Just a few months after installing our first set of solar panels, we’re already working on our second!
A bit of review: Our first array was installed back in September and went live October 4th. It’s a 6 kW array, made up of 24 itek 250-watt panels, each with an Enphase m215 microinverter. So far we have been very happy with it; every month has performed better than expected, and we are currently at 115% of our estimated to-date production. The only problem is, it makes us want more!
Originally we had no immediate plans for expansion. Our plan was to use the 30% federal tax credit from our solar install to pay down some on the loan we got for it, and some day think about expanding. However, someone planted the idea in my head that we should use that tax credit to buy more solar panels!
I wasn’t going to do it if it didn’t make financial sense, however. So I ran the numbers, and it turned out that it really did make financial sense. If we spent $10,000 and installed it ourselves, we could add another 12 panels to our system to make it 9 kW. This would make us more money in the long run than paying down the loan or a couple other options I considered. As I was working through the plan with a fellow solar owner, Keith Kemp, at some point I calculated this would pay for itself in just 4 years. I mentioned it to Keith, and he suggested an even more interesting idea.
Instead of just 12 more panels, we could get 24 more panels, and pay for it not just with the tax credit, but also with a loan from Keith. He was generous enough to offer that we would only have to make loan payments when we got the incentive payments for this additional solar array. We could double the size of our array, and not have to pay a single dollar of our own money for it: it would still pay for itself (with state money) in 4 years, including paying off the new loan! And Keith would get some interest out of it too. As you can see in the graph on the left, this would dramatically improve the return on our investment.
As itek has improved their panels in the few months since we did our first install, we’ll be getting 255-watt panels instead of 250-watt panels (which were originally supposed to be 245-watt panels themselves!). We’ll also be using Enphase m250 microinverters instead of m215s. As a result, even though the second array will be the same physical size as the original array, it will produce 6.12 kW instead of 6 kW, bringing us up to a total of 12.12 kW.
Currently, we’re just about ready to start installing. We have all the materials we need for the ground mount, and everything else should come next week, probably. Hopefully there will be some weekends in the near future with decent weather so we can get it up!
Post edited 2/24/2014 to fix the cashflow graph, which was deceptive in its prior verson.