Going solar – some thoughts

Solar (Photovoltaics) is great! Don’t let any negative spin turn your head. They simply make electricity from the sunlight for free (once you’ve paid for them and have them installed). We had wanted solar for years but every time the possibility was floated, the system conceived and totaled we backed away. This is fairly common from what I’ve found.

Three years ago I really needed a good and reliable tractor. We had been through several mowers and had a 50 year old tractor that started infrequently. We decided to stop putting “X” dollars each year into repairing and invest in a new small tractor that could mow, till and lift. It was a great investment. Some friends were over and one said her husband had tractor envy. We all chuckled. Then I pointed to my 15 year old truck and asked, already knew the answer was a newer model truck, “What do you drive?”

Why am I talking about my tractor here? I guess it’s the same logic at work. We choose to keep driving a perfectly good albeit rough around the edges 12 (at the time) year old truck and instead buy a new tractor. We did the same last year to justify the solar. “What do you drive?”

After having been through this project I thought I pass along a few things that everyone should understand before starting. I’m absolutely NOT trying to scare anyone away from going Solar, or other, I think we all need to do more of this.


Hire a professional. Nothing else needs to be said. I have a good friend that did it all himself and did fine but I wanted a pro.

Federal Tax credit. 2015 is the last year (currently) for a 30% Federal Tax Credit for home Alternative Energy installations. 30% Tax credit is a big deal but be warned that if you are self employed, as I am, that Tax Credit is NOT valid… WTF? A good account can find other ways to make an Alternative Energy installation Tax friendly but not to 30%.

Efficiency. We designed a 3.6kW system with the anticipation of generating 3.6kWh’s every sunny hour. Well, it doesn’t work like that. Our average best case is 2.7kW and here is why;

  • The panels themselves are temperature sensitive. When it’s over 25ºC (77ºF) the efficiency goes down. Not by that much but if its 95º you could loose 10%.
  • The distance the panels are from the inverter and the distance the inverter from the loads is a factor. When I first read that large scale power plants in Southern Indiana, that generate electricity for Chicago, have to generate twice what is needed because of Line Loss over distance that’s when I decided I had to have my own Solar array. Our system required the panels to be 110 feet from the batteries, inverter and loads. I don’t know what that loss is but it is another efficiency loss.
  • Those of us living in the Northern Hemisphere know that Winter comes with cold weather and short days. Here on the WInter Solstice, December 21, we get 9:26 hours of light. To make it worse, we are in a valley and get even less direct sun. 83% (of total possible) actually. When it is cold the panels are more efficient but this January we were averaging 7.6kWh a day.
  • The March 20th and September 23rd Equinox are the days that the hours of sunlight is the same as the hours of darkness. 12/12. I’ll have March’s averages soon but as of today we have averaged 11.8 kWh per day in March. So the theory is once Summer Solstice (June 21st) comes we will be up to 14:56 hours of light and look out we’ll be cooking with Photons for hours! One catch. Along with those 14+ hour days come another phenomenon. The sun rises and set far more to the North so the panels, which face true South @30º, will not get direct sunlight for all those hours. By looking at the charts below the hours of direct sun on the panels in June will be less than January… Unless you have a tracking pole mount system. So I am very curious to see what this will do to the daily averages in June and July. Check back this summer.

March 23 (2015)


Credit: http://www.gaisma.com/en/location/bloomington-indiana.html

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