I just recently got my annual true-up bill for the net metering for the year and I owe $237.80 for the entire year. I have had a set of solar panels on my house now for a full nine years. For 6 1/2 years, I have been powering Teslas with the panels. The diagram to the right shows a summary of the annual electricity charge or credit.
Last year my bill was $80 less, but in 2014, I traveled across country in the Tesla for an extended period of time.
Panel Cleanliness Test
I have paid to have my solar panels cleaned in the past. The roof is very high and quite a challenge to get to the panels. I’m not particularly fond of the challenging maneuver from the ladder to the roof, so I’d rather pay a professional a modest fee when needed. He uses a soft brush and de-ionized water. But I can quickly monitor the cleanliness of the panels on line before making an appointment.
The amount of energy I generated in early October is the same as in 2014. In the graph below I just do a quick comparison of the amount of energy generated during an interval on a sunny day during the same time of the year when there is little to no use of electricity. The panels may be a little bit dirty due to the extreme drought, but some El Niño rains should soon wash away any dirt.
Free Energy in 2017 Onwards
I have only two more years to recoup the initial investment. This calculation is extremely difficult as the electricity rates are very complex and constantly changing. I’m assuming unless things change drastically my energy will be free in late 2017. The panels themselves have a 25 year warranty but the inverter is out of warranty. I may incur a cost at some point due to equipment failure.
Just recently, PG&E has managed to increase our minimum charges from just under $5 to a little over $10. This monthly charge is our cost to be hooked up to the grid. The only alternative would be an off grid solution which would be really challenging here as the solar production is so much lower in the winter due to the sun angle. And the electricity use is relatively flat because the climate is so pleasant and the house well built and insulated, the air conditioner is only on a few days per year. I have no use for a Powerwall.
Only two more years to drive and live on sunshine for free, or $10 a month.