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Science

New Material for More Efficient Solar Cells 308

Posted by CmdrTaco from the i-knew-that-glowing-ball-was-good-for-something dept.
PunkerTFC writes "Space.com has an article on a new material that could create relatively cheap solar cells which are up to 50% efficient. This is much better than the 25% efficient silicon solar cells (most common) or the 36% efficient multi-junction solar cells (very expensive). The material was created by "forcing oxygen into a zinc-manganese-tellurium crystal" creating more band gaps, which allow the cell to create electrical energy with three seperate frequencies of light. This could lead to cheap, high-output solar cells in the future, but it will take at least 3 years to assess the feasibility of the new technology, according to the researchers."
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New Material for More Efficient Solar Cells More

New Material for More Efficient Solar Cells

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  • Solar Cell Technology (Score:4, Insightful)

    by Laebshade ( 643478 ) <laebshade@gmail.com> on Sunday May 09, 2004 @12:35PM (#9100462)
    Solar cell technology seems to be getting more and more advanced. When will the time come when we are able to use it to effectively power a complete house?

    • Re:Solar Cell Technology (Score:5, Informative)

      by Anonymous Coward on Sunday May 09, 2004 @12:37PM (#9100473)
      It exists already [google.com].

    • Transportation, too (Score:2, Interesting)

      by bcore ( 705121 )
      It would be awesome to have a car that was able to "refuel" itself while it sat idle most of the time. Cars have so much surface area that is exposed to the sun, it just seems like this would be a great fit, although the sun obviously couldn't be the sole source of power.

    • Re:Solar Cell Technology (Score:5, Interesting)

      by WegianWarrior ( 649800 ) on Sunday May 09, 2004 @12:46PM (#9100542) Journal

      Solar cell technology seems to be getting more and more advanced. When will the time come when we are able to use it to effectively power a complete house?

      We are there today. In fact, we where there several years ago. The trick is not to need more power than the solar cell generates... so obviously you can easily supply the energy a house needs from solar cells if your house don't need much energy. Say, if you live in the tropics or subtropics, there is no big deal to power everything electrical with solar cells today (even more so if you use natural gas for cooking and running the frigde). If you live above the arctic circle, the day will never arrive that solar cells are efficient enought - since when you need them the most (ie; in winter), the sun just isn't over the horisont... up here it's more a question of efficient storage of the electricity.

      I'm more interested in getting really cheap solar cells than super efficiant ones - if I can put up ten cells produsing (say) 1kWh each for the same price I can put up two producing 4kWh each, the cheaper ones are the better choice - as well as making replacing broken arrays cheaper.

      Off course, the day I can get solar cells that are both cheap and efficient, I'll pick them without a second thought ;)

      • Re:Solar Cell Technology (Score:5, Insightful)

        by busterRey ( 742370 ) on Sunday May 09, 2004 @01:22PM (#9100778)
        I looked in to doing a PV installation on my house about two years ago. I live in California in the Santa Clara county and for most of the year there is plenty of sun. The cost of putting up enough panels to power the whole house was around 17K. At the time I figured the system would pay for itself in about 15 years. The problem for me was that the basic system most solar companies sell is still connected to the power grid and your payback is based on selling your excess back to the power company. During the day you supply the grid and you use the power grid as your night time battery. I wanted to be totally off the power grid because frankly I don't trust PG&E to pay me for my electricity (some folks in my area with these system have had that problem) and I don't want to be subject to their power problems. With system I was looking at if the PG&E power goes out your system goes dark too to protect itself. When I asked about at total off grid solution, the company I was talking with kind of choked a little and said they could set up a battery system for me and added about 10K to the price for the batteries and the extra gear needed to manage the batteries - and asked which part of the garage I was going to give up to house all of it. The other problem is that the batteries had a much shorter life span (5-10 years as I recall) and would have to be replaced much more often than the solar panels on the roof. I was told that the panels have a 25 year life span. Very quickly the economics didn't work out as I would end up paying more for solar power then I would buying from the power company. I still may do a solar installation at some point but I have decided to wait another year or so to see if the technology improves. I am not sure about the environmental impact of disposing of batteries. I guess they could be recycled to some extent but it would be problem. The bigger question is which is worse for the environment - dealing with the dead batteries my installation would generate or burning the fossil fuel to generate the power for my house. I just don't know. I would really like to see more efficient solar cells but we also need better storage systems. I was kind of hoping that fuel cell technology might help out there but don't know enough about it to say.

        • Re:Solar Cell Technology (Score:4, Insightful)

          by llefler ( 184847 ) on Sunday May 09, 2004 @02:00PM (#9101014)
          If you want to be completely solar, you have to attack the problem on several fronts. You need to find any way that you can to reduce power consumption. Then there are storage and backup power problems to deal with.

          Since you didn't post capacity, it's hard to say what the $17k covers. I don't know if the programs are currently active, but in the past California had a tax rebate program that could offset about 1/2 of the cost of installation. I would be surprised if they missed that in the quote, but you might want to check. It would drastically cut payback time. Also remember that part of your payback comes in non-monetary benefits.

          The type of system you were looking at is a good one, but probably needs a few adjustments. Being connected to the grid has a lot of advantages. The grid serves as your batteries. If your usage spikes (air conditioning?), the grid will make up the difference. And the grid supplies your power at night and when you can't produce.

          When the grid goes down, you don't necessarily have to shut down too. When the grid goes down, you DO have to disconnect your PV units from the grid, regardless of whether they are producing or not. Neither you nor PG&E wants you powering their lines and electrocuting their linemen.

          And if you look at it that way, compare the cost of lost revenue from over production to the cost of batteries. If losing the money bothers you that much, slightly undersize your system so you don't produce an excess amount. PG&E will happily cover the difference.
        • Disposing of the old solar panels has enviromental costs too, not to mention the large quantity of chemicals/waste involved in their production.

          Seems to me like the best way to go is some sort of thick concrete wall structure that stays cool in the summer. Then use the latest in lighting technology [are white LEDs feasible for indoor use?] and generally minimize electronics within--find a high efficiency fridge, low power computer, etc. I think you could have made it work if you had planned the building fr

        • Home Power magazine used to be the place to learn all you needed to know about everything solar & alternate energy related. Now that you have to register to download the huge PDF, I'd say just surf the newsgroups and blogs.

          Fuel Cell technology is great if you want to run your house off natural gas, propane, whatever. Unfortunately the price has gone sky high because california sucked up every cubic meter they could so THEY could have clean electric power. Now its no longer a cheap way to heat your hous

        • do it yourself (Score:3, Interesting)

          by zogger ( 617870 )
          You can do the vast amount of work yourself, save thousands, literally thousands. shop around for the various components. it is no way any harder than building your own peecee, just much larger. You have panels, their mounts, some simple wiring, a charge controller, then usually an inverter/charger for adding grid juice into the mis, and a battery bank. You run the output to your panel box you already have, or just pick a few circuits to power. You can hire an electrician to look it over one day and do the

        • Re:Solar Cell Technology (Score:3, Informative)

          by Locutus ( 9039 )
          From what I've heard, in California, the state will pay for close to 50% of the total cost of the system . And, your electric company doesn't pay you for your daytime electricity, your meter runs backwards when you generate more than you use. This is called Net Metering and is the simpiliest way to do it as long as you just want to take care of your own energy needs.

          The part you mentioned about them paying you for your excess is probably related to what's called Time Of Use ( TOU ) metering. With TOU meter
    • Solar cell technology seems to be getting more and more advanced. When will the time come when we are able to use it to effectively power a complete house?

      Key issues here are not only power generation, but how do you store the energy? Most solar energy is generated during the day, but we need a lot of energy in the evening to cook dinner, watch TV and maybe heat the house in the winter. One could of course envision enormous batteries but this seems unfeasible and it is not even clear that this would be e
      • You would want to put together a grid connected system. You would generate your power during the day when rates are high and your usage was low since you're at work. This excess power feeds into the power grid and your meter goes backwards. Then at night you come home and pull power off the grid making the meter go forwards, but nighttime power is cheaper. 100% efficient battery thanks to the utility.
        • The sell high/buy low only works if your meter keeps track of the time of day you are producing and consuming. And you have to be on a special rate program, something power companies don't like to use on residential service. But the grid makes a nice, maintenance free battery. Even when you buy and sell at the same price.
      • You could always electrolyze water and store the hydrogen and oxygen in tanks. The tanks of gas become your battery and a power cell can be used to generate electricity on demand.

        • Re:Solar Cell Technology (Score:5, Informative)

          by f97tosc ( 578893 ) on Sunday May 09, 2004 @02:24PM (#9101114)
          You could always electrolyze water and store the hydrogen and oxygen in tanks. The tanks of gas become your battery and a power cell can be used to generate electricity on demand.

          I am not denying that this is possible, but it has to be acknowledged that now the main cost driver of your system is probably not in the solar cells but in this oxygen/ hydrogen separation, storage and electricity generation system. Which illustrates my main point which is that good solar cells are not by themselves sufficient to enable this form of a solution (although of course they are a great step).

          Tor
    • Is this going to be another one of those developments that we never hear about again?
    • That's been possible for a long time now. What would be great to see more widely is a distributed electricity grid. Individual houses and properties could generate power for themselves via solar, wind or other means. If the energy generated isn't enough, power can be bought from the grid. If there is an excess, it can be sold back to the grid. There would be far less dependence on centralised power stations, which have their own set of problems (cost to build and maintain, terrorist threats, if a single gen
    • How much do you want to pay or change your habits? The problem is smoothing out of the peaks and valleys of use and generation.

      One nice trend is that power companies (and technology) are making it easier for individuals to dump a surplus into the grid for credit. This would allow a home owner to dump power during the day when no one is home, and pull it back at night when the air conditioning, stove, TVs, etc are on, and the sun is down.

    • How much money have you got? (Score:4, Interesting)

      by Moderation abuser ( 184013 ) on Sunday May 09, 2004 @01:47PM (#9100940)
      It's possible now, but (in the UK) it costs twenty to thirty grand to put a system in. It'll recoup it's cost in maybe 25 years.

      The cells you can buy in the stores are more likely to be 15-18% rather than 25% efficient. The 25% ones are fucking expensive and the 35% ones are like rocking horse shit.

      Course, energy storage is still a problem for those cloudy days. Batteries are heavy, expensive, made of heavy metals or have to be replaced regularly which isn't exactly "green".

      Compressed air energy storage may be feasable on a small scale with the use of a compressed air powered generator, some utilities already use compressed air to store energy on a huge scale. Use solar power to compress air to several hundred atmospheres during the day and run a generator from it during the night and during cloudy periods.

    • Also, you don't have to turn solar energy into electricity to use it.

      Geothermal pumps can heat (and cool in the summer) a house and heat its water while saving you tons on your electricity bill.

      A FAQ about geothermal tech [earthenergy.ca] can be found here. I think that ALL new houses should be built with this technology.

  • Kick Ass! (Score:3, Funny)

    by SCSi ( 17797 ) <corvus@vadept. c o m> on Sunday May 09, 2004 @12:38PM (#9100477) Homepage
    Now I can overclock my cheap solar-powered calculator!

  • Competing Projects? (Score:5, Informative)

    by crem_d_genes ( 726860 ) * on Sunday May 09, 2004 @12:38PM (#9100479)
    This has been released [lanl.gov] very recently - it's based on PbSe crystals instead - at Los Alamos but also through University of California.

  • (cant come up with an appropriate topic) (Score:3, Insightful)

    by zaunuz ( 624853 ) on Sunday May 09, 2004 @12:38PM (#9100480)
    Solar panels could really be the next generation power-source, if it can be developed a cheap and efective way of using solar energy. Have you seen that short-film on Discovery Channel about the guy who built a car that runs on solar power alone? You can walk faster than it, but hey, you could walk faster than the first steam-locomotives as well. But i'd still say that hydro-plants are the way to go, if the terrain allows it.
    • One of the big problems with hydro and wind power is the effect they have on the environment. Yes, advancements have been made and designs have been altered to decrease the negative effects, but they still have negative environmental effects because of their disruption of wind/water flow and animal behavior.

      The beautiful thing about solar panels is that they can be mounted on roofs and other man-made structures. This means that we can, or should be able to, get effective power from the environment without
    • Hydo-power isn't a power source without faults. In fact many communities have realized that hydro-electric is not the panacea it was advertised as in '70s and are looking for feasible alternatives. While there are many very interesting energy generation ideas floating around laboratories everywhere I think the most promise comes from energy efficiency & conservation; and distributed power generation techniques which lessen or eliminate the need for large scale power distribution.
    • Speaking of nuclear weapons (re: your sig), if the trillions of dollars currently being thrown into the black hole of nuclear research (which includes fusion power) were spent on renewable energy sources like wind and solar, we might have solved many of our energy and pollution problems by now.

    • Re: Hydro Power (Score:2, Informative)

      by dev_alac ( 536560 )
      Hydro power is now on the way out as a major power source. Many dams have been removed in Western countries because they lead to salinization of cropland, destruction of hatcheries, and they just cost so bloody much. More dams have been destroyed than built in the last 20 years. On the other hand, wind and tidal power are becomming more viable because they do not munch the ecosystem in quite the same way. Besides, wind turbines will cool the atmosphere by some tiny amount to offset global warming.
      • Hydro power is now on the way out as a major power source. Many dams have been removed in Western countries because they lead to salinization of cropland, destruction of hatcheries, and they just cost so bloody much.

        Salinization isn't caused by dams, it's caused by irrigation. Cost isn't the issue, it costs more to tear them down. While they are there, their operation profits cover expenses. The problem is the destruction of natural habitats. I'll admit that a thorough environmental analysis needs to be d
        • > Wind turbines kill birds

          Yeah, like anything tall kills birds.
          Not that this is not something we already know [slashdot.org]. The high mortality at the Altamont was due bad placement and technology.

          According to the NWCC 0.01%-0.02% [nationalwind.org] of the deaths due to collisions are due to winplants.

          > How about geothermal? Iceland has had a lot of success with that.

          Well, maybe because it is a small island directly placed above a contintental rift. I don't know for how many regions that would work.

          But why not all of the above
    • actually, it has a major fault. Just like any other alternative energy, is is a come and go type item. One area that we need to really research is how to store this energy. One approach is via Superconductors. Another would be storage via heat such as what Boeing was testing earlier. Unfortunately, the one approach that W. has committed our country to, is out about 10-20 years (hydrogen).
    • Hey, I can walk faster than the cars stuck in traffic in my city.

    • Specific Hydro type... (Score:3, Interesting)

      by Orne ( 144925 )
      What you really want is for minimum ecological impact is a "pumped storage" hydro plant. Build a man-made reservoir at the top of the hill, and a basin at the bottom of the hill. Fill the top reservoir with water. During the day, you let the water flow with gravity downhill through a set of turbines to generate electricity. At night, power the turbines to flow in reverse, and pump the water back up to the reservoir, basically "refuelling" itself.

      But, you say, what's the sense in doing that? Conservati

  • Cool (Score:3, Funny)

    by GFLPraxis ( 745118 ) on Sunday May 09, 2004 @12:40PM (#9100501) Homepage Journal
    Now I can use it to power my computer without having to pay electric bills!

    Wait...what happens when it is cloudy?

    Of course, we all know the electric companies are going to call this "stealing energy" and patent the sun...

  • Solar power is nice (Score:5, Insightful)

    by dark404 ( 714846 ) on Sunday May 09, 2004 @12:41PM (#9100508)
    ...but until it progresses to the point where we don't need a surface of cells an order of magnitude larger than the structure they will power to use them, they're still impracticle for primary energy needs.

    I don't think we'll ever see solar cells as primary terestrial energy sources though. Cloud cover and night ruins their feasibility, but I'd wager money on them being used to augment other alternative energy sources in the future. Maybe power will go the way of Intel's new chips, multiple sources at lower power instead of one giant one at greater.

    • Re:Solar power is nice/false notions (Score:5, Insightful)

      by adzoox ( 615327 ) * on Sunday May 09, 2004 @12:49PM (#9100573) Journal
      You have false notions about the feasability of solar. You would be speaking of cheap solar whereas (as it is now) there ISsolar technology that:

      A) Doesn't have to cover the entire structure - but really is mute point - if you want solar - why not maximize its production - installation and deployment is 1/4 the cost - once it's being installed, install as much as possible - your goal is to "overproduce" if possible - did you know that your local energy untility has to BUY BACK power that you could place onto the grid if you overproduced?

      B) The GM solar race car is a marvel of engineering, is as fast as most street legal cars and it looks cool too!

      C) Cloud cover and night are of no consequence. Cloud cover only reduces production - besides power IS STORED in batteries anyway - it doesn't go straight from the sun to your light bulb or TV.

      • One nitpcik, it would be a *moot* point...
      • but really is mute point

        The point may be moot [reference.com], but it is never "mute."
      • ... did you know that your local energy untility has to BUY BACK power that you could place onto the grid if you overproduced?

        This is highly location-dependant, and not guaranteed to stay true even where it currently is true.

        Cloud cover and night are of no consequence.

        It's not of no consequence. Average available sunlight varies by regional and local conditions. That makes a difference about when solar cells become economically feasible for someone considering them. And even living in sunny sou

    • Re:Solar power is nice (Score:5, Insightful)

      by hawkbug ( 94280 ) <psxNO@SPAMfimble.com> on Sunday May 09, 2004 @01:08PM (#9100686) Homepage
      I suggest you visit:

      www.homepower.com [homepower.com]

      Solar power is very real, and many people already use it. Is it expensive? Yeah, for example a solar system to generate enough power for the average home would cost anywhere from $20k to $30k. Some states have to reimburse you for half your cost though - so immediately, you're down to $10k or $15k. Then, imagine that costing you about what a car payment would be for 5 years. Now imagine having that car payment *instead* of a utility bill. Now even better, imagine being paid off in 5 years - and then the panels and setup usually last 30 years. So, that equals 25 years of FREE energy. Most of these homes are still plugged into the grid so that at night they can either use the grid or batteries, while pumping excess onto the grid during the day to the power company has to buy that from you to power other homes in your area. Solar is great, and with rising natural gas costs, it's going to spread like a wildfire from global warming...
    • This is simply untrue. Your house could be powered by photovoltaic panels taking up just a portion of the roof. Obviously your first step would be to increase the efficiency of your home. Replace any old refigigerators (HUGE power drain), replace incodenscant lights with compact flourescant, etc etc. You have to be efficient before you put in a PV system, but if you weren't it would be silly since a watt off generation is about $5 before rebates.

    • Re:Solar power is nice (Score:5, Interesting)

      by jo_ham ( 604554 ) <joham999@noSpaM.gmail.com> on Sunday May 09, 2004 @01:40PM (#9100895)
      It's a question of what we can harness. Enough energy falls on the surface of the Earth every day from the Sun to supply the World's energy needs for weeks, we just can't harness it effectively.

      Large scale solar farms in desert and offshore areas would be a very useful source of power for the future, even if it isn't used as a primary, continuous source. An offshore solar farm could be used to electrolyse seawater to produce hydrogen for fuel cells, for example - it is currently expensive to do this because you get out less energy than you put in. Using solar energy though, that doesn't matter because the sun is free (unless the US Patent Office grants someone a patent on "a large ball of gas and dust undergoing nuclear fusion that the Earth orbits around".

      SCO will no doubt claim that the Sun also contains System V code. Darl McBride is welcome to visit the sun in an Apollo capsule to inspect it for himself. How he's going to get to the Sun's kernel is beyond me. He'd better pack some sunblock.

  • But... (Score:2, Funny)

    by lxt ( 724570 )
    ...how's it going to help me use my calculator at night?

  • Solar power is going to be big (Score:5, Insightful)

    by ites ( 600337 ) on Sunday May 09, 2004 @12:48PM (#9100563) Journal
    Oil reserves appear to be running out (looking at the recent problems Shell had with its overstated reserves, and seeing how some of the other large oil companies make even larger estimates than Shell's old ones). The future of energy production is going to be nuclear, wind, and solar. So it's very timely news.

    Personally I think the collapse of the oil supply within the next 15-20 years will be the most traumatic event in recent human history.

    Solar cells will help a lot in some ways but they won't be enough to stitch together a modern society built on the motor car and cheap fuel.
    • The interesting thing is Shell is the largest provider of PV panels now. http://www.shell.com/home/Framework?siteId=shellso lar
    • Personally I think the collapse of the oil supply within the next 15-20 years will be the most traumatic event in recent human history.

      I have a feeling that as far as useing oil for energy goes, it will not be a big deal. In fact, it is possible that it will help clean up our act while also pushing us towards new businesses. After all, the reality is that Fuel is not cheap. It has not been for quite some time. Even now, we (the US) fund its real cost via taxation.

      The real problem will be all the uses tha

  • Previous /. story: (Score:5, Informative)

    by jdrogers ( 93806 ) on Sunday May 09, 2004 @12:50PM (#9100578) Homepage
    This was already covered by /. a few weeks ago [slashdot.org], but this new space.com article does seems tohave more details.

  • Oh Great (Score:3, Funny)

    by laing ( 303349 ) on Sunday May 09, 2004 @12:52PM (#9100588)
    Just after I invest $6K in a small solar plant to run the servers here...

    --
    http://jsl.com/solar
    • ok, this of off topic, but hey laing, how come no info on your solar page? how did you do it? what materials? who did the wiring for you? How large is your array?

      Inquiring minds would love to know (if nothing else, I'd love to see how cost effective it can be).

      -- Tadghe
      t a d g h e at b a d c o d e dot o r g.

      • Re:Oh Great (Score:3, Interesting)

        by laing ( 303349 )
        I used 14 80W Sharp polycrystaline panels connected to a Trace 1500W inverter. I've got 3 85AH Costco deep cycel batteries tied through a 60A trace charge controller. I did the installation and wiring, and also designed and built the monitor and control system. I put a D.C. (switching) supply in the system to supplement the cells when the battery voltage falls below 80%. You see, this is a "Solar UPS" so the batteries always stay mostly charged. When the cells produce less than a few amps of current, t

  • Solar constant (Score:5, Insightful)

    by garglblaster ( 459708 ) on Sunday May 09, 2004 @12:53PM (#9100593) Journal
    OK friends, before we get into some highly speculative terrain here, let's get some facts straight:
    The solar constant (see for example here [solarserver.de] is about 1.somethin kW per Square meter.

    That simply means you need quite some substantial area irradiated by bright sunlight to obtain a given amount of energy.

    I think this is a limiting factor for many interesting ideas out there..

    • Re:Solar constant (Score:3, Interesting)

      by vadim_t ( 324782 )
      That's only if your equipment needs an awful amount of energy.

      According to some simple calculations I did a while ago, my laptop uses about 25W. My laptop's 30x23 cm. So, if I'm right, a panel of that size would produce about 70W.

      So, with some luck, if I attached a solar panel to the back of my screen, and sat in some sunny place, I could have my battery not ever run out? Why didn't anybody try this yet?

      In fact, this makes me really curious! When I replace this old laptop, I think I could try this experi

      • Re:Solar constant (Score:3, Informative)

        by rcw-home ( 122017 )
        So, if I'm right, a panel of that size would produce about 70W.

        1100 watts/m^2 * .23m * .3m = 76 watts

        76 watts of solar power * .5 (50% efficiency the article mentions) = 38 watts of electrical power.

        And that's if this research pans out and if the price becomes practical and if you aim it directly at the sun on a perfectly sunny day.

    • There's plenty of room in space. Make them cheap and light and send them in space.

      • Re:Solar constant (Score:4, Informative)

        by SEE ( 7681 ) on Sunday May 09, 2004 @01:33PM (#9100834) Homepage
        Make them cheap and light and send them in space

        And wait decades for them to pay off the energy required to lift them to orbit, especially at microwave energy transmission losses . . . except the panels will be rendered inoperative by micrometeorites first.

        Solar power satellites are only practical if you either have space manufacturing out of lunar/asteroid material, or a beanstalk.

    • Re:Solar constant (Score:3, Interesting)

      by Tsunamisan ( 772301 )
      I live in the Arizona desert, and the bright sunlight is BRIGHT (I've built solar ovens that bursted into flames in seconds). I would love to see this energy be put to use, lord knows there's enough of it.

      I could imagine huge solar arrays in the middle of nowhere (which is easy to come by in this state) coupled to superconducting magnetic storage coils (made by American Superconductor [amsuper.com]) to handle the few days that aren't so bright.

      *sigh* Sadly, the government in Arizona is more concerned with trying
      • Sadly, the government in Arizona is more concerned with trying to make the perfect standardized test for high schoolers.

        The only way to have a perfect standardized test for high schoolers would be to have standardized students. (Which would be funny if that didn't seem to be exactly the goal of some schools, one way or another ...)

    • KK I really don't know all the ins and outs of this, so maybe this is completely ridiculous but......

      Why not just fill all the unlivable desert space with huge solar panels and giant electricity storage units and keep sucking in the sun, converting to electricity and then allowing the juice to enter the grid? It seems so obvious that someone must have thought of that before, so I'm wondering what the catch is..

      • Re:Solar constant (Score:2, Interesting)

        by corngrower ( 738661 )
        Rignt now, the only catch is that it's still more expensive than the alternatives. Increased solar panel efficiencies, and extended lifetimes of the panels will help in changing this.

        You wouldn't strictly need to locate them in the deserts. If you can produce more value by generating electricity than by groing crops, you'ld see cropland and pastureland converted as well.

        If you could even generate electricity at 100 watts/m^2 (10% of solar output), with a long cell lifetime that would stll be enough t

        • Re:Solar constant (Score:3, Interesting)

          by amembleton ( 411990 )
          However you could use Solar towers [bbc.co.uk]. Sorry, I couldn't find a better link. These towers don't use solar cells, but instead rely on having a large volume of heated air trying to escape up a very tall tower and use a turbines up the tower to generate electricity. The heated air comes by what is basically a very large green house.
      • I doubt there is anywhere on earth that is entirely unlivable. Maybe by us, but we aren't the only organisms here. Keep in mind that drastic changes in other habitats tend to cause drastic changes in ours.

        Or, you can look at it another way. It's not possible for man to destroy the ecology of the earth. It will still be here (in some other form) long after it can no longer support us.

    • Re:Solar constant (Score:2, Funny)

      by Anonymous Coward
      No problem! I have device which will increase the solar constant 100-fold. There, in about eight minutes you should see quite a difference!


    • [The solar constant is about 1 kW per Square meter.]
      That simply means you need quite some substantial area irradiated by bright sunlight to obtain a given amount of energy.

      You didn't mention that that's at noon - over the course of a day, a square meter is going to get hit with about 6 kilowatt hours of power.

      What a "substantial area" is depends on your application.

      Assuming 50% efficency, 4-5 one meter panels would be enough for a typical house.
      You wouldn't even need to cover the whole roof.

      Or how

  • Cost per Watt (Score:5, Interesting)

    by levram2 ( 701042 ) on Sunday May 09, 2004 @12:55PM (#9100609)
    One alternate plan is to use cheap titanium dioxide to make less efficient solar cells that are significantly less expensive. Titanium dioxide is used to tint paint white and is available cheaply in bulk. While researchers are working on increasing the efficiency through nano particle techniques, do it yourselfers have made progress. [comcen.com.au]

  • Three Years... (Score:3, Funny)

    by Esion Modnar ( 632431 ) on Sunday May 09, 2004 @01:06PM (#9100668)
    ...to study technology feasibility. Hmmm. More like, 3 years to quietly let this technology get stuffed into the same warehouse along with the 60 mpg carburator and the Ark of the Covenant.
    • 3 years to quietly let this technology get stuffed into the same warehouse along with the 60 mpg carburator and the Ark of the Covenant.

      Didn't you get the memo? They moved all of the automotive (including the carburator) to a different warehouse. They needed to make room to put Noah's Ark next to the Ark of the Covenant.

      If you make a right turn at the main gate, warehouse 3i has SCO's evidence.

      -

  • Not useful if it doesn't last (Score:3, Interesting)

    by m.dillon ( 147925 ) on Sunday May 09, 2004 @01:12PM (#9100719) Homepage
    This is all well and nice but I've heard it all before. There's no point if the resulting panels do not have at least a 30-year lifespan before they degrade beyond useability. The sun does a pretty damn good job destroying things.

    -Matt

  • Solar is taking over regardless (Score:5, Interesting)

    by danharan ( 714822 ) on Sunday May 09, 2004 @01:14PM (#9100735) Journal
    Even without this advance, solar is poised for even more gains.

    Solar sales are up 30-40% every year [earth-policy.org], and have been growing at such a steady pace for a long time.

    The cost of electricity from solar cells remains higher than from wind or coal-fired power plants for grid-connected customers, but it is falling fast due to economies of scale as rising demand drives industry expansion. Solar cells currently cost around $3.50 per watt for crystalline cells, and $2 per watt for thin-film wafers, which are less efficient but can be integrated into building materials. Industry analysts note that between 1976 and 2000, each doubling of cumulative production resulted in a price drop of 20 percent. Some maintain that prices may fall even more dramatically in the future.(link [earth-policy.org])


    Naturally, this is a positive feedback loop. Lower prices mean it's affordable for more niches, which means more people buy, which in turn scales larger. At this point, it's pretty much unstoppable. It is useful in too many niches, especially where customers aren't connected to a power grid.

    There are now many countries that have more cell-phones than landline phones. It's likely that in 10 years, some countries will have more customers getting electricity from solar than from a central grid. Naysayers will say it's not ready... but then again, 15 years ago cell phones weren't either. What matters is not the absolute numbers, but the growth rate of the industry and the evolution of the technology.

    Of course, as the market matures, more people are doing R&D to find cheaper ways to build PV systems, which is only going to accelerate this momentum.
    • My electric usage this month was 564 kWh. 564 kWh means that, on average, I use 18 kWh per day.

      If I can store power efficiently, then my solar cells need to generate 18 kWh per day, in about 10 hours of nice, bright sunlight. That's 1800 watts at any given time. At $2/watt, that's $3600 for the array (ignore the storage costs for now).

      My electric bill for that month was $55.74, so I get payback in a little more than 5 years.

      The problem is, I've seen different numbers for panels. Modules for consum [solarbuzz.com]

      • Re:Let's make this more concrete (Score:4, Interesting)

        by danharan ( 714822 ) on Sunday May 09, 2004 @03:24PM (#9101379) Journal
        And on that same page, they do mention that PV prices can go as low as "$3.58 Watt: thin film and $3.16 Watt: crystalline." $5.85 is an average, which includes PVs that are designed for different systems. In my case, I only care about cost per watt as I will have a sufficient surface, others have to worry about squeezing the most energy out of a limited space. Different needs, different models and different prices.

        The most promising route will probably be solar rooftops, where solar cells are integrated with construction materials. For new construction or re-roofing, this makes a lot of sense because you don't have to pay much more for installation. With net metering, you also wouldn't need the expensive batteries. Of course, that assumes you're on the grid; if not, connection charges can be more than going the cost of going solar, including battery array.

        Solar is still expensive for now, and this has led most people that consider it to use every trick in the book to lower their energy consumption. Better lighting, appliances, windows, insulation... if it cost less money to conserve than generate, it only makes sense to spend money on efficiency. You probably do not need 564kWh/month- you should be able to reduce that by at least a third, with a payback in under 2 years.

        There are other applications too where cost alone is not a huge issue. If reliability is important, being able to have your own power supply, batteries, and a net metering arrangement with the grid could be a cheaper solution than most UPS, and give you far more autonomy.

        While you may not see it as rosey, it's hard to argue with the fact that sales are still growing, year over year. And I can't think of anything that could stop that in the next 20 years: it's all but inevitable.
      • You're not clear on whether or not you're counting state and federal rebates on your PV costs. In California we've got this program [consumerenergycenter.org] which provides serious cash for people interested in installing their own renewable energy (RE) system. If you don't live somewhere with such a rebate program you might try writing to your state representatives and ask them why.

        Also, your brand new PV system will likely last at least 25 years, possibly much more. Such a system can also add quite a bit of value to your house. A

  • More actual info (Score:5, Informative)

    by Animats ( 122034 ) on Sunday May 09, 2004 @01:14PM (#9100738) Homepage
    Here's the paper from Physical Review Letters. [lbl.gov] This was published late in 2003.

    Tellurium is about $14/lb. [usgs.gov] Gallium, by comparison, is about $1000/lb, which is why gallium-arsenide photocells, which can reach 30% efficiency, aren't widely used.

    World production of tellurium is only about 100 metric tons. Gold production is 25 times larger. Tellurium is cheap because it is produced as a byproduct of copper smelting. Nobody mines tellurium directly at present. So there may be a supply problem if demand increases substantially.

  • If they need 3 years... (Score:3, Interesting)

    by corngrower ( 738661 ) on Sunday May 09, 2004 @01:23PM (#9100782) Journal
    to study whether or not making this things is 'feasible', you can bet they're not going to be cheap. At least not initially.

    50% efficiencies are quite spectacular. If they could make these things cheaply in high volumes, solar power could be supplying the majority of energy needs in the future.

    Those who research semiconductors these days are exploring ever new clever ways to engineer these materials. Mechanisms for tailoring the bandgaps (by introducing materials that strain the crystal lattice) are becoming more widely used. The three different bandgaps allow photons over a wider range of frequencies to be captured and turned into electricty.

  • Solar cells - when? (Score:3, Insightful)

    by Hanno ( 11981 ) on Sunday May 09, 2004 @01:23PM (#9100784) Homepage
    There have been "it's just around the corner!" reports exactly like this one about solar cell tech for more than two decades. Probably even longer, but that's when I started to be interested in solar cells.

    Yet, solar cells are still a minor technology, not commonly used. Wake me up when the reports are finally true and buy solar cell powered houses and cars are sold at prices an average consumer can afford and at specifications that an average consumer is interested in.

  • Why is Slashdot using the incorrect term (Score:3, Flamebait)

    by York the Mysterious ( 556824 ) on Sunday May 09, 2004 @01:28PM (#9100807) Homepage
    It's not Solar Cell. It's Photovoltaic cell. This is slashdot for god's sake. Should I just call the computer the box on the side next to the TV?
    • Yes!

      What you call it in the privacy of your own home is none of our business. Just like what you do with it.

      Common usage is caused by the media so get used to solar cell. Hell they have been calling the bottle nosed porpoise a dolphin for 4o years because of a stupid TV show. So don't expect accuracy.

      A porpoise is a mammal, a dolphin is a fish.

  • More about the current uses of tellurium (Score:3, Informative)

    by Billy the Mountain ( 225541 ) on Sunday May 09, 2004 @01:38PM (#9100875) Journal
    From the Mineral Information Institute:

    Uses

    Half of the tellurium consumed each year is used to improve the machinability of special iron and steel products. It is alloyed with copper to make copper more ductile (that is, easier to stretch into wires), and with lead to prevent corrosion. These, and other nonferrous tellurium alloys, account for approximately 10% of tellurium use.
    Tellurium is also used to make catalysts and chemicals. Some of these chemicals are used in the petroleum industry and in making rubber. Tellurium is added to selenium-based photoreceptors to broaden the spectral range of copiers. Tellurium is also used in other electronic applications, and in the production of blasting caps for explosives.

  • From almost a month ago: "A Step Closer To The Optimum Solar Cell" [slashdot.org] is also about Walukiewicz and company's research.

  • Material properties (Score:2, Informative)

    by Anonymous Coward
    Telluride is used also in other optoelectronic materials such as CdHgTe for IR detectors, and if there ever was a nasty material to work with this is it. I would not be surprised if this new one is bad too. In fact "forcing" oxygen atoms into this crystal has to distort the lattice making epitaxiality a nightmare.

    So it might be nice and efficient once (or if) optimised) but also it might be horrifically expensive.

  • a huge leap (Score:3, Informative)

    by utexaspunk ( 527541 ) on Sunday May 09, 2004 @02:43PM (#9101214)
    let's hope these make it to market soon, and that they are cheap when they get here. this is a huge leap in efficiency, and if the price is right, it could be quite competitive with other forms of energy. this would reduce our dependence on foreign oil and could stimulate our semiconductor industry if production really took off.

    they need to figure out a way to make solar cells in more complex shapes. It even with current solar cells, the efficiency is great enough to make a decent commuter car, so long as it's covered with cells. It's not like it won't be spending most of the day in a parking lot somewhere. But a car covered with PV cells can be pretty ugly- if high efficiency PV's could be formed into body panels, particularly if combined with something like BP Solar's Laser Grooved Buried Grid (LGBG) process which hides the bus bars and allows for different colors, a normal-looking solar-powered car could be possible.
  • When these get to market it will really hurt the utilitiy companies. Revenge is fun. The amount of power that could be produced in southern NM alone is huge. Less than 8 inches of rain a year and a min of 250 cloudless days/year? Wow. But not till more efficient cells are available. I hope the get another 50% better by the time they get to market.

  • Some interesting energy numbers (Score:3, Interesting)

    by Anonymous Coward on Sunday May 09, 2004 @06:58PM (#9102311)
    Current estimates of world oil reserves (total)
    is around 2 trillion barrels.

    The energy stored in a gram of oil (on average)
    is 44000 Joules/gram, at a SG =0.9.

    1 barrel (oil) = 42 gallons = 0.159 m^3

    So 1 barrel has the following energy content,

    44 x 10^6 Joules/kg * 998 kg/m^3 * 0.159 m^3/barrel * 0.9
    = 6.3 x 10^9 Joules/barrel (6 gigaJoules/bbl)

    So all the energy stored in the worlds
    oil reserves is,

    2.0x10^12 barrel * 6.3*10^9 Joules/bbl =
    1.3x10^22 Joules of oil energy.

    (2.0x10^12 is a very optimistic value, P=0.1)

    Ok, so you think this is a big number ?

    The total power radiated from the sun is approx,
    4x10^26 watts or 4x10^26 Joules/sec.

    The sun radiates the equivalent of all the energy
    stored in oil on the earth in,

    1.3x10^22/4x10^26 = 32.5 microseconds

    The entire oil based world economy (150 years of work)
    is only a 32 microsecond job for the sun.

    By necessity "we" will become much smarter on how
    to capture solar power.

    BTW the current world rate of oil consumption
    is approximately 80x10^6 barrels/day, at
    this rate the remaining 1.5x10^12 barrels
    will be gone in, 51 years. The growing South
    Asian market will probably help cut this to 30
    years, but shifting demand will probably help
    keep complete cut off at 50 years.

  • Cheap solar cells? (Score:3, Interesting)

    by cr0sh ( 43134 ) on Sunday May 09, 2004 @08:38PM (#9102834) Homepage
    Many of you here likely know how to "homebrew" your own solar cells using a sheet of copper (google for "copper oxide solar cell" or "cupric oxide solar cell" for more details). These cells are cheap and easy to make, but they are far from efficient. They use copper oxide as the semi-conductor layer, the copper plate is the back conductive layer, and a transparent front conducting layer needs to be used (typically on homemade cells, this is done using salt water - a much better solution, though more difficult to obtain and use, is to use a silvering solution, like mirrors are made with, to deposit a transparent conductive silver front electrode onto the plate). On top of being inefficient and depending on the front electrode, difficult to make and use for long periods, they also tend to be expensive - copper sheet doesn't come cheap.

    I have thought of a possible solution, though I don't know if it will work. I would love for someone to try this possible solution, and let me know their results.

    Basically, I am thinking of using a piece of alluminum plate/sheet for the back electrode, painting the alluminum plate with copper-oxide containing anti-fouling paint (used to keep barnacles and other things off boats and ships - must have a very high percentage of copper oxide for this to have a chance in hell of working), then, while the paint is tacky, pressing a piece of copper mesh onto it (to form the front electrode) - hook up wires, sandwitch between some clear acrylic, and...profit?

    Would this work? Would this be a cheap way of building solar cells? Would it be cheaper than silicon-based cells? Cheaper than used cells (likely not)?

    Actually, I know of a way to get real cheap solar panels, which I am currently exploring - hopefully, something good will come out of it...

  • Pessimism & The Big Picture (Score:3, Insightful)

    by Long-EZ ( 755920 ) on Monday May 10, 2004 @09:05AM (#9105762)

    There have been "it's just around the corner!" reports exactly like this one about solar cell tech for more than two decades.

    Correct, but misleading. This is a semiconductor technology. It has the potential to obey Moore's Law. Power has been relatively cheap because we're fuelishly burning hydrocarbon reserves, so there has not been the same market incentive for solar cells that we've had for memory and processors. But an exponential growth rate still applies.

    Wake me up when the reports are finally true and solar cell powered houses and cars are sold at prices an average consumer can afford...

    Well, it won't be /. news then, will it?

    The market ensures that this technology will happen in large scale at the consumer level, barring some new centralized power source such as nuclear fusion. If we were smart, we'd be investing a lot of money in alternative power technologies, (solar, fusion and others), instead of the government being the lackeys of the oil industry and spending a lot of tax dollars to protect a continued supply of oil. Research into alternative energy sources benefits all taxpayers. Protecting foreign oil assets uses tax dollars to benefit only a few energy company executives and sheiks, and even that benefit only exists for the very near future. It's an unfair and unwise use of tax dollars. As a technogeek, the inefficiency and short sightedness of the US energy policy offends me. The previous success of the US economy was based on free market driven technological innovation, not special interest enforcement of the status quo. The US will either look to the future and lead, or cling to the past and follow as others step up to the technological challenges.

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