1) That capital investment doesn’t go away — our PV system will still be on our house, and operating pretty well despite some very gradual diminishment of output, after my currently 58-yr-old bod is in the ground; yes, the warranty on our (used) Solarexes only runs for 20 years and they’ve already got 6 years of use, but after 14 years, the little Solarex PV panel I bought after traveling with Greenpeace’ 1994 Cyrus (16-wheeler outfitted with a 140 sq. ft. solar array) tour is still putting out almost exactly the same amount of power it did the first day I set it up on the CA hillside where we then lived, to run my old laptop. — In the meantime, should we sell our place, we’ll get all that capital back (and maybe a bit more).

And here in MN, anyway, I _cannot be taxed_ on the appreciation in my home’s value that comes with installing a solar system.

So: since depreciation isn’t going to be a real-world factor during my lifetime (and I’m not a utility CEO charged with making money any way the law will possibly allow it), truly, now, other than greed, what reason would I have for expecting the capital investment to be paid back? — Any money we make from net production above and beyond our consumption under net metering is gravy (this will happen when we expand the system, as planned; we bought an oversized inverter and can add more panels to the array)… that will be added to the offset, on our utility bill, that comes from currently producing about as much power as we use (97% over the first year of the system). And while the income from excess production will presumably be taxable, as far as I can make out, the offset money isn’t.

2) Along the lines of your plasma TV analogy: when I was 21, I bought a used Porsche. Gee, I sure don’t remember ever asking, “What’s the payback period?” The payback came when I got behind the wheel and drove, like a young fool, 80-90mph on MA Rte. 128 (as it was then known), Rtes. 93 and 89 up into ski country, and other inviting 4-lane surfaces (I got it up to 106 once, on Rte. 2… did the same later on with a BMW 2002, which was sweaty fun at the time, tho’ the Bimmer was never as much entertainment as that old 912 — totally different handling characteristics). Well, when I wake up here on a sunny morning, I get about as big a rush as I did driving those cars — with minimal associated risks, unless I race down the cellar stairs to check the inverter readout as I used to do before we got a remote monitor installed — and _that’s_ my payback. As far as I’m concerned, experientially, I’m driving a solar-powered sportshaus. I’m simply thrilled to finally have solar on my home.

So there.

Some additional notes on our system for those interested:

We are a two-person household and use an average of around 270 kWh/month. Summer usage is higher than the average, at over 10kWh/day when our little Energy Star bedroom A/C unit (or even a fan) is operating regularly, along with a necessary dehumidifier in the basement — and, of course, the (Energy Star… 9-year-old) refrigerator is working overtime as the weather warms up. (In this La Nina year, we haven’t had to put the A/C in the window yet, so our usage is down a bit.)

After the $2k federal investment tax credit (Congress gotta renew that puppy!!), our system net cost including the oversized inverter was about $18k. This does not include a few hundred dollars spent having the 96 years’ worth of snow-sag jacked out of our roof and new 2×4s sistered to the old rafters to hold it flat, nor the cost of new 50-year shingles — as it happened our south roof badly needed reshingling anyway, so we took that $2.5k as a preexisting liability, tho’ anyone mounting a solar array on a roof would presumably want a fairly new surface underneath it and for some that could qualify as an unscheduled expense.

We bought used panels, so we weren’t eligible for the MN state rebate, which applies only to new equipment; having purchased the panels at a discount, we think the cost came out a bit in our favor compared to buying new panels and getting the rebate. We don’t have a battery bank — the grid is very stable here and we saw no need for the extra expense (not to mention replacement costs every 5-10 years); we buy green power at night and when it’s cloudy (wind, from Xcel Energy’s Windsource program… at a premium of about $3.50 per block of 100kWh; that’s partially offset by not having to pay a fuel adjustment charge, which would run a bit under a dollar a month I think).

Our array is rated at 3kW — highest real-world output I’ve seen from the inverter is about 2.7kW — and is composed of 36 Solarex 83-watt panels covering roughly 400 sq. ft., roof-mounted at a 1/3 slope with no adjustability [a nearby friend has a 1.6kW array on a manually adjustable rack that he usually adjusts 4 times a year, very workable for an array of that size but labor-intensive for a larger one]. This 1/3 pitch turns out to be a very good average angle for MN’s insolation, tho’ the array does not shed snow quickly — so I help it along with a wide squeegee on a long pole. My installer laughs at me because he figures the snow would come off pretty quickly once the sun came out, and I’m probably only gaining 1-2kWh per snowstorm for all my efforts, but I’m in it for every kWh I can get (I also wash down the panels regularly from spring through fall; they do pick up city dust, esp. when it’s dry) and besides, I kind of like the exercise — which is a LOT easier than shoveling… In the dead of winter, there is some mild offset for the low production caused by the shallow angle, since the panels absolutely love cold weather, which reduces the resistance in the metal components of the panels and allows the energy to move more readily onto the wires to the inverter.