Solar Production Impact from Cleaning Your Panels

[kevin1]

I did some analysis a while back, looking at solar panel “degradation” over time. I tried looking at daily production over 6 years. Came up with about 2% degradation per year.

Solar Production Analysis over 6 years

I’m celebrating the start of the 7th year of solar production on my SolarCity solar system this year and decided to see if I could sort out some kind of predictive calculation that was a function of yearly periodicity, days in service (dirt and degradation), plus any other time factors (like day in year). Now, my solar install preceded Sense, so all this daily production data comes from web access to data coming from my inverter over the years. First I looked via linear regression, at all the …