I jumped the gun on cleaning my solar panels. Once a year is probably too frequent for me. I only see a minor improvement in the solar panel output. Before cleaning, the maximum output to PGE was -.71 KWh and after was -.77 KWh as shown in the below graphs. The panels did have a light layer of dust and dirt, but probably could have done fine for maybe another year?
The first chart is before the panels were cleaned and shows the car being charged at night after being driven the day before. The most net output to PG&E was around -.71 kWh.
Ten days later after the solar panels were cleaned and no one was home, the output went up to -.77KWh. I also expect in a ten day period to see a slight increase in output as the sun moves closer to the panels. I will have to pay attention to this data more, but the data extraction from PG&E is not ideal.
Notice the smaller night spike as the Tesla was recharged for a few minutes but had not been driven that day.
Now that PGE provides this information, I can monitor the same days next April to see if the panels need cleaning.