Breakthrough in solar photovoltaics 676
An anonymous reader writes "The Holy Grail of researchers in the field of solar photovoltaic (SPV) electricity is to generate it at a lower cost than that of grid electricity. The goal now seems to be within reach.
A Palo Alto (California ) start-up, named Nanosolar Inc., founded in 2002, claims that it has developed a commercial scale technology that can deliver solar electricity at 5 cents per kilowatt-hour. " As always, take these claims with a dose of salt the size of the Hope Diamond.
Re:Per Square _inch_? (Score:4, Informative)
Jeroen
Re:Per Square _inch_? (Score:3, Informative)
The only thing I could think of is that it's maybe one of those numbers is per Hz, or something. .
Anyone else know?
These are probably dye-sensitized semiconductors (Score:5, Informative)
From what I read on the website: nanostructured materials, estimated lifetime of 25 years, made of "nontoxic semiconductor paint" suggests that it is about dye-sensitized solar cells [google.com]. These are based on small TiO2 particles, the same that is used as a pigment in white paint. These do not absorb visible light by themselves, but can catch and transport electrons from certain light-absorbing dyes. These solar cells were invented around 15 years ago; the necessary components of such a solar cell, TiO2, dye, solvents, sandwiched between two glass plates, are relatively cheap, but the yield is still below 10% (sunlight power to electrical power).
Apparently, this company has found a way to mass-produce cells based on this principle using plastic films instead of glass. The glass was the most expensive component; the problem with plastic films is that it is hard to make them last a long time while still being impermeable to oxygen and the liquid solvent inside the cell.
Doesn't look like a scam... (Score:5, Informative)
I think these guys are for real.
Re:Cost ? (Score:3, Informative)
Re:Per Square _inch_? (Score:2, Informative)
Taken from here:
http://www.eere.energy.gov/consumerinfo/fac tsheets
"The rate at which solar radiation strikes earth's upper atmosphere is expressed as the "solar constant." This is the average amount of energy received in a unit of time on a unit of area perpendicular to the sun's direction at the mean distance of the earth from the sun: 92,960,000 miles (149,604,970 kilometers). While the distance between the earth and the sun varies as the earth moves around the sun on its elliptical orbit, the variation in the distance does not have a significant effect on the amount of solar radiation reaching the earth. (The earth is closest to the sun in late December/early January, and farthest from the sun in late June/early July.) The average intensity of solar radiation reaching the upper atmosphere is about 1,367 watts per square meter (W/m2) or 434 British Thermal Units (Btu) per square foot.
The amount of this energy that reaches any one "spot" on the earth's surface will vary according to atmospheric and meteorological (weather) conditions, the latitude and altitude of the spot, and local landscape features that may block the sun at different times of the day.
As sunlight passes through the atmosphere, some of it is absorbed, scattered, and reflected by air molecules, water vapor, clouds, dust, and pollutants from power plants, forest fires, and volcanoes. This is called diffuse solar radiation. The solar radiation that reaches the surface of the earth without being diffused is called direct beam solar radiation. The sum of the diffuse and direct solar radiation is called global solar radiation. Atmospheric conditions can reduce direct beam radiation by 10 percent on clear, dry days, and by 100 percent during periods of thick clouds.
The daily rotation of the earth and its seasonal movement on its axis has significant implications for practical use of solar energy. For any spot on the earth's surface, the amount of energy it receives will vary on an hourly, daily, and seasonal basis. It is the angle of the sun's position in the sky relative to a point on the earth's surface that determines the intensity of sunlight reaching that spot. The lower the sun is in the sky, the more of the earth's atmosphere that the sunlight passes through before it reaches the surface, and the more it is diffused.
Direct solar radiation is generally most intense at any one spot on the surface of the Earth at solar noon, since it is most perpendicular in the sky, and has the least amount of the atmosphere to travel through. For locations at and north of 23.5 degrees north latitude, it is most intense at solar noon on June 21st (the summer solstice). At that time, the sun is at the highest point in the sky that it will reach during the year, and it is at this point that sunlight passes through the least amount of the earth's atmosphere. The summer solstice is also the longest day of the year. For these same locations, the shortest day of the year, and the day when sunlight is the least intense is December 21st, the winter solstice. (The opposite is true for locations in the southern hemisphere.) Higher latitudes have more hours of sunlight in the summer and less hours of sunlight in the winter, relative to lower latitudes. For a point on the equator, the sun will be most intense around March and September 20th and 21st (the spring and vernal equinoxes) as these are the days when the sun is directly overhead.
Solar collectors can be positioned to maximize the amount of solar energy that they receive on a daily and seasonal basis. In general, the optimum orientation of a solar collector is directly true south (in the northern hemisphere; true north in the southern hemisph
Re:Cost ? (Score:5, Informative)
this implies that the sheet 10 X14 feet produces around 1.5 killowatts, and costs around 500 bucks!!!!! GIMME GIMME I WANT ONE
Re:Per Square _inch_? (Score:3, Informative)
Q: What is the expected cost per square meter of typical Nanosolar solar cell module?
A: A square meter of (an array of interconnected) Silicon solar cells (a "module") has a product cost of approximately $300 (or $2.75/Wp) from today's cost leaders in Silicon. Nanosolar solar sheets/modules are based on much thinner cells (up to 1000x thinner in their active layer) and tend to cost as little as $30 per square meter, or 10x less. Note that this does not mean that there is a cost/performance difference by this same factor, however, as Silicon solar cells will continue to be the efficiency leaders for the forseeable future.
Re:Cost ? (Score:2, Informative)
Re:Per Square _inch_? (Score:2, Informative)
Re:Per Square _inch_? (Score:3, Informative)
So the article has got something badly wrong...either they've got the units wrong - 120W/m^2 sounds plausible, 120W/sq. ft. is theoretically possible but extremely unlikely as it would require 90% efficiency, 120W/sq. in. is totally impossible for Earth based solar - or they're being taken for a ride.
Well... (Score:5, Informative)
http://www.nanosolar.com/pr2.htm [nanosolar.com]
Re:Cost ? (Score:3, Informative)
Well, it said 12% efficiency, so I'd assume they meant per square *meter*, since 120 W/sq m corresponds to 12% efficiency.
120 Watts per square inch would rock, though -- it's about 200 times the theoretical maximum.
Re:Per Square _inch_? (Score:4, Informative)
6 kilowatts per square meter? That's a 'you must be on crack' figure.
Here [uoregon.edu] are some actual numbers:
Note that that's *peak*. Averaged over, say, a year, which includes periods where the sun doesn't shine at all ("night"), as well as periods where it's not high noon on a cloudless day, and average insolation falls quite a bit. This site [apricus-solar.com] claims a yearly average for central Australia of 5.89 kilowatt-hours per meter per day, which (if my conversion is right), breaks down to an *average* insolation of 245 watts. So just flat-out double that to get rid of the night time, and you're getting an average value of about 500 watts in one of the sunniest, hottest places on the planet.
Re:Per Square _inch_? (Score:2, Informative)
From what I've gleaned from their website and the article, they're not claiming to have created more efficient solar cells, just cheaper ones.
Somewhere in the literature they state that they're getting 12% efficiency which isn't particularily high. I think that the highest efficiency chips are in the 15-18% range. What they are claiming is that they can create these cells much cheaper than has been possible. From memory it's something like 13-18 cents/kwh for standard PV (without subsidies) and they can do it for 5.
It probably should be 120 watts per PANEL, not Square Inch.
I wouldn't discount it just by that error, it's probably a mistake by a non-technical journalist writing about a technical issue.
Re:These are probably dye-sensitized semiconductor (Score:3, Informative)
Hmm. The abundance of ruthenium [webelements.com] is about 1 ppb in the crust, so that would be about 10^14 kg. IIRC, you need only a few mg of pure Ru per square meter, so I don't think this is the issue. Of course, it might be hard to extract that kind of amounts from the crust, but that is a different story. My old 1986 edition of the CRC Handbook of Chemistry and Physics lists a price of US$4 per gram.
I agree that the dye is expensive, but I think that that has more to do with the fact that it is a complicated organic molecule that surrounds the ruthenium atom.
Technical information...???? (Score:2, Informative)
Hmmmm, I think you got it backwards (Score:2, Informative)
But far be it from me to give a Slashdot staffer any credit for correct use of the English language.
Taking care of some things in one post. (Score:5, Informative)
OK, since this is a solar photovoltaics post:
Someone is going to claim that solar will never be practical, because it is 10 - 15% efficient, while internal combustion, etc. is 30%+. Please, consider that you have to *buy the energy* that goes into that 30% efficienct machine, while the 15% efficient solar panel gets it all free - then run the numbers. The only cost that matters is the dollars per Watt capital cost of the cells upfront (which is still too high, but coming down.)
Someone is going to claim that solar panels produce less energy over their lives than it takes to manufacture them. This has not been true for about 40 years. [energy.gov]
Someone is going to claim that solar panels are a toxic danger to human health. Please consider that they are manufactured using identical processes to microprocessors, are easier to disassemble for recycling, and last 20 - 30 years plus, as compared to the five year or so length for most consumer electronics.
Someone is going to claim that solar only makes sense in certain parts of the United States. Keep in mind that, for instance, Albany, NY gets 80% of the solar radiation of Reno, NV. Since you pay twice as much for electricity in Albany, solar panels actually make more sense there. (Remember, most solar panels go on rooftops and spin meters backwards - you get retail price ($.08 - $.15 / kWh,) not wholesale ($.02-$.04) like a power plant.
Someone is going to claim you would have to blanket the desert with solar panels to make a workable power plant. Is this what you do with a distributed, smart, resource, that can occupy unused roof space anywhere? Did we take all of our microchips and assemble them into one giant supercomputer in the desert? Solar panels belong in a distributed network of generators - at the end of the wire, and putting them there is cheap and practical.
Someone is going to claim the solar industry can never meet real-world power demands. Check any industry publication for an interesting statistic - in 1996, 100 megawatts of solar were manufactured. Jan - Dec. 2004 saw about 1100 MW (about $ 6 billion worth) manufactured. Still pretty small, but an amazing growth rate.
What does solar cost now? About 1/20 what it did in the 1970s, but still about twice as much as grid electricity. Once you buy the panels, and finance them with, say, a home equity loan, you're looking at $.18 - $.25 /kWh. Getting closer every year, but still not quite there.
Finally, a comment on the article. Yeah, Nanosolar is pretty neat, but I think that Konarka [konarkatech.com] is quite a bit further along - and doesn't share nanosolar's tendency to overpromise. Here's what needs to happen. Their efficiency is fine, don't care - a 5% or 10% efficient cell, as long as it's less than $1.50 / Watt, the world will beat a path to your door. However, their longevity is not there. A normal silicon solar panel lasts at least 20 years, these things last more like 5 right now. Hence their strategy of putting them in consumer electronics that have about that lifetime anyway.To be a real power generation source, they need to get that lifetime up by a factor of 4 - doable with the right encapsulants, some chemistry, getting rid of liquid electrolytes, etc. I bet one of these poeple will be at $.10 / kWh in five years - but the conventional silicon cells can probably get there in about 8, with manufacturing and scale improvements. So it's a real race...we'll see who pulls it out.
Re:Per Square _inch_? (Score:2, Informative)
If anyone bothered to look at the website for the product http://www.nanosolar.com/products.htm [nanosolar.com] they will find the following facts:
1) the 14 foot by 10 foot model produces 110 Volts and costs about 30 dollars per square metre (they make no claims as to the wattage per square metre of their product)
2) this compares with current technology costing 300 dollars per square metre, which produces somewhere in the region of 120 watts per square metre.
3) they claim that their product produces cheaper electricity (i.e. it cost less to produce power than the current state of the art)
4) as their product is about 10% of the cost, their product only needs to be more than 10% as effecient as the current products to be better value.
In other words, someone has found a way to mass produce cheap but not very efficient solar cells
Google founders invested (Score:3, Informative)
There's a patent: #6,852,920 (Score:5, Informative)
First, by "manufactured by printing", they don't mean a roll to roll process like a printing press. They propose to deposit materials with an inkjet-like mechanism.
Second, what they call "nanotechnology" is surface chemistry. There are ways to make semi-regular structures by bulk chemical means, and that's what they're doing. They did throw a reference to "bioengineered self-assembly" in, but that's not how they do it. The processing looks much more like processes you'd do in a wafer fab. There are common fab processes like electrodeposition, chemical removal of support substrates, and heating in an inert atmosphere.
The basic idea is to address the reasons that solar cells are inefficient. In bulk materials like silicon, only a small fraction of the photons do anything useful. Most of the photons are at the wrong wavelength. And many of the photon interactions that do occur don't result in an electron being delivered to the output. They're trying to fix both of those problems.
Their policy seems to be to shut up until it works. It might work, or it might not. They're not selling stock, and they're not issuing press releases. They have VC funding and some money from DARPA.
Re:Grain of Salt (Score:5, Informative)
Most peole believe that the grain of salt is the antidote to the mistruth. The true meaning is lost in the mists of time so you might be right or they might be.
According to Word detective [word-detective.com]:
Re:hope diamond my ass (Score:3, Informative)
Re:Cost ? (Score:5, Informative)
California did not refuse to build new power plants, and has in fact been building them like mad ever since it got raped by Enron.
Enron shut down Enron's power plants, Enron moved out of state, became a distributor only, and Enron did so deliberately in order to create shortages. Enron managed to pin this on CA, and to this day, Enron's criminal behavior has gone unpunished by regulators while California seeks to get back the overcharges caused by Enron.
Clear?
Re:Taking care of some things in one post. (Score:2, Informative)
So you can get crude oil out of the ground, transport it to your location, and process it to produce gasoline, all for free?
You can dig up coal, separate it from the dirt and the other things in the ground, transport it to your location, and pulverize it, all for free?
I have to pay for those things, but I've never paid to have sunlight fall on my house.
Please explain where the double standard is. Hint: The cost of converting the fuel to another form of energy doesn't count -- that's conversion cost, not fuel cost.
Re:Per Square _inch_? (Score:3, Informative)
Those figures you're looking at are per day. See here [nrel.gov] for an excellent set of maps.
Re:Cost ? (Score:1, Informative)
Re:Cost ? (Score:2, Informative)
Re:Cost ? (Score:3, Informative)
Given that the cost of EHV transmission is on the order of a US$1 million per mile, and you're talking several hundred miles, and that total cost has to be invested before the first dollar of actual energy can flow... there's a significan prohibitor right there. Especially when a generator company looks at the existing grid, sees that they only have to run several hundred feet of wire to tap into an existing substation, and they decide to build the installation there.
Answer is much, much cheaper. So much so that there's barely any energy transfer across the Rocky mountains today as it is... that's why the north american electric grid is separated into 3 AC systems... Eastern, Western, and Texas.
Re:Cost ? (Score:5, Informative)
My girlfriend lives in a solar powered house here in BC (Canada). For 4 months she has to suplement power from the grid, but for the rest of the year, it's enough. That's big savings. Another friend lives in a passive solar house, and only had to fire up his heat for about 2 weeks this winter. And these are spacious houses with lots of windows and all the normal (power saving) appliances.
The thing about these techniques is; they're cost efective _now_, if you can aford the capital outlay. Your bills go down, and it pays for itself.
That used to be true (Score:3, Informative)
That's not necessarily true any longer. Most larger power coops will actually buy power from their customers. In the desert southwest, for instance, power companies have realized a cost savings from customers who use solar and dump their excess back into the grid. Since the power companies don't have to maintain residential solar power setups, and because they pay less than the going rate for consumer generated power, its become a real treat for them. The only thing slowing the adoption of solar in most areas is a) the expense (not just of solar cells, but large battery banks and inverting equipment) and b) less than favorable weather. This development alone may make it practical in the southwest (even to the point that power companies change their business models to just the distribution and brokering of customer generated power, with some backup of their own), and make make solar an option in less sunny climates.
Also, there are a few large coops (Progress Energy I believe is one) who in the past had advocated a distributed power distribution network based on new safe reactor designs.
Re:alternative energies (Score:2, Informative)
Alaska drilling takes up a bit more space than that, mate.
Re:Is single-sourcing all of our energy desirable? (Score:5, Informative)
They don't have the problems of past low power bulbs. They don't blink. I've never noticed a blink rate, and I've been reading by them for 4 years. They do take 20-45seconds to get to full output. A 60-watt rated bulb (actually 15 or so watts) starts out at what I would say is 40-watt equivalent light, but it gets up to full in less than a minute. That's great, if you need more than 40W incandescent-equivalent light, you're going to have the light on for more than 20 seconds, so don't anyone think about complaining about that.
Everyone that hears me should go out and buy these for their homes. I don't mean to sound demanding. I sincerely desire to know what would be a good reason not to use them, because I can't find one.
These bulbs are sold as long-lasting, or cost-saving, but they need to instead be sold as environmentally friendly, and as using 75% less fossil feuls while their on, 75% less CO2 created, etc, etc.
Re:Is single-sourcing all of our energy desirable? (Score:2, Informative)
Additionally they're not as environmentally friendly as the previous poster might have though. Flourescent bulbs contain mercury and require special handling to dispose of properly. (Ours go to a specialized recycler here in the Springs.) Still these are the ones we use because of their lower energy consumption. Once we're generating our own power I don't want wasted consumption for a bunch of wasted heat!
Ferretman
Comprehensive EU plan for CSP in Sahara (Score:5, Informative)
The results of the EU ECOSTAR CSP program have just been released at a workshop held last thursday in Brussels. The 140-page report can be downloaded from ftp://ftp.dlr.de/ecostar. CSP power stations occupying an area the size of France in the Sahara, using available technology, can produce the current total energy consumption of the whole world.
Re:theory vs practicality (Score:3, Informative)
Because the windiest areas are created by land featues.
But they do have that limitation.
I just got done explaining how they don't. Maybe you can provide some detail to back up your assertion.
Being less "questionable" doesn't make it realistic.
Ok, so we're doomed once fossil fuels run out. Do you have any better ideas?
Re:Their site lacks details (Score:2, Informative)
Art
Re:Cost-effective solar (Score:4, Informative)
Re:These are probably dye-sensitized semiconductor (Score:3, Informative)
I don't own a car, but there is probably not much ruthenium in my bikes. :)
Dyes in dye-sensitized semiconductor photovoltaics need to satisfy different requirements than those in paint. Most importantly, it should release an electron to the semiconductor when it absorbs a photon and should have a low probability of recapturing that electron from the semiconductor. How DSSC cells operate is very different from purely organic cells. The latter still have very low efficiencies and often a mediocre lifetime---they won't survive 25 years in full sunlight. Now 10 percent effiency, that is something to be skeptical about.
Indeed, at least if it had been a fully organic system. The first nanocrystalline DSSC cell ever made directly had an efficiency of 7%. Actually it is more disappointing than too good to be true that the efficiency has climbed so little in 15 years time.
Re:Energy FUD (Score:3, Informative)
Actually, in most states at least for residential scale self generation the meter does run both ways. They don't switch to the other method until the generation exceeds a certain amoutn at which point they treat you like a power plant and buy it wholesale.
Less Pot and More Facts, Please. (Score:5, Informative)
California, because it had not built enough power plants, was importing power from other states.
In order to import power you have to have your own power system suitably balanced. It's not like you put electrons on trucks and wheel them in. To do this, you offer financial incentives to buy or sell power at various points on the grid. To this day, PJM does this on the east coast and you can actually check it out here PJM LMP pricing [pjm.com]
Also, you have to adequate transmission rights to get the power in.
So what Enron did was rather clever. First, they had better software than the California ISO for determining grid imbalances and so they scheduled power deals to manipulate the grid. Import power in the north, export it in the south, boom there is an imbalance, and you can sell the power you exported back to the state for a lot of dough. Then, they would also go and buy up transmission rights into the state (which is actually pretty cheap), and then play games at peak times.
The amazing thing about the whole thing is that gaming California's stupid grid managers WAS LEGAL. That's right. Enron didn't do -anything- wrong by screwing the state of California. The state made its rules for its market place and Enron exploited them, but California should not have made those rules to begin with. To cap it all off, California deregulation stripped utilities of the ability to pass variable costs to consumers. So, if the price of electricity shot up, it should have shot up for consumers as well, and guess what, people turn their air conditioners down, and there is no power crisis. But oh no, California made it so that the utilities could not recover the costs and so they had to sell power at a loss, and all the utilities in California went bankrupt, and Enron made a mountain of money, legally.
The thing that got Enron into trouble was that they were lying on their financial statements, and for that, the company is now bankrupt, her executives are either on trial, and the accounting firm that certified those statements no longer exists.
Re:Less Pot and More Facts, Please. (Score:1, Informative)
Re:Cost ? (Score:3, Informative)
The system is ~2KW system( ~3KW spec'ed ) and we paid for the system via a home equity loan( more write offs ).
We're generating about 4000KWh per year at todays ~$.15/Kwh which is $600. If rates say steady, it'll take 13 years to pay off the system. We don't expect energy rates to stay steady.
Sherly, if we didn't have the CA Solar Energy rebate, onetime tax deduction, and the southern California sun, it'd take much longer to pay off.
I'm working on an Islanding mechanism that'll double as a home automation control system UPS so that rolling blackouts( during daylight hours ) won't shut our system down.
so it's really not as bad as you think. And if anybody is able to get over 25% efficiency out of solar panels at current panel costs, it'll be threshold crossing time IMO. Hey, hydrogen might even have a future then.
LoB
Re:Cost ? (Score:3, Informative)
True, they do pay for themselves. We evaluated spending last year's tax refund (a few grand, I never claim enough deductions) on putting a PV solar system on our house. After some number crunching, we found it would take 10 to 15 years for the system to pay for itself.
That's a whole lotta capital for a ROI way, way off in the future. Investing in mutual funds would be far more profitable, so that's what we did instead.
When it comes to saving on your power bill, what does work is converting almost every light in your house/apt to Compact Flourescent (CF). We did that and it paid off in only 1 year. I'll admit some brands of CF are pretty crappy but others are as good as incandescent, becoming bright instantly with no flicker, and having a warm yellowish hue. The trick is to buy bulbs rated one level higher than incandescent. I.e., replace a 60 watt incandescent with a CF rated for "75 watts".
YYMV, especially in a more sunny state, or one with higher electricity costs.
Re:Taking care of some things in one post. (Score:1, Informative)
I don't know how current your coal prices are, but go look up the latest spot prices; they're avidly profit-taking in the wake of skyrocketing natural gas, and they've got a lot of room to keep doing so...
Direct solar energy availability matches extremely well with peak demand in most parts of the United State - for an example in Long Island, see SEIA's comments to the NYRPS [state.ny.us], or the studies in the biography at Small Is Profitable. Have you seen data which contradicts this empirical work?
Less than 1% of on-grid solar installations involve battery storage in any way - and tehy haven't since the late 1970s. Your objections to chemical batteries in regards to solar energy are about as technically legitimate as objections to automobiles because of their noisy superchargers and NOS injectors.
The direct current to alternating current inverter (sans storage outside perhaps a small capacitor) also ties into the grid, where energy storage is handled. As for scalability at end use, they're coming up on half a dozen megawatt-plus rooftop installations.
I wish it were simpler to overcool, deoxygenate, and otherwise destroy the downstream ecosystems of major watersheds, induce greenhouse methane production in the benthic layer of reservoirs, remove thousands of acres from the public domain and ecosystem, regulate discharges for the use of dozens of interested parties without overroding the channel, eliminate the reproductive cycle of economically important fish species and negotiate dozens of irrigation, intrastate, and international water treaties, all while creating an enormous target for natural disaster or intentional sabotage, but it isn't;
=P Intra-resource ragging aside, no power source is simple, nor free, but you should be up to date on your competitors, and there's no point to trotting out technical objections that are dated or untrue...