But 27 years is a worthless payback for a personal system.
And I doubt that it's even feasible as a commercial investment.
Arizona Public Service has a solar-powered plant (on-line right now), but it's servo'd mirrors and boiler tubes. Relatively cheap to build and quick payback. (They _are_ also experimentally with semiconductors, but it's a flop.)
APS also has a nuke plant (Palo Verde)... IIRC, the largest in the US.
The only people who believe in efficient semiconductor power generation are leftist weenies and Algor worshippers ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: "skypeanalog" | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
But you do agree that now at last we do have a payback. This is unlike the past where PV solar power was always a net money sink.
I think it is crossing the line about now. The cost per Watt is still falling.
Yes. If you want even faster payback, do as many have suggested and make a solor hot water heater. They are very low cost and pay back quickly but don't cover much of the total eneergy bill.
... and those who will bring it to market, finally, and get wealthy from it. We know that since you have dismissed the idea, you won't be among them. I still would be willing to bet that the semiconductor in question will be plastic and not silicon.
Already have that. The one on the swimming pool saves me a lot of dollars.
Perhaps ;-)
That's quite possible, but it'll take a fundamental breakthrough... silicon is too costly and not very efficient.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: "skypeanalog" | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
Okay, that's $7 per watt self-installed, $9 per watt professionally installed, for panels, wiring, and inverters.
They specify oversizing the panels by 15% over actual usage, effectively increasing the cost by that same factor, or $9 x 1.15 = $10.35 / watt, professionally installed.
Battery-based systems are 20-30% more.
No, not quite--you've missed the cost-of-capital. If you spend $20k up front you have to count the cost of lost interest on that money over the next 27 years (or interest paid on any amounts borrowed to finance the system).
The upshot is that photovoltaics don't yet produce enough power to pay their cost-of capital. The payback with your calculation amounts to about 3.7% / year. You'd pay more than that in annual interest if you financed the purchase, losing money every single year. Even excluding maintenance, payback is ... never. So far.
Because the utility sells power for 3x their cost, alternative energy makes financial sense for the end-user at 3x the price where it would make sense for a utility.
As it turns out, I can toss in some numbers for amount of solar power being retained by increase of greenhouse effect. Of course, these are first order calculations and oversimplified.
The "solar constant" is about 1366 watts per square meter. The earth's mean radius is about 6,371 km. So that works out to about 1.742E17 watts, about half of which is absorbed, meaning 8.71E16 watts absorbed.
The "sample calculation" in the American Free Thinker article is for a 5 degree C rise. The 1930-1980 average surface temp. of the Earth was 15 degrees C, 288 degrees K.
If a blackbody surface is at 288 degrees K but receiving enough radiation to maintain a temperature of 293 degrees K, then outgoing radiation is .93347 times incoming radiation. This is an oversimplification since we are talking about an increase in greenhouse effect, and greenhouse effect muddies up blackbody radiation calculations.
But if one uses that .93357 figure, this means that heat is being gained at a rate of 6.653% of the rate of incoming radiation being absorbed if the earth's atmosphere and surface changes to accomplish a radiation imbalance that will warm the earth up by 5 degrees C.
This is 5.79E15 watts.
Another, higher figure can be worked from assuming the surface is a blackbody, which it is not far from at "room temperature thermal infrared" wavelengths, and figuring how much radiation it needs to get from sun, plus reflection-back from clouds and re-radiation towards surface of radiation from surface absorbed by the atmosphere.
288 K blackbody is radiating 390.05 watts per square meter. 293 K blackbody in equilibrium is receiving 417.85 watts per square meter. The difference is 18.8 watts per square meter. That times 4, pi and square of earth's radius is 9.59E15 watts. This would be multiplied by the actual emissivity of earth's surface for thermal radiation at the temperatures involved. My non-contact thermometer is hard-coded to use .95 as a "one size fits all" for nonmetallic materials.
The American Free Thinker article claims 2.5E22 joules to warm up the atmosphere by 5 degrees C and 7.4E24 joules to melt sufficient ice to raise sea level 6 meters.
Using the lower 5.79E15 watt radiation imbalance figure, this works out to about 50 days to warm the atmosphere by 5 degrees C, and about 40.5 years if all of that power goes into melting icecap ice to raise sea level by 6 meters. Of course, it will take quite a bit of time to achieve surface and atmopsphere conditions that would achieve radiation balance at
5 degrees C warmer than the 1930-1980 average, and also a lot of the energy that the earth will gain during such warming will go into warming up the oceans which will take time.
Solar-thermal plants (steam =3D> turbine =3D> electricity) make the most economic sense. Yes, they take a lot of land (Arizona desert?), but what else would we do with that land anyway?
True, Solar-thermal won't work everywere to the same degree of efficiency, and even in the US, would require a new distribution grid
- but at large scale, this has to be some of the most competitive energy around (in terms of $$$).
I think we should start building these as rapidly as possible!
I even understand they can store daytime-generated steam (or hot water) to keep the system going for many hours after sunset. It is not a panacea, but it's likely a very worthwhile bridge to the future of domestic energy policy (US).
Lots of houses around here have pv panels on the roof, despite our latitude and the fact that we're fogged in about half the time; at this instant, I can barely see the roofs on the street below.
But I'm thinking, how many homeowners will die climbing up there to wash the dirt off their panels? And how many roofs will leak from all those brackets and stuff? How many panels and roofs will be damaged by wind [1] and rust and rain? And how much will it cost to replace the roof, with all those panels attached to it? How long do the inverters and batteries last?
Too many fuzzy thinkers believe that "doing something" is good, when the thing they are doing has a negative improvement factor on the problem they're trying to solve.
John
[1] We've lost two fences to wind so far. Earlier this year, the wind took out a fence - snapped off the 4x4 posts - and sucked a skylight off the roof.
If Solar ever does become feasible, they should be built over highways, and serve a dual purpose of generating power, and providing shade to reduce the cooling costs for vehicles.
--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
You can just about triple the peak power output with a relatively simple geometric configuration of cheap flat mirrors \\_/. And do even better with suitably curved ones.
27 years is still a useless payback time. With a passive concentrator you could get it down to 9 years but even that still isn't worthwhile unless you are very green. Needs to be Don Langcaster's number is an aveage. If you live in a place with
Only a viable payback in countries like Germany where the state subsidises people to generate their own photovoltaic power.
Solar makes good sense at US latitudes for water heating. Japanese houses had that technology widely adopted in the 1990's.
As a service for the terminally stupid - I meant to type "carbon dioxide", as is obvious from the context, but made an error of omission (a typo) which I didn't notice when I re-read the post before sending it.
If Michael had two neurones to rub together, he'd know about carbon transistors - built with bucky-tubes - which are all the rage amongst university researchers at the moment. Apparently someone from GE published a paper in Applied Physics Letters back on August 15, 2005 which also mentioned carbon diodes. Google does find a lot more references to "carbon diode" where the authors clearly intended to type "carbon dioxide".
Neat idea, but for the type of system I'm talking about (long steam pipes located at the focal point of a long string of parabolic mirrors), I would think maintenance and reflector washing alone would cause too many traffic tie-ups. Even if on the median/shoulder, you know Florida drivers (or the imported snowbirds) would still crash into them!
I also once though for solar hot water heaters, that it might be preferred to have these in the driveway (strong enough to support vehicle weight, when needed). You could paint the "driveway" black and really generate some heat.
The obvious Florida advantage is you don't attach a wind collector to your home's roof!! (i.e. hurricane force wind destruction)
"Favour" is NOT the same word as "favor". The correct terminology you wanted was "in favor". At least when speaking American. Just because the English abuse American speech doesn't make it right.
We have so much of that we have to describe it as _middles_ of nowhere ;-)
Wintersburg, AZ, is so much in the middle of nowhere that some Iranian "tourists" taking pictures of the nuke plant were immediately surrounded by more cops than I knew existed in Arizona ;-)
Some other "tourists" were caught taking photos of Phoenix' water treatment facilities... which scared the pajeebers out of my daughter Jennifer who runs the facilities. Most of her reservoirs are now covered to prevent some miscreant from tossing something in.
Isn't steam "storage" already done in NYC?
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: "skypeanalog" | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
See the "Saguaro Solar Trough" paragraph, and click on it.
Efficiency has nothing to do with it. ROI is all that matters.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: "skypeanalog" | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
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