Environmentally sustainable base load power

[Loren Pechtel]

Ultimately the maximum ROI a person will accept is a personal decision. I take a conservative view, and want a 2-3 year ROI. 4-5 years is too much IMO. YMMV.

Lets say it's 5 years. That's a 14.8% rate of return and tax free besides. Where else can you make 14.8% tax free on your money???

One additional factor - at the moment, as I said, a lot of people are going solar in my area. This is largely due to 'hard sell' tactics which I am loathe to encourage - door to door solar sales are a pestilence in this suburb right now. It also means that there are many 'fly by night' operators doing shoddy installs and/or using sub-standard parts. I would rather be a late adopter, after the most of the shonky dealers have moved on because the more gullible customers have all been sold half-baked systems, and the remaining potential customers are too discerning for their shady business model.

Yeah, I wouldn't deal with a shady seller.

 

[skepticalbip]

Is this closer to what you were looking for?



Solar power density is about 1.4 KW/square meter under full sun at the Earth's surface. Solar panel effeciency is about 15% so can produce about 210 watts/ square meter under those conditions. However on light cloudy days when shadows can be seen the power output is reduced to about half or 105 watts. More cloudy days will reduce the output even more.

Sure of that 1.4 kw/m^2??? I think that's the energy density in space, not on the ground.

I'm fairly sure. At least that is the figure I have always worked with.

http://hypertextbook.com/facts/1998/ManicaPiputbundit.shtml

Bibliographic Entry Result

Tipler, Paul A. College Physics. New York: Worth, 1987: 316. "The average energy flux at this distance on a surface perpendicular to the sun's rays is about 1353 W/m2 1.353 kW/m2

"The Sun." Encyclopedia Britannica. vol. 27. Chicago: Encyclopedia Britannica, 1998: 456. "… it's radiative output, called the solar constant, is 137 ergs/m2/sec, or 1.98 cal/cm2/min" 1.38 kW/m2

Cowen, R. Science News. 152 (27 September 1997): 197. "… the sun's output had climbed from 1367.0 to 1367.5 watts per square meter" 1.367–1.3675 kW/m2

Brooks, William O. and George R. Tracy. Modern Physical Science.New York: Holt, 1957: 566. "We get energy from the sun at the rate of five million horsepower per square mile." 1.44 kW/m2

Rosner, Robert. MacMillan Encyclopedia of Physics.vol. 4. New York: Simon & Schuster, 1996: 1545. "The most obvious solar effect on the earth is radiation, roughly 1.4 kW/m2 (the so called solar constant)" 1.4 kW/m2
......................
The sun is the source of heat and energy for the earth. The solar output on the earth is called the power density. The power density of the sun's radiation on the surface of the earth is approximately 1.4 kW/m2. This value varies slightly throughout the year but by no more than 0.1 percent. One reason for this variation is the changing earth-sun distance. This distance varies by about six percent throughout the year,

And if there's enough light to cast shadows the clouds are pretty thin.

Exactly. Thin high cirrus clouds effect the solar energy density at the surface. So does dust and bird shit on the solar panels. Heavy overcast will significantly reduce the panel's power output to the point that they aren't useful unless you only want a trickle of power.

 

[bilby]

Lets say it's 5 years. That's a 14.8% rate of return and tax free besides. Where else can you make 14.8% tax free on your money???

One additional factor - at the moment, as I said, a lot of people are going solar in my area. This is largely due to 'hard sell' tactics which I am loathe to encourage - door to door solar sales are a pestilence in this suburb right now. It also means that there are many 'fly by night' operators doing shoddy installs and/or using sub-standard parts. I would rather be a late adopter, after the most of the shonky dealers have moved on because the more gullible customers have all been sold half-baked systems, and the remaining potential customers are too discerning for their shady business model.

Yeah, I wouldn't deal with a shady seller.

Huh? If the ROI is five years, then at five years, you are even - every cent you borrowed and every cent in interest has been paid back to you, and you have no more (and no less) money than you would have if you had not bought the system in the first place.

So that is a zero percent rate of return at five years; where do you get 14.8% from?

How can a percentage even make sense absent a time period? Are you assuming 14.8% per annum on an assumed life of infinity? If you can find a solar panel and inverter with infinite life, please let me know where to buy it. And if you know how to live for an infinite amount of time to enjoy their use, I would be keen to hear that too.

The lifetime return from buying a system depends on how long the various components can be expected to last (and on the cost of maintenance and repairs during that time).

 

[Loren Pechtel]

Lets say it's 5 years. That's a 14.8% rate of return and tax free besides. Where else can you make 14.8% tax free on your money???



Yeah, I wouldn't deal with a shady seller.

Huh? If the ROI is five years, then at five years, you are even - every cent you borrowed and every cent in interest has been paid back to you, and you have no more (and no less) money than you would have if you had not bought the system in the first place.

So that is a zero percent rate of return at five years; where do you get 14.8% from?

How can a percentage even make sense absent a time period? Are you assuming 14.8% per annum on an assumed life of infinity? If you can find a solar panel and inverter with infinite life, please let me know where to buy it. And if you know how to live for an infinite amount of time to enjoy their use, I would be keen to hear that too.

The lifetime return from buying a system depends on how long the various components can be expected to last (and on the cost of maintenance and repairs during that time).

True, it's 0% for the first 5 years, 14.8% thereafter until the panels wear out--but that's a lot more than 5 years.