NSTAR and the Dwindling Off-Peak Economies of TOU

[3mp_kwh]

I remember it always being the case, that the ability to shift use to off-peak hours (9am-9PM "winter", 6PM-8AM "summer") was critical, but just noticed new rate-design after 7/1/16 now carries a higher distribution and transmission charge penalty, for on-peak use. One has to shift even more, I think.

On Peak = 32 cents/kwh
Off Peak = 13 cents/kwh
A-1 steady rate = 18.5 cents/kwh

Each of the above is all-in, with the 7.6 cent supply charge. My use this last month was ~5.5X as much off-peak, as peak. The pride didn't last though, as it took our average kwh rate down only 1.4 cents below the "care free" A-1 plan. Why not hang up all the timers, forgo the fancy car charge scheduling and set the A/C to be good'n cool when I get home, at 6?

I totally understand how peak loads send the resource signal for new generation construction and subsequent rate-payer costs, because this stuff is close to my job. I witness the load spikes of the NEPOOL just before 6PM.

So, I ask what's the economic incentive to even fuss anymore? Unless I exceed 3X as much use at night/weekends, there's none. If I fall much below 2:1 with off-peak use, the TOU bills get downright punitive.

MA DPU, You've succeeded at getting average kwh prices up high enough to sponsor efficiencies and demand response, but our relationship with NSTAR (and Nat Grid) needs improvement.

National Grid, Eversource to pull out of Access Northeast gas pipeline project
"But [AG] Healey has said the region's energy needs should be met with efficiency and demand response instead. "
Going OT, a bit, but does anyone else think this was a bold thing for her to say? Especially for an AG, who ought to wear consumer's interests. I understand how higher prices change behavior for environmental aims, but should that be the new job description of the MA Atty General?

 

[David29]

Interesting. I did not know that TOU rates were even available in the Eversource (NStar) area! I had gotten an email from Eversource some months ago, inviting me to participate in an experimental program that I understood might lead to the design of a TOU rate. (I did not join for various reasons.) So I am glad to know that such rates are actually available, even if they are not quite working for you. I'll have to look into it for my car charging.

 

[David29]

From what I read on the Eversource web site, it looks to me as if the TOU rate is only available if the daily usage is 10 KW or more. I do not know if that is an average of 10, or peak of 10, or what. Seems somewhat restrictive....

 

[RAW84]

From what I read on the Eversource web site, it looks to me as if the TOU rate is only available if the daily usage is 10 KW or more. I do not know if that is an average of 10, or peak of 10, or what. Seems somewhat restrictive....

Where do you see that restriction?

Rates vary depending on your region, but I don't see a 10kW requirement for any of the TOU rates listed here:

Summary of Electric Rates

 

[3mp_kwh]

Eversource links to its offered "A5" Time of Use rate. It's a pdf file, where I agree there doesn't seem to be mention of a "10kw" restriction.
http://tinyurl.com/z5yyth4

I just noticed "Distribution" will be going back down, from $.14 to $.086/kwh come October. Most of what I was getting at was that there doesn't seem to be much incentive to conserve peak use, with the evident perils of even limited on-peak A5 TOU. Getting up above a 3:1 ratio is no easy task.

I think Nat Grid customers may still have the 2,500 minimum monthly kwh consumption, for their plan. So, things could be worse. All simpler stuff our AG could help with, rather than getting involved with much more limited constituencies and risking even more expensive outcomes.

 

[RAW84]

Eversource links to its offered "A5" Time of Use rate. It's a pdf file, where I agree there doesn't seem to be mention of a "10kw" restriction.
http://tinyurl.com/z5yyth4

I just noticed "Distribution" will be going back down, from $.14 to $.086/kwh come October. Most of what I was getting at was that there doesn't seem to be much incentive to conserve peak use, with the evident perils of even limited on-peak A5 TOU. Getting up above a 3:1 ratio is no easy task.

I think Nat Grid customers may still have the 2,500 minimum monthly kwh consumption, for their plan. So, things could be worse. All simpler stuff our AG could help with, rather than getting involved with much more limited constituencies and risking even more expensive outcomes.

I agree. I came to the same conclusion when I considered going TOU a while ago. Having saw NGRID's minimum use requirement, I contacted eversource who assured me that they didn't have such a requirement, that's why I was surprised to see the 10kW stipulation. I suspect he was looking at a commercial rate. Eversource only said that I must stay on that rate for 12 months. The risk wasn't worth the potential savings, so I never made the switch.

 

[David29]

Well, I guess I made an error. When I went to the Eversource site, somehow I ended up reading the actual "tariff," the legal document approved by DPU, and the way I interpreted it it referred to a minimum load. But the references above are pretty clear and do not mention such a minimum, so I plan to call and ask to switch to the TOU rate. I have a separate meter for just my car charging, so it would seem very advantageous to me (since I can schedule the charging through the car).
Question: The part of the cost not shown is the generation piece, which is not done by Eversource. Do you guys know if there is any difference in generation cost, peak vs. off-peak? Seems as if that is where the real savings would be, because the way power is dispatched is to run the least expensive generation as the base load, and add more expensive generation as the load grows. But if the generators don't offer TOU rates, I agree there would seem to be little incentive.

 

[pcrow]

I've been wondering about TOU rates. We have solar, so if that means in the summer we get peak rates for our solar production, that would be huge. I didn't realize that in the winter peak was at night, though.

 

[David29]

...Getting up above a 3:1 ratio is no easy task.....

Could you please explain what you mean by the 3:1 ratio? I am not following you on this point. Thanks in advance!

 

[RAW84]

Could you please explain what you mean by the 3:1 ratio? I am not following you on this point. Thanks in advance!

He's referring to the ratio of your off peak usage to your on peak usage. Below a certain point, TOU becomes more expensive than the standard rate. You wouldn't have to worry about that since your car's on a separate meter. TOU is a no-brainer for you.


To my knowledge the generation costs are not TOU, certainly not from eversource, not sure about independent suppliers, but I doubt it would be the case for residential. Tho you should call those companies to inquire.

 

[David29]

He's referring to the ratio of your off peak usage to your on peak usage. Below a certain point, TOU becomes more expensive than the standard rate. You wouldn't have to worry about that since your car's on a separate meter. TOU is a no-brainer for you.


To my knowledge the generation costs are not TOU, certainly not from eversource, not sure about independent suppliers, but I doubt it would be the case for residential. Tho you should call those companies to inquire.

Thanks! I ran some numbers based upon my estimated usage and it looks as if I could save about $10-12 per month. So I will definitely look into it.
If it were not for this forum, I would not even have been aware that Eversource has TOU rates!

 

[essaunders]

I checked out the eversource NH TOU rates. At my current consumption I'd have to shift 90%+ of my use to off peak just to break even.

 

[3mp_kwh]

The "3:1" was break-even, at Summer 32 vs 13 cent off-peak. Summer months are both shorter (June thru Sept, I believe), and the lower on-peak rate, versus the straight non-TOU rate (16-18 cents, I think) means that you do not have to reach quite as high a ratio to break even year round.

I agree, TOU = No Brainer, if you can get that meter to over-night. The 13 cent off-peak, all-in (transmission+supply) is about as good as it gets, for us. Covering area utilities, there are a couple of tiny, local public utilities who share ownership of the area nuclear plants. I think it's Reading which offers close to a nickel/kwh, off-peak (nuke is 24/7, ~over-supply at night).

The reason NSTAR and Nat Grid effectively put TOU on the tranmission side is because they're the "front end" party, who is responsible for billing. The generator provides what we see as "supply charge", and those rates are hourly wholesale charges, billed directly to NSTAR/Nat Grid. I can see the New England ISO spot rates, on a Bloomberg terminal. Over-night NSTAR / Nat Grid pick up many/most of their kwh at 2-4 cents, wholesale.

Winter on-peak can be worse than summer, because of natural gas getting redirected to retail (heating) distribution, but I am not aware of there ever being the case where over-night rates are higher than daytime. NEISO runs about 18-23GW of day demand around 4-6PM, and typically falls to, or below, 12GW at night.

 

[Hota]

I've been wondering about TOU rates. We have solar, so if that means in the summer we get peak rates for our solar production, that would be huge. I didn't realize that in the winter peak was at night, though.

Nice! Is net metering compatible with TOU? This would be great if we get to sell back power from solar at peak rates.

I just realized how expensive charging can be - I had $200 in banked credit from my solar and it got totally used up in a month after I got my car.

 

[JCL123]

Hello,

New Tesla owner in Arlington here. I also have solar, and generally right on the edge of net 0 for the year, but I expect the car will put me over and I will have a small electric bill in the winter.

The way I read this, it would be like this, let me know if my numbers work (calc below):

Now = $0.11 / kWh all the time

Fall/Winter/Spring peak = $0.17
Fall/Winter/Spring off-peak = $0.06

Summer peak = $0.25
Summer off-peak = $0.06

If they allow this with net metering, this might work well for me. I suspect you get the wholesale rate for net metering no matter what, but even so, I would not be paying the higher rates most of the time (cloudy days only), and then about 1/3 to 1/4 the rate off-peak. So, effectively 1/2 the price all the time, compared to what I pay now. Not including the slightly higher monthly minimum.

yes?

-JCL

Here are my calculations:

A1 / kWh
$0.07721 + $0.00227 + $0.02526 + $0.00250 + $0.00050 = 0.10774

TOU Oct-May / kWh
peak
$0.08692 + $0.00224 + $0.07884 + $0.00250 + $0.00050 = 0.171
off-peak
$0.05353 + $0.00224 + $0.00250 + $0.00050 = 0.05877

TOU Jun-Sept / kWh
peak
$0.14089 + $0.00224 + $0.10412 + $0.00250 + $0.00050 = 0.25025
off-peak
$0.05456+ $0.00224 + $0.00250 + $0.00050 = 0.0598

 

[andrewket]

Hello,

New Tesla owner in Arlington here. I also have solar, and generally right on the edge of net 0 for the year, but I expect the car will put me over and I will have a small electric bill in the winter.

The way I read this, it would be like this, let me know if my numbers work (calc below):

Now = $0.11 / kWh all the time

Fall/Winter/Spring peak = $0.17
Fall/Winter/Spring off-peak = $0.06

Summer peak = $0.25
Summer off-peak = $0.06

If they allow this with net metering, this might work well for me. I suspect you get the wholesale rate for net metering no matter what, but even so, I would not be paying the higher rates most of the time (cloudy days only), and then about 1/3 to 1/4 the rate off-peak. So, effectively 1/2 the price all the time, compared to what I pay now. Not including the slightly higher monthly minimum.

yes?

-JCL

Here are my calculations:

A1 / kWh
$0.07721 + $0.00227 + $0.02526 + $0.00250 + $0.00050 = 0.10774

TOU Oct-May / kWh
peak
$0.08692 + $0.00224 + $0.07884 + $0.00250 + $0.00050 = 0.171
off-peak
$0.05353 + $0.00224 + $0.00250 + $0.00050 = 0.05877

TOU Jun-Sept / kWh
peak
$0.14089 + $0.00224 + $0.10412 + $0.00250 + $0.00050 = 0.25025
off-peak
$0.05456+ $0.00224 + $0.00250 + $0.00050 = 0.0598

Based on your rates, I'm guessing Arlington, VA? Dominion? If yes, you cannot combine whole house TOU and net metering. You can combine EV only and net metering with two meters.

 

[David29]

His or her signature indicates he/she is in Mass., so he/she is in Arlington, MA, not TX.

 

[Alketi]

National Grid told my friend last week (Melrose) that they were no longer installing TOU meters at the residential level.

Has anyone been successful recently in getting a TOU meter from them?

 

[andrewket]

His or her signature indicates he/she is in Mass., so he/she is in Arlington, MA, not TX.

Ah, was reading mobile - no signatures.

 

[David29]

The "3:1" was break-even, at Summer 32 vs 13 cent off-peak. Summer months are both shorter (June thru Sept, I believe), and the lower on-peak rate, versus the straight non-TOU rate (16-18 cents, I think) means that you do not have to reach quite as high a ratio to break even year round.

I agree, TOU = No Brainer, if you can get that meter to over-night. The 13 cent off-peak, all-in (transmission+supply) is about as good as it gets, for us. Covering area utilities, there are a couple of tiny, local public utilities who share ownership of the area nuclear plants. I think it's Reading which offers close to a nickel/kwh, off-peak (nuke is 24/7, ~over-supply at night).

The reason NSTAR and Nat Grid effectively put TOU on the tranmission side is because they're the "front end" party, who is responsible for billing. The generator provides what we see as "supply charge", and those rates are hourly wholesale charges, billed directly to NSTAR/Nat Grid. I can see the New England ISO spot rates, on a Bloomberg terminal. Over-night NSTAR / Nat Grid pick up many/most of their kwh at 2-4 cents, wholesale.

Winter on-peak can be worse than summer, because of natural gas getting redirected to retail (heating) distribution, but I am not aware of there ever being the case where over-night rates are higher than daytime. NEISO runs about 18-23GW of day demand around 4-6PM, and typically falls to, or below, 12GW at night.

I took an initial look at Eversource (Eastern Mass.) rates and calculated that I would save an average of roughly $10/month. But when i did that, I did not consider preheating and precooling. I did not hink of it at first, and more or less assumed that the vast majority of my usage would be charging at night during offpeak hours. (My charging circuit has no loads except the Wall Connector and a security lamp but the llamp is motion activated and not likely to require a significant amount of energy in most months.)

So I was curious about your 3:1 ratio and looked in some more detail. The difficulty is that the costs and savings depends on some factors that are difficult to generalize, including miles driven/month (which probably varies between winter and summer for most people), average wH/mile (which varies with vehicle, driving style, type of driving (freeway vs. local, short trips vs. long), and weather), and what daytime peak usage there would be versus offpeak.

The factor that concerned me is the question of precooling or preheating the car. For me, but not for everyone, I am more likely to use precooling or preheating during peak hours, so that could be costly. The peak period rates are much higher under the TOUR structure than normal residential rates, presumabnly to provide an incentive to shift electrical demand to offpeak.

I made a calculation for myself and assumed that I would use preheating/precooling for 30 minutes/day on 20 days per month. Since I have had the car only one year and did not keep track of this last year, I do not know if that is a high estimate (I hope) or low. Anyway, for that assumed peak period usage, I would need to use 163 kWh/month to save enough (compared to residential rate A1) to have a net savings compared to staying on A1. That would only require about 500 miles of driving at 330 wH/mile. I used the figure of 330 to provide a quasi-realistic value for winter driving; I know it can be much higher in severe cold, especially for short trips. The tricky bit is that severe weather is likely to discourage taking trips, so there may well be some months in which I "lose" by using TOU rates, even if it is more economical on an annual basis.

Anyway, I have ordered the TOU service and it should be implemented in the next 30 days, according to Eversource. They require a one-year minimum commitment, so I'll have a year to see what happens and figure out if I made the right decision.