Leveraging SDGE TOU rates with an EV?

[Ampster]

It is going to be a decade of disruption.

Related to that I just saw this video of Tony Seba's keynote at at a North Carolina Transportation summit. Starting out he shows a picture of a 1900 Easter parade in NYC where there are hundreds of horse draw carriages and one car. He then shows a 1913 picture where there is one horse drawn carriage and hundreds of cars.
The disruption he talks about is bigger than just EVs, it includes autonomous driving and the use, generation and storage of energy. I would have started a new thread but I thought this would be a good footnote to where this discussion was headed.

https://youtu.be/2dR5EwjJits

[RichardCullip]

I now have nearly 10 months of actual performance from my 4kW solar and am fairly confident about which rate I should be on. At this point in time, I'm running a surplus of ~240kWh per month which gives me some flexibility in adding a EV or PHEV to our household electrical demand. In looking at the near future, TOU-DR is still a good rate for me as I can add up to 250kWh of super-off peak demand and still be at or very near to the minimum charge. I need to add at least 250kWh per month of super-off peak demand before TOU-EV-2 starts saving me money over the TOU-DR rate I'm currently on. I would need to add at least 440kWh per month of super-off peak demand before TOU-EV-5 starts saving me money.

Of course, all bets are off if SDG&E gets significant changes in their rate schedules approved by the CPUC. I suspect that I will be analyzing rate schedules and my household demand each year at True-up time as I'm locked to my current rate schedule until then.

[Ampster]

All of the above certainly makes long-range forecasting quite a challenge. Too much uncertainty about where TOU rates are headed in Calif and elsewhere. It's hard enough to do just a forecast for the next 12 months.

Yes, I think flexibility will be important. As I contemplate using my hybrid inverter more to self consume some of my solar, I may have to upgrade my battery pack.

[RichardCullip]

I have seen some of that in some small commercial rate plans with SCE where the super off peak goes from 8AM until 4PM. The peak is still 4-9PM.

At least in California with deregulation and the proliferation of CCAs (Community Choice Aggregation) The IOUs segment of the market is becoming less from generation revenue and more from distribution and transmission. For the most part the IOUs no longer own the generating assets so they are buying in the marketplace.

I had never thought about the faster degradation of transformers because of heat. The effect of rooftop solar destressing them is important. Even though the transformers are bidirectional the measurement and control equipment at substations is not bidirectional and as rooftop and other distributed forms of generation proliferate there is a future investment required to allow the grid to adapt to this phenomena.

It is going to be a decade of disruption.

All of the above certainly makes long-range forecasting quite a challenge. Too much uncertainty about where TOU rates are headed in Calif and elsewhere. It's hard enough to do just a forecast for the next 12 months.

[Ampster]

They will change their super-off-peak hours to whatever is actually super off peak.

I have seen some of that in some small commercial rate plans with SCE where the super off peak goes from 8AM until 4PM. The peak is still 4-9PM.

I have the feeling that the extra utility revenue from a large scale petroleum to EV conversion will easily pay for any necessary distribution upgrades, and probably ahead of the need. Already at the moment, the studies show that EV use lowers rates overall (even for non EV owners) as the quasi-fixed costs like labor and maintenance is spread over a larger revenue pool. At some point increased infrastructure will be needed but that's a while off.

At least in California with deregulation and the proliferation of CCAs (Community Choice Aggregation) The IOUs segment of the market is becoming less from generation revenue and more from distribution and transmission. For the most part the IOUs no longer own the generating assets so they are buying in the marketplace.

I think that still summer peak A/C use on commercial weekdays will exceed EV night demand. Distribution transformers, the key bottleneck, are limited by heat. Too much temp over time results in much faster degradation and possibility of failure grows strongly. EV's charging at night when it's cooler don't stress as much as afternoon air conditioning in heat waves when the transformers are already baking in the sun. (BTW home solar generation destresses some grid to residential transformers in these conditions and lowers utility capex needs, but commercial utilities don't really like it anyway as they'd much rather have the money of a no-solar ratepayer. )

I had never thought about the faster degradation of transformers because of heat. The effect of rooftop solar destressing them is important. Even though the transformers are bidirectional the measurement and control equipment at substations is not bidirectional and as rooftop and other distributed forms of generation proliferate there is a future investment required to allow the grid to adapt to this phenomena.

Likely the TOU will change to be more dynamic and responsive to actual daily to instantaneous grid conditions, like it is for big commercial users now. By then (20-30 years?), cars will mostly be able to communicate with utilities and with bidirectional charging & storage, know how to charge on low demand periods or even be able to supply the grid during peaks and be so compensated. If you let your utility tell you car when to charge you could get a reduced rate. Batteries are already big enough in some EVs that multiple days of average commuting can be charged in an evening's super-off-peak rate.
Increased utility risks and costs will likely come less from EV's (predictable and controllable) than from global warming (persistent heat waves) and violent climate events, storms or heat-exacerbated fires, which we've already seen.

It is going to be a decade of disruption.

[DrChaos]

It may also be worth considering, maybe in another thread, what would/may/possibly happen with respect to POCO TOU rates, tariffs and policies if use at what are now super off peak times really rises for whatever reason - lots of EVs/charging, distributed residential energy storage is suddenly seen as an advantage to the bottom line of utilities and super off peak charging becomes common or encouraged by the POCOs, whatever. If Super off peak use rises enough will super off peak rates then rise ? Will TOU rates equalize to the point that TOU becomes an anachronism ? What effect would all that have on the grid's capacities ?

They will change their super-off-peak hours to whatever is actually super off peak.

I have the feeling that the extra utility revenue from a large scale petroleum to EV conversion will easily pay for any necessary distribution upgrades, and probably ahead of the need. Already at the moment, the studies show that EV use lowers rates overall (even for non EV owners) as the quasi-fixed costs like labor and maintenance is spread over a larger revenue pool. At some point increased infrastructure will be needed but that's a while off.

I think that still summer peak A/C use on commercial weekdays will exceed EV night demand. Distribution transformers, the key bottleneck, are limited by heat. Too much temp over time results in much faster degradation and possibility of failure grows strongly. EV's charging at night when it's cooler don't stress as much as afternoon air conditioning in heat waves when the transformers are already baking in the sun. (BTW home solar generation destresses some grid to residential transformers in these conditions and lowers utility capex needs, but commercial utilities don't really like it anyway as they'd much rather have the money of a no-solar ratepayer. )

Likely the TOU will change to be more dynamic and responsive to actual daily to instantaneous grid conditions, like it is for big commercial users now. By then (20-30 years?), cars will mostly be able to communicate with utilities and with bidirectional charging & storage, know how to charge on low demand periods or even be able to supply the grid during peaks and be so compensated. If you let your utility tell you car when to charge you could get a reduced rate. Batteries are already big enough in some EVs that multiple days of average commuting can be charged in an evening's super-off-peak rate.

Increased utility risks and costs will likely come less from EV's (predictable and controllable) than from global warming (persistent heat waves) and violent climate events, storms or heat-exacerbated fires, which we've already seen.

[Mike90250]

Posting a link as a reply to a direct question is OK, unless it's a fraudulent link, like " I need to get a diploma fast"

[Ampster]

I updated the complete name of the forum.
www.teslamotorsclub.com

[RichardCullip]

I am no sure I can post a link but it is called the tesla motors forum. The specific sub forums that I spend my time on are Tesla Energy and the regional California Forum. I have been a member there since 2012 when I bought a Toyota RAV 4 EV which had a Tesla drivetrain. I was active in a RAV 4 forum and some of the posters there, also referred to the broader discussions on the Tesla forum.

Thanks.

[Ampster]

This is also a subject I’m interested in. Care to share the forum you referenced?

I am no sure I can post a link but it is called the tesla motors club forum. The specific sub forums that I spend my time on are Tesla Energy, the regional California Forum and the Energy, Environment & Policy Forum. I have been a member there since 2012 when I bought a Toyota RAV 4 EV which had a Tesla drivetrain. I was active in a RAV 4 forum and some of the posters there, also referred to the broader discussions on the Tesla forum.

[RichardCullip]

That is a subject that interests me but I don't think it would get much traction on this forum. There is another forum where those regional issues have been discussed more extensively and with input from a diverse cross section of industry professionals and consumers. The discussion on this thread has seen less than ten people post.

This is also a subject I’m interested in. Care to share the forum you referenced?

[Ampster]

.....
It may also be worth considering, maybe in another thread, what would/may/possibly happen with respect to POCO TOU rates, tariffs and policies if use at what are now super off peak times really rises for whatever reason - lots of EVs/charging, distributed residential energy storage is suddenly seen as an advantage to the bottom line of utilities and super off peak charging becomes common or encouraged by the POCOs, whatever. If Super off peak use rises enough will super off peak rates then rise ? Will TOU rates equalize to the point that TOU becomes an anachronism ? What effect would all that have on the grid's capacities ?

That is a subject that interests me but I don't think it would get much traction on this forum. There is another forum where those regional issues have been discussed more extensively and with input from a diverse cross section of industry professionals and consumers. The discussion on this thread has seen less than ten people post.

[J.P.M.]

My comments in this thread have been designed to help EV drivers or potential EV drivers see the possibilities of leveraging TOU rates to their advantage. They may be a small group but globally they are a rapidly growing segment of automobile ownership.

I don't doubt your good intentions. You also won't get an argument (not agreement - that was a typo/brain fart) from me about the idea that EVs are a growing portion of the automobile market and thus responsible for a lot of increased super off peak residential electricity demand.

However, I am of the opinion that there's a better way to save all users money, including EV owners. That way is looking at the effects that all available tariffs will have on total annual electric bills rather than what you seem to be narrowly focused on, that is, what you call leveraging of rates with super off peak to off peak rate differential being what looks to me to be the sole criteria.

My other point was only to note and maybe keep in mind that super off peak sales for EV charging are, at this time anyway, a relatively small segment of most CA POCO's sales, and, because CA EV use is roughly about half the total U.S., that leaves what would seem to be the remaining half of the of the U.S. EV market and (presumably super off peak) electricity sales to be spread among the other 90% of the U.S. population that doesn't live in CA..

Maybe not getting too parochial and myopic about EVs and CA's love of them may be something to think about.

Not everyone lives in the land of fruits and nuts like you, me, Richard and DrChaos.

It may also be worth considering, maybe in another thread, what would/may/possibly happen with respect to POCO TOU rates, tariffs and policies if use at what are now super off peak times really rises for whatever reason - lots of EVs/charging, distributed residential energy storage is suddenly seen as an advantage to the bottom line of utilities and super off peak charging becomes common or encouraged by the POCOs, whatever. If Super off peak use rises enough will super off peak rates then rise ? Will TOU rates equalize to the point that TOU becomes an anachronism ? What effect would all that have on the grid's capacities ?

[Ampster]

However, I still claim .......
I also disagree .........
Maybe a bit off topic.....
.......it does seem to put super off peak vehicle charging in a relatively small group.

My comments in this thread have been designed to help EV drivers or potential EV drivers see the possibilities of leveraging TOU rates to their advantage. They may be a small group but globally they are a rapidly growing segment of automobile ownership.

[J.P.M.]

I don't disagree with you but as a first-order approximation (I'm a physicist not an engineer) I'd guesstimate that 90% of people with EV & Solar are heavy super-off-peak consumers, heavy on-peak generators, and light to zero on-peak consumers. An EV is the only big load that can be shifted to super off peak reliably. And then the gap between off-peak and super-off-peak will dominate the difference between rate plans.

A complete complex simulation will have better calibrated results but for rank ordering the plans, it's a good start.

Nor do I disagree with your estimate that a high number of folks with both EV and solar have the consumption patterns you claim. I also have no data to counter your claims even if I did disagree.

However, I still claim that using only the gap between off peak and super off peak rate for any tariff rather than comparing total estimates of annual bills for all tariffs being considered is shortsighted and may lead to annual bills that may well be higher than a more complete analysis would produce.

I also disagree with your claim that EV charging is the only big load that can be shifted to super off peak. Maybe a bit off topic but while I'll admit that the # of applications may be few but I can probably come up with a couple. One being the high mass/superinsulated dwelling I designed for a desert climate. Any required mechanical cooling would be done at super off peak times with the long thermal time constant allowing the building to coast through the heat of the following day while having low enough thermal hysteresis to maintain comfortable temp. ranges. Kind of like a thermal battery. Battery charging at super off peak hours may also be allowed by some POCOs.

Back on topic, given the relative ease of using a spreadsheet or two to get what's likely a closer est. of total annual bill for any/all considered tariffs and so a bigger picture of the effects of choices made seems, IMO only maybe, worth the small effort. However, because every situation and customer is different, that may remain a moot point.

It may be useful if only as a side note to maybe put some perspective on the relative #'s of EV owners in the population. There are ~ 2.6 EE7 million passenger vehicles registered in CA, including light trucks, and although reliable #'s seem hard to come by, a somewhat optimistic guess as of Sept. 2019 seems to point to somewhere in the vicinity of 6 EE5 plug in electric vehicles registered in CA at that time or ~ 2.3% or so of all registered vehicles, and BTW, CA has ~ 46 - 50 % of all plug in electric vehicle registrations in the U.S, giving the other 49 states a relative paucity of EV's. Because of the way you phrased it, while that doesn't necessarily invalidate your guesstimate , it does seem to put super off peak vehicle charging in a relatively small group.

There are also ~ 7 EE6 single and attached dwelling units in CA. If each of those ~ 600,000 plug in electric vehicles is charged using power from a single family or attached dwelling electric meter, that works out to ~ < 9% or so of the residential electricity customers in CA who are, by your declaration, the only (residential) users of large amounts of super off peak electricity.