Norcal heat wave

[jjrandorin]

Yes (we’re the ones with 3PWs). I think after this event there will be a better understanding of how much of an energy hog on PWs AC can be. Assume losing power for extended periods might be worse during the winter when heating would kick on and little solar would be reaching the panels. One of the reasons I’m glad we have a gas furnace and range and not dependent on electric for that.

My heating is gas heat, so even though winter production is substantially less, "running the AC" is the single biggest drain on power in my home. I can normally get by without running it much, as it gets cool enough at night for me to use my whole home fan to cool the home.

Right now, though, its not cooling down enough for me to use the whole home fan to cool the house, at least in time enough for me to sleep, so AC it is.

 

[Big Earl]

Maybe the coolest place to sleep would be in our cars on Camp Mode. Glad we both charged our cars last night to 80% at SC.

Consider a window air conditioner or a mini-split for your bedroom. Your PWs should be able to run that for hours on end. The rest of the house will be hot, but you’ll be able to sleep.

 

[BGbreeder]

My heating is gas heat, so even though winter production is substantially less, "running the AC" is the single biggest drain on power in my home. I can normally get by without running it much, as it gets cool enough at night for me to use my whole home fan to cool the home.

Right now, though, its not cooling down enough for me to use the whole home fan to cool the house, at least in time enough for me to sleep, so AC it is.

Yes, we normally run on 20-25kWh/day, but the last few have been closer to 60kWh due to the AC load (5kW, and it is so old that it doesn't have a date on it, much less a SEER.It is at least thirty and might be closer to 50 years old). Normally, it gets run for a couple of days every other year. Hard to get an ROI on a replacement with that little use.

Locally, it isn't forecast to have an overnight cool off until Friday, and Thursday is now in the forecast for hotter than today.

I had to go out in my ICE vehicle today that under normal conditions has a great AC, but @117F, and sun filling the cabin it was borderline. Hot is just hot.

All the best,

BG

 

[cybertrucker]

Yes (we’re the ones with 3PWs). I think after this event there will be a better understanding of how much of an energy hog on PWs AC can be.

So is it a large house, old less efficient air conditioners, older code insulation and windows, or a combination of all the above?

Just seems like 3 powerwalls is a lot of capacity to burn through in one night.

Hope the weather breaks for you soon.

 

[cwied]

I'd be far more inclined to allow a down to 5% or even 0% if they'd just charge it back up to 15% from the grid after the event is over rather than waiting for the sun the next day.

I did exactly this myself manually the day before yesterday by turning on grid charging for 45 minutes after the Flex Alert was over. I have been managing my solar export to try to minimize off-peak exporting to avoid running into the estimated PV production. I should be pretty safe given the Powerwall's round-trip losses and using ChargeHQ to route extra off-peak solar to my car instead of the grid.

 

[sorka]

Have you been charging the Powerwalls from the grid? I can't think of how you would be having a problem otherwise.

No. Powerwalls charging from sun, but PGE gives me a limit that is far lower what I'm actually producing. I haven't actually hit on the B&W because I use a lot of that power without it ever reaching the grid. But during these events, I'm not running the AC but AM pulling tons of grid power during the day before to run the AC. Therefore my exports and imports are far greater because of VPP.

 

[sorka]

I did exactly this myself manually the day before yesterday by turning on grid charging for 45 minutes after the Flex Alert was over. I have been managing my solar export to try to minimize off-peak exporting to avoid running into the estimated PV production. I should be pretty safe given the Powerwall's round-trip losses and using ChargeHQ to route extra off-peak solar to my car instead of the grid.

Can I actually do this?

 

[ucmndd]

Just seems like 3 powerwalls is a lot of capacity to burn through in one night.

A typical reasonably modern/efficient 4 ton AC unit uses 3-4kw when it’s running. An older one more like 5-6kw.

3 powerwalls is ~40kwh if you run them from 100% full to empty.

Easier than you think to chew that up overnight when it’s this hot.

 

[cwied]

Can I actually do this?

Do you have the grid charging button in your app? If so, just switch to self-powered, set your reserve to your desired charge level and then turn on grid charging. It'll grid charge to the reserve. For me it charges at about 3 kW with 2 Powerwalls.

 

[SMAlset]

So is it a large house, old less efficient air conditioners, older code insulation and windows, or a combination of all the above?

Just seems like 3 powerwalls is a lot of capacity to burn through in one night.

Hope the weather breaks for you soon.

House is 3800sqft. Two story with 24 panels on south and west sides (8.16kW). AC unit is old 2014 Carrier unit, 5 tons, split between upstairs and downstairs, but still working. We paid for extra insullation in our attic and above garage when house built. Low-E Milguard double pane windows.

Typically our PWs even with AC on during day and overnight with normal summer inland temps (cools down in late evening/early morning) will take our PWs down to 20-30kW sometimes BUT the morning sun will recharge it to 100% by noon generally. With them full I can charge my car lowering amps to below incoming solar generated and still keep my PWs at 100% into late afternoon when Solar declines and the AC starts drawing down the PWs. However even with full summer sun, extreme heat when days are 100+ and nighttime temps are in the high 80s or 90s for consecutive days/nights like this, the PWs keep getting depleted mainly by AC and never get fully charged from what I’ve observed.

 

[SMAlset]

Woo hoo! Automated message from PG&E saying at 7:55p power was restored to our area. Said due to “weather”. Tesla PW app also indicates outage is over here. Glad we’ll have some AC to sleep in later tonight even if coming from grid. We still have a few more days to go until back to more normal highs. Currently on Standby at 21%.

 

[SMAlset]

Interesting that the outage map where we live was updated to show our section of town out of the outage area. However now another part of town adjacent to ours is in an outage when the map refreshed. This area is different than the one that was out yesterday evening. Makes me think they are definitely rotating areas to spread the pain around. At least the time out seems to be only an hour or two.

 

[nwdiver]

Interesting that the outage map where we live was updated to show our section of town out of the outage area. However now another part of town adjacent to ours is in an outage when the map refreshed. This area is different than the one that was out yesterday evening. Makes me think they are definitely rotating areas to spread the pain around. At least the time out seems to be only an hour or two.

Nice how CAISO appears to actually have a plan for load shedding as opposed to ERCOT that waited until their grid was minutes from collapse due to under frequency before just dumping load. And ERCOTs 'rolling' outages didn't roll.

I guess CA just has a different approach to handling demand about to exceed supply...

 

[getakey]

my house is well insulated
broke a record today. Have used 122 kWh as of 9:30pm. AC units could not keep up. Thermostats set at 80 and house was 82 all afternoon
they are catching up now

 

[holeydonut]

my house is well insulated
broke a record today. Have used 122 kWh as of 9:30pm. AC units could not keep up. Thermostats set at 80 and house was 82 all afternoon
they are catching up now

Holy crap, did you charge a car or something? I have 2 AC units that were running non stop too. It was crazing watching my interior temperatures go up with the ACs just blasting away. 6 total tons here taking 5 kW continuously for like 8 hours is still only 40 kWh lol. How did you get to 122 kWh?

BTW my home insulation is terrible... hence why I'm researching what the latest "inflation reduction act" can provide in terms of energy efficiency upgrades.

 

[BGbreeder]

Holy crap, did you charge a car or something? I have 2 AC units that were running non stop too. It was crazing watching my interior temperatures go up with the ACs just blasting away. 6 total tons here taking 5 kW continuously for like 8 hours is still only 40 kWh lol. How did you get to 122 kWh?

BTW my home insulation is terrible... hence why I'm researching what the latest "inflation reduction act" can provide in terms of energy efficiency upgrades.

Have you had an energy survey done? A real one, where they test the house for leaks and take infrared photos of your walls and roof planes? It might help sort through the higher benefit/lower marginal cost items for your house.

If you have attics, attic insulation is great, and generally inexpensive. Otherwise it is basically time for an expanded roof that gets expensive quickly.

All the best,

BG

 

[getakey]

Holy crap, did you charge a car or something? I have 2 AC units that were running non stop too. It was crazing watching my interior temperatures go up with the ACs just blasting away. 6 total tons here taking 5 kW continuously for like 8 hours is still only 40 kWh lol. How did you get to 122 kWh?

BTW my home insulation is terrible... hence why I'm researching what the latest "inflation reduction act" can provide in terms of energy efficiency upgrades.

just got a new EV and tested to make sure it would charge on my old charger. Probably did 30 kWh on it. Forgot about that
but normally on hot days above 105 I'm at 80+ kWh

 

[ucmndd]

We just had a bunch more fiberglass blown into our attic to bring it up to R-49. Just in time!

 

[SMAlset]

So far today we took just over 20kWh from the grid. Running off grid now until sun takes us out of Standby so expect that number to be larger. However in the big scheme of things a drop in the yearly usage. Usage so far today 58.2kWh.

LA Times had this recap for outages tonight in both the northern and southern part of the State and discussing the rotating blocks.

California averts widespread rolling blackouts as energy demands ease amid heat wave

The California Independent System Operator had issued a level 3 alert, a sign that the grid couldn't meet the state's electrical needs.

www.latimes.com

 

[getakey]

looking at Ca ISO Supply/Demand not sure I understand the need for blackouts tonight