 miles worth.
If the car is 5.5 feet wide and 15 feet long (roughly 7.5 m^2) and you cover it with 50% efficient cells, given the same assumptions above you would get 18 KWH/day just out of the light falling on the car. If the car used 340 WH/mile you'd get more than 50 miles/day out of the sun falling on the car (the tzero would get ~100 miles). Not so trivial any more, is it?
Scientists restrict study to entire physical universe; creationist
Ok, sounds great. I hope we'll be seeing flexible amorphous cells at the 50% mark soon, so they can conform to existing body shapes instead of having to specifically engineer flat surfaces to mount crystalline panels.
I think my previous experience with 5% efficient amorphous-Si cells gave me a bad perspective on things. I'd love to have a Tzero and run it primarily off solar, absolutely. The right technology is out there, but it's still not-exactly "off the shelf" yet. Close...
-- *My* journal is more interesting than *yours*...
But some differences in quantity become differences in quality. Being able to put cells on a vehicle and get a decent amount of range out of it is enough to tip the balance for many applications. A change from 5% efficiency to 50% does that, and more.
Last, I'll bet that any application using nanocrystals is going to be able to create conformal or maybe even flexible panels. I wouldn't mind having a solar-electric hat to run things while I'm outdoors, or a solar-electric tent fly to power camping gear.
Scientists restrict study to entire physical universe; creationist