05 August 2011

Solar: The End of the Beginning

Apparently no one got my "So. Lar." title the other day. (I wanted to start of with a casual "So...," and that happens to be the first 40% of the word "solar," which was the subject of the -- oh, never mind.)

Anyway, my last post was about our journey to determine if we should go solar. Much like our experience over the last several weeks, the post was a bit of a cliffhanger. So now I'm back to share the dramatic conclusion to that story.

As I explained, calling five companies yielded one quote (and a lot of frustration).

The lone follower-througher proposed to put 25 235-watt panels on the backside of our roof -- 11 panels on the center part of the roof (over the kitchen/dining area) and 14 above the screened porch. I was skeptical. Our newly planted crape myrtle, which is perhaps 10 feet tall right now, is likely to get much, much bigger (Basham's Party Pink is one of the taller varieties), and I was concerned that someday we would have to choose between sacrificing solar output and extraordinary pruning efforts with the tree (which always yields funny-looking crape myrtles).

I asked if there was any possibility of a different configuration that would use more of the upper roof and wouldn't come down so far onto the porch roof (toward the crape myrtle). And there was. Rotating the panels 90 degrees (portrait instead of landscape orientation), plus reevaluating the effect of our neighbors' trees on each side of the roof, allowed for more efficient use of the roof space and got all of the panels up off the porch roof. Like this:

(We started out working with a different person from the company, who drew the first proposed layout in a less understandable way that doesn't lend itself to posting here. But trust me -- that big, square bright spot on the picture above? It was covered in panels.)

The new configuration alleviated my concerns that our site would, over the years, become less suitable for solar. (Plus, the other company that came out for a site visit -- before dropping the ball on delivering a quote -- suggested that our neighbors' old trees were more likely to get shorter, rather than taller, in the future, so I was more concerned about getting the panels out of the (future) shade of our crape myrtle.)

But during the course of the discussions regarding changing the layout of the panels, I started to wonder whether we could/should add more panels, too. I did some math and figured out that we were only two panels away from maxing out the city's rebate ($3.00/watt, or $18,000), and two more panels would also help to cover the higher usage that our increasingly-common weather extremes seem to be demanding.

So I asked about adding panels (with the understanding that doing so would require putting panels back over the porch -- but only five at the highest point, not 14 covering the entire porch roof). Here's how that configuration looks:

And since we still hadn't committed to anything (so I thought maybe I had some bargaining power), I asked if they would be able to do it for just the amount of the additional rebate that the city would pay if we got two more panels (which was about $1,100). The answer? No, but after the city's rebate and the federal tax credit, two more panels would cost us only $280.

Perhaps I should back up and delve into the numbers here. (I know I would have appreciated finding this kind of information on someone else's blog back when we were starting our research, so maybe someone else can benefit from it, too.) The original quote for the 25-panel (5.8 kW DC) system was about $31,000, which breaks down like this:

$16,900 rebate from the city
$14,100 from us at the time of installation
-$4,200 federal tax credit
$9,900 net cost to us

The net cost is still a lot, I know. But we saved way more than that by doing the landscaping ourselves, which we had originally planned to pay a landscaper to do for us (I'll share those numbers someday...and you'll want to be sitting down for it), so it doesn't seem so bad to redirect it to a true investment like solar energy.

Anyway, the total cost of the system (before rebates and credits) was just over $1,200 per panel, with the net cost to us about $400/panel. So to get two more panels for under $300 seemed like a no-brainer (even though they aren't likely to save us as much as the first 25).

And I guess it was about the time that we decided to hypothetically add two more panels (to our hypothetical solar system...since we still weren't sure whether we were going to do it at all) that we decided there wasn't really any good reason not to go for it.

Yes, folks, we're getting solar panels!

Interestingly, just hours after signing the contract, I heard that ERCOT (the Electric Reliability Council of Texas, the same group responsible for instituting rolling blackouts on the coldest day this past winter) had announced that the recent (ongoing) heat wave has sent electric usage skyrocketing to the point that we're on the verge of more rolling blackouts this summer. So building our own little power plant really couldn't come at a better time. (Well, last month would have been a better time, since that would have been one more month for which we wouldn't have to pay for electricity. Shame on us for dragging our feet.) But the weird/unfortunate thing about this? Even with solar panels, as long as we're tied into the grid (which we have to be to get the rebate, and which we would want to be anyway so we have power at night without needing a costly battery), rolling blackouts will affect us just like anyone else. Doesn't matter if we're generating enough power to keep the air conditioning on for our entire block; if our zone goes down, our house is cut off, too.

That reminds me of another weird/interesting thing about the city's solar panel rebate program -- we had to sign over our "cap and trade" credits to the city. In the future, they may be very valuable, but I don't know how or whether a couple of regular folks like us would be able to use them, and it seemed like a fair trade for $18,000 of city rebates (without which solar panels wouldn't have been an option for us at all).

Clear and sunny days ahead!


  1. Wow, those rebates are great! Congratulations!

  2. I'm interested in your solar experience! We just got our house this spring, and husband was doing research on at least doing enough solar panels to heat our hot water. It seemed like a good deal, but I'd be worried about light. We have a lot of trees in our back yard and two huge crepe myrtles in the front (although they're trying to die in this heat... but that's a different story all together).

  3. Lauren, are you guys thinking about a solar water heater? We considered one as we were building our house, but it seemed awfully expensive when we're just two people who surely don't use more than $10/month in energy to heat water (although I'm unfamiliar with whatever rebates the city may have for them, which may make the cost more reasonable). Growing up in Hawaii 25+ years ago, we had a simpler kind of solar water heater -- basically a black hose coiled on the roof, absorbing the heat of the sun. Bottom line: I'm definitely a fan of anything that can do some good with ALL THIS SUN.