Grid Failure!

[+SpiceWare]

Like many others in Texas, I woke up on February 15th to find the power grid had gone down.  Due to the forecast a Storm Watch had been in effect, so my Powerwall was at 100% before the grid failed.

When I checked outside the solar panels were covered in snow and ice:

 

 

 

Yet they were still generating some power.

 

  

 

Based on this screenshot, and the fact that Powerwall was at 100% before the grid failed, I can tell the Powerwall used 23% of its capacity in about 2 1/2 hours.  During that time my thermostat had switched over to daytime settings, so the gas furnace had been running non-stop to make the house warmer (heater's set to 62°F overnight, 69°F during the day).

I checked in with my boss to give him a heads up on my status.  My plan was to keep most things in my home powered off to conserve battery power to keep the furnace running.  He was without power as well, and the UPSes had run low, so he'd shut down all of the servers.

I also checked in with my folks to see if they'd like to come over since I had power - they said the news said there'd be rolling blackouts, so they'd stay put and wait for the power to come back on.

 

About 9:30 I climbed up on a ladder and swept off the snow I could reach without climbing on the roof:

 

 

After doing that the solar production increased:

 

 

Soon after the house finished warming up and the Powerwall started to recharge, though not much as the sun kept getting stuck behind the extensive cloud cover.

 

Around noon I was watching the news and they announced the rolling blackouts had been cancelled because the outage was too extensive to facilitate it.  There was no ETA for when power would return, and I couldn't get ahold of my folks, so I carefully drove over to their place on the ice covered roads and brought them back to my house since I would have heat.

 

In the afternoon my internet connection went down, which is needed by the Tesla App to show the system status. As my Monitor the system locally post from last year shows, there is a way around it - connect your phone's WiFi to the Tesla Gateway, then system status is available via a web page:

 

 

 

Power returned soon after.  My folks decided to stay the night in case power went out again.

 

Tuesday morning my panels were free from snow and ice even though the temperature was still in the 20s. Power had remained on, so my folks had me take them home.

 

 

 

The cold spell was unusually long for here.  They normally occur every few years, we'd wake up to snow & ice, and it'd all be melted by lunch time.  This time we still had a little bit on the ground a couple days later.

 

 

My boss was not so lucky, his power didn't return until Wednesday; and after that it was up and down until late Friday, so we ended up not being able to work for the week as all of our servers are located at his place.

 

The following is a breakdown of power usage at my home on the 15th.

 

Home Usage - Peaks are when furnace would kick in. The wide peek from about 7am till 10:30 am is when the furnace was running non-stop to raise the heat in the house. The wide/flat peak just after noon is when I brought my folks over and we watched the news and took turns taking a nice hot shower.

 

Solar Energy - production was bad in the morning as the panels were covered in snow and ice, plus there was a lot of cloud cover.

 

 

 

Powerwall - going up is power being supplied to the home, down is when it was recharging.  The big spike down is when the grid came back up and the Powerwall charged back to 100% because Storm Watch was still active.

 

 

Grid - up is usage, down is when my solar panels produced more than I needed

 

 

Overall picture:

 

 

 

Based on what I saw, if the power had stayed out I believe the Powerwall would have run low in the middle of the night. I suspected if it went totally dead then I'd be without power until the grid came back as the system that controls the solar panels requires power.

 

After the outage Tesla sent an email linking to the page: Best Practices During Power Outages. It had this to say, which made me less concerned about the PowerWall running out of power overnight:

 

Quote

Running Low on Energy

If Powerwall has less than 10% energy remaining, it will enter a standby state. Powerwall will automatically attempt to recharge from solar for 6 minutes every hour between 8 am and 4 pm local time. If enough solar is available to charge Powerwall, it will remain on. Otherwise, it will wait for the next hour.