PG&E E-TOU-C vs E-TOU-D with NEM 2.0 and Powerwalls

[tiongkiat]

With the imminent expiration of E-TOU-A, what are the considerations to weigh in deciding which PG&E TOU plan to choose for those with NEM 2.0 and Powerwall(s)?

E-TOU-C: peak every day 4pm-9pm with baseline allowance (50-70% of territory average)
E-TOU-D: peak M-F 5pm-8pm with no baseline allowance

In my case, baseline allowance is less valuable after upgrading to a hybrid heat pump. I was planning on shifting moderate winter heating from gas to electricity to take advantage of NEM credits from the summer months. The amount of peak solar that can be sent back in the summer months of Jun-Sep after 4pm will be fairly modest, and it's 35 hours/week that ideally should be run from battery rather than just 15 hours/week. PSPS feel like they will occur every high fire season for the foreseeable future, and it seems prudent to keep a high Powerwall reserve percentage.

 

[getakey]

what do you consider high reserve? I have 3 and keep reserve at 33% for unexpected outage. PSPS always gives warning and you can charge. Unexpected worst case is at sunset and I can make it through the night on 33%

 

[miimura]

If you owe money at true-up, I have a hard time understanding how you can come out ahead on either TOU-C or TOU-D versus EV2. You don't have to have an EV to go on the EV2 rate, Powerwalls are sufficient to qualify you. The Off-Peak is cheaper on EV2 and the Powerwalls keep you from paying Peak prices.

In my case, the PG&E Rate Comparison tool shows that my bills would be 45% higher on either of the TOU C/D plans compared to EV2.
EV2: $1,290
TOU-C: $1,860
TOU-D: $1,865

 

[getakey]

you can go on EV2 without an EV?

 

[miimura]

you can go on EV2 without an EV?

Yes, Battery Storage is eligible for EV2

 

[getakey]

interesting. Wonder why?

 

[tiongkiat]

If you owe money at true-up, I have a hard time understanding how you can come out ahead on either TOU-C or TOU-D versus EV2. You don't have to have an EV to go on the EV2 rate, Powerwalls are sufficient to qualify you. The Off-Peak is cheaper on EV2 and the Powerwalls keep you from paying Peak prices.

In my case, the PG&E Rate Comparison tool shows that my bills would be 45% higher on either of the TOU C/D plans compared to EV2.
EV2: $1,290
TOU-C: $1,860
TOU-D: $1,865

My goal is to owe as little money at true-up as possible. I don't have an EV.

EV2-A doesn't seem that favorable as the peak is from 3pm to 12am every day, while EV-B has peak from 7am to 11pm weekdays and 3pm to 7pm weekends. If anything, the wide peak period of EV-B seems to be favorable for anyone with PV and Powerwalls who can operate in self-powered mode during those hours, at least during the summer, and can shift almost all grid use to non-peak. Trying to use NEM credits during the winter for the heat pump looks like it would be cost prohibitive quickly in either plan because heating in cold weather is not something that is realistically possible to limit to non-peak. Also, the winter peak rates on TOU are not much higher than non-peak.

The takeaway looks to be how you are able to shift usage and how you plan to consume NEM credits are very use-case specific. If I added an EV down the line, the analysis seems to get even more complicated. It will depend on how many kWh I charge on the vehicle in a given month in the winter.

 

[getakey]

I believe EV-B requires a separate meter specific to the EV

 

[SaveOurPlanet]

I guess it all depends on your use pattern, according to PG&E rate comparison page it is always lowest with EV2-A for me. I also downloaded my daily usage data and plug in the rates and daily kWh by hour and EV2-A is always lowest on my average low usage day of 20 kWH and average high usage day of 31 kWh. I think new PG&E customers cannot enroll in EV2-A anymore but existing customer can switch plan to EV2-A. I was tempted to switch but since I signed the PG&E Interconnection Agreement last month I wonder if it would delay my install if I do so, then again, my solar roof install maybe months away anyway. My personal feeling is to get enough solar generation and backup battery so you would not have to think about rate plan.

 

[miimura]

My goal is to owe as little money at true-up as possible. I don't have an EV.

EV2-A doesn't seem that favorable as the peak is from 3pm to 12am every day, while EV-B has peak from 7am to 11pm weekdays and 3pm to 7pm weekends. If anything, the wide peak period of EV-B seems to be favorable for anyone with PV and Powerwalls who can operate in self-powered mode during those hours, at least during the summer, and can shift almost all grid use to non-peak. Trying to use NEM credits during the winter for the heat pump looks like it would be cost prohibitive quickly in either plan because heating in cold weather is not something that is realistically possible to limit to non-peak. Also, the winter peak rates on TOU are not much higher than non-peak.

The takeaway looks to be how you are able to shift usage and how you plan to consume NEM credits are very use-case specific. If I added an EV down the line, the analysis seems to get even more complicated. It will depend on how many kWh I charge on the vehicle in a given month in the winter.

#1. EV-B is only for actual EV charging and it requires a separate PG&E meter. That is expensive to wire up.
#2. EV2-A is only Peak from 4-9pm, but Part-Peak from 3-4pm and 9pm-12mid. The price of Part-Peak is similar to Off-Peak on the other TOU plans.
#3 If your Powerwalls and battery are sized appropriately, you should be able to power the house all through the Peak and Part-Peak period with solar generated during Off-Peak. Like the chart below. With Powerwalls, my costs are completely Off-Peak until my daily solar generation dips below my daily consumption during those hours. Most of my annual cost is incurred during the winter months Nov-Feb.

My billable energy from mid-July to mid-August was 570kWh.
Off-Peak +631 kWh
Part-Peak -5 kWh
Peak -56 kWh

 

[RKCRLR]

you can go on EV2 without an EV?

My SGIP incentive for my Powerwalls REQUIRES me to go to EV2. No other choice.

 

[Redhill_qik]

Bumping this older thread as it wasn't answered and I have the same questions. I'm also on PG&E (with SVCE CCA for generation) with solar and 2 Powerwalls. I had PTO approval last week, but I'm still on E-1 and expect to get switch to either E-TOU-C or E-TOU-D when PG&E gets around to it. They email from PG&E said that I'm getting credits for power sent to the grid and PG&E is showing negative kWhs since I was allowed to turn the system on. Best guess is that I'm in some sort of limbo until my monthly cycle is up two weeks.

What I can't figure out is the "real" cost of the E-TOU-C vs E-TOU-D. Here is the latest PG&E tariff numbers and I added the "Actual Cost?" column.

I don't expect to ever use more than the baseline amount, so is the credit really applied? I'm confused as the PG&E "Residential Rate Plan Pricing" PDF doesn't show this and the difference between above/below baseline is very small especially in the winter.

On the Powerwall side, it seems like there is negative incentive to power from powerwalls during peak as the difference is $0.01733 and with a loss of 10% with Powerwalls that would "cost" $0.029967 ($0.29967 * 10%) to use it during the peak period. During the summer the difference is $0.06344 which is higher than the Powerwall "cost" of $0.035065, so it would help then. I'm probably not taking into account the "non-bypassable charges" that turn the winter in to a positive, but I'm not 100% sure how to calculate that.

 

[RKCRLR]

#1. EV-B is only for actual EV charging and it requires a separate PG&E meter. That is expensive to wire up.
#2. EV2-A is only Peak from 4-9pm, but Part-Peak from 3-4pm and 9pm-12mid. The price of Part-Peak is similar to Off-Peak on the other TOU plans.
#3 If your Powerwalls and battery are sized appropriately, you should be able to power the house all through the Peak and Part-Peak period with solar generated during Off-Peak. Like the chart below. With Powerwalls, my costs are completely Off-Peak until my daily solar generation dips below my daily consumption during those hours. Most of my annual cost is incurred during the winter months Nov-Feb.

View attachment 588213

My billable energy from mid-July to mid-August was 570kWh.
Off-Peak +631 kWh
Part-Peak -5 kWh
Peak -56 kWh

For me the problem is with having enough reserve for power outages. The PG&E comparison shows me with a slightly higher bill with EV2-A vs TOU-C (but TOU-C isn't an option with SGIP). Yes, I can get through peak and part-peak by powering my house from my 2 powerwalls. However, if there is insufficient solar power to recharge the batteries during the day (which will be often unless Storm Watch is activated) I will not have enough power to get through an outage. And if I set my reserve high enough to make it through outages then I will wind up paying for the shoulder periods during much of the winter.
And I have frequent power outages where I live.
And I have a heat pump for heat.

 

[miimura]

Bumping this older thread as it wasn't answered and I have the same questions. I'm also on PG&E (with SVCE CCA for generation) with solar and 2 Powerwalls. I had PTO approval last week, but I'm still on E-1 and expect to get switch to either E-TOU-C or E-TOU-D when PG&E gets around to it. They email from PG&E said that I'm getting credits for power sent to the grid and PG&E is showing negative kWhs since I was allowed to turn the system on. Best guess is that I'm in some sort of limbo until my monthly cycle is up two weeks.

What I can't figure out is the "real" cost of the E-TOU-C vs E-TOU-D. Here is the latest PG&E tariff numbers and I added the "Actual Cost?" column.

I don't expect to ever use more than the baseline amount, so is the credit really applied? I'm confused as the PG&E "Residential Rate Plan Pricing" PDF doesn't show this and the difference between above/below baseline is very small especially in the winter.

Your Actual Cost is correct. I really hate how they present these rates. They should just do Tier 1 (up to Baseline) and Tier 2 (over Baseline) to make is more like how E-1 is presented.

On the Powerwall side, it seems like there is negative incentive to power from powerwalls during peak as the difference is $0.01733 and with a loss of 10% with Powerwalls that would "cost" $0.029967 ($0.29967 * 10%) to use it during the peak period. During the summer the difference is $0.06344 which is higher than the Powerwall "cost" of $0.035065, so it would help then. I'm probably not taking into account the "non-bypassable charges" that turn the winter in to a positive, but I'm not 100% sure how to calculate that.

Remember, because you have Powerwalls, you can elect the EV2 rate plan even though you don't have an EV. That will drop your Off-Peak cost and give you more NEM credits during Peak while you're running off batteries. Remember that SVCE will pay out all Generation credits, even if you are a net generator. So, it benefits you to maximize those credits even if the PG&E distribution portion will be wiped out.

 

[miimura]

For me the problem is with having enough reserve for power outages. The PG&E comparison shows me with a slightly higher bill with EV2-A vs TOU-C (but TOU-C isn't an option with SGIP). Yes, I can get through peak and part-peak by powering my house from my 2 powerwalls. However, if there is insufficient solar power to recharge the batteries during the day (which will be often unless Storm Watch is activated) I will not have enough power to get through an outage. And if I set my reserve high enough to make it through outages then I will wind up paying for the shoulder periods during much of the winter.
And I have frequent power outages where I live.
And I have a heat pump for heat.

My basic strategy is to set the Reserve so that the headroom above it is my best case daily solar generation. That way, you will have the most possible buffer for power outages while still getting the full value of your solar. Letting the battery SOC go lower to try to cover all of your Peak or Part Peak when you can't make it up with solar generation makes little sense.

 

[RKCRLR]

My basic strategy is to set the Reserve so that the headroom above it is my best case daily solar generation. That way, you will have the most possible buffer for power outages while still getting the full value of your solar. Letting the battery SOC go lower to try to cover all of your Peak or Part Peak when you can't make it up with solar generation makes little sense.

I'll probably take a similar approach. My frustration is being forced into the EV2-A rate which isn't the best fit for me. I'll wind up running my heat pump from the grid for a couple of hours a day during the partial peak period which wouldn't be partial peak on TOU-C.
But if I still wind up with a $0 true-up I won't care.

 

[Redhill_qik]

Your Actual Cost is correct. I really hate how they present these rates. They should just do Tier 1 (up to Baseline) and Tier 2 (over Baseline) to make is more like how E-1 is presented.


Remember, because you have Powerwalls, you can elect the EV2 rate plan even though you don't have an EV. That will drop your Off-Peak cost and give you more NEM credits during Peak while you're running off batteries. Remember that SVCE will pay out all Generation credits, even if you are a net generator. So, it benefits you to maximize those credits even if the PG&E distribution portion will be wiped out.

I created a spreadsheet with a year of my hourly PG&E usage plus the hourly generation data from PVwatts to try modeling the different rate plans. Taking it further to include Powerwall charge/discharge will probably require me to write up some code.

I'm really concerned about the $0 47925 rate for EV2 during the summer. My AC isn't backed up and I'm not 100% sure how well the PW will figure out that the load is house and partially power it. If I lose the inverter for a few weeks/months I shudder to think what the bill might be.

 

[miimura]

I created a spreadsheet with a year of my hourly PG&E usage plus the hourly generation data from PVwatts to try modeling the different rate plans. Taking it further to include Powerwall charge/discharge will probably require me to write up some code.

I'm really concerned about the $0 47925 rate for EV2 during the summer. My AC isn't backed up and I'm not 100% sure how well the PW will figure out that the load is house and partially power it. If I lose the inverter for a few weeks/months I shudder to think what the bill might be.

As long as your Powerwalls are properly installed to measure your actual grid draw and now just the draw of the backup loads, the PWs will offset your A/C usage. If you already have the spreadsheet of your usage, you should know how much energy you use during the 4-9pm period and you should be able to judge how many excess kWh the PWs won't cover. Clearly, losing your solar production would definitely cost you money if you can't avoid usage during Peak periods.

 

[getakey]

I'm east of Sacramento Have a heat pump for half of the house. Temp yesterday/today was 58/38. With 3 PWs, I pull about 20kWhs to make it from 2pm to 9pm (my peak). They charge back to 100% by 2pm

 

[Redhill_qik]

As long as your Powerwalls are properly installed to measure your actual grid draw and now just the draw of the backup loads, the PWs will offset your A/C usage. If you already have the spreadsheet of your usage, you should know how much energy you use during the 4-9pm period and you should be able to judge how many excess kWh the PWs won't cover. Clearly, losing your solar production would definitely cost you money if you can't avoid usage during Peak periods.

I actually have a problem with my CT measurements for the AC load that isn't backed up that I need Tesla to come back out to fix, but that won't impact me until May/June.

I updated my spreadsheet to include battery charge/discharge with 90% loss on the discharge (I'm assuming the 90% number is roundtrip). The TOU-C and EV2 have the same Peak times, so the net there is same everyday and for the whole year would be less than -20kWh with the PW and +1,350kWh without the PW. The EV2 Partial Peak is gets to net of -600kWh (33% reserve) or is +500kWh without the PW.

Estimating the non-bypassable charges is easy ($37.40 with PW @ 33% or $88.06 without PW), but I'm still not sure exactly how the NEMs offset works to be able to get to reasonably accurate estimate for the whole year.