Demand Charges, storage costs and Public DCQC

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

WetEV

Well-known member
Joined
May 4, 2012
Messages
5,147
Location
Near Seattle, WA
A local utility has all the relevant rates online.

https://www.pse.com/-/media/Project/PSE/Portal/Rate-documents/summ_elec_prices_2021_01_01.pdf?sc_lang=en

So suppose we build a DCQC with more than 2 of chargers at 150kW or higher. We would use Schedule 26. Think https://www.plugshare.com/location/163287 or similar

Service fee of $110.51, Demand charge of $12.55/kW, $0.06556 per kWh

If one car per month charged 80kWh at 150kW, the total electric bill per car would be $1,998.25, at peak seasonal rates.

Ouch.


If one car per hour charged 80kWh at 150kW, and 5 cars maximum, the total electric bill per car would be $9.65. That's right, twelve cents per kWh, at peak seasonal rates. And one car per hour would be fairly light usage, probably never a wait for a charge, even on busy weekends.


Of course this is only part of the cost. Site costs, buying and eventually replacing the DCQC chargers, charger efficiency, maintenance, line painting, signage, security, credit card fees and probably things I didn't mention will all drive up the cost. And price would include profit.
 
WetEV said:
A local utility has all the relevant rates online.
If one car per hour charged 80kWh at 150kW, and 5 cars maximum.
Are you saying a peak demand of 150*5 = 750 kW ?

There is no doubt that increased utilization will spread out the demand charges across the users but trying to guess per user costs is a HUGE ymmv by location. And by the way, I have seen demand charges of over $20/kW in other localities. E.g.,
https://www.pnm.com/documents/396023/396197/schedule_4_b.pdf/c81201a9-42a2-4787-8552-3ecadc8be169?t=1546288357057

For my locality, 5 EVs per day per 150 kW feed works out to $16.29 demand charges per EV. My experience has been to take on ~ 40 kWh per charging episode, so that would be ~ 40¢ per kWh in demand charges. This quick arithmetic suggests that 10 EVs per day per 150 kW feed are needed to bring electricity charges down to 20¢ - 25¢ per kWh

Some locations will have big battery storage
Some locations will have small battery storage for peak shaving
And crazy busy locations may not bother with battery storage at all.

I've seen some data from Tesla in California. Utilization drops way off at night, so much so that Tesla has instituted TOU rates. I think it was prompted by congestion issues but I mention it to say that average utilization is deceiving for this analysis.
 
Another way to look at spread out demand charges is per hour which can be translated into daily utilization factor

I started with $15 per kW demand charges

If a 150 kW station is used 100 hours a month then demand charges are $22.5 per hour
If used 200 hours a month then demand charges are $11.25 per hour and the station is used ~ 27.5% of available time or over half of available daylight time. It is not an easy bar to reach, and all the more so if you want to avoid congestion.

Also, keep in mind that the above calc presumes that all of the usage is at 150 kW. That is most assuredly not true. Even an average of 100 kW is optimistic and will be a murderous per kWh rate for those cars charging at 50 - 70 kW.
 
From https://www.chevybolt.org/threads/electrify-america-outreach-webinar.36895/ (for EA):
One of the biggest threats to that long-term profitability and sustainability is demand fees. In one real-world example of a charging site in Utah, they are paying $8.55 per kWh dispensed after demand fees, and they are installing grid-tied batteries in order to offset those costs (they stated 80% or 90% of a charging station's costs are due to demand fees).
 
SageBrush said:
https://www.pnm.com/documents/396023/396197/schedule_4_b.pdf/c81201a9-42a2-4787-8552-3ecadc8be169?t=1546288357057

One car a month $4,429.21

One car an hour, 5 maximum $11.58


SageBrush said:
Some locations will have big battery storage
Some locations will have small battery storage for peak shaving
And crazy busy locations may not bother with battery storage at all.

One car an hour average isn't crazy busy.

Above is with no storage. Storage makes the most difference with low utilization averaged over a month, and peak shaving is likely a win for any site not crazy busy.
 
cwerdna said:
From https://www.chevybolt.org/threads/electrify-america-outreach-webinar.36895/ (for EA):
One of the biggest threats to that long-term profitability and sustainability is demand fees. In one real-world example of a charging site in Utah, they are paying $8.55 per kWh dispensed after demand fees, and they are installing grid-tied batteries in order to offset those costs (they stated 80% or 90% of a charging station's costs are due to demand fees).

Got to be fairly low utilization to get to $8.55 per kWh. Perhaps 6 or 7 cars a month. Yes, adding storage makes sense.
 
SageBrush said:
Another way to look at spread out demand charges is per hour which can be translated into daily utilization factor

I started with $15 per kW demand charges

If a 150 kW station is used 100 hours a month then demand charges are $22.5 per hour

Or $0.15 per kWh, if the cars have a fairly flat charging curve, like an e-tron.


SageBrush said:
Also, keep in mind that the above calc presumes that all of the usage is at 150 kW. That is most assuredly not true. Even an average of 100 kW is optimistic and will be a murderous per kWh rate for those cars charging at 50 - 70 kW.

100 hours a week at 50kW would be $0.45. The DCQC rates should be higher for lower charging rates. Or per minute rates. Have the cost and price better aligned. Or have 50kW or 70kW chargers, which would both lower demand charges as well as lower equipment costs.

EA can't afford many old LEAFs charging at 30kW.
 
I work for the utility in San Diego. When people post about demand charges and how bad they are, I feel that they are missing an important fact that is not often discussed.

The demand charges on commercial rates go hand-in-hand with much lower energy prices, on the order of 1/3 the price or 1/2 the price of non-demand charge rate pricing.

The key to success on a demand charge rate is throughput. If you're charging 10 cars per month, the demand charges will dominate the bill. But if you're charging a lot of cars, then the much-less-expensive energy will dominate the bill, and not only that, it will be cheaper overall than a non-demand charge rate.

There are probably some exceptions, but I think it would make sense for providers on demand charge rates to price charging costs in such a way as to attract drivers and get that throughput as high as they can...
 
WetEV said:
Or have 50kW or 70kW chargers, which would both lower demand charges as well as lower equipment costs.
And turn your e-tron into a Bolt during charging
 
SageBrush said:
WetEV said:
Or have 50kW or 70kW chargers, which would both lower demand charges as well as lower equipment costs.
And turn your e-tron into a Bolt during charging
Ah yes, the missing context

SageBrush said:
cars charging at 50 - 70 kW.

Having the charger's maximum power closer to the car's typical input power reduces overall cost.
 
WetEV said:
SageBrush said:
And turn your e-tron into a Bolt during charging
Ah yes, the missing context
Calm down; it would apply to any car brand. I thought you would appreciate the personal reflection. :lol:

And ... it is true.
A big part of the reason to spend more money on an EV is to gain faster charging. Tuning the DCFC network for the least common denominator is not what people had in mind when they bought a Tesla, or an E-tron, or even an ID.4, to name a few.
 
LeftieBiker said:
A big part of the reason to spend more money on an EV is to gain faster charging.

For some people. For others, it doesn't enter into the equation at all, or is a minor consideration.

That must explain all those $50k nice EVs with 50 kW DC charging. :lol: :roll:

Why just last week I charged my Tesla at 233 kW Max and thought "not *so* different than 50 kW." :lol: :roll: :lol: :roll:
 
You really have trouble seeing things any other way than your own, don't you? People who, for example, buy or lease an EV as a local, second car, and either have no plans to use it for longer trips or don't even have DCFC locally, do not care much - if at all - about DCFC speeds. If your imagination fails you there, try the people who buy or lease an EV with NO DCFC option. It isn't that hard if you try.
 
LeftieBiker said:
You really have trouble seeing things any other way than your own, don't you? People who, for example, buy or lease an EV as a local, second car, and either have no plans to use it for longer trips or don't even have DCFC locally, do not care much - if at all - about DCFC speeds. If your imagination fails you there, try the people who buy or lease an EV with NO DCFC option. It isn't that hard if you try.

You are just talking about yourself; and in case you have not noticed yet, you shop for cheap EVs.
I don't care about corner cases, and neither do manufacturers: as the EV quality and cost go up, so does charging speed. It is not much different in concept than suspension: it improves with car quality and cost to meet the general expectations of that the car buying public and their use profile. I'm sure you can find someone who *wants* a bumpy ride but they will have to mod aftermarket :lol: :lol:

A forum member here took the better part of 6 months (if not 12) to finally accept that his + LEAF was hobbled at ~ 70 kW DC charging. Part of it was not understanding the basics, but the other part was his desire impeded his learning. He is a sterling example of what the general populace *want* ... although some make do with less to save money.

GM sold the Bolt (and may still) without the DC option. Nissan did the same a decade ago. Go ahead, count the number of people who choose no DC. I bet it is a rounding error. And ask Cwerda what the pulse of the GM EV nation is about the GM decision to keep the Bolt EUV at 55 kW max charging. :lol: :lol:

You think it important to note that exceptions exist. Of course they do. So what ? Back to this thread, OP was considering the possibility of nerfing charging speeds to reduce demand charges per user. I think we will see batteries before that solution. And it was interesting to read his opinion that slower charging EVs should pay *more* (to cover the opportunity cost.) I'm sure that went over well on this forum :lol: :lol:
 
I'm talking about myself, about the woman with whom I live (who is little like me) and about people I know online. I personally don't know anyone who wants an EV for a long commute or for road trips, and who cares deeply about charging speeds. Despite that, I understand that it is a common thing. You are fairly typical for an American, in that what matters or not to you, personally, is what matters or not, period. You are also quite rude, even for an American. It isn't charming or useful. I suppose that as old as you are you aren't going to change, and that's a shame. At least try to keep the gratuitous, unprovoked hostility to a minimum, here.
 
LeftieBiker said:
A big part of the reason to spend more money on an EV is to gain faster charging.

For some people. For others, it doesn't enter into the equation at all, or is a minor consideration.
Exactly. I bought a '13 Leaf SV w/premium w/NO CHAdeMO (my leased one had it) in July 2015. I already have posted why numerous times about why back then.

I've met people who have used their DC FC inlet on their Leaf 0 times or a minimal # of times spread out over years. Turbo3 (Leaf Spy author) on his '11 Leaf when I spoke to him a few years ago I think said he'd used it like 5 times.

Many folks on Bolt FB groups I'm on have used their DC FC inlet minimal # of times or NEVER. Heck (I thought about posted about this before but can't find it), a woman at my work (who is from Japan originally) didn't even KNOW her Bolt could be DC FCed. She previously leased gen 1 Leaf and I think it had CHAdeMO, so she was used to 2 ports. I met her when we both had Leafs. She leased her Bolt pretty early on (probably was a '17) after returning her Leaf at end of lease.

She kept saying about her Bolt she can't DC FC and that she didn't pay for it. In the middle of the convo, I pushed her Bolt's charging door and low and behold, she had the orange flap covering the 2 holes (for SAE Combo). I told her, she can. (For those who don't know, http://carcharging.us/ev/bolt.php shows Bolt inlet with vs. without DC FC capability.)

I think it was related to a bunch of flaky L2 stations we were having at work at the time coupled w/high utilization. She has a commute of at least 30 miles almost all highway, each way. There are several DC FCs under 2 miles from our work that she could've fallen back on (as a last resort) if she knew she could DC FC. I don't know her job but from her title, it seems to be a technical role and our company is partly a tech company.

(Update: Found my post about the above incident at https://mynissanleaf.com/viewtopic.php?p=562830#p562830.)

This is besides people who don't even it have it. Numerous other post-2010 BEVs have been sold/leased without DC FC even as an option (e.g. Fit EV, gen 2 Rav4 EV, Mercedes B-Class ED, Fiat 500e, gen 1 Focus Electric, both gens of Smart ForTwo ED).

The last time I ever went on a road trip leaving from home was in mid-2017. I took my former 06 Prius.

I knew that Bolt wasn't a good road trip vehicle and I'm pretty sure I posted that I wasn't wanting to paying over $12K (maybe was more like over $14K more) more $ for a Model 3 MR (cheapest 3 at the time) for a better road trip vehicle with plenty of stuff I wanted and used that was n/a on the 3 (and still is n/a) and stuff that I didn't want. I was fine w/renting a car or flying instead for those times. Almost none of those issues have been addressed to this day.
 
SageBrush said:
Back to this thread, OP was considering the possibility of nerfing charging speeds to reduce demand charges per user.

What I think I said was this "Having the charger's maximum power closer to the car's typical input power reduces overall cost."

In other words, if there are a significant number of 50kW cars and a significant number of 150kW cars, it would be cheaper to have two different charging stations, one size for 50kW cars (cheaper for 50kW cars, and just as fast), one size for 150kW cars (cheaper for 150kW cars).

Sure, a 50kW car could use the 150kW charger, but would cost more.

Sure, a 150kW car could use the 50kW charger, but would be both slower and would cost more.

Not nerfing.
 
Back
Top