First Year – Results

solar power generation by month 2018

It’s now been a full year since we installed solar at the house–time to look at the numbers and see how things went in terms of production and return on investment. While planning back in the summer and fall of 2017, we calculated our estimated production using the PV Watts calculator at the National Renewable Energy Lab. Turns out it was pretty accurate on the whole: 7,705 kWh for the  year, versus actual production of 7,250 kWh.

We used 2,418 kWh of that power ourselves, offsetting power we otherwise would’ve had to buy, and pushed 4,832 kWh onto the grid for other people to use. At the current rate of 15.59 cents per kWh, that saved us $1,139.26 in 2018, a return of 7% of our investment.  In short, the system performed very much as expected.

It was interesting to see the variability in power production month to month. May was the biggest month overall, but we had an usually dry and sunny May here. One surprise was that December ended up being a bigger month than November, January, and February, which is surprising given the short days and low sun angle. But we had a lot of sunny days in December, and the cold temperatures help the panels work efficiency.

Here’s to an even better year in 2019!

 

Six Months In: Results so Far

net metering

Last month marked the half year point since our solar system went online, so I thought I’d take a moment to share some numbers and report on how things have gone in general. All in all, we couldn’t be happier–the only significant issue is that our utility company, Central Maine Power, is going through a complete billing system meltdown. Let’s just say I’m glad I keep careful records of our power usage, because they sure don’t! Continue reading “Six Months In: Results so Far”

Monitoring & Maintenance

Solar System Monitoring Data

While it was tempting to kick back and relax after the solar system was up and running, I knew it’s important to keep an eye on things and fine tune the charge controller and inverter settings for optimal performance and reliability (OK, I’ll admit I patted myself on the back the first night and cracked a celebratory brew). That’s especially true when you’re dealing with a battery bank, which is easy to damage if you’re not paying attention (particularly flooded lead acid). Continue reading “Monitoring & Maintenance”