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Power Space Hardware

DARPA Awards $53 Million for Solar Power Research 171

Posted by ScuttleMonkey from the new-technology-is-hot dept.
mygadgetbox writes "Defense Advanced Research Projects Agency (DARPA) will be giving a consortium led by the University of Delaware nearly $53 million in funding to more than double the efficiency of terrestrial solar cells within the next 50 months. DARPA wants the consortium to develop and produce 1,000 Very High Efficiency Solar Cell (VHESC) prototypes that are affordable and that operate at efficiencies of at least 50 percent. The goal is to create solar cells that operate at about 54 percent efficiency in the laboratory and 50 percent in production."
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DARPA Awards $53 Million for Solar Power Research More

DARPA Awards $53 Million for Solar Power Research

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  • Meh. (Score:5, Insightful)

    by pavon ( 30274 ) on Saturday November 05, 2005 @06:32PM (#13959656)
    We spent two decades wasting time trying to improve the energy efficiency of solar cells. The energy efficiency isn't what matters - it is the cost efficiency! If you are using solar cells as supplemental power to a house (their most effective application), then doubling the energy efficiency of the panel just means you get to use a smaller panel. Who cares - you have a whole roof's worth of space up there. Whereas if you get the price down, then you will decrease the amount of time it takes to pay off the cost of the cells, making it worthwhile to include them in more homes. And for other uses - cars, power plants, even if we had 50% efficient cells they still wouldn't generate enough power to be much use.

    I have been getting excited about some of the recent research that is making progress towards less costly, cleaner (to produce and dispose) solar cells. I guess if you are the military, and price is not an issue than this DARPA research is usefull. They need to find some way to power all this new electronics equipment that soldiers are carrying. But it is improvements in cost efficiency that will really make a difference in real world.

    • TATFA (think about the article) (Score:5, Interesting)

      by PresidentEnder ( 849024 ) <(moc.liamg) (ta) (rednenrevyw)> on Saturday November 05, 2005 @06:43PM (#13959701) Journal
      Most of what Parent says is true- for the applications in question (home use, vehicle use, consumer use in general) the cost of solar cells is the limiting factor. However, this is DARPA we're talking about here- as well as a bunch of commercial clients. The applications mentioned in the article (primarily the military) rely heavily upon efficiency and not so heavily upon cost efficiency. Yes, it would be nice if GI Joe's GPS solar cell only cost fifty cents, but if it weighs a hundred pounds? I'd rather have a five-hundred dollar solar cell producing enough in half a pound. Efficiency is important in some areas, cost effectiveness in others. Research into efficiency isn't a total waste.

      • True, the military will care about efficient power cells but is it really worth it to go the solar route? I mean we've been hearing a lot about other small energy sources as well...in my opinion solar is a pretty bad way to go from what I know about it. They're not very rugged from what I know either, which kind of describes where most of our troops end up.

        While I agree sometimes it is better to spend the money and get more efficient, I'm not sure I want my tax dollars wasted on something like this if the

        • Re:TATFA (think about the article) (Score:5, Insightful)

          by king-manic ( 409855 ) on Saturday November 05, 2005 @07:05PM (#13959819)
          While I agree sometimes it is better to spend the money and get more efficient, I'm not sure I want my tax dollars wasted on something like this if the govt decides to buy a single expensive solar cell rather than some body armor for some troops on the ground facing suicide bombers...

          Body armour may stop shrapnel. Body armour can't stop kenetic force. So it's good versus grenades, small arms, peripheral range of explosions, but piss poor against a bomb attack.
        • The solar cells used in the field are not the fragile glass units people think of. We use two flexible, folding solar arrays for our field work that are MILSPEC and they can be run over by trucks, take 7.62mm rounds, and fold down to about the size and weight of a laptop computer. Less efficient than the glass panels, but that's the tradeoff.

          And being able to set up a self-supporting field communications center with a small backpack full of gear can make a LOT more difference in war than an extra piece of
        • Have you ever thought that if the government didn't spend so much money sending troops to other countries where they are not wanted, there would be plenty of money to spend on good research such as this ?
          • Assuming we weren't all killed...

          • Re:TATFA (think about the article) (Score:5, Insightful)

            by Jeremi ( 14640 ) on Sunday November 06, 2005 @01:41AM (#13961281) Homepage
            Have you ever thought that if the government didn't spend so much money sending troops to other countries where they are not wanted, there would be plenty of money to spend on good research such as this?


            Nah, you have it backwards... if the American people weren't kept in a constant state of fear and reliance on the Pentagon to "protect" them, they wouldn't be so willing to fork over their tax dollars to support the world's largest military. That's the beauty of the system: the bigger the US military-industrial complex grows, the more the rest of the world resents and fears the USA. The more the rest of the world hates and fears the USA, the more insecure the US population becomes. The more insecure the US population becomes, the more willing they are to funnel more of their tax money into "defense", in the hopes that it will make them safer from the world that hates them so. So essentially the more money they spend, the more money they will have to spend later on.

        • After seeing the traffic jams due to hurricane Katrina in New Orleans, I was wondering whether hybrid
          cars could recharge using solar cells on the roof. If this were possible, being stuck in a traffic jam
          wouldn't be slightly less worrying, as I wouldn't be wasting money on keeping an engine going.
          • Sure they can, but you are talking about a drop in the bucket in the scheme of things. If you covered the whole car you might get 1000watts worth of cells x6 hours of useable sun, brings you up to 6000watt hours. The problem you run into on your car is the motor is something along the lines of 5-30 thousand watts. So one whole day of charging buys you 30 minutes or less of run time.

            Of course you don'tt need to worry about sitting in trafic so much, since hybrids don't burn fuel(very much) when you are

        • True, the military will care about efficient power cells but is it really worth it to go the solar route?

          Obviously you've not been watching the price of gas lately.

          in my opinion solar is a pretty bad way to go from what I know about it.

          You must know nothing about it at all. It only costs about $30,000 to take a home completely off of the electrical grid using solar with a combination of other natural sources of energy to power your house. (I'm part of a group of people here in Memphis, that have
      • I can't think of a better way to ensure the safety and security of this nation and it's citizens, than to discover a cheap method of mass producing solar cells, I don't care HOW inefficient they are, and using them to replace our dependency on foreign oil.

    • Re:Meh. (Score:3, Insightful)

      by CosmeticLobotamy ( 155360 )
      Unless you're trying to put a field of the things in a desert somewhere to supplement a city's power. Then the land costs more than the cells will, and being able to use fewer saves money and, in some cases, makes it feasible at all.

      • Re:Meh. (Score:4, Interesting)

        by thc69 ( 98798 ) on Saturday November 05, 2005 @06:58PM (#13959777) Homepage Journal
        That kind of land is probably cheap. In fact, power companies and government probably own loads of it, unutilized, already.

        Come to think of it, isn't Area 51 surrounded by a bunch of wasteland desert?

        Either way, I want solar that can pay for itself quicker than I have to pay off a loan for it, else I can't afford the capital investment. I'd plaster my whole roof with it.

        Solar roof shingles and solar standing seam metal roofing are too expensive, too.

        • Re:Meh. (Score:2, Insightful)

          by HUADPE ( 903765 )
          There is a key problem with putting solar cells in the middle of the desert. Nobody lives anywhere near it. Transmission of electricity uses up energy, so sending power from the Nevada/New Mexico border to Los Angeles can reduce its voltage by more than half at the end of the trip. The land is cheap, but you need to buy twice as much and put twice as many cells on it to have the same effect as a local source.

      • land is cheap.. (Score:3, Insightful)

        by slashkitty ( 21637 )
        compared to solar cells. Are you crazy or something? about the only place where land is more expensive is in or close to a city. Solar cells cost about $100 per sqft.. while land around here costs about $50k per acre, or about $1 per sqft. If you can get me some solar cells for less than $1 per square foot, I think we could have a good business.
        • At 50k per acre, it's almost $1.15 per square foot. Not so cheap-sounding now, is it? Suck on THAT!

          Okay, you're right.
        • $100/sqft is for consumer-grade stuff which is typically under 15% efficient. For the more efficient aerospace-grade stuff which is at least 25% efficient (IIRC, 27% was the minimum for qualification 3-4 years ago), you will be closer to $1000/sqft.

          More efficient and less expensive cells at the high-end will not translate into cheaper panels for consumer-level stuff because the pricing gap between the two grades will remain substantial for a long time to come... unless this DARPA funding leads to a major co
      • Next time you're taking off or landing from a major airport, take a look at the suburbs. Hundreds of thousands (heck, probably millions) of square meters of roof, mostly unshaded. Here in Denver, maximum solar flux (noon in June) is about a kilowatt per square meter. Typical household peak load over an hour is about 12 kilowatts, average load over the course of the day is closer to a single kilowatt. I've got maybe 20 square meters of south facing roof (and about the same west facing). 50% efficiency w

    • Re:Meh. (Score:5, Interesting)

      by deander2 ( 26173 ) * <public@nOSPaM.kered.org> on Saturday November 05, 2005 @06:54PM (#13959764) Homepage
      if you double the efficiency, you only need half as many cells.
      this would reduce the cost, even if the price-per-cell remains the same.

      personally, i say let's try for both.
      • What ever happened to the "huge" discovery [lbl.gov] 3 years ago of the large bandgap of InGaN which is convieniently tuned to the solar spectrum. They were claiming a theoretical efficiency of >50% in a single dual junction cell, 70% for multilayer junctions! Then......nothing. Not a single thing. Haven't heard a word about it since. wtf.
    • There are uses for smaller more expensive solar cells as well. Personally, I'd like a solar laptop . I suspect that we've nowhere near the power requirements for something like that but there are other portable devices that would be more convenient with solar power to extend battery life.

      • I suspect that we've nowhere near the power requirements for something like that but there are other portable devices that would be more convenient with solar power to extend battery life.

        Hrm, my laptop draws 25W at peak, 14W while idling. Bright direct sunlight is 1kW per square metre. I estimate my laptop surface area (back of the screen) is about 0.06 square metres, and with efficiency of 15% for cells and assuming 25% sunlight (cloudy days, indirect lighting), yeah it's not even close. It's out by

        • 1M62 ~= 10.7f^2 my laptop ~1 f^2 so let's use .1 square metres *.15 * .25 = 3.75w but if you use 50% eff solar cells that goes to 12.5w which would more than double your battery life. At 14w you get 14/(14-12.5)= 9.3 x as long. However, if you used 27% eff and 75% solar power 1f^2 gives 20.25 which means that if you had a detachable solar device you could add ~4-5 hours of peak useage per day anywhere.

          The problem is you don't use laptops outside all that much and when you do use them outside you tend to
    • I wonder if they could be small enough to power a PDA or mobile phone? I guess people may buy into that, even with a high cost.
    • The energy efficiency isn't what matters - it is the cost efficiency!

      Darpa is more concerned about 24 hours 7 day a week in the air solar powered UAV's with solar panels than home owners. For all they care, those things could cost $10 million a pop as long as they get the job done.
    • Comment removed based on user account deletion

    • Actual experience (Score:2, Informative)

      by Doug Coulter ( 754128 )
      I have two solar powered businesses here (a computer consultancy, and a machine/plating shop), and two homes which run off the same systems. Square feet definitely matter, as I am nearly out of useful roof space now. The 1000 sq foot building that has the machine tools is covered, and could use twice what I have now (although with a 2kw array, it could also be worse - 8-10 kWh a day ain't bad). I've got room for one more rack of 4 panels (about 500w more in full sun). A 500 sq foot building has its roof
    • $1200, >30% effeciency, and it equates to cheaper power than what you can get off the grid.

      There doesn't seem to be much excuse any more. Cheap AND effecient cells:

      http://www.greenandgoldenergy.com.au/ [greenandgo...rgy.com.au]

  • 1000000 times better... (Score:5, Insightful)

    by MichaelSmith ( 789609 ) on Saturday November 05, 2005 @06:39PM (#13959687) Homepage Journal

    ...than looking for ways to bury waste products in the ocean.

    Photocells are already fantastic technology. Not only do you save the energy you would otherwise be drawing from a power plant, you also save the energy needed to deliver the energy to the point where it is used.

    A lot of public lighting near my home is now solar powered. The big advantage is that you don't have to dig trenches to the site. Trenching is very expensive because of the associated labour costs, and labour costs feed back directly into energy costs.

    • Re:1000000 times better... (Score:1, Insightful)

      by Anonymous Coward
      In the mean time, producing a solar panel still costs more energy than what it will produce in its lifetime. Don't discard the ocean solution just yet.
      • This is not true any more. Find a single study in the last five years that supports your claim.

      • Re:1000000 times better... (Score:1, Informative)

        by Anonymous Coward
        In the mean time, producing a solar panel still costs more energy than what it will produce in its lifetime.

        Not true. ROI is about 18 months. Expected lifetime is upwards of 15 years.

        • Warranties on current production solar panels are typically 25 years.
        • I used the numbers from solarbuzz.com. http://solarbuzz.com/ [solarbuzz.com] Cost of a panel right now is $5.20 per peak Watt. For more facts, also see http://www.solarbuzz.com/Consumer/FastFacts.htm [solarbuzz.com].

          So I did some numbers. My electric bill is about $40/mo from PG&E. I use about 353KWh/month.

          I figured that there are about 6 effective peak hours of generation per day. That is, I get about 12 hours, but if you average it all hour, it's like I get peak sun for 6 hours (Solarbuzz says 5.5) in my area.

          Okay, so that means for
    • Solar powered lighting is about the dumbest idea possible. Most lights are on utility poles, or near right-of-ways, with power lines at hand. And the electricity used at night costs pretty close to nothing because it's part of the utilities' base load anyways. Not to mention, you need batteries, which are still somewhat expensive, to run nighttime loads as opposed to just connecting to the grid to run loads like, say, peak air conditioning that return a greater benefit.

      • Re:Try again... (Score:3, Informative)

        by MichaelSmith ( 789609 )
        Solar powered lighting is about the dumbest idea possible

        It is in use all over the place here in Australia. Not along every main road, but it is used where there is no easy access to mains electricity. A location in the middle of a park, or on an isolated country road easily justifies solar power.

        In my former job working on road transport systems we frequently installed solar and wireless traffic monitoring systems and emergency telephones.

        You save on trenching this way, and also on maintenance because u

  • This is good and all (Score:4, Insightful)

    by rolfwind ( 528248 ) on Saturday November 05, 2005 @06:46PM (#13959718)
    But the article is almost talking as if the goal of doubling the now 25% efficency being doubled are being guaranteed to be met which is hardly the case - it's been over 30 years (where it was what 8% effieciency?) since solar cells were introduced and many other countrie/companies have been working on improving efficiency without that huge jump in performance - Germany/France in particular.
  • ...the evil selfish "let's squeeze every drop from the Earth" oil industry doesn't buy up and discredit any commercial offshoots of this DARPA project and sweep it under the carpet. This kind of behavior is common, but the public rarely hear about it. The solution is for the world's populace to revolt by trying ever so hard not to purchase gasoline. Instead, whenever possible we should walk, bicycle or rollerblade to our place of work or relaxation until solar panels produce enough of our electricity to mak
    • ...the evil selfish "let's squeeze every drop from the Earth" oil industry doesn't buy up and discredit any commercial offshoots of this DARPA project and sweep it under the carpet.

      They love you... +1

      This kind of behavior is common, but the public rarely hear about it.

      They really love you... +2

      The solution is for the world's populace to revolt by trying ever so hard not to purchase gasoline.

      Erm...

      Instead, whenever possible we should walk, bicycle or rollerblade to our place of work or relaxation until solar
    • As a matter of interest, who do /you/ think owns BP Solar?
    • I'm not sure exactly what their motivation is for doing so, but the overwhelming majority of commodity solar cells (in terms of volume, not necessarily capacity) are manufactured by big oil companies such as Shell and BP. One could think of it as a slightly profitable PR stunt, along the lines of:

      "We're not evil oil companies, we make solar cells, too!"

      Or it could be a poorly executed attempt at product diversification, like:

      "Oil ain't going to be around forever, ya know, that's why we are making

  • A Good Start (Score:5, Interesting)

    by ckswift ( 700993 ) on Saturday November 05, 2005 @07:02PM (#13959808)
    This is a good start, but we really need to be pumping money into solar power research if we ever want a carbon free energy future. A excellent post over at the Cosmic Variance [cosmicvariance.com] recently discussed how solar power is the answer for our coming energy crises.

    Be Afraid, Be Very Afraid [cosmicvariance.com]
    ..."But we have nuclear fission, wind power, tides, biomass, hydro, and geothermo, and one day we'll have nuclear fusion...right?" No. First, he estimates that we need 10-30 TeraWatts (TW) of supply by 2050. Fission plants come in at about 1 GigaWatt (GW) of generation capacity (we don't know how to safely, securely and make efficient ones much bigger), and so we'll need to construct one new nuclear fission plant every other day -starting now- to meet the challenge. And then they only last 50 years... The biggest and brightest fusion project right now (in europe) is hoping to get break even several years from now, and then maybe built a working demonstration machine when it is probably already too late! He then continues to work down the list of all the other alternative sources, and you realize that they just won't even come close to what we need if we are truly going to stop dumping greenhouse gases into the atmosphere.

    ...

    But then he reminds us that we have one source left, and it has way more energy than we can possibly need. The Sun. Two hours of sunlight hitting the whole earth's surface gives us the equivalent of the 30 TW for a year we need to be working at. Taking into account practicalities, we can expect about 600 TW or so fairly easily, and at 10% efficiency in recovering it and putting it to good use, we still are way ahead of what we need.
    I really encourage you to read the whole post.

    ~CK
    • Also a video [mediaserve...wiscablerm] of a presentation of a guy he cites ... very worth watching.

    • Re:A Good Start (Score:3, Insightful)

      by cameldrv ( 53081 )
      Obviously the issue is simply cost. He dismisses fission because he says we'd have to build a plant every other day to make it work. Well, to replace that with solar, you'd have to build something like ten gigawatts of solar panels, install them, and hook them up to the grid or to individual consumers. The question is which one is harder. In a market economy, generally the way you figure that out is which one costs more. Solar costs more than Nuclear, and we would need a lot of undeveloped technology i
      • umm.. retardo, that is why the guy in the blog post talks about research into STORAGE being a very large item on the solar agenda. The fact though that all the nuclear power in the world could not add up in time to the power requirements (then there is the problem of storage of waste at that level of production).

        Solar may be variable on the local scale, but it is constant on the aggregate. Oh, BTW, they have figured out how to make non-silicon based solar panels, so they get easier and cheaper to make.
      • > Nuclear is reliable, has a nearly inexhaustable fuel supply, and is well proven technology.

        I grant one and three but not two!
        The uranium amount is far from being 'nearly inexhaustable', I remember vaguely that a study showed that if we switches from oil to uranium, the resource of uranium would be exhausted in two centuries.
        That's a long time, ok but it's quite far from being 'nearly inexhaustable'.
    • If the cost of hydrocarbon fuels continues to grow, power demand will also fall.

      Replacing hydrocarbon energy with clean energy is not the only way to reduce hydrocarbon use. Making things more efficient will also reduce power use. This can mean better insulation in buildings and homes; more efficient means of travel; more efficient lighting (LED?); more efficient heaters and air conditioners; etc.

      It might even mean smarter stoplights. [blogspot.com]

    • ...is catching it.

      It turns out you need a total surface area the size of a medium sized US state in about six places around the world (say one on each continent) to do the job.

      Does anybody else see a problem covering Wyoming with solar arrays?
      • not really, it doesnt have to be wasted and...

        lets see.. average house maybe 10 * 15 metres or more = 150 m^2 surface area on the roof. the sun gives a daily average of about 200 watts per m^2 (peaks at over 1KW at noon (in sunny places), drops to 0 at night)

        that gives us 150*200 = 30 KW of average power. add in a 20% efficient cell and you've got 6 KW average power, for every house, (obviously we need a way to store it during the day for night use), being way more than enough for most houses

        then youve

        • that gives us 150*200 = 30 KW of average power. add in a 20% efficient cell and you've got 6 KW average power, for every house, (obviously we need a way to store it during the day for night use), being way more than enough for most houses

          To put this in persepctive, the average home uses between 20kWh and 40kWh per day. That averages out to less than 2kW average power. So as you say, even assuming grossly inefficient storage, solar power is technologically feasible. It's the economics that have held i

    • On the one hand, we desperately need more clean fuel supplies. You don't want to ruin your home, especially if it is the only home your entire species has.

      That having been said, he's making trend estimations to 2050. 2050. That's 45 years off. People aren't particularly good at figuring out what will happen in 10 years, let alone in 45. By 2050 the world will look as different as it did in 1950, arguably moreso. Will we have simple, efficient hydrogen for power storage? Will we finally have cracked t

  • It can only mean one thing... (Score:5, Funny)

    by DieByWire ( 744043 ) on Saturday November 05, 2005 @07:10PM (#13959837)
    If this administration is spending money on solar, it can only mean one thing...

    Halliburton now owns the sun.

  • I agree with the poster that says cost efficency is the biggest problem. I'm not sure how much they cost, but my dream is to create skyscapers completely out of solar panel. I think the panels look sexy enough to be on a lot of things. They should experiment with different looks for solar panels and have entire cities dressed with solar panels. This would save a whole lot on enegry costs as would be the purpose for solar panels. They should also experiment with a impact resistant solar panel. That way we ca
    • I agree with the poster that says cost efficency is the biggest problem.

      It is a similar issue to VLSI chips. Once you have sufficent economies of scale, costs will fall rapidly.

    • Traditional solar cells are made from hard, thin materials, and are fragile. They cannot be bent or flexed, and crack easily. Rain can damage solar cells. Most of those solar car competitions are run in the desert where (A) there's tons of sun and (B) it's not likely to rain.

      There are newer materials such as flexible solar cells, but they are expensive by comparison, and are less efficient. Several posters are also saying that more efficient is better because it will lower the amount of cells required..
  • Why don't we switch to trying to develop optical rectennas. It seems to me that the only thing limiting there efficentcy is diode technology. We currently have diodes that can switch at 500 Thz. We only need to get into the 1000's of Thz to get into the optical realm.

    This would allow for a much higher top theoretical efficentcy. Maybe around 90%+ and would be far cheaper to produce.
    • The problem is the spectrum spread - even if you're 90% efficient for red light, you're wasting more than half the energy content of the blue light. And if you're 90% for blue, that's generally the cutoff; you get nothing out of red at all. You can already get efficiencies over 50% with photovoltaics at a single wavelength but the real test is can you handle normal sunlight. That's why multi-junction cells do well (and are close to 40% in the lab) - they are optimized for several different wavelengths, inst

  • Efficiency (Score:3, Interesting)

    by SuperBanana ( 662181 ) on Saturday November 05, 2005 @07:33PM (#13959944)
    Don't I recall a recent (last year or two) announcement from a university about a high efficiency solar panel, intended to be used in building construction? The panels were small, inside little cubes, and could pivot, I think?

    I'm also quite positive I remember stumbling across a webpage for a US Defense/space contractor, where they offered up solar panel "scraps" (stuff you could still assemble into working modules, with a fair bit of labor) for sale to the public. Efficiency was substantially higher than anything I've seen on the commercial market, though I don't recall figures off the top of my head. They probably cost a lot more to manufacture, but $50M amortized over -possible- solar panels sounds pretty expensive too.

    Why couldn't we just give a $50M grant to homeowners to buy solar panels?

  • The atmosphere lets through a very wide range of electromagnetic frequencies. Most solar panels use only a small part of this frequency range, and even in that range, its less efficient around the edges. If they make a cell that is 25% efficient, yet covers twice the bandwidth, they'd have the same energy output.

    Now getting closer to 100% is harder. The amount of effort spent on making something efficient for a given frequency may be better spent trying to make it cover multiple frequencies (or layering cel
    • You dont know what you are talking about.
      Seriously.

      A cell thats 25% efficient DOES convert 25% of the complete photon energy flux on its area in electrical energy.

      Thats why 25% is such a high value and even optimisation cant rise it much higher. The _quantum_ efficiency of those solar cells is almost 1, btw, So if you wanted bullshit advertisements, you could always claim 94% efficience.
      A hint for better understanding: look at a spectral graph of sunlight through the athmosthere. Its not really a blackbody-
  • If we are talking about traditional p-n type solarcells, they physically can't do better than ~37% IIRC. There is just no way to avoid some (alot!) charge recombination. In addition there is a lot of solar energy that is not within the absorption curve. I really hate it when people throw numbers around without a reference. All photovoltaics should be referenced to AM 1.5 (the typical energy that reaches the earth). The solar people all talk about photosynthesis as 'near 50%' but that is only over the narrow
    • You're right. Any who claims that photosynthesis is 50% efficient is nuts. If I remember right, total efficiency maxes out around 1% (given ample nutrients, rain, soil, and a fast growing plant like marajuana).

      The losses in the C3 (or C4) cycle are enormous, and a plant is a living creature with a metabolism and much of the sugar generated goes for other uses than laying down fiber (which is what we eventually harvest for timber or firewood or hay).

  • Alternative Energy is already here. (Score:5, Interesting)

    by Fantastic Lad ( 198284 ) on Saturday November 05, 2005 @08:13PM (#13960128)
    A family I know built a geo-thermal/solar powered house.

    This was not their original plan at the outset. --Basically, they bought a property, and cleared a lot far back from the road. Then they learned that to have AC lines brought to their house from the mains, the local power company would charge them over $10,000 for the job of sinking four poles and running cable.

    They thought, "Wow. Ten grand? Sheesh. What other options are there?"

    The result was some research and a re-jigged construction plan using alternative energy. They spent about the same amount of money installing Geo-thermal and solar panel solutions.

    10 big cells cost them about $8000 CAD. The rest of the money was spent digging trenches and laying thermal transfer pipes, air ducts and house wiring. Now they have all the power they need.

    Strategic spot lighting using 12 volt halogen bulbs rather than bathing entire rooms in light minimizes the impact on energy reserves. Laptops are used instead of desktop computers, and various other appliances, like radios and televisions are run with DC to AC converters. Water is pumped from a well to a reservoir at the top of the house which provides pressure. Even while feeding the needs of an active family of four, the array of 5 big chemical batteries which stores electricity from sunlight never dipped below a 95% full charge on any of the days I visited. (The power readings were set on a cool display for all to look at.) --And the house is also absolutely enormous; 5 bedrooms, plus various huge family rooms the size of small churches, etc. A total mansion, and after the initial investment, it costs exactly zero to light and power.

    Cooking is done on a big gas range fed from a pair of large propane tanks which contain enough propane to last more than a year. Water is drawn from a well. Refrigeration was the only puzzle still to be worked out, and while pondering it, the family had spent two years eating fresh foods while keeping milk and other such items in a basic camping cooler in the kitchen. Half the things people normally keep in their fridges don't really need to be there; milk and beef doesn't go bad all that quickly, eggs don't need to be refrigerated at all, and chicken and fish are simply bought fresh the day they are intended for consumption. --After realizing that this worked without any problems, the family basically concluded that they didn't really need a fridge in the first place. --Though, they told me that they had found a super-efficient 12 volt DC fridge on the market for homes exactly like theirs, but that they didn't think they really needed it.

    Half the problem is not the power source, but the notion that we need so much electricity in the first place. --If we change the parameters of the problem, we can start using different solutions which have already been accepted by industry. Simple.

    Despite the opposition, alternative energy is here for anybody who wants it.


    -FL

    • I agree whole heartedly with most of what you said, but im a bit curious about the "milk doesnt need refrigeration" bit.... if I leave milk out of the fridge it goes off pretty damn quick ( hours versus nearly a week in the fridge), where did you get the idea that it doesnt need refrigeration (or are you talking about long life milk, or using it all up within a few hours of getting it?)
    • "Strategic spot lighting using 12 volt halogen bulbs rather than bathing entire rooms in light minimizes the impact on energy reserves."

      Halogen lighting is absurdly inefficient. Incandescent lighting in general is. Imagine if they used fluorescent lighting in their house? Heck, even LED or HID would be much more efficient.

      I've never heard of a super-efficent 12V fridge either. Many 12V "fridges" (more like coolers) are god-awful Peltier devices which are about 10% as efficient as a compressor-based system.
      • To deliver the same power at 12V as at 120V, you have to run 10X as many amps and thus lose 10X as much power in line losses.
        Power loss is I^2R, so ten times the current is 100x the power loss.
      • I've never heard of a super-efficient fridge...

        Then you haven't looked hard enough ;-)

        Vestfrost make some. They are super-efficient because they use loads of insulation, and can subsequently get away with small 12 compressors (actually 19VAC chopped up from 12v). Chest freezers with modified thermostats also come to mind , although they're still mains-powered.

        And luxeon LED lighting would probably be the way to go - they only draw 5 watts or so tops, and you can get MR16 types that fit standard halogen sock
      • I'm not an electricity guru, but I'll try to answer as best I can. . .

        Halogen lighting is absurdly inefficient. Incandescent lighting in general is. Imagine if they used fluorescent lighting in their house? Heck, even LED or HID would be much more efficient.

        I agree that I do find LED lighting an exciting technology, but I'd be hard pressed to go with it in a house; it's a very blue and cold light. I dislike fluorescent for those same reasons and because even the special units designed to replace incandesce
    • I don't see why a fridge would be such a problem when they've got plenty of propane. You can get an 18 cu. ft. fridge [cetsolar.com] that consumes 1.5 lbs of propane per day. Even a small one would be a big improvement over nothing, and wouldn't cost much to run.
    • Not sure how well it would work in Nova Scotia, but there is a technique of refrigeration called "Night" or "Dark" Sky radiation.

      Basically, you have a heavily insulated storage "unit" - an old, large chest freezer will work fine. Get rid of the compressor, coils, etc, then seal any holes or cracks. Dig a really large hole, deep enough to hold the chest, leaving a couple of feet completely around the box. Fill the bottom up with a foot or two of straw, old fiberglass insulation, sawdust, etc - basically some

  • Solar Power is not just Photovoltaics (Score:5, Interesting)

    by necro81 ( 917438 ) on Saturday November 05, 2005 @08:23PM (#13960172) Journal
    The article discusses that the goal is to improve the efficiency of solar cells to 50%. As I mention earlier in this thread [slashdot.org], silicon-based semiconductor photovoltaics top out at a theoretical efficiency of about 25-26%. Other semiconductor technologies top out somewhere around 35%. These are the two technologies people think about when they imagine solar cells. I think the outlook for discovering and commercializing a semiconductor-based solar cell that's 50% efficient in the next 50 months to be very poor. I won't get into the physics, but the theoretical limitations have to do with the fact that semiconductor photovoltaics make inefficient use of the solar spectrum: a red photon will produce as much electrical energy as a blue photon, even though the blue photon is more energetic.

    But solar power is not limited merely to what one can do with photovoltaics. When people talk about the many terawatts of solar power that falls on the surface of the earth, most of that solar goes into two things: photochemistry (like in plants) or to heating the earth's surface. Plants make very efficient use of the solar power that falls on them, and a black, nonreflective object will convert the incident solar power to heat (or reradiated infrared light) with extremely high efficiency. If we could focus efforts to developing technologies that capture sunlight first into chemistry or raw heat and converting that to electricity, rather than the direct conversion to electricity that photovoltaics do, we may have a better chance of reaching the 50% goal.

    For instance, there was (is?) a solar power project [doe.gov] that in the California desert that was a solar-thermal generator. Hundreds of mirrors focused sunlight onto a tower, much like the Archimedes death ray (which has received some press in /. lately). Instead of trying to burn a ship, the focused sunlight heated sodium to about 1200 Celcius, which liquified it. That sodium was passed through a heat exchanger to boil water, which made steam, which turned a turbine, in a similar closed-cycle technology to a nuclear plant.

    I'll admit this isn't much use in the battlefield, which is what DARPA is aiming for, but it is not out of the question to consider a smaller solar thermal unit for an encampment, which used a different medium than sodium.
  • As wondeful as it makes me feel that someone is sponsoring a warm fuzzy feeling technology like solar energy, the importance of these particulars are dwarfed by the greater issue at hand-- that the responsibility of government is to do what markets cannot. I dont know the numbers, but it certainly feels like government research spending has dwindled. $53mil may be spit in the bucket, but its at least something; it's certainly more than any corporation would invest in a 4 year, two month project.

    Government
  • Solar cells are not now, and will not in any near term (5-10 years) be a method for general electrical energy generation.

    Generating electric energy with solar cells is a great idea, but they are still a speciality, because the price of the cells are so high. Prices are falling, and have been doing so for many years, but they still have a long way to go to be competitive to other large scale energy sources.

    Solar cells needs more researching and funding for R&D. It will be great once it becomes affordable
    • Comment removed based on user account deletion
  • Not just for solar, but for alternative energy in general. With our oil supply set to become uneconomical within forty years, we are literally in a sprint to find a replacement for fossil fuels wherever we use them today, and if we don't our society is going to hit the reset button for about a century or longer. Our entire economy is based on cheap and plentiful fossil fuels, ALL OF IT. Our commitment to alternatives so far is a joke in the US. $53 million isn't even a rounding error on what we need to be d
  • I'd just like to point out that $53m is really not a lot of money, relatively speaking.

    This is dwarfed by the subsidies [motherjones.com] that govts give to the world's richest industry, Oil.

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