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Discussion Starter #1
So...Last week I happened to hit the Jacksonville, Fla. EA station on one of its better days - it worked. I didn't really need the charge, just like to check its pulse when I;m in the area - show it a bit of love.

I checked its utility meter before, during, and after my ~ 20 minute charge session, during which I (as always) was the only one present.

Apparently the utility meter had just been read - my session was the first since the monthly cycle began. How do I know that? Demand reading.

The meter has a 120x multipler - all readings must be multiplied by 120 to know actual kW / kWh, so there is some loss of precision compared to a home or small biz meter.

Initial demand reading = 0.02 = 2.4 kW. On that basis, I conclude mine was the first charging session of the monthly cycle since no DCFC, even a De-de-de-de rated EA would stoop so low at 2.4 kW.

During the next 15 minutes, during which my Bolt drew an average of 42 kW, the demand reading slowly but steadily increased to 0.42 kW = 50.4 actual kW. After 15 minutes had passed, no further increase indicated since that's the nature of demand metering

What do I derive from the figure of 50.4 kW? That, coupled with the initial demand reading gives some insight into both standby power and conversion loss:
My initial demand reading of 0.02 suggests a standby loss of 1800-3000 Watts (range owing to loss of precision inherent in 120x multiplier) That's power used by station when no one is charging.

Net power while charging: 50.4 - 2.4 = 48 kW. That suggests a charging (480V 3 phase AC to ~360 Vdc) conversion efficiency of 87.5% (42kW / 48 kW)

Another observation - kWh reading remained unchanged at "15" throughout my session. That's reasonable, since it only increments every 120 kWh, and I only took 15, maybe 18 with conversion loss.

Final fun fact - The station hasn't seen much use...it's almost kinda "mine" for the time being. It has been up (more or less) since late August. If we call it 45 days or about 1000 hours, most of its 1800 kWh used that whole time (less than my house, BTW) has gone toward keeping its lights on, not charging cars.

Other than my own (admittedly incessant) updates on Plugshare, there are exactly two other checkins.

1800 kWh costs about $150 at local rates, but 50 kW costs an additional $500 in demand billing, every month as long as there is just one 15 minute 42 kW charging event per month. That is a painfully high cost of powering a poorly utilized DCFC station...What if a couple TayCans charged at the same time for 15 minutes?!?!
 

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Thanks for explaining this in detail.

Does the station really use ~2kW even when idle? Shouldn't it be able to disconnect or otherwise drastically reduce power consumption when not utilized?

What was the max rated amperage of that charger? If you had doubled the draw to 100 kW, would that have doubled the demand charge? If so, that means each DCFC has approximately a $1,150 monthly fixed cost just to provide the electricity, not to mention other maintenance and variable costs such as electricity consumption. How many minutes of charging is required to recoup that cost?
 

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Demand charges are balanced by higher usage or lower demand. While higher usage will come eventually, lower demand can be accomplished with an extra on site battery bank that is charged when the station isn't in use. Higher capital but lower usage costs.

You outline exactly why ultra high speed charging should be deployed strictly for road trips and that all local charging should have slower speed charging in order to reduce demand.

ga2500ev
 

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Discussion Starter #4
Thanks for explaining this in detail.

Does the station really use ~2kW even when idle? Shouldn't it be able to disconnect or otherwise drastically reduce power consumption when not utilized? [ I don't know...given the uncertainty of the meter, it could be as low as 1800 Watts...I agree that seems high, but there's quite a lot of high powered electronics, although only 2 of 4 chargers have active displays. I can't think of another explanation for the inital 2.4 kW demand reading, other than maybe an aborted charging session that lasted only a minute or two. I will look for more data.

What was the max rated amperage of that charger? If you had doubled the draw to 100 kW, would that have doubled the demand charge? If so, that means each DCFC has approximately a $1,150 monthly fixed cost just to provide the electricity, not to mention other maintenance and variable costs such as electricity consumption. How many minutes of charging is required to recoup that cost?

[Yes - a nightmare scenario would be a trio of high kW cars, such as Porsche Taycans road tripping together and charging at the same time...a small group of such cars could literally run up millions in demand chargers by touring the EA network and causing 300-400 kW demand events at each station...all it would take is 15 minutes per month per station]

Folks that work with electricity demand charges consider a calculation of capacity factor - percent of time a demand occurs. For example, if capacity factor reached 10%, ~75 hours per month at 100 kW, here's what it looks like:

kWh - 7500 (100 kW x 75 hours) + standby (750 hours x 1.8 kW = 1350) Total 8850 kWh. At $0.08 / kWh, consumption charge would be $708. Demand charge would be $1000 for a total bill of $1708

If at 100 kW charge rate EA charges $0.42 / minute, revenue would be 75 hours x 60 min/hr x $0.42 / min = $1890

So you see that's about a breakeven point for electricity use ~ 200-300 charging sessions per month.

Of course that doesn't help with capital cost, repairs, maintenance, communication network cost, customer support, administration, management, yadda yadda.

Anyone investing in a high power L3 network is in for a LONG slog toward profitability...a capacity factor of 20-30% may be needed to get there even while charging 2-3x home charging cost...thats hundreds and hundreds, maybe 1000 charging sessions per month per station.

Of course the same applies to gas / diesel filling stations - huge upfront and operating cost, but those are spread out over 10s of thousands of transactions per month. The problem with applying that reasoning to EVs is that, for the foreseeable future most charging will be done at home.

That's why I and others believe the majority of away-from home charging will continue to be by destination L2s and, eventually, much more modest L3s - 20-30 kW
 

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Discussion Starter #5
There are additional scenarios worth mentioning:

1) Microgrid with storage - if Walmart covers their roofs and (future) parking lot canopies with solar and stores excess kWh in onsite batteries, they could sell excess kWh to shoppers by charging their EVs while they shop.

2) Utility entry into the DCFC biz - they generate and or distribute electricity and could probably find ways to internally mitigate the demand problem

3) Government subsidies / regulation / exemption of car chargers from demand billing.
 

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Thanks for sharing these numbers. I've spent countless hours worrying about this. In order to charging to remain a going concern, it must be profitable somehow. That could be done by using it as a "loss leader" for a business. Demand charges could be mitigated via batteries. Also, increased usage will mitigate demand charges. Finally, demand charges themselves could be removed from EV charging. This might happen because demand charges don't make sense given the sporadic nature of EV charging. In the short term, the EV community can help by increasing utilization of the stations without pushing up demand charges. One more way that road tripping with your Bolt is helping the longevity of the (non-Tesla) EV ecosystem.
 

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Here's a previous post I made that is germane to the topic:

The law of diminishing returns applies to faster fast-charging too.

For the sake of simplicity, let's assume charge rate can be held constant to charge a battery. A 100 kWh battery charged at 100 kW would take an hour to charge. Doubling the power to 200 kW would cut the time in half, saving 30 minutes. Doubling the power again to 400 kW would again halve the 30 min charge to 15 minutes, but this time doubling the power only saved us 15 minutes instead of the 30 minutes that was saved the first time we doubled power.

100 kWh battery > 100 kW charger = 60 min
100 kWh battery > 200 kW charger = 30 min (30 min saved)
100 kWh battery > 400 kW charger = 15 min (15 min saved)
100 kWh battery > 800 kW charger = 7.5min (7.5 min saved)

Batteries can't be charged at a constant rate, so the time savings is even less than this theoretical best case scenario.

You'd need a 200 kWh battery to take advantage of 300+ kW charging.

What I'm saying is that given regular battery capacities of around 60 kWh, and given the charge limitations of current battery technology, any charger over about 150 kW wouldn't do me or hardly anyone else any good. 200 kW sounds like a reasonable limit. Do we really expect that many vehicles to have over 100 kWh batteries?

Then, as I'm always saying, the demand charge is what kills profitability for charging infrastructure. This is a monthly fee the utility bills for each kW of capability, meaning the more power the charger is capable of providing, the higher the monthly bill. This fee exists regardless of the amount of power actually delivered, as electricity use is billed separately.

To put this power in perspective, modern homes are capable of 48 kW max. A single 200 kW charger has over 4 households worth of maximum delivery capability. Households don't run at max power ever. Average household consumption in the US is 1.2 kW. A single 200 kW charger represents 166 homes just appearing on the grid suddenly. Electricity generation must match demand instantly and constantly. 166 homes appearing and disappearing randomly, at multiple locations, is no joke.

There are additional scenarios worth mentioning:

1) Microgrid with storage - if Walmart covers their roofs and (future) parking lot canopies with solar and stores excess kWh in onsite batteries, they could sell excess kWh to shoppers by charging their EVs while they shop.

2) Utility entry into the DCFC biz - they generate and or distribute electricity and could probably find ways to internally mitigate the demand problem

3) Government subsidies / regulation / exemption of car chargers from demand billing.
Utilities already collect extra revenue from ratepayers for the purpose of efficiency/environmental programs. Not billing for demand charges could be considered an environmental program for the utility with the cost being absorbed by all ratepayers.

...demand charges themselves could be removed from EV charging. This might happen because demand charges don't make sense given the sporadic nature of EV charging.
Demand fees absolutely make sense for EV charging. "Sporadic nature of EV charging" is exactly why it is costly and disruptive to the grid. If the high demand were constant, that would be much easier for the grid to accommodate because the constant demand would be factored into base power delivery. Remember, electricity generation must (almost) exactly match demand every second of every day. Ramping up generation takes time, and brownouts (under voltage) can happen when it can't ramp fast enough, and excess gets shunted (wasted) to ground to avoid over voltage.

The achilles heel to solve really is the battery. If the battery is improved in EVs, they will be adopted en mass. If batteries improved (mostly in cost), they would be economical to implement at DCFC stations to smooth between idle and high use, all but eliminating the demand fees.
 

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Discussion Starter #8
I wonder how big a DCFC charger battery would need to be to accomplish the desired effect?

If I and 2 other drivers are the only ones using the local EA station, then maybe a 40-50 kWh battery charged at maybe C/10 gets it done.

I imagine Tesla is actively working on this - their superchargers are big and busy...demand fees are likely huge.

EA is mostly at big box stores - seems a perfeact opportunity to combine solar, batteries, and charging.
 

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Discussion Starter #9
"200 kW sounds like a reasonable limit. Do we really expect that many vehicles to have over 100 kWh batteries?"

Oh heck yes we do!

Look around - There are millions of heavy duty pickups towing trailers for both work and play, soccer dads and moms driving suburbans, service companies with fleets of service trucks. Those vehicles will need 150 - 400 kWh batteries to meet expectations of current drivers and their companies. What about Amazon's 100k package delivery vans?

Rivian (backed by Ford and Amazon) promises a 180 kWh battery...that will need 400+ kW to be charged rapidly while on road trips.

City buses, dump trucks, semis will need megawatt charge rates. If we are truly to decarbonize transport, ALL vehicle classes and uses have to become viable EVs

Some initial numbers for the Tesla Semi suggest an 800+ kWh battery able to be charged at ~1500 kW.
 

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Yeah, pickups and large vehicles would need large battery capacities and could benefit from faster charging. As we've discussed, that will probably need to be addressed by a battery buffer rather than increasing grid draw.

All the other things like garbage trucks, busses, and tractor/trailers will have their own charging solutions and not rely on public DCFC.

We won't see a lot of vehicles much over 100 kWh until cost comes down significantly. You can make 3 Bolts from the battery you mention Rivian using.

Tesla's v3 Supercharger has a max rate of 250 kW and I haven't heard any plans to increase that rate if/when a truck is released.
 

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Discussion Starter #11
"All the other things like garbage trucks, buses, and tractor/trailers will have their own charging solutions and not rely on public DCFC. " Maybe / maybe not - while buses are typically owned, the rest of those are typically privately owned in my area. Regardless, they'll need a mixture of fast and overnight charging on the grid.

Battery cost per kWh has been falling 15-25% per year...that seems significant to me.

"Tesla's v3 Supercharger has a max rate of 250 kW and I haven't heard any plans to increase that rate if/when a truck is released."

Regardless of what you "haven't heard"... megawatt charging rates are coming. Google "Tesla MegaCharger" for some initial glimpses. Also, technical committees of electrical manufacturers are hashing out details of megawatt charging connectors and ports.

Senior VPs at EVGo are quoted in a recent Forbes magazine article as considering 1.0 - 4.5 megawatt charge rates for semi tractors.

An Electrek article mentions Diamler working toward 3 MW for its electric trucks.

The pressure to electrify Diesel transport is actually much more intense than gas cars because Diesel emissions are so much worse, and global rules are ever tighter. The cost and complexity of buying, maintaining and repairing over-the-road Diesel emissions components is skyrocketing.

VW's $2 billion investment in the EA network is a footnote compared to the overall cost of that scandal and the multi-hundred billions being spent by auto and truck makers worldwide to go EV.
 

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Battery cost reduction is a process of diminishing returns too, and is unsustainable.

We'll probably see faster charging at some point in the future (15 years?), but I don't see chargers regularly going above 250 kW for consumers any time soon. Rivian might be supplying 180 kWh batteries in their trucks, but then again their sales will be measured in the hundreds for the foreseeable future.
 

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Discussion Starter #13
Less than 20 years ago, I worked automation projects at a paper mill - I remember hearing they paid $20k for a single 42" flat screen display in their main control room...prices have dropped 20x.

Look also at solar PV panels - same massive price drop.

Bloomberg new Energy Finance lists EV batteries as costing $176 / kWh today, and predicts $64 by 2030.

Price parity of EV cars vs ICE cars was thought to be 5 years out; now they are saying 2-3 years out.
 

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Price parity of EVs versus ICEVs is said to be between $150 and $200 / kWh. But I believe that's at the assembled pack level. I'm not sure what that translates to at the cell level. It's probably a moving target, depending on the efficiency of building a pack out of cells. I'm sure the overhead is different between GM/LG Chem and, say, Tesla/Panasonic.
 

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Discussion Starter #15
"Price parity of EVs versus ICEVs is said to be between $150 and $200 / kWh."
That seems high to me - given that the heavier SUVs and full size pickups favored by so many US drivers are going to need battery packs 100 - 200 kWh, that number seems high.

My guess is that $100 / kWh will get us close, and $75 should seal the deal, assuming continued rapid deployment of very fast chargers and batteries that can take high rates of charge and last the life of the vehicle - 10+ years / 250k miles with no more than 10-20% capacity degradation.

I think we'll get there, possibly by 2025.
 

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The ICE vs EV breakeven point gets much sooner than previous estimate as battery cost drop has been even better than projected. Current consensus, as I read, is now is $100/KWh battery by 2025. I would not be surprised if it ended up being 2022.
 

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"Price parity of EVs versus ICEVs is said to be between $150 and $200 / kWh."
That seems high to me - given that the heavier SUVs and full size pickups favored by so many US drivers are going to need battery packs 100 - 200 kWh, that number seems high.
Yes, this is a valid point. I think the $150-$200 number was for cars. But the car market is dying in favor of SUVs and Pickups, which require much larger batteries. For a mid-sized sedan (e.g. comparing Tesla Model 3 to Toyota Camry), 75kWh is probably enough. But a full sized pickup would certainly need double that to be viable.

So I think both ranges are valid, but for different markets. Thank you for pointing that out.
 

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Yes, this is a valid point. I think the $150-$200 number was for cars. But the car market is dying in favor of SUVs and Pickups, which require much larger batteries. For a mid-sized sedan (e.g. comparing Tesla Model 3 to Toyota Camry), 75kWh is probably enough. But a full sized pickup would certainly need double that to be viable.

So I think both ranges are valid, but for different markets. Thank you for pointing that out.
Keep in mind that high end (not even "luxury") pickup trucks and SUV's have a huge built in profit margin due to their popularity, so hitting price parity would actually be easy without sacrificing too much of the profit margin if it makes the auto maker look "green" in the eyes of the public at large. They would still make a substantial profit on an EV pickup today at the same price point... just not the obscene profit margin they make on a Diesel pickup.

Keith
 

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Discussion Starter #20
I'm not sure the Diesel pickup markups are as excessive as one might think - the engines themselves are much more complicated and spendy than their gas counterparts. Transmissions have to handle much more torque, and the emissions control systems have become fiendishly complex.

Everything EV hinges on the battery - three key areas: Reduce cost per kWh to 1/4 or less what it is today, increase maximum charge rates; both while also increasing durability.

The average age of cars on the road today in the US is almost 12 years. Wide uptake of EVs will demand that battery degradation not be a significant issue out to a quarter million miles.
 
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