PG&E Rate Schedules: "Home Charging" (EV2-A) Goes Live vs. Others

[Skryll]

Look at how many kWh you use during the 4-9pm Peak period and also the 3-4pm and 9pm-12mid Part-Peak periods. From an arbitrage standpoint, there is no point to having more Powerwall battery (plus Reserve for blackout) than you use in one day during those times. So, unless you use more than 20kWh/day during Peak (unlikely in SF) you don't need the third Powerwall.

I have two Powerwalls but only 4.3kW of solar. My arbitrage is limited by my Summer Peak consumption (no A/C) of about 10kWh/day and then in the late Fall to early Spring, it is limited by my solar generation. With your larger solar system, you will probably only be limited by your Peak and Part-Peak consumption, not your generation.

To me, the incremental increase in Off-Peak price from EV-A (~$0.14/kWh) to EV2-A (~$0.17/kWh) is minor compared to the drop from Part-Peak (~$0.34/kWh) to Off-Peak (~$0.17/kWh) they imposed on our solar generation from 7am-3pm. It used to be that the vast majority of my solar generation earned Part-Peak prices and I could use double the kWh during Off-Peak for EV charging. No more. It's 1:1 solar to EV charging because they're both Off-Peak.

Interesting. We are on the 'far east bay' so 90F summers are normal and the AC use is horrendous. Also our dryer doesnt have a timer on it and so doesnt run over night, probably pulling a good 4kW/h so between cooking and all that, the summers may easily be over 20kWh.

Mhm, a new dryer may be cheaper than the third powerwall... or replacing the AC with one that isnt from the 80s, or replace windows, but those two projects cost a lot more than the extra powerwall.

 

[miimura]

Interesting. We are on the 'far east bay' so 90F summers are normal and the AC use is horrendous. Also our dryer doesnt have a timer on it and so doesnt run over night, probably pulling a good 4kW/h so between cooking and all that, the summers may easily be over 20kWh.

Mhm, a new dryer may be cheaper than the third powerwall... or replacing the AC with one that isnt from the 80s, or replace windows, but those two projects cost a lot more than the extra powerwall.

Keeping 15% reserve you could still time shift 23kWh/day in the Summer with two Powerwalls. The third Powerwall would earn you little to nothing from arbitrage except a few exceptionally high usage days. It would mostly just allow for a larger reserve for outages.

 

[GenSao]

Would it make sense to have 3 powerwalls instead of two if the total project cost difference ended up being only $3k more for the 3 powerwalls?

Outside of backup, Powerwalls make the most economic sense offsetting your peak energy usage. If two Powerwalls are enough, then the third one is a waste of money ($6,353 after 26% Fed tax credit, no SGIP).

It may make more economic sense to add more solar ($7,770 after 26% Fed Tax Credit). You effectively prepay your energy and hedge against future price increases.

Assuming a 1st year annual production of 5,066 kWH (estimate for my recently installed west facing system) for Tesla's small (3.78 kW) solar system , 20 year of useful life, 0.70% degradation factor, conservatively comes out to $0.082/kWH production. Using an optimistic 0.20% degradation factor, and 25 years of useful life, the cost comes down to $0.063/kWH.

To minimize non-bypassable charges ($0.03/kWH), consider charging your EVs at solar production during off-peak TOU rates. I hope Tesla's can support this feature to match actual solar production vs home usage.

 

[Skryll]

Keeping 15% reserve you could still time shift 23kWh/day in the Summer with two Powerwalls. The third Powerwall would earn you little to nothing from arbitrage except a few exceptionally high usage days. It would mostly just allow for a larger reserve for outages.

And more degradation, the ten year warranty allows 70% capacity by the end to not be a warranty case?

Another thing I wonder about - wasnt there some talk about the powerwall having a solar inverter built in that would allow adding solar panels without additional inverter possible? Or was that speculation that didnt pan out.

 

[miimura]

Another thing I wonder about - wasnt there some talk about the powerwall having a solar inverter built in that would allow adding solar panels without additional inverter possible? Or was that speculation that didnt pan out.

Powerwall 2 is purely AC coupled. The integrated inverter charges and discharges the batteries based on commands from the Gateway computer. That's it. No solar interface and no generator interface.

The Powerwall 1 was DC coupled and used a DC-DC converter to control the power flow in and out of the battery pack. It required an external solar inverter like a StorEdge.

 

[Ulmo]

Winter sux. My Powerwalls soaked up all but 3kWh of solar (generation during Peak hours) during the whole billing cycle and my generation was still short 200kWh of my Peak usage.

You need more solar panels, plus you can 10x (ten times) your electric storage to last through dark weeks. Since you're an electrical worker, you could swing it by buying surplus/used good value panels and engineering + paperwork + ground mounting them yourself to save labor, and I don't know what to do about suggestions to you for electric storage, but at least post up a bit more for that too, funds allowing. Finding good value inverters would be hard. To get permission to connect to your home, you might have to isolate your home from your electric utility and go "selfish solar": use the grid as an actual backup, with a manual throw switch that isolates the solar panels OR isolates the utility, not both or neither, and then just never touch the utility except during exceptional weather times. Also, with selfish solar, you can build a bridge between the electric utility and your home microgrid that is one way and minimal, so you never violate any utility connection rules but still get to sip dinojuice utility electricity during dark weeks.

 

[R1Bill]

I just checked and am still on EV-A. Am I grandfathered in? Did anyone get moved?

 

[miimura]

I just checked and am still on EV-A. Am I grandfathered in? Did anyone get moved?

Yes, I was kicked out of EV-A to EV2-A. There must be some reason you were not kicked out.

 

[ucmndd]

I just checked and am still on EV-A. Am I grandfathered in? Did anyone get moved?

If you have solar you are grandfathered on EV-A for up to five years from your initial system interconnect. So for me, our solar went live in 2017 and if I'm reading things correctly we'll be able to remain on EV-A until 2022.

The Powerwall talk has been interesting as I've been doing the same sort of math. They make no economic sense for me right now on EV-A, but should pay for themselves pretty quickly once I get shifted to EV2-A, which the PGE plan estimator says will cost me almost 90% more per year with my current usage.

Right now my plan is to have them installed in 2021 so I can take advantage of the last year of the solar tax credit at 22% rebate and be ready for the rate change in 2022.

 

[Skryll]

also there is a 5 year from install deadline for having the solar tax credit apply to a powerwall retrofit according to my installer

 

[ucmndd]

also there is a 5 year from install deadline for having the solar tax credit apply to a powerwall retrofit according to my installer

That's good to know. Thanks.

 

[Skryll]

Is it better to install outside where the sun shines on it and wind and rain hammer it two months a year, or in the garage where there is less airflow and it heats up in the summer ?

also is being accessible to random trespassers outside a concern ?

also, can they be installed two in front of each other instead of side by side ?

 

[miimura]

also there is a 5 year from install deadline for having the solar tax credit apply to a powerwall retrofit according to my installer

When claiming the ITC for Powerwalls, it doesn't matter how old your solar system is. You just have to charge the Powerwalls 100% from on-site solar to get the tax credit.

 

[miimura]

Is it better to install outside where the sun shines on it and wind and rain hammer it two months a year, or in the garage where there is less airflow and it heats up in the summer ?

also is being accessible to random trespassers outside a concern ?

also, can they be installed two in front of each other instead of side by side ?

If you're talking about Powerwalls, the garage is usually better. Outdoor is OK unless in direct sunlight throughout the afternoon. Accessible is relative. Mine are mounted on the outside wall and behind a gate, so I don't worry about it.
Powerwalls can only be stacked in thickness if their weight is directly supported by the floor.

 

[JPP]

FWIW I was on EV-A until last November, then rotated off (5+ years since PTO on a 2013 SolarCity 16kW install). Did not have my Powerwalls yet. Worst PG&E plan offered was EV2-A, so I temporarily switched to TOU. My Powerwalls are now live as of today (complicated install on 3 separate days with 2 different teams over 1+ weeks). I just applied to switch to EV2-A. Had to fill out the on line app with VINs etc. Got app accepted, but rate plan does not switch until the end of the next rate period (just missed it so March 2nd). I assume that I will overall maximize my savings on EV2-A with arbitrage. Fingers crossed.

 

[astrorob]

FWIW I was on EV-A until last November, then rotated off (5+ years since PTO on a 2013 SolarCity 16kW install). Did not have my Powerwalls yet. Worst PG&E plan offered was EV2-A, so I temporarily switched to TOU. My Powerwalls are now live as of today (complicated install on 3 separate days with 2 different teams over 1+ weeks). I just applied to switch to EV2-A. Had to fill out the on line app with VINs etc. Got app accepted, but rate plan does not switch until the end of the next rate period (just missed it so March 2nd). I assume that I will overall maximize my savings on EV2-A with arbitrage. Fingers crossed.

i hadn't actually considered that EV2-A would improve things with powerwall - TOU-A looked best vs. EV2-A without storage. clearly EV2-A is really bad for me the way things stand. i should take a look at EV2-A with PW. for now i have 8 months left on EV-A.

i see in the various powerwall threads that there is a lot of confusion about exactly in what mode to run the PW2, and how to configure the rate schedule to make sure it maximizes the arbitrage. for me, a back of the envelope calc showed that around this time of the year, on EV-A that i'd pick up ~$2 per day if the powerwalls can satisfy all my peak demand and all of the peak solar is exported to the grid. it's not clear that the powerwall's logic will consistently do that though. and my primary purpose for having the PW is to have backup during PSPS, so i'm inclined to run it with a pretty high reserve. not sure if it's safe to rely on tesla enabling "storm mode" before a PSPS. well, lots to think about.

 

[Skryll]

i hadn't actually considered that EV2-A would improve things with powerwall - TOU-A looked best vs. EV2-A without storage. clearly EV2-A is really bad for me the way things stand. i should take a look at EV2-A with PW. for now i have 8 months left on EV-A.

i see in the various powerwall threads that there is a lot of confusion about exactly in what mode to run the PW2, and how to configure the rate schedule to make sure it maximizes the arbitrage. for me, a back of the envelope calc showed that around this time of the year, on EV-A that i'd pick up ~$2 per day if the powerwalls can satisfy all my peak demand and all of the peak solar is exported to the grid. it's not clear that the powerwall's logic will consistently do that though. and my primary purpose for having the PW is to have backup during PSPS, so i'm inclined to run it with a pretty high reserve. not sure if it's safe to rely on tesla enabling "storm mode" before a PSPS. well, lots to think about.

powerwall should help with lowering impact of EV2-A vs EV-A, but if you charge your cars a lot at night the raise from 0.13 cents to 0.17 cents does definitely hurt. Powerwall helps shifting the production from before 3pm to after 3pm, which is in my case about 50% of all production.

 

[R1Bill]

If you have solar you are grandfathered on EV-A for up to five years from your initial system interconnect. So for me, our solar went live in 2017 and if I'm reading things correctly we'll be able to remain on EV-A until 2022.

The Powerwall talk has been interesting as I've been doing the same sort of math. They make no economic sense for me right now on EV-A, but should pay for themselves pretty quickly once I get shifted to EV2-A, which the PGE plan estimator says will cost me almost 90% more per year with my current usage.

Right now my plan is to have them installed in 2021 so I can take advantage of the last year of the solar tax credit at 22% rebate and be ready for the rate change in 2022.

My system went online in 2012 and I just checked. Still on EV-A. I won't be saying anything to PG&E about it!

 

[famdrive]

Hey all if there is a better thread to post about what I am expressing can you please point me there? Im trying to figure out how much it will cost me in PGE if I get a Model X. Currently I have a Tahoe and sick of paying for gas so I've been hunting around for another SUV and the Model X is something that will work for me since I do not need the bigger Tahoe anymore.

I live in the "far east bay" where it is hot in warmer months and also have a solar lease with SolarCity/Tesla since it was a requirement when I purchased my home a couple years ago. I just started looking at the PGE rate plans and I swear its confusing lol.

 

[wwu123]

Hey all if there is a better thread to post about what I am expressing can you please point me there? Im trying to figure out how much it will cost me in PGE if I get a Model X. Currently I have a Tahoe and sick of paying for gas so I've been hunting around for another SUV and the Model X is something that will work for me since I do not need the bigger Tahoe anymore.

I live in the "far east bay" where it is hot in warmer months and also have a solar lease with SolarCity/Tesla since it was a requirement when I purchased my home a couple years ago. I just started looking at the PGE rate plans and I swear its confusing lol.

Use the PG&E rate comparison tool to compare various plans based on your actual last 12 months of usage. BUT also do the simple 5 question estimator that will factor in new EV usage as well as any other behavioral changes. For example, you say your summers are hot, but if no one is home in the afternoon, could you timeshift some A/c usage to later in the evening?