Time of Use Power Shifting for Powerwall 2

[ohmman]

TOU-D-Prime - need to have an EV or Electric Storage. .49 4-9pm .13 9pm-4pm. Weekend .27 4-9pm, .13 9pm-4pm.

Interesting. This looks like a rate plan that actually reflects the realities of rooftop PV and the duck curve. Not ideal for consumer arbitrage, but an efficient rate plan shouldn't be.

4-9pm is an easier schedule not to use the AC, then crank it the rest of the day.

Depending on location. I'm not in SoCal with you, but in Sonoma the times I need AC are generally in the 6pm-9pm range in the summer. The house stays cool until dinnertime, and the sun hasn't yet gone down to cool things off. Once the sun is down, windows are open because it drops to the 50s pretty quickly. So for me, TOU works well. My peak is 2pm-9pm here.

 

[nwdiver]

Interesting. This looks like a rate plan that actually reflects the realities of rooftop PV and the duck curve. Not ideal for consumer arbitrage, but an efficient rate plan shouldn't be.

I wish more utilities would get out in front of this. I arranged 2/3rds of the panels in my last ground install facing South-West to better match production with demand in anticipation of future rate changes but the customer won't see much if any benefit until then. Easy to do stuff like this now. Not even remotely cost-effective later...

 

[NuShrike]

For SCE Customers: New plans become available April 30 . Time-Of-Use Residential Rate Plans

TOU-D-Prime - need to have an EV or Electric Storage. .49 4-9pm .13 9pm-4pm. Weekend .27 4-9pm, .13 9pm-4pm.
This seems pretty good but there is a .40 Daily Charge.

My current grandfather plan - SCE Grandfathered Rate Plans
TOU-D-A

Off-Peak: 29 cents from 8 a.m. to 2 p.m., and 8 p.m. to 10 p.m.
Super Off-Peak: 13 cents from 10 p.m. to 8 a.m.
On-Peak: 51 cents from 2 p.m. to 8 p.m.

With minimum daily charge of .35. But you get a 200kw allowance or $14 credit each month.

Not sure - but the TOU-D-Prime seems pretty good. Especially in the winter months when days are shorter and there are more cloudy days. .13 for all the off peak time seems like a great deal.

With the Powerwall I could easily wipe out any grid use during 4-9pm.

Not sure - but the Prime rate seems pretty good.

I'll have redo all the math I had set up for TOU-D-A with PWs.

I've been doing well with storing up the summer FiT credit for winter, so I only pay NBCs which at ~2c per kWh is fine. I had majority of panels set for SW, a couple for NW (although it now appears to be in neighbor's roof shadow), and a couple for SE.

Prime is going to devalue all of that that and make it tough to build up any credit during summer, so requiring battery-storage, and then still end up paying the grid, or in this case subsidizing the natural-gas producers.

 

[cwied]

I wish the utilities would get to the next logical step and enable time-shifting solar production by allowing exporting from batteries during peak if they were charged from solar. You would think this would help flatten the duck curve significantly. In fact, if the off-peak rates and schedules are somewhat reflective of actual costs, I would think they could even remove the solar restriction.

 

[wwhitney]

To my reading of the relevant PG&E tariffs, this is allowed. It's just not implemented in the Powerwall software.

 

[Ulmo]

Question - I just had two powerwalls installed. They set it up where pretty much my whole home is backed up. The only items outside the backup are EV charging circuits (which I use at night) and one of my two solar systems.

I have two solar systems - one 11.6kw and one 13.2kw. Tesla put the 13.2kw system on the backup to charge the batteries. The 11.6kw system is outside just to back feed the grid. (I have a total of 76 panels on my roof - I should be able to way over produce during the year).

Maybe it would have cost more to set it up this way, but if you had put 24.8kw of solar all on the battery side, you could have lasted longer during power outages, but power outages are a very unusual use case in most of California, so I can see why saving money by not going that route makes a lot of sense, if indeed it was less expensive (having to do with max in a box, wire sizes, etc.).

 

[Ulmo]

So my basic question - how should I configure my powerwall setup? I find that Time of Use will start sending all my solar production back to the grid during peak time and power the house off batteries. This seems counter intuitive because as soon as it gets dark my batteries may already be depleted by 50% when it could have saved all that power for evening / shoulder times?

The Peak rates are from 2pm-8pm M-F. In the winter it gets dark by 5pm and in the summer it will be nearly dark between 7-8pm. For sure the powerwall should save energy for Peak times when there is little to no production.

How are the rest of you dealing with this? I almost feel like self powered makes more sense - but at night when rates are .13 it does not make much sense to use the powerwall - and power should be saved for the shoulder time at 8am the next morning when rates are more but solar production is not enough to cover the current needs.

Any tips / ideas?

I agree with everything you said.

Given your two Powerwalls, I assume most of their capacity would be used in your evening peak times, and there wouldn't be enough left over to hand out to the grid. You would end up using a small amount of power (whether grid or battery) at night rates, and if you still need to charge cars at any time other than during the day from your 24.8kw solar, you would do so at the lowest night time rates.

That leaves just two things that are hard to do: charging your EV's from the sun in the day and (1) still having enough left over sun energy to charge your batteries for your evening use, shutting off the car charging before the sun goes down, then starting the car charges after evening peaks (at the night rates), and then (2) holding the battery depletion (i.e., not using battery) for your overnight trickle use so you can deplete the rest of your battery during morning mid-peak rates before the sun comes up. While both those things seem like obvious things Tesla software ought to support, I'm not aware of any way to do so. Also, there could be other difficult things with the regimen I just described, such as starting and stopping EV charging twice a day (once during sun and once at low night rates), which may be entirely irrelevant if you're not home in the sunny daytime, but if you are home in the sunny daytime, then part of which is determined by how far you commute and whether your work has daytime solar charging or not, and whether it's winter or summer (and for most people I'd also say it's hard to keep the car charging rate within the solar array power levels and yet enough for what's needed because you'd have to change the charging power level potentially twice per day, but your 24.8kw solar arrays makes that potentially a lot smoother and easier to figure out). Since most likely you're one of us 99.9% of EV slobs who don't charge EV's during the high-solar day, that's at least made a bit simpler (since you exclusively charge EV's at lowest night rates), and your main difficulty is (2) holding battery depletion (I mean not using battery) at low night rates for use during morning peaks.

(As if you couldn't tell, I'm a fierce advocate of charging EV's during the sunlight hours from solar panels, but that's kind of like shouting at a huge fusion reactor and hoping someone is listening.)

 

[Ulmo]

I wish more utilities would get out in front of this. I arranged 2/3rds of the panels in my last ground install facing South-West to better match production with demand in anticipation of future rate changes but the customer won't see much if any benefit until then. Easy to do stuff like this now. Not even remotely cost-effective later...

Our roof install did the same thing, but I'm finding now that I lose out on morning solar when our usage is strong enough that we would benefit from direct sun use and sun charging our PowerWalls, but instead the way we installed it the current outdated rate plans charge us an arm and a leg for "peak" morning use while our PowerWalls are already fully depleted in the morning, and we get gouged for that use despite there being a solar surplus in the actual grid (due to many utility scale tracker solar farms that ramp up quickly in the morning (partially also because they are designed to avoid mountains and forests casting shadows)). Hopefully someday we'll add to the other side of our roof for just that reason (to catch some morning sunlight as well as more mid-day sunlight), or ancient foot-dragging stupid PG&E will correct their rate plan, soon, to cover that situation. Either way, adding solar on that side of the roof would add to the total amount of energy we receive, so that would help either way.

 

[Ulmo]

To my reading of the relevant PG&E tariffs, this is allowed. It's just not implemented in the Powerwall software.

I think I agree. California Public Utilities Commission, Pacific Gas & Electric, AND Tesla have all been dragging their respective feet around. Right now, there are tariffs for load shifting due to large industrial-sized entities getting CPUC & PG&E to register those tariffs, but Tesla hasn't done the footwork necessary to get the software and paperwork in place to take advantage of that. Tesla is so large they could lobby CPUC & PG&E to yield to any consumer needs necessary to shoe-horn into that, and the three of them could then maintain and adjust the rules from there on. We've seen none of those benefits.

There are even third party paperwork-only companies trying to cash in on this type of stuff, and yet Tesla wants none of that improvement action whatsoever. It's completely baffling.

 

[cwied]

To my reading of the relevant PG&E tariffs, this is allowed. It's just not implemented in the Powerwall software.

Fair enough, I should say I wish that Tesla both supported this and also requested interconnection agreements compatible with doing this. I keep forgetting that others have different interconnection agreements. As mentioned before, my interconnection agreement does not consider the batteries NEM-eligible.

 

[jesseasi]

Update to my first posting. I super appreciate all the feedback so far.

Going to cover two different issues in this post:

First: In Jan/Feb I added a 2nd string of solar and 2 Tesla Powerwalls.

Imagine my horror when I get my first bill and my monthly rates go from $1-2 per month to $56 in my first month!

I did not realize that any changes I made my electricity with SCE would automatically take me off NEM1.0 and put me on NEM2.0.

Now I will be paying "Nonbypassable Charges" each month. Of course neither the Solar Panel installer nor Tesla's Battery team warned me of this.

"Non-bypassable charges (NBCs) are per-kilowatt hour charges that are built into utility electric rates. They add up to approximately 2-3 cents per kWh and go towards funding energy efficiency, low-income customer assistance, and other related programs.

In the original net metering policy, system owners did not have to pay NBCs on the electricity that they bought from the utility on a month-to-month basis. Under NEM 2.0, new system owners will have to pay NBCs, but only for the kWh of electricity delivered by the utility. None of the solar electricity generated and used at home will be subject to NBCs."

So it looks like I will be paying approx 2-3 cents per kilowatt hour going forward for any and all electricity that I actually use from the grid.

I made two phone calls to SCE and I got different answers each time. One rep told me that I used 1719 kilowatts during that month and that is my charge. Another rep told me that when my production exceeds my usage I will be able to cancel out these charges. However based on what is published on SCE's website - I think the 1st rep was right.

So it really sucks that I go from paying $12-24 per year in monthly charges (not including my early settlement charges) to what potentially looks like like $600-800 per year in "Non-bypassable charges" . That is just crap.

Second:
I have decided it is probably best for me to take advantage of the TOU credits by generating as much as possible during peak times - 2pm-8pm. In the summer time I could be earning 51 cents per kilowatt hour and 33 cents in the Winter. This should maximize my savings / credits. Then I guess I could just use a bunch of electricity during non-peak times.

But if the 1st part of this post is going to be true - this just ruins this whole experience.

 

[jesseasi]

Update to my first posting. I super appreciate all the feedback so far.

Going to cover two different issues in this post:

First: In Jan/Feb I added a 2nd string of solar and 2 Tesla Powerwalls.

Imagine my horror when I get my first bill and my monthly rates go from $1-2 per month to $56 in my first month!

I did not realize that any changes I made my electricity with SCE would automatically take me off NEM1.0 and put me on NEM2.0.

Now I will be paying "Nonbypassable Charges" each month. Of course neither the Solar Panel installer nor Tesla's Battery team warned me of this.

"Non-bypassable charges (NBCs) are per-kilowatt hour charges that are built into utility electric rates. They add up to approximately 2-3 cents per kWh and go towards funding energy efficiency, low-income customer assistance, and other related programs.

In the original net metering policy, system owners did not have to pay NBCs on the electricity that they bought from the utility on a month-to-month basis. Under NEM 2.0, new system owners will have to pay NBCs, but only for the kWh of electricity delivered by the utility. None of the solar electricity generated and used at home will be subject to NBCs."

So it looks like I will be paying approx 2-3 cents per kilowatt hour going forward for any and all electricity that I actually use from the grid.

I made two phone calls to SCE and I got different answers each time. One rep told me that I used 1719 kilowatts during that month and that is my charge. Another rep told me that when my production exceeds my usage I will be able to cancel out these charges. However based on what is published on SCE's website - I think the 1st rep was right.

So it really sucks that I go from paying $12-24 per year in monthly charges (not including my early settlement charges) to what potentially looks like like $600-800 per year in "Non-bypassable charges" . That is just crap.

Second:
I have decided it is probably best for me to take advantage of the TOU credits by generating as much as possible during peak times - 2pm-8pm. In the summer time I could be earning 51 cents per kilowatt hour and 33 cents in the Winter. This should maximize my savings / credits. Then I guess I could just use a bunch of electricity during non-peak times.

But if the 1st part of this post is going to be true - this just ruins this whole experience.

Found another thread that covers NBCs (non-bypassable charges). Self powered might be my best option going forward. Then move all my usage to the day time when I am generating power?

Has anyone done the math? When you hope to generate the same or more than you consume in a year. Is there a "best" way to use your powerwall? Seems like fighting NBC's might make more sense for me.

NuShrike - mentioned this right after my first post. I did not even know what NBCs were then.

 

[Nitro]

I’ve had Powerwalls for some 12-18 months now and have been tracking the monthly usage over the past three months (Australian summer) with a breakdown of energy data month to month.

Note, no EV currently. Have a Model 3 reservation for when they come to Australia

December 2018 - A hot December made cooler with Powerwall 2's - Tesla Straya
January 2019 - My January electricity bill just arrived... - Tesla Straya
February 2019 - February 2019, do I have a credit or a debit? - Tesla Straya

I plan to post these updates monthly as it really helps be break down solar/Powerwall ROI

 

[NuShrike]

Update to my first posting. I super appreciate all the feedback so far.

Going to cover two different issues in this post:

First: In Jan/Feb I added a 2nd string of solar and 2 Tesla Powerwalls.

Imagine my horror when I get my first bill and my monthly rates go from $1-2 per month to $56 in my first month!

I did not realize that any changes I made my electricity with SCE would automatically take me off NEM1.0 and put me on NEM2.0.

Now I will be paying "Nonbypassable Charges" each month. Of course neither the Solar Panel installer nor Tesla's Battery team warned me of this.

"Non-bypassable charges (NBCs) are per-kilowatt hour charges that are built into utility electric rates. They add up to approximately 2-3 cents per kWh and go towards funding energy efficiency, low-income customer assistance, and other related programs.

In the original net metering policy, system owners did not have to pay NBCs on the electricity that they bought from the utility on a month-to-month basis. Under NEM 2.0, new system owners will have to pay NBCs, but only for the kWh of electricity delivered by the utility. None of the solar electricity generated and used at home will be subject to NBCs."

So it looks like I will be paying approx 2-3 cents per kilowatt hour going forward for any and all electricity that I actually use from the grid.

I made two phone calls to SCE and I got different answers each time. One rep told me that I used 1719 kilowatts during that month and that is my charge. Another rep told me that when my production exceeds my usage I will be able to cancel out these charges. However based on what is published on SCE's website - I think the 1st rep was right.

So it really sucks that I go from paying $12-24 per year in monthly charges (not including my early settlement charges) to what potentially looks like like $600-800 per year in "Non-bypassable charges" . That is just crap.

Second:
I have decided it is probably best for me to take advantage of the TOU credits by generating as much as possible during peak times - 2pm-8pm. In the summer time I could be earning 51 cents per kilowatt hour and 33 cents in the Winter. This should maximize my savings / credits. Then I guess I could just use a bunch of electricity during non-peak times.

But if the 1st part of this post is going to be true - this just ruins this whole experience.

Sorry to hear you got "tricked" out of NEM 1.0. They're supposed to give you multiple notices about this, especially when applying for PTO with SCE. I would blame Tesla for not telling you, or not pointing it out in the SCE forms.

Note you won't earn 51/33c per kWh. Always subtract 2c because NBCs is their trick of "lowering" electricity prices while increasing generation charges.

So when you use peak, SCE will charge you 51c. When you generate peak, SCE will pay you 49c. Honestly, the new summer rate is a lot "better" than last summer's 48c use/46c gen. I'd banked a lot of credit, and I'm now "burning" it off. However, I'm still paying about $25 per month in NBCs. I have reasons for my setup. However as we're seeing, SCE can play with the rates all they want to their advantage under NEM 2.0.

The bulk of your generation will actually be between 10am and 3pm because orbital dynamics, so don't take the morning hours for granted. DST is what makes 4pm to 7pm actually relevant.

Move all your high-usage into daytime to avoid any NBCs, or super-off-peak where electricity is effectively 2c per kWh, and good fortune to you...

 

[bkp_duke]

I am in a similar situation, and because I work from home I've been able to mitigate most of the NBCs with the following:

1) charge during daylight hours, when the sun is shining (if possible), at a lower charge rate than max (20-30A) so that I'm not tapping from the grid any extra usage above solar production.
2) use the powerwalls (3) in self-consumption mode so that the rest of usage is mitigated as much as possible

We've had our 3 powerwalls, with a 12kw SunPower solar system, for about 12 months and in that time we've only pulled about 450 kwh from the grid by using the above. It is, however, highly dependent upon being able to charge during the day.

Our pool will go live in a few months, and I'm curious to see how NBC usage changes with pool pumps running and good portion of the day.

 

[SD Diver]

OK - so I am trying to resend to an ohm hour and wanted to start the powerwall powering the home. Switched to self-powered at 7:40 pm to force the battery to be used instead of the grid. 8:35 pm and the change has not taken affect. Is there a was to force a new setting to be used?

 

[liuping]

OK - so I am trying to resend to an ohm hour and wanted to start the powerwall powering the home. Switched to self-powered at 7:40 pm to force the battery to be used instead of the grid. 8:35 pm and the change has not taken affect. Is there a was to force a new setting to be used?

The Powerwalls only pick up changes once an hour. The exact time seems to change from time to time, and may be different for many people, to keep the servers from getting hit at the same time. Currently mine is 45 past the hour.

 

[cwied]

OK - so I am trying to resend to an ohm hour and wanted to start the powerwall powering the home. Switched to self-powered at 7:40 pm to force the battery to be used instead of the grid. 8:35 pm and the change has not taken affect. Is there a was to force a new setting to be used?

Easiest way I know to force a setting change is to go through the setup wizard on the Powerwall. Any changes you make there will take effect immediately. This is what I use for OhmHours.

 

[Frankman60]

To do this, do I need to log in as the Installer or Customer? I am able to log into the Gateway using my customer log in credentials but those same credentials do not work to log in as an Installer.

Easiest way I know to force a setting change is to go through the setup wizard on the Powerwall. Any changes you make there will take effect immediately. This is what I use for OhmHours.

 

[cwied]

To do this, do I need to log in as the Installer or Customer? I am able to log into the Gateway using my customer log in credentials but those same credentials do not work to log in as an Installer.

Installer. Try your gateway serial number with "S" in front of it (if not already there) as the password. I believe if they changed the password you should be able to go through the password recovery procedure to log in.