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Saturday, September 10, 2022

Storm Watch Becomes Fire Watch

Tesla Powerwalls have an opt-in feature called Storm Watch. This is a reassuring feature; if there is a some danger in your area that could interrupt power service, your Powerwalls will charge up so you won't lose power if the grid goes down. If you have a medical device that you depend on and it must be powered, this can literally mean the difference between life and death, but it is also handy to keep the items in your freezer from melting or to keep your HVAC system operating.

Nowadays winter storms are not the only thing taking down the grid. In the summer, days are now hotter and that means more air conditioner usage. This can stress the grid. There are high winds. These can down lines or cause fire risk. That's what's happening as I write this. We received the below warning:  

High Wind Forecast & Potential PSPS Activity

Communities around the area may experience Public Safety Power Shutoffs (PSPS) this weekend due to high wind forecasts and elevated fire danger.


Portland General Electric (PGE) is considering safety shutoffs for pre-identified high hazard areas in their service territory. These include select areas in the Tualatin Hills, Coast Range Foothills, and Chehalem Mountain. If initiated, this would impact approximately up to 15,000 customers. Impacted residents have been notified by PGE and would continue to receive notifications both before, during, and after the potential shutoff.

Potential Public Safety Power Shutoffs areas in NW Oregon

This Storm Watch mode is now a year-round feature. Below is the notice that we received from the Tesla app. 

This event put the Powerwall on notice and it began charging up immediately. Usually, the Powerwall only charges from solar. This type of emergency event is the exception, it will charge from the grid and it will charge up regardless of the current solar production level or the current time-of-day electricity rate. The goal is just to get to full as fast as possible. 

Tesla App - Powerwall in Storm Watch Mode

In the image above, you can see our Powerwalls are 100% charged and the active Storm Watch indication. We generally let our Powerwall discharge down to a 20% reserve level in the evening to avoid peak rates as the sun sets. This could mean that, if we unexpectedly lost power, we'd only have 20% of our battery available to get us through the night until the sun comes up the next morning, allowing solar to power our home. Storm Watch is a nice set-it-and-forget-it method to ensure that we have 100% of our battery capacity available when we're most likely to lose power. In the winter, we bump that reserve amount up to 50% since solar production is not as assured.

Red Flag At Night 

For the US, Tesla uses Red Flag events from weather.gov as the trigger Storm Watch events. When we received the notice, I went to the national weather service website to see all of the impacted areas. Here's the map:  

From https://www.weather.gov/ 

As you can see, most of the west coast is under some level of warning and apparently all of Wyoming with most of Idaho, Nebraska, and South Dakota. 

Zoom in on NW Oregon

As we moved into the weekend, the red flags continued. The winds continued to create an ongoing fire danger. Here is a map of the active fires in Oregon: 

Active Wild Fires In And Around Oregon

With the ongoing fires and increasing winds, PGE did move ahead with the safety shut-off. So if you were in this area, unless you have a generator, home batteries, or an EV like the Ford F-150 Lightning with a Home Integration System, you were in the dark. 


Disclosure: I am long Tesla


  1. Is there a common "alert" mechanism that power companies, weather bureau's and what not use that Tesla's software listens to in order to decide what action to perform? I know individual customers can sign up for alerts, but was curious how specifically this works across the various vendors across the country. Pretty cool for sure.

    1. Yes, in the US there is a common alert mechanism via the National Weather Service. You can sign up for alerts in your area by email and/or text message. https://www.weather.gov/mqt/redflagtips