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Advice for PG&E Service Connection/Rate plan

wizputer

Member
Sep 13, 2015
18
1
Bay Area
Next year, I'm going to have a rather extensive remodel so there's no chance of keeping the EV-A rate plan.
Before I talk to PG&E/Tesla, I wanted to solicit some advice so I can be prepared when talking with the reps.

Unfortunately, due to how much is being changed, I have no way of modelling my energy usage post-remodel.

Some key points:
  • Gas is being completely disconnected (so I'll be eligible for All Electric baseline)
  • New/upgraded electric panel will need be installed
  • Heat pump water heater
  • Heat pump + HRV for interior
  • Model 3 RWD LR (~50 mi day)
  • Model S AWD (~15mi day)
  • ~1000 sq. ft. of southern facing roof
So the questions that I'm curious about currently, especially if anyone else has experience:
  1. Should I install submeter for the EV chargers?
  2. Will it still be worth getting Powerall(s) on the new rate plans?
 

miimura

Well-Known Member
Aug 21, 2013
6,539
6,347
Los Altos, CA
If I had it to do over again, I would get a main panel with two meters. One for the house and one for EV charging. To me, Powerwalls are the most compelling for backup power, especially in this "new normal" where PG&E pre-emptively shuts off the power to reduce the chance of triggering fires. With the two meter setup, you won't be able to back up your EV charging, but that's the way my Powerwalls are configured now, even with only one meter. If you have solar and Powerwalls on the house meter, you should be able to use Net Meter Aggregation to assign some generation credits to the EV meter. However, it really depends on the relative size of your solar array to your household consumption. I would call the solar customer service department to make sure this is possible.
 

jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,459
3,465
Northern California
I assume your are going to end up on a Time of Use plan, since that seems to be what PG&E pushes. With that, the one thing I think you can do with a Powerwall is draw from it during the expensive times, 3-9 or 4-9 PM M-F. For me the difference is between $0.40 and $0.20/Kw. If a Powerwall lets you avoid pulling power during those windows it could well be worth the money.

I am located in the East Bay, so we use a lot of A/C at those times plus TV, oven, etc. I also just went through 2 days without power due to the PSPS and looks like we may lose power again on Wednesday.
 

GenSao

Member
Aug 3, 2017
565
966
Pleasant Hill, CA
So the questions that I'm curious about currently, especially if anyone else has experience:
  1. Should I install submeter for the EV chargers?
  2. Will it still be worth getting Powerall(s) on the new rate plans?

TL;DR

1. Likely No.

2. Depends, likely Yes.

1. Detail
The only reason I see doing this is to stay on a similar rate schedule to EV-A. Do your own due diligence, but do consider the following:

Although the summer off-peak rate for overnight charging for EV-B ($0.135/kWh) is less than EV2-A ($0.162/kWH), I expect PG&E to eventual raise the rates of EV-B to match EV2-A. The E-1 Tier 1 rate ($.230/kWh) was recently increased to the point where it is close to the E-TOU-C off peak rates (Summer: $0.241/kWh; Winter: $.202/kWh).

The installation of a sub-meter adds complexity to your billing, an initial cost (meter install), and ongoing cost (Delivery Minimum Bill Amount (per meter per day of $0.32854) for two meters. You'll be required an annual $240 minimum payment to PG&E.

If going for solar anyways, you may not be able to offset your EV use on a separate meter (I am not certain on this).

2. Detail
Depends on your actual daily use, during peak period. I imagine even two Powerwalls will help offset (save) quite a bit of the cost with backing up most load (60A). With electrical only, you may be forced to go to 3 or more Powerwalls to cover the AC, hot water, ando ther very high powered devices (90A+).

Utilize EV2-A off peak rates. Heat you home in the winter with the heat pump and run high powered devices (cloths dryers, dish washing machine w/hot water). You can pre-cool the home in the summer with off peak-rates as well.

You can still model the electrical use for heating. The gas therm equivalent (1 therm = 29.3 kWH) with an proximate adjustment for more efficient appliances can be used.

Although you have only 1,000 SF southern exposure for a roof, the western and eastern faces can be utilized as well. For a remodel, if you need to replace the roof, the solar roof would be very tempting. I think solar w/Powerwalls are great to mitigate for future rate increases.
 
  • Helpful
Reactions: jjrandorin

Boatguy

Active Member
Apr 3, 2014
1,000
668
SF Bay Area
I remodeled 4 yrs ago and went with two meters, each 200a. Same problem, no way to predict my usage with all LED lights and gas radiant heat. One is on EV-B for cars, one on E-1 for the house. I don’t know if it’s optimal, but the incremental cost in my remodel was not significant.

Now I’m looking at PV+PW for the house. I’ll leave cars on their own for now, until I see how the PV+PW powers the house. I can bridge them later for further optimization.
 

MikeW

Member
Dec 4, 2012
33
25
Cupertino, CA
You can still model the electrical use for heating. The gas therm equivalent (1 therm = 29.3 kWH) with an proximate adjustment for more efficient appliances can be used.
It's a heat pump so you need to divide the kWh by the COP of the heat pump, which can be found on the heat pump data sheet. It's typically around 2.2-4.4 depending on the model and the outside temperature.

Since you are upgrading your electrical panel, get 225A instead of 200A, the additional cost is minimal. Also make sure the panel is compatible with energy monitoring such as sense.com, i.e. make sure the main breaker is not "parallel wired" where it has four smaller gauge wires feeding it instead of two larger gauge wires.
 

Patrick66

Member
Oct 27, 2019
77
42
Honolulu
If you want to install solar today, not having batteries is a mistake. You might be able to fit 12kW onto the south roof with normal setbacks, depending on the overall layout. That could translate to 2-3 powerwalls to maximize your payback. At this point, I would try to put in about 125-150% of your estimated annual energy needs in panel capacity, and maybe 110-125% inverter capacity.

Generally you aren’t going to be able to game the tariff schedules with multiple meters if your needs are “common.” But, if it was me I would get a 400A, double meter/main for my service equipment, 225A breaker for the house panel and a spare 125A breaker for flexibility. I would bring the 225A to a new 400A panel with a 225A main, and a spare conduit to a junction box from the 125A.

The details depend on how big your house is and what all you want to be on the powerwalls, if you want to net export in the winter without EV loads, etc.
 
  • Informative
Reactions: Sherlo

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