Tesla App Utility plan configuration: Multiple Peaks, Buy/Sell Behavior, etc

[Redhill_qik]

I will try that. Basically make the buy and sell difference negligible, like by 1 cent?

The differences between buy/sell in each period and between periods is small, but it is more than the 10% efficiency loss on the Powerwall recharge for buy/sell and more than the PG&E NBCs between Peak/Off-Peak. I settled on this after some experimentation when the change happened and I am happy that it does what I want it to with the following conditions:

• Off-Peak - Solar goes to house first, then to Powerwall and then to the grid
• Peak - Powerwall takes over and solar goes to grid

I would prefer that Peak would use solar first and then the Powerwall and then the grid as I am a net generator and my annual excess is bought back at a flat/non-TOU rate, but it is close enough.

 

[skepticcyclist]

My main thing is trying to get the peak period to behave like it did during balanced. In the old balanced mode I had it that during peak solar went to the house and then the grid. The battery would only be used if there wasn't enough solar. So during peak period the house use both solar and battery, no grid use. When solar was completely gone then the house would use all battery. That is what I am trying to accomplish

 

[skepticcyclist]

Just made the off peak and peak prices differ by 1 cent as well as buy and sell. Now the solar is going to both home and battery instead of all battery.

Interestingly, when I use the default prices by simply entering my utility plan, it automatically sets both buy and sell to the same value. But if I try to enter the prices myself it will not let them be the same value. Sell has to be less

 

[BGbreeder]

Just made the off peak and peak prices differ by 1 cent as well as buy and sell. Now the solar is going to both home and battery instead of all battery.

Interestingly, when I use the default prices by simply entering my utility plan, it automatically sets both buy and sell to the same value. But if I try to enter the prices myself it will not let them be the same value. Sell has to be less

I took a page out of @Redhill_qik's work, and made the sell price lower than the buy price by both the Powerwall efficiency loss and the NBC, and it seems to function reliably to use the solar for the house first and grid second during the peak period, until the solar production tapers away and then the Powerwalls pick up the slack.

All the best,

BG

 

[Redhill_qik]

I took a page out of @Redhill_qik's work, and made the sell price lower than the buy price by both the Powerwall efficiency loss and the NBC, and it seems to function reliably to use the solar for the house first and grid second during the peak period, until the solar production tapers away and then the Powerwalls pick up the slack.

All the best,

BG

What were the numbers that you used for each?

 

[aesculus]

I took a page out of @Redhill_qik's work, and made the sell price lower than the buy price by both the Powerwall efficiency loss and the NBC, and it seems to function reliably to use the solar for the house first and grid second during the peak period, until the solar production tapers away and then the Powerwalls pick up the slack.

I just used the WAG (3 cent delta) price for three reasons:

1. The one way losses are already factored into the storage costs (ie what you put in is not what is stored)
2. The loss as a $ standpoint is sort of weird since it's really a kWh loss but I see what you are doing with TOU.
3. I witnessed my small delta causing the change I needed. It may not be highly accurate (see the discussions on the Impact value), but operationally it seems to do the trick.

BTW since I did create these offset prices I have seen a greater push to use solar during peak to offset the house load (Export Everything) where before (with Export Solar) it would drive just filling up the PWs first and then when it hit peak, rely on PW energy only. Still a lot to learn by both me and my system in this area.

On another note I got my True Up for the last year and it was only around $200. The reason is we had no downstairs AC during 4 months of the summer and I basically drove 4k less miles. Since we upgraded the heap pumps to more efficient units I am going to have to do some deep calculations to figure out how to set all of this so I don't run into over crediting my account $-wise. I won't over produce for sure.

 

[Redhill_qik]

I just used the WAG (3 cent delta) price for three reasons:

Does this mean that you set Peak with $0.12 Buy and $0.09 Sell?

 

[skepticcyclist]

Just made the off peak and peak prices differ by 1 cent as well as buy and sell. Now the solar is going to both home and battery instead of all battery.

Interestingly, when I use the default prices by simply entering my utility plan, it automatically sets both buy and sell to the same value. But if I try to enter the prices myself it will not let them be the same value. Sell has to be less

This also got the peak period to do what I wanted too. Solar going to my house and supplemented by battery, instead of all solar going to the grid.

Once my AC shut off and the house was using less than what the solar was producing, excess solar went to the grid.

 

[aesculus]

Does this mean that you set Peak with $0.12 Buy and $0.09 Sell?

I wish. My peak is buy is 60 cents so I set the sell to 57 cents. Same on all my other periods. I made the sell price 3 cents less than the buy.

 

[Redhill_qik]

I wish. My peak is buy is 60 cents so I set the sell to 57 cents. Same on all my other periods. I made the sell price 3 cents less than the buy.

Neither are mine, I just want the Powerwall to do what I want and I don't care the value/cost reporting as it won't be right anyway. Watch the system after Peak ends and again in the morning as it often wants to discharge again in the Off-Peak times before the sun comes up.

 

[aesculus]

Watch the system after Peak ends and again in the morning as it often wants to discharge again in the Off-Peak times before the sun comes up.

Mine never does this. It can occasionally discharge a little bit in partial peak just before peak on a Friday confident that it really won't need much to fill the PWs on Sat (which is mostly off peak).

 

[BGbreeder]

What were the numbers that you used for each?

For EV2A, here are the values that I used;
Summer:
For peak: buy $0.60, sell $0.56
mid-peak: buy $0.30, sell $0.27
off-peak: buy $0.17, sell $0.14
Winter:
For peak: buy $0.45, sell $0.41
mid-peak: buy $0.33, sell $0.30
off-peak: buy $0.16, sell $0.13

I am not saying that these are "right" or exact.

I am sure it could work with a smaller delta, but I haven't played around with it, as your data suggests, and @aesculus's wag seems to work as well.

All the best,

BG

 

[BGbreeder]

I just used the WAG (3 cent delta) price for three reasons:

1. The one way losses are already factored into the storage costs (ie what you put in is not what is stored)
2. The loss as a $ standpoint is sort of weird since it's really a kWh loss but I see what you are doing with TOU.
3. I witnessed my small delta causing the change I needed. It may not be highly accurate (see the discussions on the Impact value), but operationally it seems to do the trick.

BTW since I did create these offset prices I have seen a greater push to use solar during peak to offset the house load (Export Everything) where before (with Export Solar) it would drive just filling up the PWs first and then when it hit peak, rely on PW energy only. Still a lot to learn by both me and my system in this area.

On another note I got my True Up for the last year and it was only around $200. The reason is we had no downstairs AC during 4 months of the summer and I basically drove 4k less miles. Since we upgraded the heap pumps to more efficient units I am going to have to do some deep calculations to figure out how to set all of this so I don't run into over crediting my account $-wise. I won't over produce for sure.

I agree that the loss is really happening as energy, but since the transaction ends up getting priced by the utility, I decided to do the math as dollars and cents rather than kWh. From the energy perspective, what gets put in gets shaved, as does what is in the battery, as does what comes out, so I took a crude net/net as 90%, since my battery standby losses happen whether or not I import/export energy. To your broader point, yes, it makes the optimal use of the solar power if energy can go directly to the grid or the house as there are no conversion losses, preferably during peak TOU rates.

Personally, I don't sweat it, as long as before peak TOU rates kick in, the batteries charge enough each day to carry us through peak TOU, which they do, preferably with only off-peak imports, if needed.

All the best,

BG

 

[skepticcyclist]

To Mimic The Old "Balanced" Mode

This worked for me after doing what Redhill_qik suggested.

• Set your Sell price to one cent less than the Buy price for both Peak and Off-Peak. The actual amount doesn't matter
• Set your Peak price higher than your Sell price. Again the amount doesn't matter as long as it is higher and thee Sell is still one cent less than the Buy (I set my Peak to be one cent more than the Off-Peak.)

 

[iollmann]

The most representative day was last Friday. However, the backup reserve was set to 20% (all else was the same). Things to note:
1. The Powerwall discharges between 3:45am and 8:20am. It shouldn't be doing that
2. At 3pm the Powerwall is at 87% charge. I want Powerwall to start powering the house at this time, and send solar to the grid. However it continues to use solar to charge the Powerwall (to 89%)

AM / PM inversion?

 

[scotsmanswan]

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)

 

[JWM3]

I set up powerwall on Time-based control to save my electric bill. However, today I’m surprised powerwall is not providing power for home use during peak time, it’s 100% draw from the grid. I have to switch to self-powered in order to let powerwall provide power. My back reserve set only 20%.

 

[tfan2018]

What’s your rate plan and what’s your peak and off peak rates?

 

[JWM3]

SCE TOU Prime, peak time 4-9pm $0.54/kWh, off peak $0.22/kWh

 

[Redhill_qik]

SCE TOU Prime, peak time 4-9pm $0.54/kWh, off peak $0.22/kWh

And the Tesla app has these settings? If so then there is no reason for the behavior that you observed.