Leveraging SDGE TOU rates with an EV?

[DrChaos]

Remember the POCO stocks are an investment to some and the investors expect increasing returns or they go somewhere else with their money. It is a bad economical spiral for the POCO to keep providing more to their investors then other business investments as well as their promise to keep the lights on for their customers.

This is a good reason in my opinion to have municipally owned utilities. In California, the municipal utilities, (LADWP, SMUD, Pasadena, Riverside, etc) have consistently lower rates than their for-profit peers, even with the usual management issues with a long term government project. In LADWP a manager making $300K is a scandal. In SDG&E/Sempra the top can make $5-10 milliion and charge higher rates.

SDG&E in particular has a clear incentive to prioritize fossil fuel use. They're owned by Sempra which is an unregulated company that just happens to own natural gas pipelines and generating stations supplying SDG&E territory. If you were a SDG&E executive, the way up to a much higher compensation is clearly to get promoted to Sempra. So, will anybody with power at SDG&E make efforts to reduce fossil fuel use and encourage more self and other generation that doesn't profit Sempra? No, it's to keep the gas flowing from the electric & gas utility side.

[scrambler]

Have you overlaid some scenerios of a two EV family who drives say 50 or 100 miles a day and therefore could consume 25 kWhrs per day at off peak?

I have not done that either as there was no need for me as I already have 2 electric cars, but that would be farily easy to add.

Changing consumption profile would require for me to create a second component where I would customize hourly data for the whole year based on different user scenarios.

I could for example create a side spreadsheet that would take the existing Hourly usage data of someone who doe not have electric cars, then automatically add daily electric car charging number to it based on a few variables like car efficiency, daily miles, charging only at night or day and night etc…

That hourly data could then feed the existing spreadsheet that compute the solar/battery / grid usage.

[Ampster]

...
Just wondering what tools you use that led you to the conclusion that those two tariffs were optimum or best for EV + Solar users.

I'm also interested in maybe learning some new tricks or things I might improve upon in my bill generation algorithms.

Have you overlaid some scenerios of a two EV family who drives say 50 or 100 miles a day and therefore could consume 25 kWhrs per day at off peak?

[scrambler]

Since most every situation and best solution is different, or at least perceived as different by most every electrical customer, such tools might be useful in the decision making process.

Just wondering what tools you use that led you to the conclusion that those two tariffs were optimum or best for EV + Solar users.

I'm also interested in maybe learning some new tricks or things I might improve upon in my bill generation algorithms.

I personally built a basic spreadsheet that uses hourly usage data from my POCO and hourly production data (from PVWatt before install, from solar reporting after). I can customize the spreadsheet to take into account different rate schedule and prices, as well as what operating mode the solar system is running (including with or without a battery system).

Defending on the NEM system it would need to be customize further as the buy back is different with each. the spreadsheet right now is PG&E with or without MCE (who has a better buyback than PG&E).

What I noticed using the spreadsheet is that with the recent change with EV rate and schedule, the gain from buyback actually went down in my configuration.

It sounds like you may have gone a step further, can you describe what you did?

[J.P.M.]

Back to the original question: I am in SDG&E with solar and an EV. My solar generation, over a year, is about net even with my consumption including an EV. I don't yet have air conditioning.

I chose the TOU-DR-P rate. I think it is optimal for my condition. More specifically: in summer months there is a 10c difference between "off-peak" (when most generation happens) and super-off-peak (when I would charge the EV and consume the most), so I can accumulate credit faster than energy use. Additionally, there is only a 1c increment for the on-peak, when I may use electricity and solar generation is low to zero. I like not having to stress too much about the on-peak hours.

The issue though is that there is a large penalty rate for the Reduce Your Use days, which are called occasionally on very hot summer weekdays (no guarantee but nearly always true)---a $1.16 increment to rate between 2 to 6pm on those days. Summer 2019 there were none, Summer 2018 there were four. But as they were 2-6pm, as I planned to totally minimize consumption on those times they ended up being a very good generating bonus as I had net generation during those hours, maybe $15 in credit per RYU day!

SDG&E rates here: (bookmark this page!): https://www.sdge.com/total-electric-rates

If I were to be a heavier consumer, e.g. with significant AC use, then the EV-TOU-5 rate would be optimal---as there is a huge gap between generation hours rates and super-off-peak (EV charge time) rates, and this gap is present year round. At the cost of $16 per month of hard money that can't be offset with generation, plus the non-bypassable charges, so maybe $25 per month? The upside would be that I would earn large generation credit from rate arbitrage that could be used for AC or other consumption.

For TOU-DR-P the combination of minimum bill and NBC's + taxes results in a net minimum hard money bill of about $12 per month.

I think the best rate plans for EV+Solar users in SDG&E are TOU-DR-P and EV-TOU-5.

Note there is also TOU-DR rate (not really advertised) that is like the other TOU rate that SDG&E is pushing, but with a lesser gap from on-peak to off-peak. But the gap from off-peak to super-off-peak is more like 6c vs 10c, similar to EV-TOU-2 and DR-SES (which are almost the same).

What tools do you use that led you to the conclusion that TOU-DR-P is the optimum for you ? Are they quantitative tools ? Spreadsheets ? Other ?

When I found out, and pretty much what I'd already guessed as a blinding flash of the obvious, that most of the residential PV decision for most folks was financial, I then saw an important part of the decision process would require a way to accurately compare what a residential electric bills would be both before and after PV additions under various available tariffs, with considerations for knowing or at least defining things as unknowable for the future.

Took a while to get there, but now I've got methods to estimate bills for SDG & E at least for me and most any residential SDG & E customer in a way that I believe allows for reasonably accurate and quick bill generation based on use, with or without solar generation and comparisons.

Since most every situation and best solution is different, or at least perceived as different by most every electrical customer, such tools might be useful in the decision making process.

Just wondering what tools you use that led you to the conclusion that those two tariffs were optimum or best for EV + Solar users.

I'm also interested in maybe learning some new tricks or things I might improve upon in my bill generation algorithms.

[J.P.M.]

It will have the perverse incentive of encouraging needless consumption and probably fossil fuel use.

It may well do that. I agree. It may also do more.

My point however, was that there is always uncertainty in assumptions about the future with respect to residential PV. In those assumptions, cooking in the idea that because rates will always increase (which seems a reasonable bet IMO), while not considering or ignoring that the POCO will likely do what it can to it's best benefit (which seems another reasonable assumption IMO only), and in so doing make PV less cost effective, may not be the best set of assumptions.

While not disagreeing with you, in what ways do you all think residential users, PV owners and others, will see/perceive such an increase in the min. billing period charge that would possibly encourage them to consume more electricity ?

Also, what possible impact(s) do you see on the go/no go decision for those residential POCO customers who may be contemplating adding PV ? Bigger arrays ? smaller ? No/forego PV for now ? Changes in PV project budget $$'s ? Other, such as more conservation in lieu of PV ?

[SunEagle]

Agreed, no charge should remove the incentive to be less wasteful and save energy. Decades before
my solar, I had many an electric bill under $20. Back then all agreed (at least to the public) it was best
to minimize consumption. Now everything is oriented to guarantee extracting as much $ from the
customer regardless of consumption. One reason I went solar was to avoid all these extra charges
that I see keep expanding on any monthly account. I avoided that by eliminating connection to the
gas company, but cannot operate here without net metering with the electric co. Bruce Roe

Unfortunately I feel most POCO's are trying to justify additional charges due to their loss of customers that use to purchase as much power as they had before because of installing solar. The sad part is the loss to the POCO due to local solar power generation is less then what they get with the additional charges to all customers.

Remember the POCO stocks are an investment to some and the investors expect increasing returns or they go somewhere else with their money. It is a bad economical spiral for the POCO to keep providing more to their investors then other business investments as well as their promise to keep the lights on for their customers.

[bcroe]

It will have the perverse incentive of encouraging needless consumption and probably fossil fuel use.

Agreed, no charge should remove the incentive to be less wasteful and save energy. Decades before
my solar, I had many an electric bill under $20. Back then all agreed (at least to the public) it was best
to minimize consumption. Now everything is oriented to guarantee extracting as much $ from the
customer regardless of consumption. One reason I went solar was to avoid all these extra charges
that I see keep expanding on any monthly account. I avoided that by eliminating connection to the
gas company, but cannot operate here without net metering with the electric co. Bruce Roe

[DrChaos]

Yea. Don't know how that will wring out as it winds it's way through the lobbies and cloakrooms of the CPUC.

If it does become reality in some form (?), and depending on how it's structured, and similar to the ways NEM rate/T.O.U. time restructuring lowered array cost effectiveness by ~ 22 - 25% or so, such a charge may wind up as another example of some of the risks of oversizing an array based on assumptions of increasing array cost effectiveness from rates that are assumed to only go up, and that such an assumption is not a always a slam dunk or the only thing that affects an electric bill.

If that $38 min. charge/billing period is against usage, and again, depending on how it's structured, for this oversimplified example only, that could reduce the value of an array's first $ 38 worth of generation per billing period to zero. That is, the $38 charge might well be there regardless of the amount of any PV generation.

It will have the perverse incentive of encouraging needless consumption and probably fossil fuel use.

[DrChaos]

More FWIW: I didn't see T.O.U. rates with a tiered overly - at least in CA - until a couple/3 years ago. I believe SCE and PG & E started them ~ the same time. SDG & E didn't have one until ~ 18 months ago. The SDG & E T.O.U tariff for residential PV users does not use/overlay a tiered rate, at least not at this time. Other SDG & E T.O.U. tariffs do.

It took me a while to get the spreadsheets for tiered rate T.O.U. tariffs right, mostly because of how the basic daily allocation and thus billing period allocations for determining tier one sizes and so credits are determined. Not conceptually difficult as that's needed for the old, straight tier tariffs, but more details than necessary for straight T.O.U. only tariffs if accuracy is wanted.

Some (most ?) residential customers of SDG & E and probably the other 2 CA I.O.U.'s will probably be on a tiered T.O.U. tariff either by ignorant default or by informed choice/design at some future point.

Back to the original question: I am in SDG&E with solar and an EV. My solar generation, over a year, is about net even with my consumption including an EV. I don't yet have air conditioning.

I chose the TOU-DR-P rate. I think it is optimal for my condition. More specifically: in summer months there is a 10c difference between "off-peak" (when most generation happens) and super-off-peak (when I would charge the EV and consume the most), so I can accumulate credit faster than energy use. Additionally, there is only a 1c increment for the on-peak, when I may use electricity and solar generation is low to zero. I like not having to stress too much about the on-peak hours.

The issue though is that there is a large penalty rate for the Reduce Your Use days, which are called occasionally on very hot summer weekdays (no guarantee but nearly always true)---a $1.16 increment to rate between 2 to 6pm on those days. Summer 2019 there were none, Summer 2018 there were four. But as they were 2-6pm, as I planned to totally minimize consumption on those times they ended up being a very good generating bonus as I had net generation during those hours, maybe $15 in credit per RYU day!

SDG&E rates here: (bookmark this page!): https://www.sdge.com/total-electric-rates

If I were to be a heavier consumer, e.g. with significant AC use, then the EV-TOU-5 rate would be optimal---as there is a huge gap between generation hours rates and super-off-peak (EV charge time) rates, and this gap is present year round. At the cost of $16 per month of hard money that can't be offset with generation, plus the non-bypassable charges, so maybe $25 per month? The upside would be that I would earn large generation credit from rate arbitrage that could be used for AC or other consumption.

For TOU-DR-P the combination of minimum bill and NBC's + taxes results in a net minimum hard money bill of about $12 per month.

I think the best rate plans for EV+Solar users in SDG&E are TOU-DR-P and EV-TOU-5.

Note there is also TOU-DR rate (not really advertised) that is like the other TOU rate that SDG&E is pushing, but with a lesser gap from on-peak to off-peak. But the gap from off-peak to super-off-peak is more like 6c vs 10c, similar to EV-TOU-2 and DR-SES (which are almost the same).

[J.P.M.]

This is probably old news, but in case you missed it, SDG&E has a proposed rate change in front of the CPUC. It includes a $10 fixed monthly charge and a monthly bill minimum of $38. The $10 fixed charge is not included in the monthly bill minimum. If approved by the CPUC this rate change will go into effect in 2021. The main driving motivation behind this change is that low electrical users, such as those of us with solar, aren't paying our fair share of the fixed costs for maintaining/improving the grid. Ouch

https://sdgenews.com/article/fixed-c...ll-whats-story

Yea. Don't know how that will wring out as it winds it's way through the lobbies and cloakrooms of the CPUC.

If it does become reality in some form (?), and depending on how it's structured, and similar to the ways NEM rate/T.O.U. time restructuring lowered array cost effectiveness by ~ 22 - 25% or so, such a charge may wind up as another example of some of the risks of oversizing an array based on assumptions of increasing array cost effectiveness from rates that are assumed to only go up, and that such an assumption is not a always a slam dunk or the only thing that affects an electric bill.

If that $38 min. charge/billing period is against usage, and again, depending on how it's structured, for this oversimplified example only, that could reduce the value of an array's first $ 38 worth of generation per billing period to zero. That is, the $38 charge might well be there regardless of the amount of any PV generation.

To greatly oversimplify: Say I use 1,000 kWh over a billing period and I generate 1,000 kWh over the same period, and I pay $0.38/kWh flat rate to the POCO.

Without the $38 min. charge, my bill is $0.

If the $38 charge is in place, and if it's against usage, even though my POCO usage = zero, my bill is still $38.

So, for this very oversimplified example, my array's ability to offset $38 of my bill per billing period just disappeared, making the investment in the (now oversized) PV less cost effective, probably by something like 10% or so for this oversimplified example.

Or, looked at another way, since there's no way array capacity can make up that $38 by more generation (except by the almost as cost ineffective method of getting ~ $0.03 to $0.05/kWh for excess generation at trueup), the array just became oversized by about 10 % or so. I'll have something like 1,200 kWh/yr. of excess generation that is worth $0.03- $0.05 or so at trueup. If I'm already oversized, things just got worse.

Now, I sure didn't know that was going to happen when I sized the array any more than I knew rate restructuring would make my array less cost effective. I'm just saying that there are a lot of uncertainties about array sizing, and some of them can run counter to the usual logic that oversizing will always be a safe bet with respect to getting the most bang for my buck.

If that min. charge does become reality in some form, my guess is it'll have the effect of reducing array sizes for informed potential future PV owners but have little to no effect on the thinking (or lack of thinking) by most potential PV owners.

Guess we'll all have to wait and see what flushes out of the pipe.

A bit off topic, but for my situation, NEM, 1.0, tiered rates, with an additional min. charge in place my bill will increase by 12* $38 = $456/yr. A very simplified analysis: The array size I require for a 100% offset of my current usage is 3,924 STC W. The array size that offsets all but $456 of that usage is 3,150 STC W. I'm not complaining, and unlike most it seems, I didn't get an array with any hope of cost effectiveness as a design goal, and I knew things are subject to a future full of unknowns, but if I was doing the same thing with a $38/billing period min. charge in place, I'd have probably taken that into account.

[RichardCullip]

This is probably old news, but in case you missed it, SDG&E has a proposed rate change in front of the CPUC. It includes a $10 fixed monthly charge and a monthly bill minimum of $38. The $10 fixed charge is not included in the monthly bill minimum. If approved by the CPUC this rate change will go into effect in 2021. The main driving motivation behind this change is that low electrical users, such as those of us with solar, aren't paying our fair share of the fixed costs for maintaining/improving the grid. Ouch

https://sdgenews.com/article/fixed-charge-minimum-bill-whats-story

[J.P.M.]

Is that based on some policy directive from the CEC? The change in rates that I see more clearly is the transition to a more fixed component of the rates. As noted above by @RichardCullip one of the SDG & E EV rates has $16 fixed component.

Well, since we're talking about a tariff, and since the CEC does not have the authority with respect to rates or tariffs for the CA IOU's, the answer to your question is "I don't believe so".

The way I understand it, the CEC is the state's primary energy policy and planning agency.

The CPUC on the other hand and through its oversight, regulates the I.O.U.s with respect to rates, and for this conversation, tariffs.

There is a difference.

BTW, with respect to the change in rates that you see more clearly as the transition to a more fixed component of the rates: Is that based on some policy directive from the CEC or other CA gov. agency ?

Since my crystal ball is still in the shop, what I wrote is based on my opinion only, as is most or at least a lot of what gets written around here.

More opinion here: Your insightful question might have been more helpful if you had shown the rest of my post and not, in effect, taken what I did post more than a little out of the context of tiered TO.U. rates being a rather recent development. If you had quoted or at least understood the context of my post, it might have been clear to you that my opinion was based on prior events with respect to new or revised tariffs as I saw them, and the direction I see them headed, not unlike what seems to me to be your opinion that rate changes are more clearly a transition to a more fixed component of the rates.

As you write, and like you (I'm inferring your opinion here and not some factoid based on policy), I'm reasonably confident the POCO's would like to see a more fixed form of revenue and a larger fixed fee component of rate structures such as SDG & E's proposed 400 % hike in min. billing period charges, some .

On the other hand, tiered T.O.U tariffs look, to me anyway, as an up and coming way for the POCOs, IMO only, to game the system by making the already murky (for what seems to me to be most consumers anyway) rate schemes more muddy.

It's all opinion, but that's just my $0.02.

Take what you want of the above. Scrap the rest.

[Ampster]

....
Some (most ?) residential customers of SDG & E and probably the other 2 CA I.O.U.'s will probably be on a tiered T.O.U. tariff either by ignorant default or by informed choice/design at some future point.

Is that based on some policy directive from the CEC? The change in rates that I see more clearly is the transition to a more fixed component of the rates. As noted above by @RichardCullip one of the SDG & E EV rates has $16 fixed component.

[J.P.M.]

FWIW, the TOU tariffs I have chosen over the past 8 years have never had a tiered overlay. I have always had two EVs during that time and tiered rates are something I avoided because of the diminishing returns as kWhr usage goes up.

More FWIW: I didn't see T.O.U. rates with a tiered overly - at least in CA - until a couple/3 years ago. I believe SCE and PG & E started them ~ the same time. SDG & E didn't have one until ~ 18 months ago. The SDG & E T.O.U tariff for residential PV users does not use/overlay a tiered rate, at least not at this time. Other SDG & E T.O.U. tariffs do.

It took me a while to get the spreadsheets for tiered rate T.O.U. tariffs right, mostly because of how the basic daily allocation and thus billing period allocations for determining tier one sizes and so credits are determined. Not conceptually difficult as that's needed for the old, straight tier tariffs, but more details than necessary for straight T.O.U. only tariffs if accuracy is wanted.

Some (most ?) residential customers of SDG & E and probably the other 2 CA I.O.U.'s will probably be on a tiered T.O.U. tariff either by ignorant default or by informed choice/design at some future point.