Official Southern California Edison thread

[Boomer23]

I was really happy to learn some new info from the SCE reps at the LA Auto Show today.

We've been wondering and debating about how SCE calculates when to bump us from Tier 1 to Tier 2 on a Time of Use rate plan. Well I finally understand it. I'll use the TOU-D-TEV rate plan to illustrate.

Basically, your Tier 1 allowance is calculated monthly, not hourly or daily.

To calculate your monthly Tier 1 allowance,
1. get your baseline daily allowance from SCE's web site http://www.sce.com/CustomerService/billing/tiered-rates/baseline-chart-map.htm

2. Use this list of communities to get your baseline region. http://www.sce.com/NR/sc3/tm2/pdf/ce62-12.pdf

3. I'm in Region 6, so my Summer baseline allocation is 9.2 kWh, Winter baseline is 9.6 kWh.

4. Calculate your monthly Tier 1 allocation by multiplying by 1.3 to get 130% of baseline, then by 30 for a 30 day month.

5. 9.2 kWh X 1.3 X 30 = 358.8 kWh/month.

6. Now, in any Summer month, any power usage above 358.8 kWh for a month bumps me into Tier 2 of any of the three rate time periods. Winter would be 374.4 kWh. There are only two Tiers.

I have solar power that generates more than I use, and in the past four years, there has only been one month, a December, when I used slightly more than my 374 kWh Tier 1 allowance. So I would almost never have entered Tier 2 pricing on the TOU-D-TEV rate schedule.

If I drive my LEAF 9,000 miles per year and I get 3 miles/kWh NET from the wall plug, I'd need to charge 3,000 kWh/year, or 250 kWh/month. If I look at the year 2009 and add 250 kWh to each month's net usage that the SCE meter would see, I'd have only entered Tier 2 in December of that year.

So I'll almost always be in Tier 1, even with 3,000 kWh of charging per year. The best TOU rate is 10 cents per kWh during the Super Off Peak midnight to 6 am period. And looking back at 2010, there were five months when I'd still have had a net generation in excess of usage.

By the way, this is BETTER than if I had the dual meter TOU-EV-1 plan, which has a best rate of 11 cents per kWh.

 

[xtremeflyer]

6. Now, in any Summer month, any power usage above 358.8 kWh for a month bumps me into Tier 2 of any of the three rate time periods. Winter would be 374.4 kWh. There are only two Tiers.

I still don't know that this is entirely true.. Look at my Oct bill that I posted earlier. You'll see that they allocate your Level 1 rates into each On-Peak/Off-peak period. In this case, they allocated my On-peak at 18% and my off-peak at 82%. I still can't figure out how they came up with those numbers since my on-peak was negative and my off-peak was positive. Because of this allocation, I hit Level 2 rates. If they had allocated it differently, I may not have hit it. In this case I only uses 282kw, yet my Level 1 allowance should have been about 369kw.

 

[Boomer23]

I still don't know that this is entirely true..

Okay, my brain is hurting now. I agree with you, we wouldn't expect any of the Level 1 allowance to be allocated to On Peak if your On Peak usage was all negative. I recently received my first bill on my TOU-D-T rate plan, and it showed almost 54% of my summer Level 1 allowance allocated to On Peak. And like you, all of my On Peak usage was negative.

I've developed a pretty good relationship with an analyst at SCE, a young guy named Jordan Sugar. In fact, I happened to meet and talk with him at the LA Auto Show yesterday, and he is the source of most of the information I posted here. I've sent him a link to our forum page showing my comments and yours. He'll be back in the office on Monday and I should hear back from him soon after that for clarification.

 

[xtremeflyer]

Ok.. I just figured it out, although I still don't understand it.

Looking at my Summer On-Peak, thats -50kW, my Summer Off-Peak is 227kW. Thats a spread of 277kW. 50/277= 18.05% .. So now I know how they get the percentages, I'm still not sure I agree with why that would be an appropriate number.

Now, lets say I add the 250kW's in for the EV at Super Off-Peak. Lets assume for now that my Off-Peak usage was 75% Off-Peak (270kW) and 25% Super Off-Peak (90kw). So for this bill I would have net generated 80kW (rounded for ease) during On-Peak and net consumed 270kW during Off Peak and consumed 340kW (250+90) during Super-Off Peak.

This would give me an 80/270/340 ratio or 11.6%/39.1%/49.3%.
My summer allocation is 10.2 *1.3 * 30 days = 398kW.
Distribute that based on the percentages - 46kW/156kW/196kW
This means my allocation would look like this:

On-Peak
Lvl 1: -46kw
Lvl 2: -34kW

Off-Peak
Lvl 1: 156kW
Lvl 2: 114kW

Super Off-Peak
Lvl 1: 196kW
Lvl 2: 144kW

Clear as mud yet? This means that if I stay with one meter, in September, half of my vehicle charging would be at lvl 2 or 16c instead of 11c

This is why I think that Super Off-Peak should not be part of the allocated amount. If you have two meters the EV meter would not be part of the allocation. But now, the second meter might be a no-go, so why not just remove the allocation on the Super-Off Peak and make it easy on everyone.

 

[garygid]

Looks like their billing program is defective, treating -50 as if it was +50, at least in part of the calculation. For the %Peak it would seem that the -50 should be treated as ZERO, for 0% Peak usage ... most likely?

 

[Boomer23]

Ok.. I just figured it out, although I still don't understand it.

I follow your math, but it doesn't match what Jordan told me. He said that any net usage for the month over your 398 kWh Level 1 allocation would spill each time frame (On Peak, Off Peak, etc) into Level 2. So for you, you'd have 270+340-80= 530 net usage, less 398 Level 1 allowance = 132 total kWh charged at Level 2, divided into your Off peak and Super Off Peak time frames, not 258 as your math shows.

For me, I net generated 276 kWh in Sept. If I had charged an EV 250 kWh in that month, I'd still have net generated 26kWh, so my bill for that month is zero. By your math, I'd have 241 kWh of Level 2 Off Peak, and 217 kWh of Level 2 for Super Off Peak, less any dollars that SCE pays me for my negative generation during On-Peak. I have to figure that Jordan's method is correct.

Let's see what my communications with Jordan tell me after Thanksgiving.

 

[tbleakne]

I think both of you and xtremeflyer are really close to figuring this out. It is so confusing but the challenge is great fun.

Ok.. I just figured it out, although I still don't understand it.

I follow your math, but it doesn't match what Jordan told me. He said that any net usage for the month over your 398 kWh Level 1 allocation would spill each time frame (On Peak, Off Peak, etc) into Level 2. So for you, you'd have 270+340-80= 530 net usage, less 398 Level 1 allowance = 132 total kWh charged at Level 2, divided into your Off peak and Super Off Peak time frames, not 258 as your math shows.
>>>>>>
I believe my understanding is consistent with what Jordan told you for the case where the net usage, over all TOU, is greater than the total Baseline*1.3 allowance. However, I am not sure that it is correct to distribute the excess usage kwh among the TOU as you describe. Instead, I would say that you must apportion the ALLOWANCE among the TOU, and then subtract this apportioned allowance from the actual total net usage during each TOU.
<<<<<<<

For me, I net generated 276 kWh in Sept. If I had charged an EV 250 kWh in that month, I'd still have net generated 26kWh, so my bill for that month is zero
>>>>>
I think this might be simplistic for TOU calculations. Even though you have highly negative usage for On-peak, you have positive usage for both Off-peak and Super-off-peak, and your EV 250 kwh during super-off-peak might exceed the fraction of the allowance allocated to that TOU.

If your EV super-off-peak went to 300 kwh, but off-peak stayed the same, then more of the allowance would shift to super-off-peak. This shift would lower the amount above level 2 for super-off-peak, but raise it for off-peak.

xtremeflyer is reporting that the negative usage during On-peak affects the allocation percentages rather than being entered as a zero. We all agree that seems strange. I did not follow his math in detail. The negative usage should work in a way that gives you more margin in positive TOU before you hit level 2, but that does not seem to be the case.
<<<<<<<<<<<<<<<

By your math, I'd have 241 kWh of Level 2 Off Peak, and 217 kWh of Level 2 for Super Off Peak, less any dollars that SCE pays me for my negative generation during On-Peak. I have to figure that Jordan's method is correct.

Let's see what my communications with Jordan tell me after Thanksgiving.

I look forward to his clarification.

 

[xtremeflyer]

Ok.. I just figured it out, although I still don't understand it.

I follow your math, but it doesn't match what Jordan told me. He said that any net usage for the month over your 398 kWh Level 1 allocation would spill each time frame (On Peak, Off Peak, etc) into Level 2. So for you, you'd have 270+340-80= 530 net usage, less 398 Level 1 allowance = 132 total kWh charged at Level 2, divided into your Off peak and Super Off Peak time frames, not 258 as your math shows.

For me, I net generated 276 kWh in Sept. If I had charged an EV 250 kWh in that month, I'd still have net generated 26kWh, so my bill for that month is zero. By your math, I'd have 241 kWh of Level 2 Off Peak, and 217 kWh of Level 2 for Super Off Peak, less any dollars that SCE pays me for my negative generation during On-Peak. I have to figure that Jordan's method is correct.

Let's see what my communications with Jordan tell me after Thanksgiving.

I definitely like your math better, and I hope your right!!

This doesn't help the people out that aren't on solar though. They are going to have to expect that a lot of their charging is going to be Level 2 unless they get the separate meter.

 

[Boomer23]

This doesn't help the people out that aren't on solar though. They are going to have to expect that a lot of their charging is going to be Level 2 unless they get the separate meter.

You're right about that!

 

[tbleakne]

I now have gone through the math that xtremeflyer reported on his statement. I regret my cheerful tone on my previous post, because I agree what SCE is doing now with solar + TOU does not look fair. xtremeflyer's statement seems to say that the more solar you generate, the more the baseline amount is allocated to on-peak, leaving less allocation for off-peak and super-off-peak, forcing more of your car's charging in super-off-peak to level 2. This is just not fair.

Rather than just zeroing out the allocation for negative on-peak, it would be more fair to simply assign a negative allocation to negative on-peak, boosting the baseline allocations available to both off-peak and super-off-peak. With this change, the more solar you use, the more you could charge the car in super-off-peak before you hit level 2. The sum of the allocations over all three TOUs would still equal the baseline*1.3.

It doesn't help that both Jordan and the senior SCE guy I talked to, Glen Picus, have told a similar story that does not match xtremeflyer's statement. I agree we first wait to hear back from Jordan. I will also call Glen back next week, and we see if they at least understand what we are saying. If neither of them are in a position to carry our concerns up to a higher level, I propose that we generate a formal letter and send it to the SCE VP who has signed these tariff documents. We request that he have one of his people who wrote this tariff contact us for resolution. It is possible that there was a unintentional error made in the translation of the legal words in the tariff document to the software that calculates the statement. In any case the wording of the tariff should be made clearer. I know the tariff documents are periodically reviewed and changed, because I saw that happen last June or early July. If both of you, xtreameflyer and Boomer23, agree this is worth doing, would you both be willing to review/contribute, and sign the letter ?

 

[mwalsh]

If you guys are right, because (being honest) I can't get my head around what you're talking about, then I may be in the club too, and would be happy to participate in any protest action. I hadn't figured ever being on anything but Tier 1 for off-peak/super off-peak.

 

[xtremeflyer]

If you are on Solar, you actually want On-Peak to be in Tier 2, its something like 35c a kW that you'd get back.

But, there's one easy solution. Do not count Super-Off Peak as part of your allocation. This would make it equivalent to having a second meter. They already do something similar for medical equipment. That's what I would want to speak with SCE about regarding the tariffs.

 

[garygid]

With your PU's rates (as you describe them), it would appear that charging some large "reserve" Battery Pack (presumably for possible EV re-charging during the day) during Super-Off-Peak and, if not "needed" the next day, using it to "feed" the grid during the On-Peak period ... would be profitable?

 

[Boomer23]

I now have gone through the math that xtremeflyer reported on his statement.

I was waiting to post until I had taken the time to work through the logic and the math. I still don't think that xtremeflyer's assumption is correct. Even though I still need to do some thinking about this, I think we're getting way ahead of ourselves. So please take a breath and relax before we put together a grass-roots rebellion.

xtremeflyer's concern is based on the calculation of On-Peak and Off-Peak that is shown in the small box titled "Additional Information" in the upper right corner of his bill. I agree that SCE is treating negative kWh as positive kWh in that calculation, BUT I don't think that is affecting his actual $ charges.

Take a look at his actual charges in the body of the bill detail. They show that he is getting credit in negative dollars for his solar production, just as he should be, regardless of how the additional information reads in the small box.

Regarding his concern that making additional solar kWh puts you in a worse situation for tiered charging, I believe that is not going to happen. As support for this position, take a look at my recent billing for October (with small parts of September and November) below, which I refer to as "Exhibit B".

You can see that with my larger solar production, I do indeed get credit for my larger amounts of solar production, shown on the bill detail as negative dollars. And all of the On Peak amounts are negative, which is correct, because all of my On Peak activity was solar production, not net usage. And all of the amounts in Level 2 are very small. So my larger solar production is doing what we want it to do. And finally, notice that my final bill is in negative dollars, -$4.67.

I think that all is well in the shire, and that we shouldn't be concerned about SCE's billing practices until we see a bill that proves me wrong.

Edited to include a larger, readable image.

 

[garygid]

It appears that I need a link to the high-res picture of Exibit B.
Thanks

 

[xtremeflyer]

Boomer, your bill proves my point.. Even with all of that solar generation you are hitting Level 2. Level 2 is good for Onpeak solar as you can see, BUT if you are already hitting level 2 now, just think what will happen when you add 250 kW per month. All of your level 2 numbers will go up, which means you'll be charging super offpeak at 16c. The negative generation during the day will combat some of that for us with solar, but what about those without solar.

 

[Boomer23]

It appears that I need a link to the high-res picture of Exibit B.
Thanks

Fixed now, Gary.

 

[tbleakne]

With your PU's rates (as you describe them), it would appear that charging some large "reserve" Battery Pack (presumably for possible EV re-charging during the day) during Super-Off-Peak and, if not "needed" the next day, using it to "feed" the grid during the On-Peak period ... would be profitable?

An interesting question. The answer is yes, whether or not the TOU billing worked like xtremeflyer's statement seems to show, or like my proposal.

Assume, for simplicity, that you have no solar, no on-peak usage, no off-peak usage, but you are fully charging your Leaf's battery every super-off-peak period, and then somehow discharging it through an external inverter back into the grid during on-peak. Ignore the fact that the QC port surely has diodes to protect you from actually doing this. I have actually had someone ask me whether this was possible, because he was thinking that the batteries in lots of electric cars could help the grid avoid on-peak A/C overloads that were due to a shortage of generation capacity during a hot spell. Effective distribution capacity would also be helped because your generation would be close to the load, and not coming from some far-off desert. It would be fair for you to make some money from this because you are helping the utility avoid building extra capacity that would only be used during peak usage periods.

Discharging the battery during on-peak TOU will look just like solar. Lets assume the battery is 100% efficient, with no net loss over the charge-discharge cycle. As Boomer23 has remarked, we know there actually is some loss, and it might be quite significant, but we don't yet know what it is. Assume we are charging and discharging 20 kwh/day so we don't stress our battery too much. That would be 30*20 = 600 kwh/month.

For many of us 600 is > Baseline*1.3 for at least most of the year. With xtremeflyer's billing interpretation, for this example, half of Baseline*1.3 is allocated to on-peak TOU, and an equal amount to super-off-peak. Assume Baseline*1.3 = 500 kwh. Then we would have (600 - 500/2) = 350 kwh in Level 2 for both TOU. Assuming all generation is URG with no DWR (worst case), our Summer bill would look something like this, delivery + URG:

On-peak Level 1: -250 kwh @ + .03 -.31 = -$.28/kwh -> = -$ 70.00
On-peak Level 2: -350 kwh @ -.32 - .31 = -$.63/kwh -> = -$220.50

Super-off-peak Level 1: +250 kwh @ +.06 +.04 = $.10/kwh -> $25.00
Super-off-peak Level 2: +350 kwh @ +12 + .04 = $.16/kwh -> $56.00

Net profit for month: (220.50+70 = $290.50) - (25.00+56.00 = 81.00) = $209.50

In this example assigning half of the baseline allocation to the on-peak negative usage costs SCE because it then has to pay at the Level 2 rate. Their high .32 price for delivery is paying off for user here.

 

[tbleakne]

I now have gone through the math that xtremeflyer reported on his statement.

You can see that with my larger solar production, I do indeed get credit for my larger amounts of solar production, shown on the bill detail as negative dollars. And all of the On Peak amounts are negative, which is correct, because all of my On Peak activity was solar production, not net usage. And all of the amounts in Level 2 are very small. So my larger solar production is doing what we want it to do. And finally, notice that my final bill is in negative dollars, -$4.67.

I think that all is well in the shire, and that we shouldn't be concerned about SCE's billing practices until we see a bill that proves me wrong.

I agree we can all take plenty of time to assess this carefully. My intention about suggesting writing a letter to the SCE VP was just to mention that as a possible option down the road. Collecting data from more real-world statements can only help us understand better whether TOU in its present form is working for us. I was responding to some of your previous comments that seemed to show some concern that TOU without a second meter might not work for you. My initial response, before I did much calculation, was that if you were generating more than your total usage over all TOU, it would be unfair for you to ever go into Level 2. I agree that my response was premature.

Your bill is a little more complicated because it spans the point in the Fall where SCE switches from Summer to Winter rates. Your next 100% Winter statement should illustrate my point more clearly. I agree all your positive and negative amounts have the correct sign. What I failed to appreciate in my previous post is that the allocation of part of the Baseline*1.3 to your negative on-peak TOU can more than compensate you for pushing part of your off-peak positive usage into Level 2, because this results in more on-peak Level 2 generation, which increases the $ that you are credited for your solar. I am not yet sure that will be true in all cases.

For those of us with more modest solar output relative to our usage, this allocation of some Baseline to on-peak reduces how much we are paid for negative on-peak usage from our solar generation. I also note that the switch from Level 1 to Level 2 is much more severe for Summer on-peak than Winter on-peak.

 

[Boomer23]

I now have gone through the math that xtremeflyer reported on his statement.

You can see that with my larger solar production, I do indeed get credit for my larger amounts of solar production, shown on the bill detail as negative dollars. And all of the On Peak amounts are negative, which is correct, because all of my On Peak activity was solar production, not net usage. And all of the amounts in Level 2 are very small. So my larger solar production is doing what we want it to do. And finally, notice that my final bill is in negative dollars, -$4.67.

I think that all is well in the shire, and that we shouldn't be concerned about SCE's billing practices until we see a bill that proves me wrong.

I agree we can all take plenty of time to assess this carefully.

No worries, Tom, and thanks for your comments, as well as xtremeflyer's. I've had a chance to look carefully at both his and my bills and I finally see that the concern is more than just a sign error in the summary statement in the small box. Looking at the billing detail, SCE does certainly seem to be counting our net negative kWh as if they were positive usage kWh as they assign usage to billing tiers. On both bills, if you disregard the signs and add the absolute values of all Level 1 kWh, the total about equals the calculated Level 1 allocations for the homes.

When I spoke with Jordan at SCE, I came away with the impression that SCE would subtract our net negative daytime kWh from our positive kwh usage during Off Peak and Super Off Peak and apply the Level 1 allocation to the result. That was where I got my hopeful comments in my earlier post. In that scheme, since for the month of October I used just 11 kWh more than I generated, if I charged a LEAF at 250 kWh, my total usage would only be 261 kWh, well below my Level 1 allocation of about 360 kWh, and so all of my charging would be on Level 1.

As tbleakne mentions, the compensating factor in SCE's billing scheme would be that my negative On Peak dollar charges for my net generation would offset my monetary charges for Level 2 charging. The Summer Level 1 On Peak rate is 19 cents, which would offset the Tier 2 Super Off Peak rate of 16 cents. But in Winter, that comparison is 13 cents L1 On Peak vs 16 cents L2 Super Off Peak. So we gain 3 cents per kWh in Summer and lose 3 cents in Winter. I guess it balances out. We could model some scenarios and see what they look like. What do you guys think?

I'll write to Jordan at SCE and ask him to explain why they count our negative kWh as positive in my TOU-D-T billing, and how that jives with his explanation to me last Monday.