Need help to understand approximate costs to charge Model Y @ home

[RayB]

Math is confusing, more so for me than others it appears....
Stats app and TelslaFi allow me to enter in "Price per kWh". I'm not sure what approximate rate I should enter and hope someone here can help me. I typically only charge between midnite and 10am (off -peak hours).

We live in the SF Bay Area and installed a smaller size solar system on our roof about 12 years ago (through Solar City). PG&E does a "true -up" with us each October.
Our latest PG&E statement shows the following...
Rate Schedule: Time of Use Plan (Peak: 4pm-9pm, Every Day)
Enrolled Programs: Net Energy Metering (NEM)


Minimum Delivery Charge: $9.53
Peak rate 59.6792 kwH @ $0.32104 = $19.16
Off Peak rate : 166.9351 @ $0.30372 = $50.70
Baseline Credit: 226.6143 @-$0.07584 = -$17.19
Generation Credit: $23.60
Power charge indifference adjustment (??): $10.78

Plus...

Peninsula Clean Energy electrical charges of...
Generation Off-Peak Winter 166.9351 kWh @ $0.04713 = $7.87
Generation On-Peak Winter 59.6792 kWh @ $0.06141 = $3.66

Based on the above...what amount should I figure I pay to charge up the Tesla during off-peak hours??

Thanks in advance!

 

[miimura]

These are the total rates on TOU-C. Worst case is that you are over baseline and you don't charge during the 4-9pm peak time, so ignore the Baseline Credit. The PCE Generation is not additive because PG&E gives you a Generation Credit.

Basically, your Winter charging cost is kWh used X $0.30372. Summer rate season starts June 1, then your cost will jump to $0.35469/kWh.
You may also want to consider whether the EV2 rate will save you money. It really depends on the size of your solar and how much charging you do at home. The charging cost is only $0.18366/kWh Summer and Winter.

 

[Silicon Desert]

Math is confusing, more so for me than others it appears....
Stats app and TelslaFi allow me to enter in "Price per kWh". I'm not sure what approximate rate I should enter and hope someone here can help me. I typically only charge between midnite and 10am (off -peak hours).

We live in the SF Bay Area and installed a smaller size solar system on our roof about 12 years ago (through Solar City). PG&E does a "true -up" with us each October.
Our latest PG&E statement shows the following...
Rate Schedule: Time of Use Plan (Peak: 4pm-9pm, Every Day)
Enrolled Programs: Net Energy Metering (NEM)


Minimum Delivery Charge: $9.53
Peak rate 59.6792 kwH @ $0.32104 = $19.16
Off Peak rate : 166.9351 @ $0.30372 = $50.70
Baseline Credit: 226.6143 @-$0.07584 = -$17.19
Generation Credit: $23.60
Power charge indifference adjustment (??): $10.78

Plus...

Peninsula Clean Energy electrical charges of...
Generation Off-Peak Winter 166.9351 kWh @ $0.04713 = $7.87
Generation On-Peak Winter 59.6792 kWh @ $0.06141 = $3.66

Based on the above...what amount should I figure I pay to charge up the Tesla during off-peak hours??

Thanks in advance!

Looks to me like 30 cents should be about right because that is what you are paying for off peak rates and that is usually when you charge. That should be close enough to give you an idea of what it is costing to charge your car. Actually, I am surprised why the peak and off peak rates are almost the same. I would expect a much bigger difference in the rate.

 

[RayB]

These are the total rates on TOU-C. Worst case is that you are over baseline and you don't charge during the 4-9pm peak time, so ignore the Baseline Credit. The PCE Generation is not additive because PG&E gives you a Generation Credit.

View attachment 663214

Basically, your Winter charging cost is kWh used X $0.30372. Summer rate season starts June 1, then your cost will jump to $0.35469/kWh.
You may also want to consider whether the EV2 rate will save you money. It really depends on the size of your solar and how much charging you do at home. The charging cost is only $0.18366/kWh Summer and Winter.

THANKS so much. This answers my question.
Also...just to update you...we have a 3.2 KW solar system, which generates about 4,100 kWh/year. Both of us work from home, so our driving is less than most people.

 

[RayB]

These are the total rates on TOU-C. Worst case is that you are over baseline and you don't charge during the 4-9pm peak time, so ignore the Baseline Credit. The PCE Generation is not additive because PG&E gives you a Generation Credit.

View attachment 663214

Basically, your Winter charging cost is kWh used X $0.30372. Summer rate season starts June 1, then your cost will jump to $0.35469/kWh.
You may also want to consider whether the EV2 rate will save you money. It really depends on the size of your solar and how much charging you do at home. The charging cost is only $0.18366/kWh Summer and Winter.

I just thought of another question...should I add the charges from Peninsula Clean Energy onto the PG&E rates? Not sure I understand why I need Peninsula Clean Energy anyways... Is this mandatory?

Peninsula Clean Energy electrical charges of...
Generation Off-Peak Winter 166.9351 kWh @ $0.04713 = $7.87
Generation On-Peak Winter 59.6792 kWh @ $0.06141 = $3.66

 

[whisperingshad]

Seems like you need more solar...

 

[miimura]

I just thought of another question...should I add the charges from Peninsula Clean Energy onto the PG&E rates? Not sure I understand why I need Peninsula Clean Energy anyways... Is this mandatory?

Peninsula Clean Energy electrical charges of...
Generation Off-Peak Winter 166.9351 kWh @ $0.04713 = $7.87
Generation On-Peak Winter 59.6792 kWh @ $0.06141 = $3.66

No, you don't add it in. Here's how the math works using your original numbers:

Generation Off-Peak Winter 166.9351 kWh @ $0.04713 = $7.87
Generation On-Peak Winter 59.6792 kWh @ $0.06141 = $3.66
Power charge indifference adjustment (??): $10.78
Franchise Fee Surcharge ($0.00048/kWh): $0.11 (my calculation)
Total Generation Service: $22.42
PG&E Generation Credit: -$23.60
PCE saved you $1.18 versus the PG&E full tariff rate.

So, using the full PG&E tariff rate to calculate your EV charging costs will always be over-estimating a little bit.

 

[RayB]

No, you don't add it in. Here's how the math works using your original numbers:

Generation Off-Peak Winter 166.9351 kWh @ $0.04713 = $7.87
Generation On-Peak Winter 59.6792 kWh @ $0.06141 = $3.66
Power charge indifference adjustment (??): $10.78
Franchise Fee Surcharge ($0.00048/kWh): $0.11 (my calculation)
Total Generation Service: $22.42
PG&E Generation Credit: -$23.60
PCE saved you $1.18 versus the PG&E full tariff rate.

So, using the full PG&E tariff rate to calculate your EV charging costs will always be over-estimating a little bit.

Thanks for explaining this to me. This is very helpful!