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Monday, March 22, 2021

Spring 2021 Has Sprung! First Net Positive Day w/ Tesla Solar and Powerwall

On Friday March 12th, we generated more electricity than we used. Here in NW Oregon, we usually have short cloudy/rainy days in the winter. Well, spring is here and the days alternate between sunny blue skies and rainy.

When July/August hit, we'll have more sun, but the AC will be on, boosting our energy use, raising the bar for energy-positive days, so these sunny spring days are the easiest. 

Looking at the timeline for our net positive day, there are a few interesting moments. 
  • 3AM the EVs charge up. You can see the big spike in energy use. On a power level, this event is far bigger than anything else that happens throughout the day. 
  • 6AM peak rate hour start. The Powerwalls start discharging to remove our home from the grid load. 
  • 7AM the sun comes out. Our PV system started generating power. Since we were running in Cost Savings mode, the PV energy is sent to the grid during peak hours. 
  • 10AM peak ends. I'm not sure why, but the battery continued to discharge. This is not what usually happens. 
  • Noon Powerwalls start charging with solar. 
  • 1PM Powerwalls stop charging. They were not full but stopped charging for some reason. 
  • 2:30 PM Powerwalls start charging again. 
  • 5PM evening peak starts. Once again the Powerwalls start discharging to remove our home from the grid load. 
  • 8PM peak ends. The evening peak ended and yet the Powerwalls continued to discharge for another 2 hours. 
  • 10PM off-peak. As we hit off-peak, the Powerwalls stopped discharging. 
Why did the Powerwalls continue to discharge? We have the system in Advanced mode which is an intelligent mode that uses weather forecasts to "make room" to store anticipated solar production. That means that occasionally you might see mid-peak discharging. 

Of course, if you don't want all of this charging and discharging, you can just put the system in Backup-Only mode, but that's no fun.

Happy Spring Time, enjoy it while you can.  

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