Method for $1/Watt Solar Panels Will Soon See Commercial Use 502
An anonymous reader writes "A method developed at Colorado State University for crafting solar panels has been developed to the point where they are nearly ready for mass production. Professor W.S. Sampath's technique has resulted in a low-cost, high-efficiency process for creating the panels, which will soon be fabricated by a commercial interest. 'Produced at less than $1 per watt, the panels will dramatically reduce the cost of generating solar electricity and could power homes and businesses around the globe with clean energy for roughly the same cost as traditionally generated electricity. Sampath has developed a continuous, automated manufacturing process for solar panels using glass coating with a cadmium telluride thin film instead of the standard high-cost crystalline silicon. Because the process produces high efficiency devices (ranging from 11% to 13%) at a very high rate and yield, it can be done much more cheaply than with existing technologies.'"
cost benefit analysis (Score:3, Insightful)
Re:cost benefit analysis (Score:4, Insightful)
Re:cost benefit analysis (Score:5, Interesting)
I run on 20 year old Solar panels here. I buy only used and discarded from solar plants out west and they look brown from the years of solar exposure but cost me far FAR less than buying new so I can afford more watts for the money. Decent used one approach $2.00 a watt but that is at higher voltages. and my panels will last another 30 years easily with care.
Re:cost benefit analysis (Score:5, Funny)
Depending on the investment in the solar panels, I might even consider setting up some sort of permanent awning to protect them from the sun at all times - protecting my investment as it were.
Re:cost benefit analysis (Score:5, Funny)
Re:cost benefit analysis (Score:5, Funny)
Re:cost benefit analysis (Score:5, Funny)
Re: (Score:3, Funny)
Re: (Score:3, Funny)
Re: (Score:3, Insightful)
It's an interesting thought, although I have to admit it reminds me of that guy in college who didn't want to work out because he didn't want
Re: (Score:3, Informative)
Just for clarity for those who don't know:
Watts are a rate of flow for Joules.
Joules are a unit of energy (kg m^2 / (s^2)) which describe the dista
Re: (Score:3, Interesting)
Back of the envelope (Score:5, Interesting)
So let's see the solar panels are 100000 cents per KiloWatt. if the last 4000 then that's breakeven. We'll assume that the power is available 10 hours per day. That's not realistic for individual use but perhaps with batteries, and selling back to the grid this could be done. So 4000 hours is 400 days. Or about 1 year. Not too bad.
Now that ignores the efficiency of either pushing back to the grid or battery storage. Let's assume 50% loss. Then this is 2 years to payback on the cells. But now we also have to payback on the batteries. Let's assume the batteries needed const aout the same as the solar cells. That would double this payback to 4 years.
Finally this is assuming capital is free. Assume one borrows at 8 % interest. Then this another 5 months to payback.
So the whole operation needs to run undegraded for 4 to 4.5 years I estimate for break even.
That figure could be cut in half if one could sell back to the grid rather than batteries. ( Fine--as long as there is a grid and every one does not do that!. )
If the cells were down to 50% effiency after 4 years then this extends out to ~7 years to payback. If one cannot get that watt for the full ten hours then this gets even longer.
It sounds to me, roughly speaking that at 1 dollar per what things are in the ballpark for breakeven.
Re: (Score:3, Interesting)
Re: (Score:3, Informative)
Re: (Score:3, Informative)
Doesn't have to be break-even. Most people don't buy the most efficient vehicle that will meet their needs, they go larger. Decisions are not always purely economic.
Of course, how much value an individual puts into being green or grid-independent varies, so it's tough to calculate. Solar panels, perhaps unfortunately, aren't as sexy as hot cars.
Still, solar has made sense in a number of remote locations for years no
Re:Back of the envelope (Score:5, Insightful)
Since this may seem implausible consider this. The world is on track to double its energy consumption by 2040. To reach that point in a linear fashion--not geometric one--would mean bringing on line three gigawatt class power plants every day from now until then. Right now the figure is about 10 GW plants per year because we are in early long tails of that geometric growth curve.
About now your jaw should be dropping as you ponder the implications.
Thus what has to happen, other than permanent blackouts in most of the world and carbon poisoning of the planet, is that the growth rate must be stifled. And that is going to happen when the price of electricity hits ~$10/KW-hour and all then people will economize and buy energy saving appliances.
I did not make up those numbers. read the 2030 report from the department of energy.
So I was being generous assuming 25 cents per KW-hour grid rates.
Of and by the way, note that the plant for solars cells will produce 200MW
Re: (Score:3, Informative)
Re:Back of the envelope (Score:4, Insightful)
economics and population growth (Score:3, Insightful)
You do realise that he was right? The green revolution along with declining birth rates in the western world has ensured that we have enough food - but starvation is a reality elsewhere.
That's the thing about many, I won't say all because I consider myself one, environmentalists don't and won't consider, as people improve their economics they have fewer children. Up until recently the countries with the highest population growth were China and India. However now that their economies are booming their p
Re: (Score:3, Interesting)
A concern in China is that in a generation or two there won't be enough working adults paying for an aged population. Whereas now there's something like up to 10 people working for every retired person then there will be only 3 workers. Falcon
In theory the one child per couple policy in China has been going on long enough that those children are marrying and each of those couples will be expected to look after 4 parents in later life. Worse still the couple's single child will marry and have 4 parents and 8 grandparents to worry about eventually.
Re: (Score:3, Insightful)
The population has leveled off in China because the dictatorship there has decreed that couples may only have one child each. It has little to do with the economy there 'booming.' The booming economy may, however, be a result of the 'one child' dictate. That's one of the benefits of the 'one child' policy that the government explicitly cites.
While China's one child per family has had an affect, the booming economy also has a part in reducing the reproductive rate. India has no such law mandating only on
It makes me kinda wonder how (Score:3, Interesting)
Will it be mostly in the industrial sector for example?
Will it just mean more energy used in currently third world countries?
Re: (Score:3, Informative)
In the developed world we have substituted materials that did not require so much energy for ones that do. To follow your line of reasoning consider the can opener in your kitchen and compare it with your grandmothers first canopener. Heres was a carbon steel blade, she might have even had the knife sharpener man who came by sharpen it from time to time. it was probably made in chicago or some place near a train depot.
Re:Back of the envelope (Score:4, Insightful)
I for one am a big supporter of earth-berm homes for their efficiency and ground-source heat pumps as well. Put a greenhouse on your southern exposure above ground, and use the heat from that in the winter. Eating more fresh fruits and vegetables grown locally cuts down on cooking energy and transport energy. In short, making smart choices for how to live with the land instead of separating ourselves from it so much can make a big difference.
Of course, in a 40-story high-rise, it's a little difficult to do many of these things. It's also not like we're going to get everyone to switch to a rural lifestyle. Mass transit, green rooftops, and light-colored exterior surfaces are some steps in the right direction in cities. It's an architectural challenge to make the interior rooms on the middle floors of a skyscraper passively heated, cooled, and lit. Yet it's not like we want all that vertical space to sprawl out horizontally either. This is tough stuff to figure out, and I hope some very smart people are working very hard on it.
Re: (Score:3)
Re:cost benefit analysis (Score:5, Informative)
--
Rent solar power for your home and save: http://mdsolar.blogspot.com/2007/01/slashdot-users-selling-solar.html [blogspot.com]
Re:cost benefit analysis (Score:5, Informative)
cadmium telluride thin film on glass... (Score:3, Interesting)
Re:cadmium telluride thin film on glass... (Score:5, Interesting)
You don't need to worry about the environmental impact of cadmium, but rather the environmental impact of cadmium versus the environmental impact of current energy production from fossil fuels, etc.
Re:cadmium telluride thin film on glass... (Score:5, Interesting)
Fuck this liberal environmentalist whining... (Score:3, Funny)
Anonymous Coward Sig 2.0:
--
Write in George W. Bush in
Your Heavy Metal Atmosphere (Score:3, Informative)
Re:One more question (Score:5, Insightful)
And after they place the condemnation notice on your front door, they'll kick your dog.
Seriously, what makes you think that the engineers building this thing are so incompetent that they haven't considered the possibility of hail falling on your roof? They actually do run tests like that. Second to last paragraph here [colostate.edu].
I also find it very interesting that you didn't mention the dangers of actually living in a poison-dusted home, but only the danger that the EPA might deny you your God-given right to live in said death trap.
Tell you what, when serious people who actually know about the toxicity and regulatory requirements of cadmium telluride start telling me that this solar technology may present problems, then maybe I'll start worrying.
Re: (Score:2)
Re:cadmium telluride thin film on glass... (Score:5, Funny)
Therefore, the solution to the cadium waste is obvious. Put it in the water. After all, dilution is the solution to pollution.
Impresive (Score:2, Insightful)
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Re: (Score:3, Interesting)
Add another $.50-1/watt for the inverter [wholesalesolar.com] and miscellaneous, and you're up to $3/watt of capacity.
10k hours, figuring 8 hours a day, 365 days a year would be 3.4 years for raw payback on the panels. If you're not that optimum, it'd stretch to 4-5 easily.
Figure in the cost of the inverter and installation, and it jumps to 12-15 years easily, before any cost of capital expectations.
They not only have to make
Re:Impresive (Score:4, Interesting)
conventional panels have always been restricted by the amount of pure silicon that can be produced, and with microprocessors using the same pure silicon its been tough for solar panel makers to have enough supply to meet demand. in fact the major tech companies have multi year contracts on 99% of the pure silicon being produced world wide.
btw this technology does not cheapen solar power to utility electric rates.. according to a website about solar energy Around 59% of world solar product sales installed the last five years were in applications that are tied to the electricity grid. Solar Energy prices in these applications are 5-20 times more expensive than the cheapest source of conventional electricity generation, although they may only be 3-5 times the electricity tariff that utility customers pay. By contrast, PV can be fully cost competitive on economic grounds in remote (off-grid) industrial and habitational applications.http://www.solarbuzz.com/StatsCosts.htm [solarbuzz.com]
so cutting the solar panel cost to 1/2 of what it was before makes solar a preffered method of off-grid electrical applications, and brings the total consumer cost down to levels (15cents/kwh) that they would actually pay for electricity. still not ideal, if they can bring the cost down further with economies of scale, then this will start a revolution for earth-friendly consumers who will be able to take out a loan to buy a $10k system that cuts their electric bill by 25% (to fully power a house with typical energy usage would run about $40k with these pannels, or $80k with normal solar pannels) which means the pannels would have to last at least 34 years to recoup the cost invested in installing a solar system. (theyd have to last for 68 years with normal solar panels) now if youre using a grid+solar setup you can probablly keep using those solar panels as long as theyll crank out energy, but of course they do degrade over the years, producing less energy... and widespead solar power adoption will cause winter energy spikes, but if they have to have coal fired plants that they only run 3 months a year, because of widespread solar adoption... well itll be an improvement.
$1 per watt is frankly about 10 times more expensive than we need to get solar energy for solar electric companies to adopt the technology without government subsudies/regulation.
this is why companies like excell energy are turing to wind turbines to meet the 20% renewable energy production mandate minnesota has put them under by 2020.. wind turbines are ALREADY produced around the COST per kwh of coal fired plants. (theyre sold for more obviously though)
wind energy is a natural byproduct of solar energy, and with the new tidal stream generators it is possible that the uk and scottland could see more than 10% of their total electrical consumption produced entirely from rapidly moving undersea currents.
tidal projects obviously have less problems with home owners that wind farms, and since areas with high tidal streams tend to be far from good scuba diving sites there should be little complaint about installing tidal stream generators.. in the handful of places where they are genuinely viable.
its nice to know that more californians will be able to afford a basic solar install, but this isnt something so revolutionary that were going to stop building coal fired plants because of it.
So, how many watts per sq. meter ? (Score:5, Insightful)
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Simple conversion (Score:5, Insightful)
Re:Simple conversion (Score:5, Informative)
Re: (Score:2)
Re:Simple conversion (Score:5, Insightful)
Eh? Power = Energy / Time
1.6kW is a measure of power, not energy. You probably meant that 1 square metre receives 1.6kW hours of energy in an hour, which would give 160W hours per hour per square meter, or in power terms, 160W/m^2. That is, about the same power as would be necessary to power 3 strong light bulbs.
Somehow I think a 1m^2 window would be simpler, and if you use a triple glazed argon filled one ( as the Germans do for the passive-house standard) then you can neglect heat loss (in fact, you can get a net heat-gain ), making them considerably more efficient than chaining a 11% solar panel to an energy saving light bulb with 7%-8% efficiency (giving an overall efficiency of about 0.8% ).
No, really, in the vast majority of cases your money is better spent on insulating your house.
Re: (Score:3, Interesting)
Re: (Score:3, Informative)
http://www.pages.drexel.edu/~brooksdr/DRB_web_page/papers/UsingTheSun/using.htm/ [drexel.edu]
According to ASHRAE, a horizontal surface on the earth will get around 256 btuh/sq ft peak at noon on a clear, sunny day. By my calcs, that's about 800 Watts/sq meter.
For yesterday's data on actual insolation at the surface in the Western US, see this:
http://www.soils.wisc.edu/wimnext/insol/westinsol.html/ [wisc.edu]
H
That's if you're up in space (Score:4, Informative)
- Night (50% averaged for the year).
- Suboptimal angling on the panel relative to the sun throughout the day (guessing pi/4 since I'm too lazy to do the integral).
- Weather (highly dependent on location but this report [agci.org] says 54% in the northern hemisphere, let's use 30% to account for light that manages to get through the clouds).
- Panel efficiency (12%).
- Conversion losses. I should be including losses converting solar panel DC into the AC most household appliances use, but let's be optimistic and say these panels spur development of DC appliances.
- Battery efficiency. Unless you plan to use your lights only during the day, you're going to have to store electricity for night use. Lead acid batteries are about 90% efficient. Wild guess, but say a half of your daily electricity use will be drawn off the batteries, yielding an average 95% battery efficiency. Yeah you could draw electricity off the grid at night, but since we're hypothesizing DC appliances and throwing away conversion losses, I think this is the smaller of the two.
Phew. So what do we have? 1600 W/m^2 * 0.5 (atmosphere) * 0.5 (night) * pi/4 (angling) * 0.7 (weather) * 0.12 (panel) * 0.95 (battery) = 25 W/m^2. That's probably a more realistic figure to use if you want to calculate how much electricity use the panels will save you over a year. The average U.S. home consumes about 1 kW (averaged over the year), so to completely take each home off the grid would require about 40 m^2 of panels. You'd probably want more than that to get you through the Winter months and long bouts of bad weather, but that's very location-specific. We'll just use 40 m^2 and calculate a minimum.Assume the $1 per Watt figure is under ideal conditions (companies love to do that). 800 W/m^2 * .12 = 96 W/m^2. So a square meter of this stuff will run you $96. Multiply by the required 40 m^2 to yield $3840 per home.
Figure an average electricity cost of $0.13 per kWh (in the higher priced areas where this stuff will be used first). Average home burning 1 kW (yearly time-average) would thus spend 24*365*1 kWh = 8760 kWh for the year. At $0.13 per kWh, that's $1139/yr in electricity costs. Ignoring installation labor, the panels would pay for themselves in 3 years and 4.5 months at earliest. Adjust up depending on your latitude and weather. Adjust down if you aren't as power-hungry as homes in the U.S.
I think we have a winner.
Re: (Score:2)
Re:So, how many watts per sq. meter ? (Score:5, Informative)
It did mention efficiency, so you can calculate it. Find an insolation map [wikipedia.org], find your location on it, find the average kWh/day you get, and multiply by the 11-13% figure mentioned in the article.
Cost/Benefit Analysis (Score:5, Informative)
Basically, it looks like, if they last a couple years, they would pay for themselves (166 days of full utilization, but that's not going to happen in the real world). Not bad. If they're durable (and last 5-10 years), they could really cut down on electric costs.
Oh, plus the whole saving the planet from destruction thing. I guess that might have some value.
Re: (Score:2)
There is always a catch (Score:3, Interesting)
b)How fragile are they
c)What temperature ranges can they survive
d)How strong light do they need
e)What environmental impact will the cadmium have
Sure, if it works all will be happy and dandy, but I somehow suspect there are some catches not mentioned here.
Found some. (Score:3, Insightful)
The cost to the consumer _could_ be as low as _$2_ per watt.
Anybody spot the weasel word? Then there is the $2 cost to the consumer, rather than the $1 which is the cited production cost. Also, the article makes no mention of what levels of incoming radiation these numbers were calculated for. $1/W means something quite different in Egypt than it would mean in Sweden. Is the $2/W derived from the peak efficiency under ideal weather conditions, or is it the average over a year?
Essentially, if you wa
This is not a unique claim. (Score:4, Interesting)
So this year there was a big dollar-per-watt announcement from Oerlikon. If you don't know who they are, they're a Swiss provider of turn-key thin film or amorphous silicon solar panel factories. They've got several partners in Taiwan already including, most recently, some of the large-scale optical media manufacturers who already use similar techniques and equipment and have some cash to invest.
The local Oerlikon rep was saying that producers will be at sixty cents per watt within forty eight months and that this will mean actual product at the dollar a watt level. Hey, I'm just passing along what the sales rep said. Obviously he's got a reason to overstate his case, but that's what he claimed was coming down the piple.
I think it's also worth noting that a former Slashdot sweetheart that went by the name of Spheral Solar has basically dropped off the map because they realized that amorphous silicon was going to take over.
Oerlikon bought up Excimer laser of the UK last year. One of the repeated steps in doing thin film solar is laser etching.
I'm not too sure about the tech being referred to in this piece, but dollar-a-watt PV, which is what the UN and other agencies have said is the tilting point where solar is cheaper than coal or natural gas, is already being spoken of at industry trade shows and shouldn't be seen as a wildly implausible announcement.
This is not high efficiency (Score:2)
high efficiency devices (ranging from 11% to 13%) (Score:2)
Yeah, yeah, I know: Subjective term relative to current efficiency levels... still, they're pushing it.
What does it matter? (Score:3, Informative)
Approvals (Score:3, Interesting)
I wonder if RoHS will be relaxed for solar energy?
Put me down for 5Kw (Score:2)
$2/watt retail? I'm there. I'll take 5Kw worth of panels, a couple wind turbines, and backup diesel generator and the power company can kiss my big, white butt. Already have my battery boxes built, best start working on those wiring diagrams!
Interesting (Score:5, Informative)
1.5 to 2 KW worth of panels is enough to run a typical house unless you have a machine room. Even if you use more power then your panels can produce, it's actually all to the good because it means the panels are recovering the highest-tier electricity costs for you, dropping you down to a lower tier with your utility company.
You don't want batteries unless you are off-grid, and most people will be on-grid. There are many grid-tie solutions available and costs have come down considerably over the years. Batteries are of course essential if you are off-grid but knowing the many hackers here I'm sure many of you would like to be able to disconnect from the utility completely, survive blackouts, and so forth... but generally speaking, the batteries and equipment required to do that adds a lot to the cost of the system and involve considerably more maintenance and worry.
A straight grid-tie system is completely maintenance free. I literally have not had to touch my system since the day it was installed. I just pop into the garage and stare at the cumulative power display every so often
http://apollo.backplane.com/Solar/ [backplane.com]
-Matt
Re:Interesting (Score:5, Informative)
Like you, I have a residential grid-tied system. The panels cost roughly $5/kW, plus a similar amount for the inverter, installation, etc., and I decided it was a reasonable investment if the lifetime of the panels was 25 years. If the panels only cost $1/kW, then the whole thing would have been a reasonable investment even if the projected lifetime of the panels was 5 years. Actually I find it a little frightening to have so much of my money tied up in this physical object sitting on my roof. It's covered by insurance in case of an earthquake, etc., and by warranty under some other conditions, but in general, if someone offered me a system with much cheaper panels, and told me I might have to get them replaced more often, I would probably prefer that, because it would tie up less of my capital in the system.
This may vary from place to place. I live in Southern California, and my electric company is SCE. The way the deal here works, it's a really bad idea to pay for a system that generates more in a year than you use in a year. SCE bills me yearly. If I generate a little less than I use, they send me a small bill at the end of the year, which is fine. (If you realize you're consistently generating less than you use, you can always add more panels later, assuming you have the roof space. You've already invested in the inverter, so it's not a big deal to add more capacity.) If I generate more than I use, then they don't send me a check, they just say, "Thanks for the free electricity." If I overproduce, it means I goofed big-time, because I spent more money than I needed to on my system, and it isn't returning any more on my investment than a smaller system would. Basically if you do things right, you end up with something that almost exactly covers your yearly electricity, and that means you couldn't care less what the rates are on your schedule (schedule D, TOU, whatever) -- when you pay zero, you don't care what rate you're paying at.
Re: (Score:3, Interesting)
That rule has always annoyed me, since it removes the incentive to use your roof's insolation to the extent possible. I wonder if there is some way around it, perhaps by going co-op with your neighbors (e.g. so that if you overproduce, your bill goes to zero and your neighbor's bill is reduced by the extra amount... then at the end of the year your neighbor send you a check for the difference, o
batteries are still a HUGE problem (Score:4, Informative)
If we take 10% of 250 we get 25 watts. This is about as much as a high efficiency mini florescent uses.
To run a toaster we will need 40 square meters of solar panel and to roast a turkey and cook on top of the stove as well we look at 40 amps @ 240 volts (check your main panel folks) which is about 385 square meters at 25 watts per square meter.
Thing is that we might want to roast the xmas turkey after dusk, so we better plan on batteries.
A deep cycle 12 volt battery (lead acid) can be expected to hold 60 amp-hours.... at least this is what the Hawker batteries I use for my UPS system are rated for.
12*60 = 720 watts hours. To roast the turkey say takes 4 hours at a draw of say 30% of 40 * 240 which is about 11,250 watt hours. So we need 15 batteries for this. Next if we draw them down any more than about 20% the number of cycles goes into the toilet so we'll need about 5x as many so we can draw each to about 20% of their max rating. We'll need 75 batteries.
New these batteries cost more than $250 bux so that is a battery investment of $18,750.
Clearly one will not be running an electric range off that solar system.
I'm not scoffing at the idea. I think its good but one has to find a way to store that energy and perhaps the best use of it will be to create hydrogen.
The thing is that sure it can feed into the grid during the day. All this does is put idle the current generating infrastructure and we still need that infrastructure for night operation. Of course it would save the fuel needed to operate the plant.
But then what would we use the existing generating stations for when they are idle? Generating hydrogen?
Somehow it doesn't make sense to burn fuel to create electricity to make hydrogen when we can simply for instance chemically take the Methane apart and get hydrogen that way.
One really has to think about how this cheap solar technology fits into the full cycle of energy needs.
Nevertheless I think it is good and maybe we should use it to pump water up hill. Then at night we can let the water flow back through the pump and turn it into a motor-generator. Batteries are just one way to store energy. It can be stored as compressed air, water at the top of a hill, chemically such as hydrogen gas... but it will need to be stored and in great quantities if this technology is going to go anywhere.
Plants such as trees are another good solar collector. We tend not to use them. They are reasonably efficient and serve as their own battery system because if you need more heat you can chuck another log on the fire. Since most of us tend not to use the solar collectors mother nature already created for us, I suspect that there will be huge issues to overcome in order to deploy even cheap man-made ones.
Now here is another thought. The best efficiency of these collectors is say 10%. If we capture the same energy for space heating our houses we can easily get over 80%. Yet, most of us do not even do this.
A super heated house with R70 in the ceiling and R50 in the walls costs about $1 dollar per square foot of building envelope extra during construction. This will eliminate the vast majority of summer cooling and winter heating loads. Here in Calgary for instance a house like this does not need a furnace and we can have winter days that are 40 below for weeks on end. A house like this can get by with a nice fireplace and wood heat and will burn less than 1 cord of wood per year. That wood costs about $100 dollars.
But, most of us don't even do this.
I think solar is a great idea but a low
May not be for real. Wait for pilot plant. (Score:5, Interesting)
OK, let's see if this is for real.
First, the "story" is a regurgitated press release. [avasolar.com] For an more critical story by a local reporter, see "AVA Solar enters crowded field", by Tom Hacker [ncbr.com].
The AVA Solar web site has almost no useful information. But they have a patent on the manufacturing process [uspto.gov], which discloses what they're trying to do. Among other things, the patent tells us that "AVA" stands for "Air-Vacuum-Air". The process is mostly conducted in a low grade vacuum, with some preprocessing in air before the vacuum chamber and some final steps after vacuum processing. The big deal is supposed to be that there's only one trip in and out of vacuum, which simplifies the production process. This patent was filed in 2000, so they've been working on this for a while now.
They're trying to make cadmium-telluride solar cells, which aren't new. The new thing is making them with a continuous process, instead of in batches.
AVA Solar has some job ads on Dice. [dice.com] They're looking for a plant manager, and on Dice they say "200+" employees, rather than the "500+" mentioned in the press release. AVA Solar doesn't seem to actually make anything yet, so they have to build and run a new kind of manufacturing plant of their own design without an organization experienced in doing that. That's hard.
They're supposedly building a pilot plant, to be running by the end of 2007. So wait a few months. If that works, it's worth looking at them again.
Another baby step along the way (Score:3, Insightful)
More is needed, though - even with cheap and plentiful solar cells you're still up against some physical limits. You've only got so many square feet of southern exposure you can put panels on - and it's not anywhere near enough to support your current level of electric power consumption. Keep in mind that solar panels are rated at "full sun" and in the middle of winter you'll be lucky to get 10% of that on a bright sunny day.
So a good place to start is to find ways to reduce your power consumption. Not "feel good" little reductions, but serious cutbacks. Think about things like skylights in kitchens / bathrooms (free lighting), better insulation and weather stripping, and even some automatic controls on things like lighting, heating, etc. - these will remember to shut off the lights, turn down the heat, etc. even when you forget.
Pick up a small watt meter; something like the "Kill a Watt" can help you discover where the power is going. You'll find that a lot of it is pure waste and easily eliminated. Use task lighting instead of lighting up the whole room / house, look for more ways to reduce consumption.
You'll have to make some concessions and adjustments to live a low power consumption lifestyle - it's up to you to determine how far you can comfortably go. But if you can cut your consumption by 50% or more (very possible) then you're getting to the point where those solar panels can supply enough power to keep you going.
And you're going to need some kind of backup generation for those dark and dreary winter days. House sized generators are usually NOT cost effective, battery banks are expensive and troublesome. Grid-tied systems are clean and easy - but get the facts from your local utility before going this way. Some are very reasonable, some want to pay you their "generated cost" (less than wholesale) for the power you put into the grid - but charge you peak rate for the power you pull from the grid. This can wipe out your solar savings; be careful. Choose which ever of these best fits your needs and hope you never need to use it.
4 square feet of glass is $17.40 in the store (Score:5, Interesting)
Even the cheapest solar cell should be expected to cost more than plain glass since it includes at a minimum plain glass.
Next.
Solar constant is 1300 watts per square meter in space and max 1000 on the surface of the earth.
One can expect on average 12 hours of darkness. Then we can expect only 50% of this max because most of the time its not high noon. One actually has to integrate the sin curve.
So we can say 12 hours at 500 watts average maximum collection and at best we can hope for about 50% of this. This 50% discount takes into account rainy days and snow blowing on it and maybe it gets a little dirty because people don't wash it often enough.... there are lots of things that can go wrong here. So I pick 50% out of the air as a practical fudge factor to convert to what is theoretically possible to what one might expect.
This is 3000 watt hours per day falling on the panel in a useful way, and the efficiency of the panel is say 10-13% so I'll use 10%. We can expect to get say 300 watt hours per day per square meter. This is 0.3 kwh which in worth say about 3 cents at a rate of 10 cents per kwh. This is still 25 watts per square meter for 12 hours and this is what a mini florescent draws.
But from the article - they say $1 per watt so I assume they mean per watt peak capacity.
This would be 100 watts per square meter since we have 10% of 1000 and the 1000 is peak. The duty cycle is at best 1/4 of this. Nevertheless, $1 per watt * 100 watts is $100 per square meter.
Thing is $100 per square meter is only 2x the cost of a plain glass windowpane so its actually unreasonable to expect they will be able to sell these panels at anywhere near 2x the cost of plain glass. A complete window assembly is in the order of a few $100 bux. Maybe we get the complete panel retailing at $200.
What should we expect to really get out of a $200 panel in terms of energy?
At best, 25% of max and this is about 25 watts per square meter and this is over 12 hours. Hence one should expect the thing to capture at most say 300 watt hours per day.
As I calculated before this is about 0.3 kwh = 3 cents worth of power. $0.03 * 365 = $10.90
Invest say $200 in a panel when it retails and get $10 per year from it in electricity. This is a 20 year pay back not counting installation, maintenance, and so forth. At a 5% interest rate (cost of capital) it has a ZERO Return on Investment (ROI).
Now the real issue. Suppose everyone does this. It will have the effect of destabilizing the grid because it puts the power company in the position of standing by ready to supply energy at night and when the sun doesn't shine but meanwhile when the sun is shinning their expensive infrastructure sits idle. So long before this gets deployed the rules get rewritten.
The thing is that we can already capture solar energy passively and build houses that will save way more than $1000 per year in energy and do this for a capital investment of less than $5,000. All we need to do is put R50 and R70 in the walls and ceilings. We can do a LOT more than this. To capture say $1000 per year with say these high efficiency panels will cost 100x$200 bux = $20,000 of capital and this does not include the control systems.
Re: (Score:3, Informative)
Re:13% is considered "high efficiency" now? (Score:5, Informative)
Re: (Score:2)
Re: (Score:3, Insightful)
The trouble is cost. (Score:5, Interesting)
I too live off-grid, in a small observatory at the top of a high mountain. Even though the cost of AC mains to the site was well-beyond my means, the only reason I could afford to generate my own electricity was because I work in the electrical industry and got the batteries, heavy cable, components for regulators and inverters, etc, for free.
The only things I had to pay for was the PV array and that was not a trivial expense, at $10 per-watt, excluding taxes and shipping.
My off-grid system works very well, but it requires a lot of on-going TLC, far more than most people I know could be bothered with providing. They want systems they don't have to think about and which "just work". Few have the self-discipline and willpower required to minimise their loads, letalone perform regular maintenance checks.
I've always been a Renewable Energy geek, but if I could have got an affordable AC mains connection to my site, I would have one. As much as I love playing with windgens and solar setups, with a wife and two kids now, I simply don't have as much free time on my hands as I used to.
Re:The trouble is cost. (Score:4, Insightful)
- efficient lighting
- 12v brushless dc motors in appliances
- use gas to heat stove, dryer, water heater
You can buy a nice solar array for the actual cost (not the subsidized cost) of bringing residential electric onto your property to the meter base and on into the breaker panel.
Re:The trouble is cost. (Score:4, Insightful)
It is more efficient than burning coal/oil/natural gas to produce heat, converting that heat to electricity, transmitting that electricity for several miles, and converting it back to heat. However you are correct - there is no dryer that is anywhere near as efficient as a clothes line.
Re: (Score:3, Insightful)
Balls. The sun produces about a bazillion gazillion megagiga superwatts, and about a squazillionth of that actually goes into drying your clothes. That must be the least efficient clothes dryer you could possibly imagine, unless you try and dry your clothes from a more distant star or mabe by bouncing sunlight off the moon.
Re:The trouble is cost. (Score:5, Insightful)
nah, I think the sunlight directly onto the clothes is more efficient.
Re:13% is considered "high efficiency" now? (Score:5, Insightful)
On grid, every watt generated by the panels goes somewhere and does something, because you feed it back to the grid, where it reduces the demand for fuel-burning electricity.
So living off the grid can be rewarding for those who want to be very non-urban, but it should not be confused with being green, energy wise.
Re:13% is considered "high efficiency" now? (Score:5, Informative)
However, that's actually not relevant to the main issue. You don't want to live close to the edge. You want to be sure you have capacity for when you need it. But you also want your batteries returned close to full by the end of the day to provide your power needs that night and into the next run of cloudy days. So you have to provide enough solar wattage to make sure you do that most, if not all days. Or you need to have an alternate power source for peaks (like a generator.) But most solar people don't want to use a generator.
Anyway, point is on the many days when you use less than capacity and the batteries are fully charged, you are just throwing away the power when the batteries are full. That's not the green thing to do. Certainly the people who go off-grid on a property connected to the grid are being foolishly non-green. The grid provides both a way to get any excess power you need during low solar periods, and a way to make sure all the power you generate goes to good use. That's why government rebates etc. only apply to grid-tie solar installations.
Re: (Score:3, Insightful)
Anyway, point is on the many days when you use less than capacity and the batteries are fully charged, you are just throwing away the power when the batteries are full.
How is that "not green"?
Do you need it spelled out for you? His point is that if someone is so concerned about the environment that they'd invest in all that solar, going completely off-grid is actually a step backwards because excess power can be fed back into the grid. Every excess solar generated watt that doesn't get used by some smug monied neo-enviro who's disconnected himself from the grid on principle could essentially buy off a "dirty" watt and reduce the generation of CO2, nuclear waste, or other detrimental emission by
Re:13% is considered "high efficiency" now? (Score:5, Insightful)
Assume the panels are 1/2 the cost of the system so the total system costs $4/Watt, or $8,000 for a 2 kW system. Assuming 6 hours a day generation, that's 4380 kW-hrs a year, or at $0.10 kW/hr that's $438 worth of electricity. 438/8000 = 5.4% tax free return on investment. If you live in the US with a decent income, you would have to earn over $700 to have $438 for your power bill after taxes.
If you don't like my numbers feel free to substitute your own.
Re: (Score:2)
Re:13% is considered "high efficiency" now? (Score:5, Informative)
-Matt
Re:13% is considered "high efficiency" now? (Score:5, Insightful)
I would mod you up for that if I could. I try to not think about places that require AC at night
FWIW, this area has around 30 days over 100 per year. Nights are usually comfortable and the daytime humidity is low.
Shit, durring the summer in TX we're lucky if it gets below 90 at any point durring the night. Last night around 3am it got down to 87, and the AC was off for more than 15 min. AC units pretty much run 24/7 may-october here and a $350 july or august electric bill isn't at all uncommon ($.11-.13 per kw/hr here in Dallas). Temps typically only fluctuate 8-10 degrees between highs and lows here. I think solar would be a great argument here durring the summer...
You Borked the math (Score:4, Informative)
Now this hocus pocus about the after tax situation is wrong too. If you want to include that then you have to include it on the 8000 dollars as well so Since the 8000 cost is after taxes, there's no point in calling the return on investment after taxes. Or if you want to then it costs 12300 of pre-tax income to buy the 8000 panels.
The ROI is negative since 437 electricity minus 640 interest is a 200 loss every year.
Re: (Score:2)
A old linear power supply has a efficiency ~40%, and is considered low efficiency and unacceptable.
Solar cells may be used - and in fact are already in use in some areas - even if they have n ~ 10-20%.
A key factor is that here we are converting a different form of energy in electrical energy, while a converter has the same type of energy at input and output. It is usually supposed that light is widely available and space is relatively cheap, although there are places
Re:13% is considered "high efficiency" now? (Score:4, Funny)
Perhaps making heat is not the best way to use electricity? I have a gas-powered coffee maker, myself.
Re: (Score:3, Informative)
http://www.solarpanelstore.com/solar-power.large-solar-panels.solarworld_sw.sw_165.info.1.html [solarpanelstore.com]
Re: (Score:3, Informative)
http://www.backwoodssolar.com/catalog/solar_panels.htm [backwoodssolar.com]
The SW165 is just under $5 per watt, and many are between $5/w and $6/w
To answer your question about a 100w panel for under $800, the MF125UE (125w for $690) seems to be one.
Re: (Score:3, Informative)
Re: (Score:2)
Re: (Score:2)
1. A meter that measures and records power going both directions so the power company can pay less for the power it gets from the home owner than the home owner pays the power company.
2. Circuitry that disconnects the solar system from the power grid in the event of a power company power failure so the linemen working on the power lines don't get electrocuted.
Re: (Score:3, Insightful)
Re: (Score:3, Informative)
Watt is a per-time unit. 1 Watt = 1 Joule per second.
A watthour is a 1 watt, sustained for an hour; a kilowatthour 1000 Watt, sustained for one hour.
"Watt per minute" doesn't make sense, except when talking about things like a change in power.
Re: (Score:2)
talking about a unit of power (energy per unit time) per unit time is meaningless. it's like asking how many watts your computer uses per second, your computer doesn't use watts, it uses energy. the power is the amount of energy per unit time.
what's important is that you can, instead of paying 8 cents or whatnot for electricity per unit energy, you can instead pay an upfront cost of $1/watt and produce your own energy. the important question is the device lifetime
other people have done this calculation,
Re: (Score:2)
Or you'll end up with Libraries of Congress per Soviet Russia times Old Koreans.