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Science Technology

Students Show Off Super-Efficient Solar Homes 33

Posted by timothy from the hey-it's-breezy-in-here dept.
mmol_6453 writes "An article at voanews.com describes the 'first-ever solar decathalon,' where the students show off effecient solar-powered homes." As a former Airstream resident, tiny efficient homes have a special place in my heart. Anyone in the D.C. area who can get out there and take pictures, links to photos would be much appreciated in comments.
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Students Show Off Super-Efficient Solar Homes More

Students Show Off Super-Efficient Solar Homes

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  • Um. No. (Score:3, Interesting)

    by WolfWithoutAClause ( 162946 ) on Monday October 07, 2002 @03:26PM (#4405568) Homepage
    "Solar energy is global. The people in Japan have the same amount of sunlight as the people in America. It's a very equalizing source of energy. Your neighbor has as much as you. You don't have more than your neighbor, unless [they] have more trees."

    They've clearly never been to Scotland then. If it's raining 'all' the time you genuinely do have less sunlight ;-)

    • Often the compliment of a lot of rainy and cloudy weather is plenty of wind. But you're right, sun is not a constant, there's also the lattitude factor as well.
      • Often the compliment of a lot of rainy and cloudy weather is plenty of wind. But you're right, sun is not a constant, there's also the lattitude factor as well.

        Typically you'll find plenty of wind wherever your country's politicians happen to be on any given day. Or, you could try to find yourself a property near a Taco Bell.
        • Typically you'll find plenty of wind wherever your country's politicians happen to be on any given day.

          Well, I do live in "the Windy City". Not everyone knows that this never really referred to the weather.

  • Solar... Yeah right (Score:3, Insightful)

    by MerlynEmrys67 ( 583469 ) on Monday October 07, 2002 @03:39PM (#4405655)
    Here in SUNNY San Diego there is a huge power shortfall. They are saying by 2005 there won't be enough transmission line capacity to bring in the power needed to run the city...

    The politicos solution, build solar power capacity... Only problem is they would have to cover 1/2 of southern California to cover the power debt that this area has. What they need to do is build 3-4 Nuke plants that will take up a small area, and supply the power needed to run this place for real.

    Solar is a nice niche way to produce a little bit of power, but when you need multiple MegaWatts, nothing beats a real source of power that can be depended on for decades to come Time for another (Mod -1 Troll) for me, but at least I will tell it like it is

    • Do you have the numbers to back that up? Even if it was true, wouldn't an increment in solar help? Probably the big saving in that area would be to reduce the demand for air conditioning by improved design. Or is the big demand industrial?

    • Re:Solar... Yeah right (Score:5, Insightful)

      by Kevin Stevens ( 227724 ) <kevstev@@@gmail...com> on Monday October 07, 2002 @04:39PM (#4406149)
      Well.. I doubt that you would need to cover 1/2 of southern california to provide all the energy needs... but even taking that as a fact... Consider what would happen if everyone, or even a significant number of people (thousands to millions) put a couple of panels on their roof. You are talking about a serious amount of energy production, and just as important, a serious amount of energy production when it is needed most, during the hottest part of the day when everyone has their air conditioners on high. The point of the student's exercise was not to turn people's houses into Multi-Megawatt power plants, but to make homes more self sufficient, energy efficient, and able to produce in aggregate large amounts of energy in a pollutionless manner. After tax incentives and rebates in my area (LI,NY) the cost for solar power is about $3/ watt as I recall (which is considered by the industry to be a magic price point, ala the $1000 PC). So you say everyone spends $3000 on a system, or all new houses incorporate a system, and produces 3kW of power during the day. Times 1000 homes is 3 megawatts, without all the impending doom problems that lurk with nuclear power (dont peg me as some tree hugger though- nuclear is my preferred method of power after hydroelectric and solar). Nice added benefits: reduced reliance on fossil fuels and thus the middle east. Also... power outages are less problematic. I dont think any of the students or even any solar energy zealots really believe that solar is the answer to all of our energy problems, but solar can make a huge dent in our energy needs.
      • Ok I just realized my math was off there, so $3000 would have each house produce 1kW, which would mean you would need 1000 homes per megawatt, or 3000 homes for 3 megawatts, aka a "few" megawatts.

        • Re:Solar... Yeah right whoops. (Score:2, Informative)

          by Anonymous Coward
          Your numbers need a bit more adjusting. $3/hr might buy you the panels if you're getting a heavy subsidy from somewhere. You may want to get an inverter and batteries to actually run your house off of those panels though. I think we got quoted at $8-10/W total. You also might want to account for the fact that you're only getting about 8-10 hours of usable sunlight per day. Another thing to check is how many homes and how much money it will cost if you actually scale your generation up to the size of a nuclear power plant. A large plant (Palo Verde in Arizona) does about 3700 MWh.
          • Well, like I mentioned tax rebates and power company incentives bring it down to that point. Also, in my area the power company will allow you to reverse the meter (thus helping put more power back in the system when they need it most), elminating or at least reducing the need for a large battery system. I forget if you still require an inverter using that system... I forget the details of how the systems work.
      • Have my current electric bill in front of me... $0.1103/kWh. So to produce a kWh will cost me $3.00, my monthy return is 11 cents, not a good ROI for my investment... (and this is after I have to pay for the government rebates, yada yada yada)

        That said, for very small niche applications it is nice, but when you have an industrial deficit of electricity, you need to build power plants, and frankly no one here is willing to do that in California (gotta love the BANANA people)

        • Re:Math Time (Score:3, Informative)

          by Kevin Stevens ( 227724 )
          Correct me If I am wrong... but... we are producing 1kW with our pretend $3000 array on our house. Now, lets say you get that peak power for 8 hours a day. 8 hours *7 days * 4 weeks we get 224kilowatt-hours each month. * your rate... .1103... we get $24.70 as your monthly return... without factoring any of the other benefits (clean energy, power outages not as large a problem, etc...). It will take about 10 years for the array to pay for itself. However, as I mentioned before, this is about alot more than just saving money. You are pretty lucky, in my area rates average 16 cents per kWh, making monthy savings about $35.

          • Re:Math Time (Score:3, Informative)

            by Graymalkin ( 13732 )
            PV cells are clean? It sure would be nice if everyone could ignore the costs of manufacture. Just because it generates energy from sunlight you are already getting doesn't make it clean.
            • Is it a significantly dirtier process? Is it dirtier environmentally than building an oil plant? nuclear? gas, etc? (Obviously I am asking on a per kilowatt basis, not one cell against an entire plant). I am curious... I could not find any information on the environmental cost of producing a solar cell...

              • Re:Math Time (Score:5, Insightful)

                by Graymalkin ( 13732 ) on Monday October 07, 2002 @09:51PM (#4407774)
                Yes, to made crystalline PV cells requires the same sort of chemicals and plant processes used in making semiconductor chips. It isn't necessarily dirty but very power intensive. Amorphous silicon PVs are also dirty to produce because of the amount of power needed and the chemicals used. Even if the chemicals are handled responsibly by the manufacturer there is no guarantee that the chemical's manufacturer handled the chemicals safely.

                Calling PV power generation clean is an absurd falsehood by those promoting it, not to insult you but instead to point out the people who convinced you PV was the clean wave of the future. To generate power you need to spend power, on the whole it is a zero sum process, you don't get moreo ut of what was put in.

                The reason oil is cheap easy and popular is because the energy it contains has been put there over the course of millions of years by microbes decomposing organic matter. The energy required to tap fossil fuels is much less than all of the energy contained in fossil fuels. The same goes for fisson power, the energy in the uranium was put there by a supernova billions of years ago. All we have to do is spend a little energy to tap that. Water, wind, and solar power sources are clean on the level they don't produce emissions themselves but the processes constructing them sure as hell do.

                PV is clean in the same way electric cars are clean. Sure the eletric car doesn't produce emissions itself but it did take quite a bit of power to construct. There there is the fact that 55% of the nation's power comes from coal power plants, so for every kilowatt an eletric car uses you need to chalk up the fossil fuel emissions that generated that kilowatt. ULEV cars are cleaner overall than electric ones.

                Hydroelectric and geothermic power generation is typically the cleanest IIRC all things considered. They are both just redirecting energy being emitted naturally and require a minimum amount of dirty processing to construct. They also last much longer than PV or wind generators and produce most power.

                The only real way to clean up power usage is to make things more efficient and work with what you already have. PV cells require too much material alteration to be long term efficient. Lower power electronics, higher efficiency lighting, better industrial resource planning, solar heating, and efficient building design are all measures that can clean up power generation simply because less power is required. PVs can help lighten loads of the power grid by they are far from being a clean power source or an effective alternative to fossil fuels.
                • OK, maybe I'm being stupid here (in which case feel free to jump in and tell me ;) but PV's are redirecting the energy from the sun. They may take energy to produce but then over their lifetime they generate energy - so how can it be a zero sum process? Surely if they keep producing energy then sooner or later they will have repaid their energy debt and will then produce clean energy. Doesn't that kind of invalidate your point?
                  • No it doesn't because a PV cell has a limited lifetime with diminishing returns as it ages. A 30 year old PV cell is practically useless for generating power for your household, by the time its thatold you might as well just rig it to your Palm Pilot and it MIGHT be able to charge its batteries. They're only being at most 15% or so efficient so it takes them a long long time to pay for themselves ad by the time they do their effiency has already dropped signifigantly. Calling it a zero sum process is a bit pessimistic on my part but the net gain is not as high as some would like you to believe. If you consider semiconductor manufacturers and industrial chemical suppliers dumping toxic waste where no one will find it (anytime soon) clean then thats your perogotive. I call it being duped by clean energy activists into thinking there is a magical solution to generating electricity cleanly.

                • Not zero sum. (Score:3, Interesting)

                  by raygundan ( 16760 )
                  The idea that solar panels take more energy to manufacture than they produce in their lifetime is not true. It is NOT a zero-sum process. Assuming solar panels require about 40% of the energy they will produce in their lifetime to manufacture, you are getting a 150% return on energy investment.

                  Solar panels are certainly energy intensive and dirty to manufacture-- but they get a whole lot cleaner after your first generation:

                  1. make panel from energy from fossil fuel
                  2. put panel on roof
                  3. use energy from panel to make next panel

                  This, of course, doesn't remove the need for nasty semiconductor manufacturing chemicals, but there IS a net gain. The system isn't zero-sum because the sun is dumping a whole lot of energy into it. You DO get more out than you put in. 150% more, roughly.

                  Whether that's enough to make it worth it financially is a different question altogether.

    • What about: You learn how to save energy, therefore you don't need this much energy. Then you need less solar panels to gather enough energy to fill your lessened demand?

    • Re:Solar... Yeah right (Score:5, Informative)

      by Camel Pilot ( 78781 ) on Monday October 07, 2002 @05:32PM (#4406438) Homepage Journal
      Throwing about hyperbole does not help

      Doing a quick calculation and using the sq mileage for San Diego County of 4281 sq miles [ca.gov] and the nominal energy density of solar at that latitude of 3.1 KWh/m^s/day and a 1% conversion factor gives:

      3.1 KWh/m^2/day * .01 = .031 KWh/m2/day

      4281 Sq Miles * 2.58 x 10^6 Sq Meters/ Sq Miles = 11 x 10^9

      11 x 10^9 x .031 = 343 x 10^6 Kwh/day

      Or 343,000 Megawatts-Hours for a small California county.

      Not that I am proposing to cover an entire county with PV panels but if you are going to "tell it like it is" then do.

      BTW, can we bury the Nuclear afterproducts in your backyard?

      • Yeah right again (Score:1, Informative)

        by Anonymous Coward
        Finding the electricity attained from covering an entire county in panels is crazy, not like that's going to happen. Lets be even MORE realistic!:

        Monthly average residential consumption of electricity in the United States in 1999 was 866 kilowatt hours. (Source: US DOE)

        Now that thats out of the way, luckily you live in California and get 8 hrs of sunshine every day (optimistic!).

        So at .070 watts/sq inch * 8 hrs = .56 w*hrs/sq-in
        (source: http://howstuffworks.com)

        so 866,000 W*hrs/(.56 W*hrs/sq-in) = 1546428 sq-in ... that translates to a 100ft*100ft panel for each house.

        While even this may be feasible, thats much larger than most roofs where I life (and others I've seen).

        Plus! A 17ft * 17ft panel costs $16,000 (source: http://howstuffworks.com) so its hardly even financially feasible. (Even if you saved all your money for all your electric bills for 10 years.)

    • Re:Solar... Yeah right (Score:5, Informative)

      by bcboy ( 4794 ) on Monday October 07, 2002 @05:42PM (#4406501) Homepage
      > but at least I will tell it like it is

      Or at least how right-wing kooks want you to believe it is.

      You're overlooking two things. First, solar thermal. Most of our power demands are for thermal applications, which are cheap and easy to do with solar. Photovoltaics get all the press because they're "sexy", even though they don't collect much power.

      Second, demand. It's very, very easy to lower demand without changing lifestyle, because we currently waste enormous amounts of energy. California demonstrated that during the last manufactured energy crisis. Basically, if *any* effort is made to lower energy use, demand drops dramatically. In particular, it's easier, cheaper, and affects our lifestyle less to lower demand, rather than pouring more money into centralized power generation so we can turn around and waste it again.
    • Only problem is they would have to cover 1/2 of southern California to cover the power debt that this area has.

      That seems a little large, do you have numbers to support this claim? Those numbers didn't come from the Nuke companies, by any chance?

      Some solar groups claim that covering Southern California in solar panels would generate enough electricity to power all of the US.

      Not that I believe them, but I just want to point out another example where understanding is a three edged sword: Your side, their side and the truth.
    • A little common sense might be in order here.

      Solar cell producers have to pay for the power it takes to build the solar cell. They wouldn't sell me a solar panel for less than it cost them in power.

      Solar panels have 25 year warrantees. A 4 megawatt-hour system fits on my roof easily (24 panels) and generates $935 per year at current California energy prices.

      The cost is under $12,000 before the 50% rebate and the tax deductions. The payback period is 5 to 7 years.

      And there are no hidden costs of pollution, or armies to guarantee cheap oil.

      Check out http://www.akeena.net/Content/What_Size_System.htm [akeena.net] for a nice discussion of all this.

  • I just found a retraction on the web and wrote it up on my website. Check out the two articles right at the top about the Daily Evergreen plagarizing a joke page about a Filopino ship being named "the big ass spanish boat".

    Go ahead and mod me down, it's OK. But I just had to tell somebody.

  • Pictures are here... (Score:3, Informative)

    by Hyped01 ( 541957 ) on Monday October 07, 2002 @07:56PM (#4407277) Homepage
    PICTURES [doe.gov]

    - Rob

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