It's the start of a new year and the time that I normally do a lookback at how well my rooftop solar system has done over the past year.
I installed the solar panels and inverter at the very end of 2017, so I now have 3 complete years of data.
Here are links to previous posts:
Home Solar System Performance - Year 1
Solar System Performance - 2 year review
Here is the annual comparison of the monthly energy generation data from the inverter vs my yield expectations. I probably should adjust my model a bit for summer and winter, but on average it's pretty close. I track my energy consumption data (utilization) on a separate spreadsheet that accounts for net energy to/from the grid. Unfortunately, my utility provider, Portland General Electric won't give me access to the Net Meter data, so I actually have to do a manual daily read of the meter.
My average annual utilization is 5.25 MWh which is below the 5.39 MWh average that the system generates. So, I have a small net contribution to the grid (the energy cost gets donated to low income customers).
I had hoped that I could average 5.46 MWh generated annually, but I was only able to achieve that this year. We had an exceptionally sunny September, but with the terrible wildfires in southern Oregon and northern California, we had lots of smoke and hazardous air quality for about 10 days which reduced solar production by about 20 kWh per day. Otherwise, we would have been well over the yield estimate....
My breakeven point for system cost is 25 MWh, so I'm still on track to reaching that within 5 years. I'll certainly celebrate when that time arrives 
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genebren
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