Regarding the discussion above of non-bypassable charges, I’m looking at a friend’s SDG&E bill, and his net metering summary shows NBCs of just 52 cents, and that’s 5 months into his first true up period. He got a new meter at the same time of the solar installation, and it shows about 1700 kWh consumed and 3800 kWh pushed back into the grid. How could the NBCs only be 52 cents?
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Powerwall Arbitrage DEAD: San Diego's SDGE
- Thread starter Princeb
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I think I figured it out. It's that "non-bypassable charges" really means "non-bypassable charges in addition to minimum charges". The "minimum charge adjustment" on this bill is $49.31, which mean the actual non-bypassable charges amounted to $49.31+$0.52. It's just the weird and confusing way SDG&E does accounting on their billing statements.
Since he's generating a lot more than he uses, he can accumulate up to about $120 a year in non-bypassable charges on his account with no affect, because everyone has to pay a minimum of that much, anyway. (There are actually a couple things than get subtracted after the minimum bill, it seems, like California Climate Credit and Reduce Your Use awards.) Good to know when trying to estimate the affects of NEM 2.0 on your bill!
What's really annoying is that SDG&E's bills don't have enough data on them to reproduce the calculations. They don't even put the monthly meter readings if you're a net metering customer!
The PG&E bills likely have the data required, but I tried to calculate based on the tariff and came up with figures much larger than what people were actually being charged. The Tariff also doesn't talk about the Adjustment portion. I would go into more detail here, but it probably belongs in the existing PG&E NEM 2.0 thread.
NathanielHrnblwr
Member
Did you end up going with the PW2's? How many did you get?
Curious how everything went as I'm considering the option as well.
Xminus6
Member
Agreed. Mine is this way as well In PG&E land. You’re always better off finding some productive way to use that excess energy rather than selling it back at wholesale rates. Run a pool pump longer or whatever else that is beneficial to you.
SDGE land; NEM 1.0. PV 3.8kW Solaredge; EV x2 charging at night. EVTOU2 schedule
--My understanding: Grandfathered into Pk hours 12n-6p for 5 years until 2023.
Added PW2 x1. two weeks ago and learning some interesting things.
Setup: While on grid - and in self-consumption mode --- works like you'd expect
Priority house usage draw is solar>battery>grid.
Priority CHARGE is house >battery>grid.
-there is NO way to discharge the battery to the grid under current programming. ie no full arbitrage. If you want to do that, don't use PW. Get traditional batteries to do it.
-the closest you're going to get is time shifting energy for self consumption. This is key for NEM 2.0 and future folk where peak TOU is 6-9pm or any future non solar days.
-the discharge support is 5kw. That's good for most anything except AC and EV charging.
The total cost of tesla install was $7600 - SGIP ~3500 - ITN ~2300 = ~2000 for backup +time shifting capabilities. ROI is probably 5-7 years at best, so not cost effective compared to direct solar panels (but we've tapped out of roof space).
--My understanding: Grandfathered into Pk hours 12n-6p for 5 years until 2023.
Added PW2 x1. two weeks ago and learning some interesting things.
Setup: While on grid - and in self-consumption mode --- works like you'd expect
Priority house usage draw is solar>battery>grid.
Priority CHARGE is house >battery>grid.
-there is NO way to discharge the battery to the grid under current programming. ie no full arbitrage. If you want to do that, don't use PW. Get traditional batteries to do it.
-the closest you're going to get is time shifting energy for self consumption. This is key for NEM 2.0 and future folk where peak TOU is 6-9pm or any future non solar days.
-the discharge support is 5kw. That's good for most anything except AC and EV charging.
The total cost of tesla install was $7600 - SGIP ~3500 - ITN ~2300 = ~2000 for backup +time shifting capabilities. ROI is probably 5-7 years at best, so not cost effective compared to direct solar panels (but we've tapped out of roof space).
It might be worth factoring in demand-reduction into your equation. As far as I can tell, you can get quite a significant amount of money from OhmConnect if you have an EV and are in the San Diego area (although all areas down there might not be equal). There is an OhmConnect user who's getting $2000/year because he can change his usage by 7-8 kWh during his OhmHours by charging his EV on other days. With the Powerwalls, you can make sure your usage is 0 during the hour.
It appears like the demand reduction payments are somewhat less up here in the SF Bay Area, but I did get over $8 for each of the last two events (with about a 1.5 kWh reduction). So far this year, I've been getting 5-6 of them per month. One drawback is the income is taxable and will be reported on a 1099 if you exceed $600/year.
Note that demand-reduction is mutually exclusive with self-consumption. You have to have a demand from the grid to reduce. You can manage this by setting your schedule so you demand-reduce for part of your peak (usually after the sun goes down to avoid penalties from cloudy days) and self-consume the rest.
It appears like the demand reduction payments are somewhat less up here in the SF Bay Area, but I did get over $8 for each of the last two events (with about a 1.5 kWh reduction). So far this year, I've been getting 5-6 of them per month. One drawback is the income is taxable and will be reported on a 1099 if you exceed $600/year.
Note that demand-reduction is mutually exclusive with self-consumption. You have to have a demand from the grid to reduce. You can manage this by setting your schedule so you demand-reduce for part of your peak (usually after the sun goes down to avoid penalties from cloudy days) and self-consume the rest.
Frankman60
Member
This is the first time I have heard of the OhmConnect program. I read through the OhmConnect website but would appreciate hearing others experience with OhmConnect and Solar, and Powerwall users with OhmConnect. It seems like you may not get much advance notice for when an OhmHours event occurs and at that time the PWs would need to be in Self-Generation mode and providing all of the energy to the home. How does one effectively manage this to actually money?
I've been using it for a few weeks. They are advertising hard on Facebook from my POV. Overall, it's a much better demand-response system than SCE's, and doesn't seem to be a scam.
I don't give them my login password for SCE (at the end after signups), but I signed them into SCE's the third-party data access system. I've already moved my high-usage appliances and equipment to TP-Link smart-plugs so OhmConnect can automate turning things off (including Ecobee 4).
To control for event occurrences, you set preferred hour-bands to outside your PV hours "Times You'd Like to Receive #OhmHours ". Mine is set 12AM-7AM, and 6PM-12AM. This removes it from using PV hours that would fluctuate depending on weather. Weather is low occurrence in SoCal, so personal preference on settings.
Whenever Tesla's Gigafactory actually puts-up and actually starts shipping PWs to installers, such as Infinity Solar so I can get mine installed, I plan to use the PWs to cover more bands.
If one does EV charging, maybe the charging system has an API to automate synchronization with OhmHours.
The way I do it is to keep my Powerwall at 100% backup reserve except during OhmHours. The other trick with solar is to make sure not to get OhmHours during net-negative times as a cloudy day can ruin your OhmConnect streak. Streaks are key to earning the best return for OhmHours. Whenever an OhmHourhits, I set my Powerwall reserve to 50% (using IFTTT and a node server script I wrote) and that gets me the reduction I need. I don't have an EV, so I don't need to coordinate the charging.
My TOU peak time is 12pm-7pm during the summer, so I intend to run self-consumption until 7pm and then be available for OhmHoursafter that. That means on most days the Powerwalls will be off after 7pm. If I get into SGIP, I may need to add some consumption hours overnight to qualify.
The Powerwall is a great match to OhmConnect, because you don't have to worry about switching any of the backed-up loads off during an OhmHour. Self-consumption takes care of it automatically. With the IFTTT automation, I essentially don't have to do anything at all to get the benefit.
One thing about demand reduction that bothers me a little bit is that there is a perverse incentive to use more energy on non-event days. Given the payout levels, it seems like you profit off of extra usage that boosts your baseline for the OhmHour calculation (it uses the average of the same hour on the 10 previous non-event weekdays or 4 previous non-event weekend days).
My TOU peak time is 12pm-7pm during the summer, so I intend to run self-consumption until 7pm and then be available for OhmHoursafter that. That means on most days the Powerwalls will be off after 7pm. If I get into SGIP, I may need to add some consumption hours overnight to qualify.
The Powerwall is a great match to OhmConnect, because you don't have to worry about switching any of the backed-up loads off during an OhmHour. Self-consumption takes care of it automatically. With the IFTTT automation, I essentially don't have to do anything at all to get the benefit.
One thing about demand reduction that bothers me a little bit is that there is a perverse incentive to use more energy on non-event days. Given the payout levels, it seems like you profit off of extra usage that boosts your baseline for the OhmHour calculation (it uses the average of the same hour on the 10 previous non-event weekdays or 4 previous non-event weekend days).
Frankman60
Member
Thanks for your comments cwied and NuShrike. I have solar and will be getting 2 PWs installed in a new months. It seems that if I want to sign up with OhmConnect I should do it maybe two weeks before the PWs are commissioned because they measure a baseline using 10 days of history? Once the PWs are working, they should be providing 100 percent of the home’s electricity usage between 4 PM and midnight. EVs begin charging at midnight when rates are lowest. In my area (SDG&E) peak period is 4 PM to 9 PM. If I am understanding this correctly, my baseline would be calculated using my pre PW usage. After the PWs are installed, there will be no grid draw during that time, although some energy will be sent to the grid during that 5 hour period. In my case would it be best to define the OhmHours as 4 to 9 PM (peak)?
You may want to sign up earlier because clearing the "paperwork" through your utility may take a couple weeks. It did for me with SCE ...
You don't have to participate until you want -- opt-out whenever you want (though if you want to keep your "streaks" ...). However, even the little things, like turning off fridge or tv(s) during OhmHours is enough to participate.
With your solar, your more effective OhmHours would be 5-6 to 9pm due to solar. You can calculate how using peak-power without PW vs with gives you better arbitrage. Such as not using PWs between 8-9pm most of the time (would be covered by net metering anyways?), and then once a week during OhmHours, use the PW to zero 8-9pm usage for the points.
Just calculate it out to your own preferences and tolerances.
NEM 1.0 does not have Non-Bypassable Charges. Only NEM 2.0 has those. That said, if you are on NEM-2 and you generate and export 50kWh per day during daylight hours and consume the same 50kWh during overnight hours, you still have to pay the NBCs for the 50kWh consumption. That is the whole point NBCs - you owe something for the consumption that cannot be offset by your generation.
Just to emphasize: self-consumption and demand-reduction are mutually exclusive. For each hour of the day, you have to decide which you want to do. The baseline is always the last 10 non-event days, not the ones from before you start the program. If you self-consume on those days, your baseline will be 0 and you will not be able to reduce further.
In my case, my peak hours mean that I can't arbitrage effectively after 7pm anyway, since I'd be using shoulder electricity stored in the battery to satisfy shoulder load. You probably have to do a more complicated calculation to see which would pay more. Don't forget income taxes when calculating OhmConnect's payoff, though.
In my case, my peak hours mean that I can't arbitrage effectively after 7pm anyway, since I'd be using shoulder electricity stored in the battery to satisfy shoulder load. You probably have to do a more complicated calculation to see which would pay more. Don't forget income taxes when calculating OhmConnect's payoff, though.
Tesla needs to come up with a Demand Response program tailored to the Powerwall and run it through the California regulatory system. Then they could offer an aggregated Powerwall virtual demand response power plant with compensation to individual owners who opt-in to that program. OhmConnect is just not suited to the normal Powerwall user.
SoundDaTrumpet
Member
The OhmConnect doesn't go very well with solar. Because it is based on 10-day history, it's okay for me to opt-in in the spring/summer as the days grow longer, and when I actually have real controllable loads like A/C. Opting-out in the fall/winter destroys streaks so I only participate once a week (a setting), and schedule only the night hours. It's a game, and not a set and forget type of demand response. I have gone as far as charging my car before 7AM with hopes of catching an OhmHour... sounds wrong... creating demand when there is a better time to do it. OhmConnect has dropped their support for my EV and my JuiceNet enabled EV charger, so EV charging has to be stopped manually. Considering this is a Tesla forum ignore Juicenet (all their hardware is non Tesla connector), hopefully Tesla can introduce a demand response program for their chargers as well. Juicenet I estimate $50/yr. OhmConnect $80/yr. No Powerwall for the above.
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