Greg, you got it. We have above average daylight in the summer but below average in the winter. I installed several arrays at some of our remote sites up here with great success but we use the sites only in the summer. In SE Alaska where I live, it is a rain forest so it's cloudy a lot here. In the peak summer time, you can expect only 4 isolation hours a day to less the 2 in the dead of winter. Interior Alaska fairs better in the summer but much worse in the winter. We also lose some energy to the atmosphere because its "thicker" and defuses more solar energy.
I did a cost analysis for a camp 3 miles from the end of the utility line. The cost of transporting fuel and running their generators did not offset the cost of building solar arrays for their camp. The money would have been better spent on extending the power line to their camp. Most of SE Alaska is on hydro power so solar is not cost effective.
I do disagree with panel efficiency goes down in colder conditions they actually put out more power when they are colder then they are when they are hot. In fact, there are additional precautions taken when putting panels in a cold environment. Again, the atmosphere is thicker and less daylight in the winter will give you less total daily output.
An adjustable solar array in a snowy environment tends not to collect snow because they are aimed at a steep angle in the winter to improve solar collection when the sun is lower over the horizon. Where I'm at, it is advantageous to put the panels at 72 degree angle in the winter for better collection. That is almost vertical. An arrays efficiency goes down when the array is not perpendicular to the sun. Our arrays in the winter trickle charges the batteries so they won't freeze so we can use high capacity wet cell batteries.
Last edited by sparkyinak; 01/25/13 04:58 AM.
