03 August 2011

So. (Lar.)

So...it's been six weeks since we started thinking about installing solar panels. And it's been quite a roller coaster.

We called a total of five solar companies (out of about twenty that are approved installers for the city's rebate program). The current rebate, which is $3.00/watt instead of the usual $2.50/watt, has created a solar frenzy, so follow-through by many of the companies has been sorely lacking. Of the five companies, one has recently stopped doing residential work (can't fault them for that), one didn't return my call (twice), one responded to my initial e-mail but then never got in touch to make an appointment for a quote, and one came out for a preliminary visit but (after stringing us along for a couple of weeks) finally said that they were too busy for our job. Only one -- a company that is involved in a variety of green building technologies, and with whom we've worked previously -- managed to make an appointment, keep the appointment, and follow through on putting together a quote.

Here's their guy up on our roof, taking sun/shade measurements:

His measurements, based on the angle of the house to the sun and the slope of the roof, are important because the layout of the panels has to satisfy the city's requirements of unimpeded sun from 9 a.m. to 3 p.m. or 10 a.m. to 4 p.m. every day of the year -- which is mostly only an issue in the winter, when the sun stays lower in the sky and nearby trees are more likely to shade the roof during these critical hours. (If you're wondering, as I did, the city doesn't give "credit" for the sun shining through the bare branches of deciduous trees during the winter. I think the way the panels collect the sun's energy doesn't really allow for partial collection when parts of the panel are blocked by branches.)

So, taking the information collected up on the roof, along with the electric usage data we provided from our first 11 months in the house (and extrapolating the 12th month), they calculated that 25 235-watt panels would pretty much meet our needs. That's 5,875 watts of D.C. (direct current) output, but 4% is lost in the process of converting it to alternating current, so it would boil down to about 5.6 kilowatts (which is what the rebate would be based on). The system wouldn't have a battery (that would be really expensive), but since it would be tied into the city's system ("the grid"), the electric company acts as a battery of sorts. When we generate more than we need -- say in the middle of a sunny spring day -- the excess would go back into the grid, and our meter would actually run backwards! Since solar customers are still billed monthly, though, there would be months when we get a bill for excess usage (most likely cold, cloudy winter months) and other months when we get money back -- but only at wholesale rates, which are a fraction of the retail rate at which excess use is charged. If we could settle up on an annual basis, we would be able to minimize this discrepancy, but alas, the city calls the shots....

So we had one quote and wanted to get one or two more...and that's when things got really difficult with the other companies that had appallingly poor service (all I ask is a simple "I'm sorry, we're not going to be able to accommodate you" up front so no one wastes their time). Between that and some questions that came up regarding the best way to attach the panels to our particular type of metal roof -- and the nagging feeling that something new was going to come out as soon as we had bought a system (iPod syndrome) -- it was looking like maybe it just wasn't the time for us to embrace solar power.

All of this was taking place against a backdrop of record high temperatures -- and our twelfth utility bill, received midway through this frustrating process, was 20-25% higher than any other month (the first time our electric usage has reached anywhere near $100). And the fact that the enhanced rebate has caused a bit of a run on the fund was ever-present on our minds, so even though I wasn't sure we were going to do it, I asked the one company that had proven its ability to follow through if they would be willing to file the rebate application for us before we had signed a contract. And they were, so we were able to lock in the rebate at the current, higher rate while we continued to consider the pros and cons.

It's been a tougher decision than we expected. Doesn't this roof just cry out for solar panels?!

Panel me, it says. Use my uninterrupted, sunnier-than-sunny expanses to harness the energy of the sun and use it to power the ice cream maker!


  1. Yes, your roof demands solar panels! Interesting (and disappointing) about the sun through the branches. I think that just about kills solar at our house...

    Note that, according to what I read somewhere (i.e., verify it if you so choose), that the city is obligated to buy excess power generation but only at a quarter of the consumer rate. And when you need that power in the evening? You pay full rate. Or so I am told... Even given that, solar is cool!

  2. You're right that the city sells at retail rates but buys at wholesale...but since it's only tracked monthly (based on meter readings on our appointed day each month), we would only have to pay for the excess of whatever we used during a given month over whatever we generated during that month. It's just that, if we were to use 100 kW more than we generated in February but then generated 100 kW more than we used in March, we wouldn't come out even (in dollars) because we would pay for the February usage at retail and would only be reimbursed for the March excess at wholesale.

  3. Solar, Solar, Solar...

    But actually I get the idea about the iPod syndrome...

    You'd still end up ahead of someone who had to pay retail for all of their power all of the time. :)

  4. Thanks for that clarification: That's better than I thought!

    I bet you also get some benefit from partially shading your roof as well.

  5. Oops -- in my example above, I meant kWh, not kW. All this thinking about solar panels is interfering with my unit-recognition skills....