For the cost of a conventional power plant, how many homes could be outfitted with solar panels capable of supporting household needs?
That’s rather like asking, “How long is a piece of string?”, as the cost of building a power plant varying considerably with its nature.
As you can see from this link, the capital cost of solar PV is reckoned at about 6 to 7 times the capital cost per kW-hr of generic distributed power; looking at various specific types, we see that that cost range from 11 to 13 times the cost/kW-hr of a conventional gas turbine, to about twice of an advanced nuclear plant. Solar thermal runs about 65-70% of the capital cost of PV. Note that storage costs are not counted in the case of solar.
But that is for large industrial installations. Home PV solar installations would be much more expensive per Kw.
-
-
- Just for some math fun, I distinctly remember seeing some solar cells in a surplus catalog a while back. They were one foot square, and delivered 12 volts @ 20 milliamps in full sunlight, and cost $20 each. I remember that this was a pretty good price for solar panels at the time.
-
- My smallish 3-yr-old house has circuit breaker switches totalling about 275 amps (@ 120 volts, mostly). I doubt that is the sustainable capacity of a typical home wiring system though. Delivering one fourth of that amount continuously doesn’t sound outrageous (just expen$ive), so I will assume the solar panels have to be able to deliver ~70 amps @120 volts, 'round the clock.
- Quickly and carelessly, it would require about 1000 square feet to produce 120 volts @ 10 amps. Really it only takes 500 square feet, but if you want power at night, you have to be able to run your stuff in the daytime while also charging up a storage system to run off at night. (the cost of the storage system is not included at all here)
- My smallish house is about 1500 square feet floor/roof area. The whole yard is only about 6000 square feet, and the whole property would probably go for $75,000 as it is. To deliver 70 amps round the clock, I’d need about 7000 square feet of solar panels, at a cost of about $140,000. ~~~ Of course, careful home design and more energy-efficient appliances would help the problem here, but they’re not going to solve it. My typical monthly power bill is about $140. At current electricity prices, the house is going to rot and fall over before the solar panels would start paying for themselves. - MC
A valid criticism. But, jsochock seemed to be asking, “What if the money used to build a conventional power plant were instead used to install PV panels as a lummp sum?” (I may be wrong in interpreting the question). Thus, I would expect economies of scale to make the task cheaper than going to Rat Shack and buying 1 m[sup]2[/sup] of PV panel.
(Actually, if I called up a PV panel manufacturer and said, “Gimme 500 MW of panels by next Friday”, I expect that the sales rep would have a stroke. But, that’s another story.)
Akatsukami, your criticism is not valid. I did not say every home owner goes to Radio Shack and buys his stuff and installs it. I am saying that one 10 MW PV solar plant in the desert would be way cheaper to build and maintain than 10,000 separate 1Kw in people’s homes, even if they were built as one big project.
-
-
- Also note that with either installation (individually or one single area) solar panels do not grow on trees. Production of solar panels is an energy-intensive endeavor in itself; one that produces industrial-grade pollution. Converting to solar energy would require vast increases in production, and would essentially only be exchanging one type of pollution for another and/or shifting the pollution somewhere else -hardly what could be called a solution. - MC
-
I have been looking into this a bit, being a CA resident its a bigger issue. There are a bunch of state programs giving zero interest loans and or grants for installing residential alternative energy sources and or upgrading to more efficent appliances. The PV place I looked at most of them claim 10-15 years to break even for any given PV array. PV panels have a 25 year warranty, 5 or so on most of the other components.
Also CA is a “net metering” state. If you have a PV array and you produce more than you need, the power co gets it but they “owe you” that much power without billing you. Make 5KwH excess during the day, you get it back for free at night. Battery packs are less of an issue for that unless you want them as blackout power. There are also some reasonably priced systems where you can sell power to your neighbors.
>> The PV place I looked at most of them claim 10-15 years to break even for any given PV array. PV panels have a 25 year warranty, 5 or so on most of the other components.
I would be interested in seeing some actual figures because, in my experience, these numbers are mostly fudged to the point of being meaningless. Some actual figures would be very interesting.
I love the solar threads they always seem to come with my utility bills so I have some numbers to put down while the paper work is at the top of the pile and I don’t have to dig for them.
My electric bill:
This month I used 386 kWh of electricity. I live in San Diego and this is our second summer of electric capacity problems. So I have done a pretty good job of reducing our electric consumption. Taking into account all the costs my electric bill before adjustments for meeting the conservation goals is $57.19 for a charge of $0.1482/kWh. Lets say I want to live off grid entirely. I need to generate 12.5 kWh of electricity per day. Given fixed panels i.e. no motors on the panels so they are always facing the sun you can get a good six hours of sun a day on average. In the morning and evening they don’t put out their full rated power because the sun does not shine on them directly. They only put full rated power when the sun is shining on then straight. In addition colleagues of mine at work have some solar power setups and they generally say that they get about 75% of the rated power in full sun.
Assuming 6 hours a day with 75% capacity I would need 2.78 KW of panels. My colleagues have said that panels can be had for around $10 a Watt which I note is way cheaper than the $80 a Watt that MC is talking about. So I have $27000 for the panels on my house. 39 1/3 years to pay off at my current rates.
About $10 a Watt http://www.tasmanenergy.com.au/solar_panels.htm
in England land of bright sun http://www.silverclouds.freeserve.co.uk/powergre.htm
Some cheaper ones http://www.marksnyderelectric.com/catalog/pv_Uni-Solar.html about $7.60 a Watt
So lets say $21,000 for the solar panels. This would take 30.6 years to pay off at my current electricity prices assuming that money now is worth the same as money in the future, a really bad assumption. I have not included the other electronics that you need to make this work. You have to have electronics for converting DC to AC. These are expensive around $3,000 depending on load. Now it takes 35 years to payoff.
These are just the main parts you need mounting fixtures ect. And someone to install it. If you have ever hired someone to do home improvement projects this is not a minor expense I just don’t have a good handle on them. There are a lot of regulations about how electric equipment is installed it must be up to code if you want to sell your house so this is not really a job for a handy home owner. In past solar threads I have some forward advocating a little sweat equity to bring the cost down but the premise of this question is can we install solar instead of building power plants. This is not ancient Egypt so we cannot draft to populace directly for these big public works projects. So we will hire some one to install the panels. I don’t have a good estimate for this but it is not small.
I have left out batteries because they really throw the numbers off. Batteries are really expensive and they don’t last a long time. They cost about $.12 a kWh to operate but when do they operate in the above scenario is something I don’t want to figure out.
I don’t think that a case can be made that it is more cost effective to install solar instead of building a power plant.
I went digging on this a bit and found that the payoff was calculated based on a 50% grant from a state program that they process for you. So your 30 years looks right on the money, so to speak. So I guess right now in CA it might be worth it because of the incentive programs we have. otherwise, look a little ugly.
One other item that might be worth looking at is the new charges for over baseline usage. A PV system would help prevent you from paying another 2-4 cents a KwH if you have a spike in your energy needs. I live in Fresno, it is not unknown for us historically(sp?) to have 14 days of 100+ degree weather. Weather like this will drive up your bill but a few weeks of lower usage with the PV arrays doing their thing could help lighten the bill considerably.
For the record I think PV is a neat idea and workable under many circumstances but not a perfect solution. I think it would be cool to have PV just as a metaphorical “kiss by backside” to PG&E. I checked I cant afford the startup, so I just pay my bill.