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slmitchell737
Member
I love everything about TOU
Just wish there was an app that could consider price and tou during route planning.
Just wish there was an app that could consider price and tou during route planning.
That's something I've been unclear about for some time. So you pay three separate demand charges every month, one for each rate period, and not just the largest of the three? That sure adds up fast.
Does Tesla or the utility own the transformers at their supercharging sites? The utilities obviously work transformer costs and losses into the different rates for each delivery voltage but we don't know if those tariffed numbers reflect reality. It makes sense that the demand and energy charges would be higher at lower voltages since the transformer and its losses becomes the utility's responsibility, but it's interesting that the meter charge is higher at the higher voltages. I suppose those meters are made in smaller quantities and/or cost more to service.
I don't think the actual cost of the meters has anything to do with it. They just want to collect a minimum amount for the fact that the service and transformer and everything is there, even if you don't use it. Then when you do use it, they really get to charge you.
So Rates 101
As a company you buy stuff and resell it or charge others who use it. You have to receive enough revenue to make a profit worthy of investors.
So if you buy a transformer and connect it to the grid, and buy a meter you have to charge enough to recover your cost and make some profit. The transformer size, proportional to cost, is determined by the maximum consumption rate (in kilowatts). In fact there is a whole capacity cost from the meter back to the power plant that is recovered by the demand charge. That capacity cost is amortized over time so it is not collect all at once on the first bill. It is charged monthly. The demand varies monthly so the amount charged varies monthly but the rate is designed to cover the cost of the capacity including maintenance.
If the customer wants to own the transformer then that part of the capacity cost is removed from the rate he pays. But unless otherwise agreed, he is on the hook for maintenance and replacement. Some larger customers go this way. When I worked, we also had some customers who had their own substation and took delivery at 138,000V. One such was the steel mill southwest of Dallas. Their peak demand was about 150MW. That is 150,000kW.
Variable costs that is costs proportional to usage are billed on a consumption (kWh) basis. Mostly that is fuel.
Since residences have very similar load shapes we can cover all costs fairly with a consumption (per kWh) charge. Commercial customers have a very variety of load shapes so a uniform consumption rate is not fair giving undercharging some and overcharging others.
Metering costs are born by the customer. A residential meter is typically capable of 240V single phase and 200A. A commercial customer may take power delivery at 480V and 800A so more expensive metering must be used and is aid for by a larger customer charge.
You can imagine the metering cost of a customer taking power at 138,000V and several hundred Amps is very high. They have a higher customer charge based on that high cost.
As a company you buy stuff and resell it or charge others who use it. You have to receive enough revenue to make a profit worthy of investors.
So if you buy a transformer and connect it to the grid, and buy a meter you have to charge enough to recover your cost and make some profit. The transformer size, proportional to cost, is determined by the maximum consumption rate (in kilowatts). In fact there is a whole capacity cost from the meter back to the power plant that is recovered by the demand charge. That capacity cost is amortized over time so it is not collect all at once on the first bill. It is charged monthly. The demand varies monthly so the amount charged varies monthly but the rate is designed to cover the cost of the capacity including maintenance.
If the customer wants to own the transformer then that part of the capacity cost is removed from the rate he pays. But unless otherwise agreed, he is on the hook for maintenance and replacement. Some larger customers go this way. When I worked, we also had some customers who had their own substation and took delivery at 138,000V. One such was the steel mill southwest of Dallas. Their peak demand was about 150MW. That is 150,000kW.
Variable costs that is costs proportional to usage are billed on a consumption (kWh) basis. Mostly that is fuel.
Since residences have very similar load shapes we can cover all costs fairly with a consumption (per kWh) charge. Commercial customers have a very variety of load shapes so a uniform consumption rate is not fair giving undercharging some and overcharging others.
Metering costs are born by the customer. A residential meter is typically capable of 240V single phase and 200A. A commercial customer may take power delivery at 480V and 800A so more expensive metering must be used and is aid for by a larger customer charge.
You can imagine the metering cost of a customer taking power at 138,000V and several hundred Amps is very high. They have a higher customer charge based on that high cost.
This is the first I have seen a supercharger with TOU pricing outside of CA: Supercharger - Tigard, OR
The original comment also said they had seen it in the Seattle area as well.
The original comment also said they had seen it in the Seattle area as well.
Observed this south of San Francisco, CA recently, when I started supercharging near 3:45 pm,
then seeing the TOU notice from the map screen for that location kicking in at 4:00 pm with a rate 50% higher.
I wondered which rate would apply (or a blend of both) if I overstayed. At first the charge on
the screen seemed to jump at 4:00pm, with my total bill being $21.06 at the end. I didn't keep precise
notes on kWh used over which interval, but amusingly, when I got home to check the Tesla account
charge it was only $14.04 -- the starting rate to the penny!
I'm not sure if I'd rely on this gift, thinking that I'll now plan to finish charging by that certain time
in the future. However, it makes sense this way -- if one was at an old-fashioned
gas pump and the displayed rate changed during the middle of a tank fill the reaction would be swift.
Perhaps this is why county, state, or provincial entities have started to regulate that EV "pump"
digital signage for kWh will be required.
then seeing the TOU notice from the map screen for that location kicking in at 4:00 pm with a rate 50% higher.
I wondered which rate would apply (or a blend of both) if I overstayed. At first the charge on
the screen seemed to jump at 4:00pm, with my total bill being $21.06 at the end. I didn't keep precise
notes on kWh used over which interval, but amusingly, when I got home to check the Tesla account
charge it was only $14.04 -- the starting rate to the penny!
I'm not sure if I'd rely on this gift, thinking that I'll now plan to finish charging by that certain time
in the future. However, it makes sense this way -- if one was at an old-fashioned
gas pump and the displayed rate changed during the middle of a tank fill the reaction would be swift.
Perhaps this is why county, state, or provincial entities have started to regulate that EV "pump"
digital signage for kWh will be required.
It's pretty simple math, but can be fairly hard to implement this type of dynamic pricing adjustment too easily.. Tesla may have just said let it be for now.
This is where I love having my MS with Free unlimited supercharging for life.. 
Somewhat related to the various TOU pricing tiers continuously expanding & changing at the California SuperChargers, but is there really no TMC wiki or other crowdsourced site/google spreadsheet containing the latest TOU (or otherwise) charging pricing at various locations?
Yes, can manually go check this in the car's nav... but where's the fun in that?
Yes, can manually go check this in the car's nav... but where's the fun in that?
Me too! I've supercharged 4 times in 3.5 years and 60k miles!This is where I love having my MS with Free unlimited supercharging for life..
FlatSix911
Porsche 918 Hybrid
This is where I love having my MS with Free unlimited supercharging for life..
Agreed... I had no idea that Tesla had implemented TOU charging rates.
ChrisJ
Member
For generation they probably can in some areas of California. But it may not be worth the extra hassle.
Mrbrock
Active Member
Saw this in Petaluma yesterday but it wasn’t really a peak/off-peak timing. It was daytime/nighttime. 9am-9pm was $0.30 and 9pm-9am was $0.09. I think I have a picture on my phone I will post later. $0.09 is cheaper than almost any current PGE TOU home rates (unless there is a super old grandfathered one that is less) so if this was closer to me it would definitely have me supercharging late at night or early morning vs charging at home until I get solar and net metering going. That is about $0.02/mile. ICE cars would have to be 150mi/gal at $3/gal to equal that cost.
SageBrush
REJECT Fascism
This is the sterile version of how charges are set, and it actually is a pretty good description of commercial charges. It completely breaks down though with residential due to regulatory overview. If you go to PUC meetings you will hear some variation of the following:
- We the utility have to (want to) collect this much revenue to cover expenses. Let's decide who to charge how much to reach that number
- We the utility invested this much money last year. We expect a 10% ROI
I believe this was a promotional Tesla thing for the holiday weekend?
Tesla tests Supercharger limited time discounts to offset expensive peak demand charges - Electrek
Mrbrock
Active Member
Yep, we’ll see how the feedback goes and if it worked as planned. I think without a pop up notification it went unnoticed by most people. Maybe we’ll see it each weekend and during holiday travel.
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