Thursday, January 27, 2011

One Year of Solar Panels

(Note: This post is a departure from the regularly-scheduled content of this blog.)

Today marks the one year mark of having our solar panels up and running, so I thought I'd post a quick update. (Technically, it's the one-year mark of having the monitor up and running, the solar panels were actually working for almost a week before that.)

After a full-year we've generated 6074 kWh of electricity and consumed 6371 kWh, so we've used 297 kWh more than we've produced. One of our two inverters broke last August so we were down one set of panels for about three weeks (you can see that reflected in the second graph below) until the new one came in and they could replace it. Based on how much we were generating in the months around that breakdown, my estimate is that if it hadn't broken it probably would've generated pretty close to that 297 kWh necessary for us to break even over the course of the year.

Once we got to April we pretty much stopped paying for electricity (it's still about $7 a month to be connected, though), except for August when we lost the inverter. With the shorter days we have currently we'll likely have some net kWh usage in January through March (so a small electric bill), and then go into positive territory for the rest of the year until December or so. Not too bad.


  1. That's great, thanks for the stats! One important question, though: how does it feel to be (on average-basis anyway) electricity self-sufficient?

  2. is there a difference between various kind of solar panels? what's the brand on yours?

  3. This is good. How much do the solar panels cost & what's involved in installing & using them?

  4. @Sami - It feels pretty good!

    @rrr - My panels were made by Canadian Solar. I think there are minor differences between panels and manufacturers, but most roof-top panels are of the same design. There are other types of panels being developed (thin film solar shingles, fore example), but I think my kind is still dominant.

    @Downes - The cost of the Solar Panels is complicated by all the incentives that are in place (federal tax rebate in the U.S., rebate from our utility company). The "Total System Price" for us was about $33,000 US, but the out of pocket was only $10,600 and after the tax rebate the following year, more like $3000.

    Installation was pretty straightforward. They first do a site design based on your orientation to the sun and develop a schematic of where they'll install them. They then mount rails on the roof to attach the panels to, attach the panels, and run electrical from the panels down to the inverters, which then connect to the grid. They also added in a net-meter than can run both ways and keeps track of the net total energy usage (or surplus).

    No real maintenance needs to be done unless something fails. After about 10 years some things need to be replaced, but otherwise it should last about 20 years. We did get a really muddy rain storm soon after they were installed, so I went up and hosed them off once (I was up there cleaning gutters anyway), but that's not necessary on a regular basis.

  5. Mr. Fisch,
    I find it interesting that your school would have produced as much electrical power as you used. It makes me wonder why, with the current cost of energy, more alternative forms of energy are not being used. Perhaps the start up costs are higher, but the rewards would pay off fast.