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Comments: 502 +-   Method for $1/Watt Solar Panels Will Soon See Commercial Use on Sunday September 23 2007, @02:22PM

Posted by Zonk on Sunday September 23 2007, @02:22PM
from the i'll-take-five dept.
power
business
money
science
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.'"
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  • by acdc_rules (519822) on Sunday September 23 2007, @02:28PM (#20721227)
    ya, but for how long do they last
    • by arivanov (12034) on Sunday September 23 2007, @02:31PM (#20721251) Homepage
      I agree. A few obvious questions: what is the actual performance deterioration curve, what is the efficiency after 5-10 years and what are the disposal requirements (it has the dirty "C" word in so do not expect them to be accepted at the tip).
      • by Lumpy (12016) on Sunday September 23 2007, @03:14PM (#20721623) Homepage
        Exactly! $1 a watt panels are darn expensive if they only last 5 years.

        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.
        • by Anonymous Coward on Sunday September 23 2007, @05:05PM (#20722367)
          Well, if exposure to the sun is going to cause them to deteriorate and turn brown, you should probably try to install them in a shady location to prolong their life.

          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.
          • by Anonymous Coward on Sunday September 23 2007, @05:12PM (#20722401)
            But an awning can only offer so much protection ... really the only surefire way to protect your solar panels from sunlight-induced degradation is to install them in some kind of underground environment where they are completely isolated from the environments.
            • by MrNaz (730548) on Sunday September 23 2007, @07:10PM (#20723163) Homepage
              You guys are amateurs. I have installed my solar panels in an underground cave with a sealed access point along with my wind turbines. My solar panels never deteriorate due to solar degradation and my turbines never suffer the terrible wear and tear that is caused by constant motion. I figure that they should last 10x as long as an irresponsibly deployed solar/turbine array, which means I'll get 10x the return on my investment!
              • by irtza (893217) on Sunday September 23 2007, @09:33PM (#20723967) Homepage
                wow, I was reading this thread and was utterly shocked at how people could get things so backwards. solar panels were meant to be used - degradation is inevitable. There is no need to protect them from the environment; you need to expose them to more environment. With only 11% efficiency you need as much light energy as possible to capture. That is why I poor kerosene on mine and light them ablaze. With all that direct light from the fire, I get unbelievable amounts of power before the unit dies.
      • Back of the envelope (Score:5, Interesting)

        by goombah99 (560566) on Sunday September 23 2007, @03:32PM (#20721743)
        Lets see. Assume the competing cost is at present 10 to 25 cents per KW-hour. We'll use the upper end because future power prices will rise whereas the Solar panel is a fixed cost.

        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.

          • by goombah99 (560566) on Sunday September 23 2007, @04:02PM (#20721933)
            I don't dispute that there's a big pile of assumptions there. The thing is there is geometric rate of increased consumption in power and we are not building new capacity at a parallel rate. As consumption curve starts to hit the production cruve the cost of power which has varied little for decades is going to go through the roof. 25 cents per KW-hour will seem like a pipedream in 2040.

            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 /year. That's a drop in the GW/day bucket.

            • by feepness (543479) on Sunday September 23 2007, @06:09PM (#20722797) Homepage

              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.
              You know who else was concerned about exponential growth? [wikipedia.org]
              • by mr_mischief (456295) on Sunday September 23 2007, @09:26PM (#20723905) Journal
                This is exactly why rooftop panels are so popular. It's area that already needs covering with something. Getting more panels then roof size, though, comes to a trade-off of what else the area could be doing, like growing crops or forests.

                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.

      • by mdsolar (1045926) on Sunday September 23 2007, @03:54PM (#20721883) Homepage Journal
        FirstSolar uses CdTe http://www.firstsolar.com/environment_cdte.php [firstsolar.com] and the durability of the panels remains an issue, but one they are addressing. Their aim is to demonstrate 20 year performance above 80% of the initial efficiency. The trick is to do this in less time than 20 years and they are getting help from NREL to pull this off. Their cost of production is $1.19/Watt and headed down.
        --
        Rent solar power for your home and save: http://mdsolar.blogspot.com/2007/01/slashdot-users-selling-solar.html [blogspot.com]
    • by An Onerous Coward (222037) on Sunday September 23 2007, @03:51PM (#20721857) Homepage
      According to this article [colostate.edu], they expect the things to last about twenty years, but they're still running stress tests. Same program, but a little over a year ago.

  • by cyfer2000 (548592) on Sunday September 23 2007, @02:29PM (#20721239) Journal
    I have always been worrying the environmental impact of the cadmium. Could some one show me that the cadmium used in the photovoltaic has little or no environmental impact please?
    • by Dunbal (464142) on Sunday September 23 2007, @02:42PM (#20721343)
      Could some one show me that the cadmium used in the photovoltaic has little or no environmental impact please?

            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.
      • by cyfer2000 (548592) on Sunday September 23 2007, @03:51PM (#20721855) Journal
        I would like to use other cheap thin film photovoltaics like amorphous silicon, CIGS or polymer based instead of the CdTe PV. I handle cadmium a lot in my work, to me, the environmental impact of cadmium versus the environmental impact of current energy production from fossil fuels is like plastic bag or paper bag. Both of them are not the solution.
    • Let's be like China and make electricity the man's way - with coal! And let's go back to burning leaded gasoline so we don't have to fuck with this unleaded crap that limits engine compression. Also, catalytic converters suck. I always take mine off after inspection or go to shops that don't care. Also, we need to get rid of welfare and we need George W. Bush for another eight years! And fuck solar cells. Solar cells can't even power calculators properly.

      Anonymous Coward Sig 2.0:
      --
      Write in George W. Bush in
    • A 2003 study on French dietary intake showed an average intake of 3.6 micrograms cadmium per day. Multiply that by the us population of around 300 million, and the US population should be able to safely consume at least 9 grams of cadmium per day. Multiply that by 365 days a year, and we (as a nation) should be able to ingest at least 3.2 kilograms over the course of the year.

      Therefore, the solution to the cadium waste is obvious. Put it in the water. After all, dilution is the solution to pollution.
        • by An Onerous Coward (222037) on Sunday September 23 2007, @04:30PM (#20722135) Homepage
          Yes.

          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.
  • by fymidos (512362) on Sunday September 23 2007, @02:34PM (#20721285) Journal
    The article doesn't mention how many watts per square meter this panel will produce. The cost of the panel is important, but so is the cost of the land required and the return of your investment.
    • Simple conversion (Score:5, Insightful)

      by Khyber (864651) <khyberkitsune@gmail.com> on Sunday September 23 2007, @02:49PM (#20721393) Journal
      One square meter of land on a bright sunny day will get appx 1.6kW of light in an hour. Assuming 11-13% efficiency as mentioned in the article, you'd get just a little over 160 watts per square meter per hour.
      • Re:Simple conversion (Score:5, Informative)

        by Zebra_X (13249) on Sunday September 23 2007, @02:53PM (#20721429)
        1.6 is very high. A more practical estimate is between 800W and 1.2kW.
      • by BlueParrot (965239) on Sunday September 23 2007, @03:19PM (#20721659)

        One square meter of land on a bright sunny day will get appx 1.6kW of light in an hour


        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.
      • by Solandri (704621) on Sunday September 23 2007, @08:51PM (#20723713)
        ~1600 W/m^2 is the solar energy flux in space (I've heard 1500, but let's go with your figure). The atmosphere absorbs a good chunk of that, so on the ground you're talking more like 700-900 W/m^2. Then you factor in:
        • 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.

    • by rcw-home (122017) on Sunday September 23 2007, @02:58PM (#20721487)

      The article doesn't mention how many watts per square meter this panel will produce.

      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.

  • by saterdaies (842986) on Sunday September 23 2007, @02:40PM (#20721325)
    Well, 1 kilowatt for an hour costs me 25 cents (thereabouts). To make a kilowatt, I would need to spend $1,000 on these. That means that they would have to operate for 4,000 hours for me to make my money back (well, 4,000 hours of electric usage).

    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.
  • by BlueParrot (965239) on Sunday September 23 2007, @02:43PM (#20721349)
    a)How long do they last
    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.
    • by ahfoo (223186) on Sunday September 23 2007, @03:15PM (#20721631) Journal
      Here in Taiwan, we just had the annual solar trade show which is becoming a really big deal on the silicon island. Solar has become a huge because it dovetails right in with other semi industry players that get put together in industrial parks.
              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.
  • Approvals (Score:3, Interesting)

    by Alioth (221270) <no@spam> on Sunday September 23 2007, @02:45PM (#20721363) Journal
    Cadmium... so not RoHS compliant, so not saleable at all in Europe and many other parts of the world. Oh dear.

    I wonder if RoHS will be relaxed for solar energy?
  • Interesting (Score:5, Informative)

    by m.dillon (147925) on Sunday September 23 2007, @03:03PM (#20721523) Homepage
    The real question here is how will these panels stack up to current poly panels with regards to their life span? All solar panels degrade over time - that is, produce less power as they get older. Rule of thumb for a poly panel is around 25 years. While there are many types of panels only a few are actually in mass production and have the required life spans. If you are looking to install solar now, polycrystalline panels are what you want to get.

    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)

      by bcrowell (177657) on Sunday September 23 2007, @05:07PM (#20722371) Homepage

      The real question here is how will these panels stack up to current poly panels with regards to their life span? All solar panels degrade over time - that is, produce less power as they get older. Rule of thumb for a poly panel is around 25 years.

      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.

      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.

      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.

  • by cdn-programmer (468978) <terr@NoSPAM.terralogic.net> on Sunday September 23 2007, @03:11PM (#20721587)
    The solar constant is about 1300 watts per square meter (in space). On earth the best you can hope for is about 1000 watts peak. So on average we will look at about say 50% of 50% and less on a cold winter day when we need both heating and more lighting. In fact on a winer day at about 51 degrees latitude we get about 8 hours of light and even then its less than 250 watts per square meter.

    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
  • by Animats (122034) on Sunday September 23 2007, @03:27PM (#20721709) Homepage

    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.

  • A 2 foot by 2 foot chunk of window glass in the store is $17.40 at Rona. A square meter is 10.76 square feet. So a 1 meter square piece of glass would cost $46.82 at these rates.

    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.
    • by Jarik C-Bol (894741) on Sunday September 23 2007, @02:32PM (#20721267)
      actualy, a 20x20 foot aray with good batterys and inverters will power a home with a family of four quite nicely. (I myself lived in a house that was totaly off the grid for about 5 years, pure sunlight on a 20x20 grid in the summer, minor supliment by propane generator in the winter months)
      • The trouble is cost. (Score:5, Interesting)

        by Anonymous Coward on Sunday September 23 2007, @03:08PM (#20721569)
        Unless they have no alternative to home-generated electricity, the cost of alternative generation systems is an uneconomic solution for most people.

        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.
        • by rrhal (88665) on Sunday September 23 2007, @03:38PM (#20721779)
          "The Grid" is highly subsidized. If people had to pay the full capitol costs of bringing the Grid to their property up front they would find many situations where solar arrays on the house was the cheaper option. It's also pretty easy to save most of the electricity we use:

          - 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.
            • by rrhal (88665) on Sunday September 23 2007, @04:27PM (#20722109)

              Great, so instead of electricity, we're burning more fossil fuels. This is progress?

              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.
                • by Oktober Sunset (838224) <sdpage103.yahoo@co@uk> on Sunday September 23 2007, @08:11PM (#20723497)
                  as opposed to all that, but instead of applying the sunlight directly to the clothes, absorbing the light millions of years ago with trees, so that the light falls on the leaves, the trees photosynthesise, and store the solar energy as cellulose, then burying and preserving those trees and then compressing hem for millions of years to process them into coal or oil, then digging into the ground, sending people down to mine the coal out with huge drills and cutters, or pumping the oil out, often at sea on huge floating platforms and carrying the coal in trucks, and pumping the oil through pipelines, so a place where it is burned to heat water, which tuns turbines, which turn big magnets which move electrons down wires,which turn other magnets and heat bits of metal, so that fans attached to the magnets can punch air over the hot bits of metal, and other magnets can turn a big drum.
                  nah, I think the sunlight directly onto the clothes is more efficient.
      • by btempleton (149110) on Sunday September 23 2007, @03:21PM (#20721677) Homepage
        Note that it's very hard to be green with an off-grid system. Off-grid systems tend to use batteries, and for proper operation you don't want to discharge the batteries too deep, and so quite often you overprovision your cells and you end up throwing away the energy from the cells into mostly full batteries a lot of the time. You can try to live greener (more efficient appliances etc.) and that's almost a must off-grid, but the off grid electricity itself is very expensive.

        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.
          • by btempleton (149110) on Sunday September 23 2007, @05:10PM (#20722391) Homepage
            If you want to correct people, you should check your facts first. I was referring to deep cycle batteries. They are called that because they can do far more deep cycling than typical car batteries, but in fact if you research it you will find that the deeper you discharge them the shorter their lifespan. Generally you want to design your system to not go below half in ordinary use, and drop down from time to time in peak use.

            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.
    • by xs650 (741277) on Sunday September 23 2007, @02:52PM (#20721419)
      There are several houses on my area in Northern California that have photovoltaic installations that produce more electricity than the homes consume. The excess goes to the power company for a credit against future use. These are homes with air conditioning and people that don't live austere lives. Their installations cover less than the entire south facing slope of a conventional roof. The problem is that they wouldn't come close to paying off without big fat gumnt subsidies. At $2.00/Watt they would be economically feasible without subsidies.

      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.
      • by m.dillon (147925) on Sunday September 23 2007, @03:22PM (#20721683) Homepage
        Be careful here. In California, which is where I live too, it doesn't get dreadfully hot like it does in the midwest, or at least not for more then a few days a year usually. A solar array of the size normally needed to reach net-zero with the power company doesn't even come close to being able to generate the power needed to run even small whole-home air conditioning systems. As long as the AC is only used a few days out of the year (which is typical in California), then you can still reach net-zero over the whole year. But in somewhere like Texas you wouldn't have a chance. AC is usually not in the cards if you are trying to achieve energy independence.

        -Matt

          • 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)

        by goombah99 (560566) on Sunday September 23 2007, @03:45PM (#20721823)

        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 $438 for your power bill after taxes.
        Huh? That makes no sense. first include the time value of 8000$ at 8% interest rates. That's $640 dollars per year what you have to borrow or not make from investment.

        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.
    • by number11 (129686) on Sunday September 23 2007, @03:15PM (#20721627)
      It doesn't matter if the panels are $0.01/watt if I still need the entire neighborhood covered in them to run the coffee maker

      Perhaps making heat is not the best way to use electricity? I have a gas-powered coffee maker, myself.
    • Re: (Score:3, Informative)

      Right now, the grid acts as a nearly perfect battery by distributing power around as needed. During the daytime, electricity use is far higher than during the night, so solar panels are really very nice in terms of when the provide power. The solar panels installed in houses would decrease daytime load on power plants, resulting in better efficiency throughout the system. Think of it as the solar panels working towards supplementing the grid with enough extra power to handle air conditioning and other day-t
      • Re:Impresive (Score:4, Interesting)

        by kesuki (321456) on Sunday September 23 2007, @04:01PM (#20721921) Journal
        with conventional solar pannels the cost per watt is around $3-$5. so the $1 per watt price isnt that impressive, what is impressive is the scale at which they can produce these new panels... they could sell self install kits at wal-mart and still have no problem with inventory..

        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.
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