More Solar Capacity and an End to Net Metering

 I first installed solar panels on my new garage roof in 2009.  The six panels met the needs of my house by Net Energy Metering standards.  The NEM program credits you for any electricity you feed into the grid based on the rate you would pay if you drew energy from the grid at the same time. So, if I generated electricity during peak pricing hours, I would get a credit for that amount.  Then I would do laundry on the weekends during off-peak hours and get to use nearly two KWh for each KWh I generated.  This allowed me to bank excess power during the summer and draw against it during the winter.  My net electric bill for the year was under $50. 

In 2012, I bought the purple Mitsubishi i-MiEV and needed to generate more electricity to power the miles I would be driving.  I did some rough math and estimated four more panels would essentially cover most of my home EV charging needs.  The NEM program was still in effect, so again I was able to bank summer electricity for use in the winter.  My yearly cost for powering the house and charging the car with the new system remained under $100 and included nearly 10,000 miles worth of driving.

My original solar panels (in yellow) and my upgraded panels (in green)

In 2018, I bought the blue BMW i3 and passed the Mitsubishi onto my partner.  Between the two of us, we were driving nearly 20,000 miles a year.  In 2019, I replaced the main inverter on the original solar panels with microinverters, which improved their afternoon energy production by about 10%.  (I have a power/telephone pole next to my garage that casts a shadow across some of the panels.)  Still, I was running over my production by $600 to $800 a year.  So, I planned to add to the solar panels.  But my garage roof was now full, and I would have to put the panels on the main house roof.  But the house roof was installed in 1997 and had exceeded 25 years of age, so I would have to replace the roof before installing the new solar panels. 

Alas, I waited too long to get started on the roof replacement, so my NEM program was terminated when I upgraded my solar system.  Under the new solar program, I am credited the wholesale cost of any energy generation (not transmission), which is about 15% of what I pay for electricity.  I had eight new solar panels installed, each generating up to 410 watts.  (The original panels generate up to 230 watts.)  I also had to buy battery storage for the excess electricity I generate during the day to use after sunset.  The original recommendation was to install one house battery, with a new subpanel to dedicate some circuits for use when the power would go out.  Because I usually need to charge one of the cars at night, I realized one battery would not be enough.  By adding a second battery, I am able to meet most of my charging needs, and I was able to eliminate the electric subpanel, which paid for half of the second battery.  (Two batteries provide enough current to power the whole house – except for the A/C unit.)  I discovered the backup batteries were working one day when my next-door neighbor asked if my power was also out.  Power outages are much less stressful now.