I was reading about the powerwall. I notice TOU shift loading is not available at the moment. Is this really a limitation or is there something going on legally. The reason I ask is because I feel that this could actually be a money making scheme if you can do that. I think they are just blocking it so you don't try to charge your battery at say 12 cents per kwh over night and then sell it back at peak for 40 cents per kwh. Net metering is something that is legal in California, I think they are stopping all shift loading for that reason. Anyone have thoughts?
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Time of Use shift loading
- Thread starter mattack4000
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zanary
Active Member
It's not yet available because the software (both the Powerwall and the iOS app) are still in development. Expect to see it by December 31 according to their support lines.
Note, when you do install the Powerwall (at least in my case with PG&E), you have to accept and sign the PG&E Interconnect License, which explicitly states the obvious, that any power you store in your Powerwall (which you purchased from PG&E when using Time of Use costs) cannot be sold back to the provider, or cannot be fed back into the grid.
I was also informed that the Powerwall when configured as Whole Home Backup or Time or Use Load Shifting (when it arrives), prevents you sending power from the Powerwall back into he grid.
I don't think it's a legal thing, but more of a prioritization thing at Tesla. Their first goal was to support Solar installation 1st, followed by WholeHome Backup, and finally (which is pending) is Time of Use Load Shifting (coming soon).
Note, when you do install the Powerwall (at least in my case with PG&E), you have to accept and sign the PG&E Interconnect License, which explicitly states the obvious, that any power you store in your Powerwall (which you purchased from PG&E when using Time of Use costs) cannot be sold back to the provider, or cannot be fed back into the grid.
I was also informed that the Powerwall when configured as Whole Home Backup or Time or Use Load Shifting (when it arrives), prevents you sending power from the Powerwall back into he grid.
I don't think it's a legal thing, but more of a prioritization thing at Tesla. Their first goal was to support Solar installation 1st, followed by WholeHome Backup, and finally (which is pending) is Time of Use Load Shifting (coming soon).
Also, it's highly unlikely your utility will let you "sell" electricity to them at retail rates. Here in PG&E territory, with solar, TOU, and net metering, any electricity sent to the grid during the day is only "credited" at retail rates, which you can then use to buy electricity at night. At the end of the year, if you do have a net surplus generation, they only pay you at wholesale rates (something like 4 cents/kWh). Definitely not a money making opportunity.
Tam
Well-Known Member
What you are talking about is arbitrage: buy electricity to charge your battery at night with a low price then sell it back during daylight with a high price to earn a profit.
I think Europe like Germany would encourage people to make money so the adoption of renewable and storage energy is faster.
However, I don't think most USA utilities are happy about its competitors so they brand solar/battery owners as "parasites".
It's really hard for home owners to earn a buck with solar/battery in the USA unless the laws would change!
You mean regarding the wholesale payment? Yes. At end of the 1 year true-up, any surplus energy is paid out at wholesale rates. Keep in mind this is a true-up of actual kWh generated vs used which is unrelated to the TOU $ credit system.
I don't ever have a net negative, but I could have negative in certain tiers. My true up bill has nothing to do with it as I can see the total before the true up, I always have to pay monthly.
The credits are always at retail rates, however should you have a negative balance due to your solar production, you will be paid out at wholesale rates. The TOU arbitrage is not a way to make money given what they will pay you is miniscule but what does do is significantly reduces your overall costs if you are a EV user like myself. You will never pay peak or partial peak rates since you use the powerwall that is charged at night at off peak. And the solar that is generated is sold back at peak/partial peak rates. Each kw of solar generated will be worth 2-4x than what is being used from the grid
This is why you never build your system to be net positive overall. Anyway, this is my thinking. I want to have a powerwall for backup purposes (I currently have a little Honda) even though my house rarely loses power and I am in a busy suburb. It's tough to justify spending 10K for something that might only get used once every three year, I should add that I have a small 1kwh solar system. It doesn't work during power outages so unless Tesla can wire it to work with the solar only. It is also useless.
Anyway to help offset the 10K cost, that means I need to find ways to justify it. I am thinking since the life expectancy of the battery is 10 years, that means the cost is $83 a month. If I can use it to shift load like I currently do, I feel like I can put a case up that the net cost of it is smaller than what it truly is. For example, if I can charge the battery during offpeak hours (.12/kwh) , I can try to schedule it to hold the power until 5PM when peak starts. The battery would be able to net my meter (I think it is .44/kwh) against my usage and send some power back to ensure I am always at zero since the bulk of my energy cost is in peak time. It's probably not a lot since the battery is only so big, but I feel like this is minimum a gain of 30 cents per kwh. The battery can probably do 10kwh per day, that means a potential $3 saving per day and you multiply that by 30. It will get me to the 90 that i am looking for. Did I think correctly or am I completely off? Sorry it's been a while since I studied my electric bill and I just started looking at the battery.
Anyway to help offset the 10K cost, that means I need to find ways to justify it. I am thinking since the life expectancy of the battery is 10 years, that means the cost is $83 a month. If I can use it to shift load like I currently do, I feel like I can put a case up that the net cost of it is smaller than what it truly is. For example, if I can charge the battery during offpeak hours (.12/kwh) , I can try to schedule it to hold the power until 5PM when peak starts. The battery would be able to net my meter (I think it is .44/kwh) against my usage and send some power back to ensure I am always at zero since the bulk of my energy cost is in peak time. It's probably not a lot since the battery is only so big, but I feel like this is minimum a gain of 30 cents per kwh. The battery can probably do 10kwh per day, that means a potential $3 saving per day and you multiply that by 30. It will get me to the 90 that i am looking for. Did I think correctly or am I completely off? Sorry it's been a while since I studied my electric bill and I just started looking at the battery.
Most if not all of the people commenting in this thread so far appear to be in PG&E territory. I assure you that Net Metering works the same way throughout PG&E territory. In any given month and any given TOU period, any negative kWh total gets full retail credit. The dollar amount for the month is rolled into your true-up totals. This total is treated in one of 3 different ways.
1. You owe a dollar balance at true-up. This balance is the total energy charges. Your minimum charges that you have paid throughout the year month by month are subtracted from this total to find the final amount that you owe.
2. You have a dollar credit balance at true-up, but you are a net consumer of kWh. You owe nothing and are paid nothing. This credit balance is wiped out because you are not owed Net Surplus Compensation.
3. You have a dollar credit balance at true-up and are a net generator of kWh. The total surplus kWh that you generated is added up and you are paid "wholesale" for that surplus. That amount has historically been $0.03-$0.035 per kWh in recent years.
This gets a little more complicated if you are on a CCA which has become the default in San Mateo, Santa Clara (except San Jose), and Marin County. At least for Silicon Valley Clean Energy, you are paid the typical Generation price for all net generation. So, if you are in category #2 above, you will get a check or a rollover credit from SVCE where you would get nothing pre-CCA. I'm pretty sure PG&E will still wipe out all Distribution credits for category #2 and #3 above at true-up.
Now, about PowerWall. It appears that the PG&E battery interconnect agreement does not allow pushing power from the battery into the grid. At all. That does not mean that you can no longer be a net generator, it just means that the battery will only satisfy loads behind the meter (in your house) and any generation that passes into the grid must be coming from your solar system, which is still allowed to feed into the grid for Net Metering credits. This is the main reason that I want TOU controls on my (future) PowerWall. I don't want to "waste" my battery energy charging my EVs overnight because the value of energy is lower overnight than my solar generation (Off-Peak vs. Part-Peak). If I can prevent the PowerWall from discharging during Off-Peak period, my starting SOC will be higher in the morning and will be full earlier in the day from my solar generation. That will allow my solar to earn me more credits in the afternoon while still eliminating my household usage during the Peak rate period through 9pm well after my solar has stopped generating. This does not violate the battery interconnect rules and gives me the best arbitrage benefit while also flattening the "duck curve" for the utility.
1. You owe a dollar balance at true-up. This balance is the total energy charges. Your minimum charges that you have paid throughout the year month by month are subtracted from this total to find the final amount that you owe.
2. You have a dollar credit balance at true-up, but you are a net consumer of kWh. You owe nothing and are paid nothing. This credit balance is wiped out because you are not owed Net Surplus Compensation.
3. You have a dollar credit balance at true-up and are a net generator of kWh. The total surplus kWh that you generated is added up and you are paid "wholesale" for that surplus. That amount has historically been $0.03-$0.035 per kWh in recent years.
This gets a little more complicated if you are on a CCA which has become the default in San Mateo, Santa Clara (except San Jose), and Marin County. At least for Silicon Valley Clean Energy, you are paid the typical Generation price for all net generation. So, if you are in category #2 above, you will get a check or a rollover credit from SVCE where you would get nothing pre-CCA. I'm pretty sure PG&E will still wipe out all Distribution credits for category #2 and #3 above at true-up.
Now, about PowerWall. It appears that the PG&E battery interconnect agreement does not allow pushing power from the battery into the grid. At all. That does not mean that you can no longer be a net generator, it just means that the battery will only satisfy loads behind the meter (in your house) and any generation that passes into the grid must be coming from your solar system, which is still allowed to feed into the grid for Net Metering credits. This is the main reason that I want TOU controls on my (future) PowerWall. I don't want to "waste" my battery energy charging my EVs overnight because the value of energy is lower overnight than my solar generation (Off-Peak vs. Part-Peak). If I can prevent the PowerWall from discharging during Off-Peak period, my starting SOC will be higher in the morning and will be full earlier in the day from my solar generation. That will allow my solar to earn me more credits in the afternoon while still eliminating my household usage during the Peak rate period through 9pm well after my solar has stopped generating. This does not violate the battery interconnect rules and gives me the best arbitrage benefit while also flattening the "duck curve" for the utility.
Exactly, that's why I asked what I asked. My system is too small to be self sufficient, so even if the battery will just eat all the peak and partial peak time charges for me. I would already be golden and the battery would pay for itself. How sure is it that we will be able to do all of that with the "update"
