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Students Show Off Super-Efficient Solar Homes
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.
They've clearly never been to Scotland then. If it's raining 'all' the time you genuinely do have less sunlight ;-)
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"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.
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
I have mod points and I am not afraid to use them
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.
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.
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.
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.
I'm a loner Dottie, a Rebel.
- Rob
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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.
I'm a loner Dottie, a Rebel.
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.
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.
I'm a loner Dottie, a Rebel.
Solar energy doesn't have to provide ALL your power...
What's this Submit thingy do?