It’s now been 6 months since my rooftop solar panels were brought online and started producing power so I figured it was a good time for an update.  So far I haven’t had any problems with the system at all and am very satisfied.

Below are charts of weekly total kWh, blue is pure solar generation, green is power grid net draw/return, and yellow is how much the house actually uses (load):

All three overlaid for comparison:

You can see that mid-February net grid usage went way down, I think this was due partly to just more sun as we headed into the end of winter, but also because I disabled the Powerwall’s energy arbitrage stuff, that wasn’t benefiting me at all anyway, and went back to flat-rate billing (not time-of-day).

Below is a list of my PSEG bills for the past 6 months.  

Overall, not a lot to report, but it is nice to see these net-zero utility bills finally. My two tips for other people with solar are to opt out of time-of-day billing with your utility, and don’t do the Powerwall arbitrage feature.

When I first powered on the system, Empower did tell me I should disable time-of-day billing but I didn’t do it because I didn’t understand what they were saying, but they were right. Due to the way credits are bucketed, time of day billing is worse than useless for me, since it buckets my peak generation into a peak bucket and can’t be applied to off-peak usage at all (which is when I charge my car).

The Powerwall energy reselling feature dovetails with the time-of-day stuff, and again, it generates tons of credits for you during peak times, but if you use anything during off-peak (e.g. charging your car) you have no credits. Most of my high bills in the past 6 months were due to massive super-off-peak utilization from charging the car.

Other than that, nothing really to report. I’m looking forward to seeing how this all plays out in the summer when my baseline usage goes way up.