The Nitty Gritty
- 4.2 kW grid-tied array of 20 Sanyo 210W PV Modules (2 strings of 10 modules); mounted with a 32 degree pitch, 180 degree orientation (south)
- Sunny Boy 4000US inverter located in our basement laundry room. Note: the inverter makes a high pitched humming sound when it is on, so if you are sensitive to these frequencies (most women are) be sure to locate it away from living space.
- Total cost of this system, purchased through the Solarize Portland group-buying project: $28,560 (I estimate this system would have cost us $37,800 without the Solarize Portland group discount.) Energy Trust Incentive payment: $9,450. This payment came from ETO to the contractor before I even got the bill, so the check I wrote to the contractor was $19,610. That is still a heck of a lot of money. But, after all of the tax credits are taken this system will have only cost us $6,700. That’s a little better.
- We estimate the system will have paid for itself at around the 10 year mark (2019). In the meantime, we’ve factored it all out and our solar panels are generating power for us at a cost of 6 cents/kWhr (prepaid). Given that rates are already above 10 cents/kWhr with PGE and rising, we feel we’ve locked in a nice power production rate. As PGE rates continue to rise, our payback time frame will shorten.
- Our contractor was Imagine Energy, and I can’t say enough good things about them.
Earliest Measurements
In February of 2009, our PGE bill reflects we consumed an average of 23kW hours of grid-power per day. In February of 2010 (after our panels were installed), our PGE bill reflects we consumed an average of 5kW hours of grid-power per day. It was indeed a sunny February this year, and we were thrilled to have a solar power plant on our roof to make use of all that unusual weather.
Unintended consequences
The female head of household (that’s me) is quite pleased to report that having a power plant on the roof has increased the entire household’s awareness about power consumption. All my failed strategies to get people to turn off the lights were, evidently, missing one component that measurable, in-house production provides. When you can see your production, it becomes a game to make your consumption match (or even fall below) that production number. Now we’re all thinking about ways we can lower our consumption, which means we’re REALLY thinking about (and even measuring) our consumption in ways we hadn’t before. Like, item by item. Activity by activity (note, this could become crazy making). And the fact that even the resident 5 year old is in on the race is thrilling to me.
How we came to our solar panel decision
The female head of house (me again) helped start the first Solarize Portland project with Tim O’Neal of SE Uplift and Lizzie Rubado of the Energy Trust of Oregon. “Find out if solar panels make sense for our home” had been an item on my to-do list for like 7 years. When the opportunity presented itself to start this program, I hesitated at all the work it would mean… finally sorting out all my questions about solar. But within a few minutes of having met with Tim and Lizzie, I learned there was a wealth of solar information in Portland that just needed to be pulled together in one spot for homeowners like myself. So, that’s what we did. And, we made some of the key big decisions that ALWAYS trip me up in any home related project = like, who to hire. Once the project sorted out all of the details that normally SLOW me down so much I stall out, it was clear solar PV was practical and within reach.
Which left one big decision we had to make for ourselves = how big of a system do we buy? In the end, I have to give the credit to the male head of household (credit? blame?) for the size system we purchased. He made a number of arguments in favor of the 4kW system (I was initially more comfortable with the cost of the 3kW system). I liked the “give the boot to Enron” argument a lot = you’re going to spend this money on electricity anyway, why not divert the money from a company the likes of Enron and channel it into your own system. I also liked the “reduce volatility argument” he made one morning over breakfast. Obviously, the energy market is volatile and prices are generally only expected to tick upwards, but at what rate no one knows really. With a 4kW panel investment we’d be locking in a 30 year electricity production cost of $.06 per kWh from our solar panels… that is already lower than the price we pay per kWh to PGE. So, I’m sort of pre-paying for $6700 worth of energy and getting a discount for doing so… I think. But here is the volatility argument only I could love (and I REALLY love it). We’ve owned a few stocks and I’ve disliked 95% of them. The very arrival of a stock statement represents volatility, for my moods, as the principal of what we’ve invested evaporates. But I can divest myself of “stock” investments (reducing volatility in my moods as statement time arrives) AND channel that money into my own little power company right on my roof. It’ll even pay dividends. Fewer stock headaches + dividends + boot Enron = we bought a 4kW system for our house.
