PowerWall...Why?

[MorrisonHiker]

For myself it would simply save me the inconvenience when the power goes out. It's a bit weird because a few years back I hardly ever lost power, and now days I'm lucky to go a month without a short power outage to the entire area around me.

Now if I lived in California with rolling blackouts I absolutely would get a power wall. They're probably selling like hot cakes in California right now.

I've lived in the same neighborhood for nearly 24 years. Until 2019, the longest power outage we had was a 6 hour blackout when we received nearly 4 feet of snow in one big storm. Then we got our Powerwalls installed last year and had a 45 hour outage after receiving only a few inches of snow in March 2019. The Powerwalls kept things running great the first 24 hours but then had problems with our inverters the second day since the Powerwalls were putting out too high of a frequency for the inverters. Tesla fixed the issue the next day by updating the inverter firmware.

We decided to put things to the test and we're currently on day 6 of an extended off-grid test and haven't had any issues. We got nearly 9" of snow last night so I cleared off a few panels this morning. They are already covering half the household use. Another 30 minutes and the Powerwalls will be charging up again.

 

[SOULPEDL]

Without solar, it is not worth it. With solar, it turns your system into an automatic emergency backup generator, which usually cost $15,000 installed.

... and it makes better use of your solar panels. When you don't have battery storage, and your solar makes more power than you need at each moment, then it gives back to the grid (not cost effective). With batteries, you save every ounce of power you create instead of giving it away, literally in some areas.

Furthermore, if you're in Az, to save on you power bill they sign you up for TOU (Time of Use) which means you need to pre-chill the home before a peak period, then turn things off (bake) until it's cheap again. That wastes energy because you're trying to get it colder than you would normally in trying to pre-chill your home (laws of thermodynamics). I will set the temp for how I feel without regard to peak costs, therefore it's a more functional system.

So it's not just convenient by using power no matter what time it is, but using all of the power you generate. We went with 8.19 kW Panels, and 2 PWs, installed today. I wanted whole home backup (not just essential circuits) in the event of grid loss. In that case you might need 2 PWs for A/C units, we did. My net power bill might go up a bit (because of the extra battery), but it still has a theoretical ROI within 16 yrs. Batteries may not last that long, but solar's good for 30yrs. By then they'll have cheaper batteries using Maxwell's dry cells for a quick swap someday. For all the fun in doing this, and the fact that I might even save money in the end, and for all this convenience, I'm sold and I know it's the right thing to do.

 

[SOULPEDL]

And we did this when we don't really need emergency backup here in Az. Our outages are extremely rare.

 

[KY-Lonewolf]

I bought 4 powerwalls understanding I would not get a payback because we have net metering.
The reason I purchased them was it was driving me crazy that the 46 300 watt solar panels on the roof were absolutely useless during grid down before I had PWs.
Also......I have a whole house natural gas generator for backup. These house residential generators (e.g. Generac, Kohler) are not commercial grade quality and really aren't designed to run continuously for long outages. The powerwalls give me great flexibility and keep me from beating the generator to death by running it all the time. Also, believe it or not, as crazy as it seems, the pumps that maintain pressure in the natural gas lines are dependant on electricity from the grid.