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abusing Time Of Use rates

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moonlight23

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Aug 8, 2022
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Here are my utility’s rates based on Time Of Use (TOU):
  • $0.42/kwh - on peak (4pm - 9pm)
  • $0.07/kwh - super off peak $0.07/kwh (12am - 6am)
Hypothetically speaking, if I just got 1 solar panel just so utility company can approve NEM to sell back to the grid, would there be any technical or ethical reasons why I shouldn’t hook up a few batteries to fill at super off peak then unload it all at on peak times to bank up a large bill credit? This would effectively cancel out a need for solar at all by abusing the cost disparity.
 
Most likely they will credit you the off peak. They are in the business doing this full time, think they are going to give money away that easy?
 
moonlight23 said:
Here are my utility’s rates based on Time Of Use (TOU):
  • $0.42/kwh - on peak (4pm - 9pm)
  • $0.07/kwh - super off peak $0.07/kwh (12am - 6am)
Hypothetically speaking, if I just got 1 solar panel just so utility company can approve NEM to sell back to the grid, would there be any technical or ethical reasons why I shouldn’t hook up a few batteries to fill at super off peak then unload it all at on peak times to bank up a large bill credit? This would effectively cancel out a need for solar at all by abusing the cost disparity.
Click to expand...
Go for it! They've got capacity to burn off peak and need some help when they are peaking. Hence the rate structure.

Edit: I should add that pretty much any attempt to 'screw the man" usually fails and that 99% fail.
 
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moonlight23 said:
got 1 solar panel just so utility company can approve NEM to sell back to the grid, would there be any technical or ethical reasons why I shouldn’t hook up a few batteries to fill at super off peak then unload it all at on peak times to bank up a large bill credit?
Click to expand...
Yes, it is most likely is not allowed in your NEM agreement. Have you costed out the equipment to do that? How long is the pay back?
 
moonlight23 said:
Here are my utility’s rates based on Time Of Use (TOU):
  • $0.42/kwh - on peak (4pm - 9pm)
  • $0.07/kwh - super off peak $0.07/kwh (12am - 6am)
Hypothetically speaking, if I just got 1 solar panel just so utility company can approve NEM to sell back to the grid, would there be any technical or ethical reasons why I shouldn’t hook up a few batteries to fill at super off peak then unload it all at on peak times to bank up a large bill credit? This would effectively cancel out a need for solar at all by abusing the cost disparity.
Click to expand...
Usually the permit to generate will limit arbitraging the rate with batteries.
Probably a no export rule on battery power.
 
Umm time of use is usually for consuption only.

Excess solar wholesale back to the grid is typically time averaged over the entire year and the untilty cuts a check if the excess generation exceeds consuption. In you’re case with losses you’ll never have net excess.
 
moonlight23 said:
why I shouldn’t hook up a few batteries to fill at super off peak
Click to expand...
Say by chance you could pull this off - you would not batteries but an inertia UPS. Very common in the commercial world for something like this. For example a large meat factory cools off the warehouse freezer at night using the lower rate. At the same time they spin the large flywheels to store and power required during the day. They are not selling it back to the grid though.
 
These guys use nissan leaf batteries to store energy to sell on peak hours

They claim to store solar, but I'd be willing to bet they buy, and store off-peak, then sell on-peak

Really you're doing a service, if you do this.
 
If you are using any appreciable amount of power between 4pm and 9 pm why bother with the complexity of selling back? Just have batteries that are charged during off peak hours and use battery power during peak.. you'd save more money that way without all the complexity of trying to sell back.

Edit: I may be missing the point and OP knows this but wants to take this to the extreme by trying to make money by taking advantage of the huge price differences.
 
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740GLE said:
Excess solar wholesale back to the grid is typically time averaged over the entire year and the untilty cuts a check if the excess generation exceeds consuption. In you’re case with losses you’ll never have net excess.
Click to expand...

There is a difference between bill credits at the end of the month, and "true up" at the end of the year where they pay chump change.
 
I guess this doesn't work in every area, but at least for my area, straight from their website I don't see anything that disallows this.

"…every excess kilowatt-hour your system generates is credited to your account at the higher rate during the summer on-peak period."
Click to expand...
I read that as yes, you can sell back to us at the higher rate

"The higher credits you receive can offset the cost of electricity during times when you may need electricity from the grid"
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I read this as yes, you can use those credits when you need it, like charging a battery ?

reference:

Make an Informed Rate Choice | San Diego Gas & Electric

www.sdge.com www.sdge.com
 
Their website isn't going to list all the terms and conditions. With PGE, NEM 2.0 and a battery, the agreement is that you will not sell them back grid power. They'll let you move around solar generation and shove it all back in peak time, but they don't want to buy back their own power.
 
BradCagle said:
Really you're doing a service, if you do this
Click to expand...
I agree it is probably doing the grid some good. However there are programs to do this, but you have to apply to the program and sell back when they request power. Tesla has a Virtual Power Plant where participants can get paid as much as $1per kWh. I don't know when others will be able to participate.
 
Ampster said:
I agree it is probably doing the grid some good. However there are programs to do this, but you have to apply to the program and sell back when they request power. Tesla has a Virtual Power Plant where participants can get paid as much as $1per kWh. I don't know when others will be able to participate.
Click to expand...
Yeah, good points. I participate in Ohmconnect, they pay me $1.67/kWh once or twice a week all summer. It would help the OP's payback on this project, but it's not a daily/year round income.
 
moonlight23 said:
Lots of different answers. Someone be the first to try this!
Click to expand...
740GLE said:
Umm time of use is usually for consuption only.

Excess solar wholesale back to the grid is typically time averaged over the entire year and the untilty cuts a check if the excess generation exceeds consuption. In you’re case with losses you’ll never have net excess.
Click to expand...
I get full credit at the peak, off peak, or super off peak rates. This is netted with usage at the same rates depending on which way the power is flowing.

The TOU rate times were far more generous in years past. IIRC noon to 8pm was on peak rates and the solar would really provide a generous credit. The first seven years of solar I produced maybe 40%-50% of my usage and with the favorable TOU it brought my annual bill from $2500 to $100. Very lucrative with system cost fully recovered in five years. No batteries.

Now that the utility has an abundance of solar power the times have changed and my bill has increased substantially. My permit to generate listed some details of my system and included no batteries. Might get away with some but if producing full wattage into the dark it will be rather obvious.
 
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