Curt Blank's

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Will Going Solar Pay Off?

In the long run, yes I think it will. First off the pay back period. At first I was predicting 10 to 12 years, that was before the system was in operation. Now that it is in operation, although it might be a little early to tell, it might be as soon as 8 years. The Kyocera PV Panels are guaranteed for 25 years so I really don't have to worry about them for a while.

I'm seeing good production on sunny days, and even good production on cloudy days which amazed me. So I happened to mention that to Tron Melzl over at Magnetek and he explained the good production on a cloudy day phenomena to me. I may not do this justice but I will try to explain it best I can.

It appears the particles in the clouds act like mirrors and direct sunlight that otherwise would not hit the PV Panels onto the PV Panels. This makes sense but then one would think that the clouds would direct sunlight away in an equal amount so the net gain would be zero. This would probably be true if the Sun were perfectly perpendicular to the PV Panels but during the Summer when I noticed this, the Sun was not perpendicular to the PV Panels. So, some of the sunlight that is redirected by the clouds is actually hitting the PV Panels at an angle of incidence closer to 90° then the direct sunlight is, thus the concentration (W/m2) is higher resulting in more power produced even though the actual Solar Radiation is low as compared to cloudless days.

The next stumbling block that comes up is that, sure you're getting good production in the Summer when the Sun is out for 15 hours a day, but wait until Winter when the days are short. That was my thinking too until the subject came up in separate conversations with Tron over at Magnetek, and Andrew at H&H. Both indicated to me, just wait until Winter, then you'll see some good power production. This seemed counterintuitive to me so I started asking why would this be??

Again, something I never thought of was explained to me. The higher the temperature, the lower the voltage produced by the PV Panels. The higher the temperature, the more resistance in the substrate of the PV Panels. OK, having a electrical/electronics background this was starting to make sense. So, bottom line, during the colder days of Winter the PV Panels will operate at a higher output voltage thus producing more power.

I've been doing more research lately and learned a few more things. In January the Earth is 3.3 million miles closer to the Sun. This then equates to a ~7% increase in the amount of the Sun's Energy that reaches the Earth. So even though the days are shorter and with the declination of the Earth's axis affecting the angle of incidence of the Suns rays on the PV Panels, this ~7% increase in energy may offset that a bit. So even though the days of Winter are shorter, the power produced may still be good. I'm looking forward to finding out!

(I'm working on calculating the Altitude Angle and Azimuth of the Sun by minute while the Inverter is running in order to determine the real amount of the Sun's energy that is striking the panels in W/m2. The Solar Radiation value that is currently being reported is that which hits the Earth on a horizontal plane and does not take into account the compass position and inclination angle that the PV Panels are mounted at. Click here to use my Sun Azimuth and Altitude Calculator.)

So, the answer is yes, I think this will work out nicely. Even if the pay back takes 12 years, after that it's free electricity. And that'll be right around the time I'll be thinking about retirement, perfect...

And lawyers and people that do investments have talked to me about investing the money instead of using it for this Solar Power System. It all sounds good, but running the numbers at worst it be a wash, at best no investment could match it. And couple that with the fact the the cost of electricity is always going to go up and up every year, any return on an investment would have to match that increase and I doubt any would.

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