In late June or early July of 2015, the grid-connected solar at our house was switched on by Xcel Energy (I’ve lost the precise date). By July 19th of 2016, I had twelve months worth of electrical bills during which the panels had been producing for the entire month. Here are some thoughts and data.
- Our install included APsystems microinverters that malfunctioned on systems installed throughout the state. That meant the during the “sunny” months, the panels were limited to producing about half of their potential. The inverters were reprogrammed in May of 2016. In total, the system produced about 77% of what it was expected to over the course of the year.
- Even with that hiccup, the system produced 3,367 kWh, or 17% more than our house used over the 12 month period.
- We used 14% less electricity during the year than the previous year. I think some, but not all can be explained by the real-time metering that came with the system. I’ve spent far too many minutes (hours?) looking at the dynamic egauge chart, thinking about reducing peaks and total usage. (The winter of 2016 was warmer than 2015, but the summer was about equally hotter, so I’m calling weather factors a wash)
- I need seasonal energy storage. July production was 6.5 times January production. I’m curious to see if next January is any better now that the inverters are fixed. We use electric heat in a small attic space, which means our electric usage in winter is probably above normal.
- Our neighbors used more of our solar energy than our house did. Xcel has two meters on our home now, so over time they can track what is being provided to our plugs from our system, what is being provided by their grid, and how much energy is being exported. Over 12 months, our solar array delivered 25% of the kWhs our house used, and the grid delivered 75%. To put it another way, other grid users got 75% of the kWhs our solar array produced, while we only got 25%. This is primarily a function of when our house uses the most electricity (morning and nighttime) compared with when the array is producing (midday). The effect is most pronounced in the winter when it is dark both when we leave and when we return home.
- Our system produces when energy is most expensive for the grid operator.
- Including the payments we made to finance the system, we paid about 13% less in total for electricity in this 12 month period than the period prior.
- Putting solar on your roof is a great way to start conversations with your neighbors! People are curious, and love to ask how it is working, how much it cost, and who installed it.
- After the sun comes out, snow slides off in a couple of days.