Solar System Update

I got my FPL bill today.  It's for $31.66.  My September bill last year was $119.14.  It appears that I saved about $88 this month.  I had solar power during the day every day this month, and I did not have solar power last year.

This is somewhat unreliable, because bills on corresponding months from one year to the next are never the same anyway.  My bill last month, which included one week of solar power during the day, was $98.05.  The corresponding month last year, the bill was $134.68.  The July 18 bill this year was $107.40, and the July bill last year was $149.10.  This year's June bill was $122.36, and last year's was $131.81.  So I was already using less electric power monthly this year than last, and I don't know the reason.  I don't think I did anything different this year, although it looks like I must have.  One difference is a new central AC unit I got, which was in July last year.  It's possible that it resulted in a decrease in my electric power usage, if it was much more efficient.  I usually turn on my central AC in about May.  This past May, my bill was $85.20.  The May bill from last year was $111.72.  So, I saved myself about $26 without the solar panels.  My June savings was about $9.  The July savings was about $42.  It's hard to make sense of savings, except to say my current bill, in a very hot month, is really low compared to last year's bill for the same month.

So, the question is, about how much are these solar panels worth to me on an average monthly basis.  For the moment, I have one month to use as an example-- imperfect as that example is-- and the suggestion is that it could be around $88.  I said before that after I get my tax credit, the panels will have cost me about $13K.  If I saved an average of $88 every month, it would take me about 148 months to get back the money I spent for the panels.  That's almost 13 years.  The warranty for almost all of the components of the system is 10-12 years, with one component warranted for 25 years.  The expected degradation of performance is about 0.6% per year.  So, by the end of the 13 years it will take for me to get my money back, the panels will be about 8-9% less efficient.  It might, then, take me more like 14 years to get my money back, unless the panels stop working after the warranty period.

In the meantime, I get the intangible benefit of knowing I'm using less of the non-renewable sources of electric power.  That would please some people to know, and other people wouldn't care.  In my case, it pleases me to know it.

There are two other things worth mentioning about solar panels at my house.  One has to do with my car.  It's purely electric, and when I plug it in, it uses much more electricity than does everything else in the house.  On days I plug it in, which I do during the day, it uses all the solar power I make, and significantly more.  This usage lasts for about 4-5 hours, until the car's batteries are full, at which time it doesn't draw electric power any more.  If not for my car, my electric bill this month would be about $10.  It's a tricky business to know when to plug in the car.  If I plug it in during the day, I'm using (free) solar power as part of the electric source.  This is good.  But electric power I buy from FPL is more expensive during the day than it is at night, so the power I'm buying during the day, which is only part of what I need to replenish the batteries, costs more per kWh than electric power I would buy from FPL at night, of which I would need to buy more, because I don't get the solar boost at night.  I haven't figured out how to calculate which is a better deal.  I'm working on it.

The second feature of solar power is that if the power goes out during the day, I still have power, at least for about 7-8 hours.  And it's enough to run everything in the house, except powering the car.  I can run the AC, the refrigerator, lights, the computer, whatever I need to run in the kitchen, and do laundry.  But only during the day.  I have no power at all from late afternoon to about 10:00 AM when the power is out.

That's my solar system update.  I still say solar panels on Village buildings would be a great idea, if we weren't diverting so much money to the attorney.