SRP demand (kW) number is huge different with Powerwall app

[justsomerandom]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that charge and last longer. Anyway I know this is poorly explained but I’m hoping there is a trick.

 

[justsomerandom]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw continuous or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that higher fee from kicking in.

 

[power.saver]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw continuous or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that higher fee from kicking in.

The Powerwall doesn't have an operational mode to do what you want. It can't respond to a demand level and only discharge to offset it. Self-consumption mode is close, but as you discovered, you'll discharge when you don't want to (below 3kW demand) and run out of energy. Adding more Powerwalls would extend your run time, but would not solve the problem of always discharging.

 

[scotsmanswan]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw continuous or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that higher fee from kicking in.

I think you will want to set up the appropriate peak periods. See a couple of my prior posts on the topic.

I would seriously look at the E-27 and probably the slightly better E-15 (the latter averages the daily peaks so soothes out the occasional cloudy / very hot day). To your point these plans given you access to net metering and a very low rate as long as you can load balance. I'm on the E-15 plan now (was on the E-27 for the first year and it was annoying that 1 day skewed bills so I switched) and with 3K sqft efficient home with 2 heatpumps (5T & 2.5T), 8.4Kw Solar a 1 Powerwall 2 I can generally ride out summer with minimal demand charges (this winter I've had $0 of demand charges but the averaging heled a couple of months). With 2 Powerwalls 2's this would be easy to manage.

Sharing resent change I made that influenced the desired behavior...

I had my summer TOU set up as follows:

• Off peak (8pm-2pm):
  • Buy: $0.04
  • Sell: $0.04
• Peak (2pm-8pm)
  • Buy: $0.25 (actual buy is $0.05 but I have demand charges to use $0.25 to simply reflect a materially higher buy cost)
  • Sell: $0.05

This worked well and I was getting some cost arbitrage during early part of peak as some power would get sent to grid (even though battery was not fully charged) but as things are getting hotter and the latter afternoon sun is becoming a less predictable here in AZ I was worried that AI would not account for this and I'd be left without battery before end of peak (and get penalized by the punitive demand charges SRP has). I therefore made the following adjustment:

• Off peak (8pm-2pm):
  • Buy: $0.04
  • Sell: $0.04
• Peak (2pm-8pm)
  • Buy: $0.25 (actual buy is $0.05 but I have demand charges to use $0.25 to simply reflect a materially higher buy cost)
  • Sell: $0.04

A minor change but now excess solar charges battery then goes to grid (presumably as AI sees no value in pushing power back at same cost is it could buy the next day)

 

[justsomerandom]

I think you will want to set up the appropriate peak periods. See a couple of my prior posts on the topic.

Thank you

 

[ptdusn]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw continuous or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that higher fee from kicking in.

Sounds like you are with SRP in AZ. Best thing to do to save $$$ is CHANGE to E-13 plan. There are NO demand charges on this plan. Additionally, change your powerwall setting to self-consumption. Additionally, call tesla and get them to activate the charge from grid feature, so you can get the PW charged to 100%. These days with no A/C running we are hitting 100% on our 2 PWs around noon and putting extra back to the grid.

 

[Vines]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw continuous or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that higher fee from kicking in.

Site Import control should help you to reduce draw from the grid. Ask your installer if they will enable this for you.

 

[ptdusn]

I recognize this is an old post but I’m new on here and can’t start my own thread. I’m an e-27 customer with one powerwall and 9.6 kw. I’d prefer the powerwall to only come on when my supply from the grid hits 3 kw continuous or higher due to demand charges. My system got turned on a few days ago. It seems like the powerwall does great at preventing grid use until it runs out of juice and then for 30 minutes I use enough to hit the >5kw fee/usage charge. If I could get the powerwall to help me out with anything over 3 kw demand it would prevent that higher fee from kicking in.

Just to let you know, our Feb 16, 2023 bill from SRP was $29.00!!!