4.5 Megawatt Charging For Electric Cars?

1 year ago by Mark Kane 65

Fast charging comparison

Fast charging comparison

Audi e-tron quattro concept - charging inlet CCS Combo

Audi e-tron quattro concept – charging inlet CCS Combo

Swiss EPFL (École polytechnique fédérale de Lausanne) sees the future of electric cars in ultra-fast charging, comparable to refueling of conventional cars.

While we appreciate all the improvements to decrease the charging time, the topic was highly exaggerated by EPFL.

Their press release begins with several statements that we simply can’t agree with:

Electric cars will be competitive when they can be charged in the time it takes to fill the gas tank. EPFL researchers have found the solution to this problem without bringing down the power grid: intermediate storage.

Electric cars will only be truly competitive when it doesn’t take longer to charge them than it does to fill a gas tank. The storage capacity of batteries is improving exponentially, but the power grid is the weak link: how could it possibly charge thousands of cars at the same time? This is especially problematic in the case of ultra-fast charging, which requires more than 10 times more power. EPFL researchers have found the solution: intermediate storage.

It only takes a minute and a half to put enough fuel into the tank of a diesel car to run for around 1,000 kilometers. After being charged for the same amount of time, the best electric cars will only go six kilometers. The only way to make the charging process faster is to increase the power flow going in. But such a quick charge would require 4.5 MW of power – equivalent to 4,500 washing machines. This would bring down the power grid.

Charge 'Em Up

Charge ‘Em Up

Well, electric car competitiveness is complex – because there are many different aspects (strong and weak sides). But for sure EVs don’t need to charge as quickly as ICE to be competitive, because their whole concept relies on home/work charging for over 90% of time – so every day you begin with a fully charged battery.

If the battery is big enough for decent range, and price is relatively affordable, then quick charging on long journeys could be one-half hour, or maybe even a full hour after 300 miles (500 km) at 150+ kW or so.

Charging in five minutes or less would be swell, but let’s not get all crazy on MW power.

EPFL’s idea is to use a buffer lithium-ion energy storage system at the charging site to generally lower the power needed, as well as eliminate power surges on the grid.

Their demonstration project includes 80-100 kW fast charger and ESS, which enables 20-30 kWh charging in 15 minutes – that’s for sure not a pace on par with refueling, about which they discuss in the press release.

It’s also expected that for fast charging 200 cars a day (at undisclosed power and undisclosed constant power draw from the grid), ESS would need to be 2.2 MWh (11 kWh per car) and add $220,000 in additional cost for battery cells alone, even if we assume only $100/kWh.

“Low or medium voltage
“We came up with a system of intermediate storage,” said Alfred Rufer, a researcher in EPFL’s Industrial Electronics Lab. “With this buffer storage, charging stations can be disconnected from the grid while still providing a high charge level for cars.” And this can be done using the low-voltage grid (used for residential electricity needs) or the medium-voltage grid (used for regional power distribution), which significantly reduces the required investment.

Intermediate storage is achieved using a lithium iron battery the size of a shipping container, which is constantly charging at a low level of power from the grid. When a car needs a quick charge, the buffer battery promptly transfers the stored electricity to the vehicle. The grid is not even used.

To prove the system works, the researchers at the EPFL Energy Center and Industrial Electronics Lab built a demonstrator together with their partners from the Swiss Federal Laboratories for Materials Science and Technology (EMPA), the Swiss Federal Institute of Technology in Zurich (ETHZ) and the Bern University of Applied Sciences. The demonstrator is a trailer holding the intermediate storage battery. It draws power from the low-voltage grid and, in the space of 15 minutes, provides the 20 to 30 kWh needed to charge a standard electric car battery. “Our aim was to get under the psychological threshold of a half hour. But there is room for improvement,” said Massimiliano Capezzali, deputy director of the Energy Center, who coordinated the project.

Determining the capacity of tomorrow’s charging stations
What is also interesting about this concept is that it can be used to determine how much capacity future charging stations will need. Gas stations from the last century will gradually give way to electric charging stations. And just as owners had to assess how big their fuel tanks needed to be, future suppliers of electric energy will have to estimate the needed capacity for their buffer storage. To help them in their task, the researchers developed an equation that factors in a number of parameters, including traffic statistics on a given stretch of road, the estimated number of electric cars, the charging capacity of the batteries, users’ charging needs, and so on.

The simulations, which are based on actual figures from French-speaking Switzerland, show that the scenario is entirely realistic. A station able to quickly charge 200 cars per day would need intermediate storage capacity of 2.2 MWh. This is the same order of magnitude as the energy consumed by one home in one year. In volume terms, it corresponds roughly to four shipping containers. “Electric cars will change our habits. It’s clear that, in the future, several types of charging systems – such as slow charging at home and ultra-fast charging for long-distance travel – will co-exist,” said Dr. Capezzali.”

Source: EPFL

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65 responses to "4.5 Megawatt Charging For Electric Cars?"

  1. ffbj says:

    This article and its thrust contain a glaring oversight. They focus on speed, stating the ridiculous that it takes only 2 minutes to fill a vehicle with gas. Say 10 minutes, to be fair, on average.

    The oversight is the fact that you can charge at home fully, and then who cares if it takes hours, since most people just park their cars overnight?

    The thing is when you make a comparison between the to motivational methods, ice vs bev, you should examine all areas of that comparison looking at ALL the pluses and minuses of each.
    Extending that analysis very few people can actually fill up at home with gasoline.

    Another way to look at it is to say if there were no at home charging of evs say like fcv then evs would be dead, and that’s a fact jack, but they don’t even mention this.

    Additionally with increasing range you need to charge less on the road as most of your driving needs can be met by simply charging at low rates at home overnight. Of course not everyone can do that, but the large majority can, say 75%.
    Just having some letters before or after your name does not mean that you are right or that your analysis is complete or accurate.

    1. ffbj says:

      I should add that Mark also pointed out the flaw in the ointment, that they did not even mention home charging.

      1. Foo says:

        Hmm, “flaw in the ointment” is a mixed metaphor

        I think you meant either “flaw in the argument” or “fly in the ointment”.

        1. scott franco says:

          Methinks you need to back to humor 101. Sure as dogs can fly.

          1. ffbj says:

            Customer: What is this fly doing in my soup?
            Waiter: Hmm, it looks like the backstroke.

            You must cut Foo some slack as he ain’t from around these parts. Besides he is hilarious. I merely try.

          2. Steven says:

            Given sufficient thrust, dogs got quite well.

    2. jerryd says:

      Yes you can tell they are shilling for their system.
      But most 4kv-13.2kv feed lines easily handle the load especially as EV’s become more common steadies the loading.
      And they are most everywhere as what feeds the transformers on the powerpoles.
      That most EV’s take 20 seconds to charge 90%+ of the time and gas fills take a lot longer than 2 minutes just to pump, the 15 minute to charge is not much the few times needed.
      Also SC already will charge the model S 150 miles in 20 minutes and the 3 because it needs less power/mile, in just 15
      While battery packs buffering fast charging is a good thing, a shipping container is rather much. 300-500kwhrs should do it.

      1. Bill Howland says:

        That’s an overgeneralization and is usually not correct. At the phone company building I worked at we wanted to install a 750 kva transformer on a new 4kv service. The utility company would not allow anything larger than 500 kva, and this was just outside the most congested part of downtown Buffalo. Of course, if we paid to have their substation rebuilt larger, they’d do it, but we rearranged our request so as to have to not contribute inordinant funds.

        For suburban or rural areas, you’d be just dreaming.

        1. Pushmi-Pullyu says:

          Bill, your posts are frequently amusing, but quite rarely address the point.

          So, you can point to one case where a single commercial building would put the local electric substation “over the limit” of what the electric utility had planned to build in the near term, and so the utility had an excuse to try to extort money from your company to do what the utility would have to do anyway, sooner or later. That, unfortunately, is the type of B.S. that monopolies can get away with, since they have no competition.

          But that doesn’t in any way apply to a home owner buying an EV and using home charging. The utility has no excuse by which to compel any single home owner to pay for the sort of upgrades to the grid which are an everyday necessity. At worst, they can increase the cost of electricity for all their customers to pay for an upgrade.

          From Green Car Reports.com: “PG+E Data: Electric Cars Have Almost No Grid Impact So Far”


        2. jerryd says:

          Bill, like 500kw is way more than needed.
          A big battery system like this could likely get by with just a 200kw service for an 8 unit station.
          And places where these will be put usually has much larger lines than 4kv though it too will do.

          1. Bill Howland says:


            The article talks about 4500 kw charging rate for the avg car. The article also states the avg car will take 11 kwh from the dump battery. If the battery is a mere 60 kwh that means 49 kwh must come directly from the line, assuming dreamland 100% efficiency. If the much more likely 100+ kwh is taken from the charging station to get 60 kwh into the battery that means 89+ kwh is taken from the line. 200 kw ain’t gonna cut it.

            The 8 stall tesla sc by me charges 4 cars at 120 kw or 8 cars at 60 kw. The utility has a 500 kw transformer feeding the complex. “Unnecessary” though it may be, that is what they have. This article is talking about 4500 kw to the car.


            You have absolutely no idea what you are talking about. When National Grid provided me why they were limiting ‘us’ to a 500 kva transformer, I fully agreed with their rationale, and as mentioned decided to go with a Cheaper more cost effective route for Verizon. My suggestion of slightly enlarging the planned emergency generators, and fully utilizing the existing 40 year old dual electric services, so that no extra monies need be spent on any infrastructure at all was accepted by the Project Manager since it was by far the lowest-cost solution which met Verizon’s objectives.

            The utility’s 2 choices given Verizon (the customer) were perfectly fine – stick to their limitations or pay $millions for a huge upgrade. They gave us a choice, like it or lump it. I suggested to the PM therefore, to lump it, which is the way it is now.

    3. scott franco says:

      “They focus on speed, stating the ridiculous that it takes only 2 minutes to fill a vehicle with gas”

      Agree. The comparision is not with a crackhead trying to fill up on the way to his next fix. 15 minutes is acceptable, 5 minutes is equivalent.

      I have already done 5 to 10 minute fillups with my leaf. If I need to get home, and am running low, the Blink Chademo can fill up enough to do the job. It charges by the minute, and they charge more than it costs me to fill at home. So it makes no sense to charge up more than I need.

      1. ffbj says:

        Right, and that brings up a point that was completely overlooked in the article: the fact that a certain percent of charging will just be those 10-15 minutes you need to get home, where you can fill up. So you don’t sit at the charger for hours everytime.

    4. Speculawyer says:

      Yep . . . people need to break free of the 5-minute fill-up mode of thinking.

      EVs are just used differently. 95% of the time, you just wake up to a fully charged car, unplug it in seconds, do your daily driving, plug it back in in seconds, and go to bed. The fact that it charges relatively slowly is irrelevant because it happens when you sleep.

      Slightly longer trips can be handled with a level-2 charger at your destination where you will spend a few hours or a 30 minute DC-fast charge.

      The only difficult case is the multi-hundred mile trips. However, such trips are generally rare. Tesla has the only pure EV solution . . . the superchargers. But they do require you to take periodic hour long stops. But they are good times for meals. But one could also rent or carshare a traditional hybrid for such trips.

    5. Philip d says:

      Yeah. They exaggerate gas fueling speed and lowball EV charging speed.

      Even if It took only 5 minutes at most to fill a tank then with a Tesla Supercharger charging at 120 kW then it’s more like 30 miles/48 km in 5 minutes.

      Unless you’re on a road trip that 5 or so minutes and 30 miles on top of what charge you had left will give you more than enough extra to get you where you need to be at the end the day to charge overnight.

    6. Braben says:

      Not sure how you spend your time at gas stations, but I never need 10 minutes to fill up a car as long as I can pay at the pump. Takes 5 minutes tops.

      Recharge time is a problem in the real world, whether you like it or not. People do make trips away from home where overnight charging may not be readily available.

      Then there is the problem of charging station scalability. Right now Tesla’s charger network works because few cars are using it. But there are already reports of congestion at popular supercharger locations such as between LA and Las Vegas. Now imagine what will happen once millions of vehicles need to use the chargers, each blocking a stall for half an hour or more.

      I think the long-term goal has to be that charging times are short enough so that people can wait by the car while it’s charging. If it takes longer than, say, 10 minutes, people will tend to walk away and do something else, and their car will block the stall for a long time. You don’t want to wait in line for half an hour or more for a charger to become available when you need to get somewhere.

      1. GSP says:

        After driving for two hours, I am not only going to fill up. I will definitely be making a restroom stop, and maybe also buying a coffee and/or snack. A 30 minute charge stop is perfectly acceptable on road trips.

        There never is a need to charge on the way to or from work. That might have been a 5 min gas stop, but it is now zero minutes since I have a full charge every morning.

        The people at EPFL must not be driving EVs. They don’t understand yet what the real requirements are for electric transportation.


        1. Pushmi-Pullyu says:

          This is not realistic. Nobody wants to hang out in a convenience store for 30 minutes. If you expect customers to wait that long, then you need a coffee shop, restaurant, or shopping mall within walking distance.

          But yeah, there’s no need for a two-minute EV recharge time. Generally speaking, the only time you’d need to use a superfast charger is on a long trip, when you’d probably want a bathroom break at the stop anyway. A 10 minute charge time should be perfectly acceptable, given that for most drivers, that will only be needed a few times a year. As has been said, the time required for home charging is only about 20 seconds — the time it takes to plug your car in at night.

          Those who think larger EV battery packs will require longer charge times are ignoring the fact that EV charge times are already coming down with newer EVs, even as battery capacity increases. It’s inevitable that competition will drive down charge times to 10 minutes, and quite possibly even lower. Tesla’s Chief Tech Officer said Tesla wants to get down to a 5-to-10 minute charge time, and I think this is what we should expect to see in the future. Note faster recharge times don’t merely benefit the customer; they also benefit the superfast charger station owner, because that lets his station service more customers per hour.

          It’s true that charging, say, 300 miles of range in 10 minutes, or faster, will require batteries with a higher charging efficiency, and therefore less waste heat while charging. There have been a number of laboratory demos of batteries which can charge 5, 10, 100, or even 1000 times faster (or so they claim) than batteries currently used in EVs.

          It remains for such tech to be commercialized. It is inevitable that competition will drive the commercialization of such technology.

          1. Bill Howland says:

            Pushy you seem to be hanging your hat on what JB said.

            Seeing as Tesla had had power problems with 4 out of 5 charging schemes (MC,UMC in the Roadster), 15-50P adapter (first version overheated until 2 fixes were applied – software dropping of charging current rate from 40 to 32 and then dropping again if necessary -, and then more importantly, including a fusible link in the plug to shut off the juice prior to fire), plus initial problems with the 80 amp HPWC initially limited to 60 amps ) indicates to me Tesla historically has not completely thought through their designs.

            In fact, the current charging situation with the 15-50P is a bit of a nuissance. If the serving utility is unwilling to ‘robustify’ their facilities to prevent the Tesla S or X charging at 40 amps from decreasing to 32, or decreasing even lower, as what happened to my Canadian friend, then they are stuck charging at a slow-poke 24 amps since the software THINKS this is due to plug deterioration when it is normal Load-NoLoad excursion of the ‘grid’ to the house to feed the load.

            What TESLA should have their software due is to use the GPS in the car to tell it the ‘historical’ pressure drop at each charging location, and ONLY invoke current reduction if it is dangerously increasing. The two issues, in the general sense are unrelated. An installation coincidentally on top of the utility’s transformer could easily overheat due to poor connections, and the software as current constructed wouldn’t catch the trouble, whereas another house with a distant utility distribution transformer may have large ‘voltage droop’ when attempting to charge the car, and the car will decrease to 32, then 24 amps unnecessarily even though everything is running cold.

            But Tesla seems to like to talk about future products rather than stick to their knitting on the existing products – at least at times – lately they have been sticking to their knitting in finally releasing the X, a good thing, especially for people who had put down deposits.

            I’m not even talking about Superchargers. To my mind the lack of a way to shut down the power to the car is in violation of over a decade of National Electrical Code directives, namely 60 amps or more, and 150 volts to ground (earth) or more requires one.

            The recent fire at a SC site proves the wisdom of providing an accessible disconnect.

            By the way, the Canadian electrical code has similar disconnect requirements and I was not given an answer when the Toronto Inspection representative was given the same question.. He said it is something they are looking into….

            I sensed a fear to issue a ruling going against Tesla. I don’t see the problem. Just install the disconnect on the back of each stall. Problem solved.

            1. Pushmi-Pullyu says:

              Bill, I don’t know what point you were trying to make, but your wall-of-text post doesn’t seem to be in any way related to what I posted, nor to the topic of discussion.

              High current and high voltage electrical systems can, and routinely are, designed to work reliably and safely. But that doesn’t mean there won’t ever be malfunctions. Occasional electrical fires are something we have to live with, as a society. If you find living with the hazard of electrical fires unacceptable, then go live in central New Guinea or any other region with no electrical power. Occasional fires at gasoline stations are also something we have to live with, but few people are suggesting we shouldn’t have gas stations because of that hazard.

              I agree that Tesla Supercharger stations should have a manual power shutoff, but again that doesn’t seem to have anything to do with the topic under discussion.

              1. Bill Howland says:

                You IDIOT. I used to work at a steel plant. My dept used as much electricity as the entire town I lived in. They very carefully matched electrical usage so as not to pay excessive demand charges, and especially the demand contracted for, usually trying to run the blast furnace (for the more inferior grade steels) which indirectly provided lots of free electricity to mitigate the demand from the utility.

                The irksome thing about this is you repeatedly know NOTHING about the real world, but criticize those who do. It would be helpful if you KNEW something, about ANYTHING.

                Usually, you try to teach people conversant with accounting their business, when it is obvious to the casual reader that, even though 4 others give carefully reasoned responses, you dismiss it as you HAVE to be right. When you are PROVEN to be wrong, you just say, well, I’m not an expert.

                The real comedy is that you, who have never been near an electric car , (you certainly have no idea how their air conditioners work), tell those of us who have had several EV’s what ‘we’ do.

    7. Bone says:

      “They focus on speed, stating the ridiculous that it takes only 2 minutes to fill a vehicle with gas.”

      Depends on the tank size. At 10 gallons per minute, you get 20 gallons in two minutes. Not so far from average gas tank size. I can fill up my Ampera (8 gallons or so) in less than a minute.

      You can’t argue the fact that filling up gas is very fast compared to charging EV, but EVs don’t need to equal the gas cars in every aspect. EVs have many pros but some cons as compared to gas cars. Masses will buy EVs when positives overweight the negatives.

      1. GSP says:

        It still takes more than two minutes. You have to swipe your card, enter your zip code, say no to the car wash, yes to the receipt, and select a grade of fuel. I also wash my windows. Five minutes minimum, but zero for an EV.


        PS. After buying a coffee and lotto ticket, standing in a line of 2-4 people to pay, it can be a 15 min stop. That already provides meaningful range on a Supercharger.

        1. Bone says:

          I don’t see a single reason why it would be any different for EVs. EV surely needs window washing just as much as a gas car, and card payment would the most simple way to pay for charging just like it is for filling up gas.

      2. Speculawyer says:

        Yeah, it is definitely more than 2 minutes. There is the time you spent going out of your way to get to the gas station. Time getting out of the car, swiping your card, entering ZIP code, getting the pump into your gas inlet, gas pumping time, putting the pump back, getting the receipt, getting back in the car, seat belt, getting back on your way. 5 minutes seems much more fair when it is all considered. Maybe slightly less sometimes . . . more other times (crowds, issues with the pump, etc.)

        When you plug in at home, that is your destination, you were getting out of the car anyway, there is a few seconds putting the charger into the inlet but that is it.

  2. Brian says:

    Their dramatically oversimplified calculations lead to some absurd numbers. From their numbers, it looks hopeless for EVs. Yet the only real problem with today’s top-of-the-line EVs (i.e. Teslas) is their price.

    By the way, if you need to buffer 2.2MWh over 24 hours, that’s an average rate of 92kW. So it’s almost like running a single supercharger port 24/7.

    If you can provide more power (obviously Tesla already does at their stations), you either don’t need as large of a buffer, or you can charge more cars per day.

    I’m really tempted to run my own “study” (i.e. simulation) based on my own opinions having owned an EV for almost 4 years now. I bet I’ll end up with wildly different numbers.

    1. Speculawyer says:

      Well, a multi-hundred mile trip in a Tesla does have some downsides:
      1) It requires superchargers on the route. There are places that still lack them or they are not on your intended route.
      2) They require periodic hour long stops to recharge . . . something you don’t have to do with gas cars.

      That said, I don’t view those as significant problems. The Supercharger network continues to grow and has pretty much everywhere that I would drive covered. And multi-hundred mile trips are very rare. Thus, such 1 hour long rest stops are not something one would experience often.

      1. Anon says:

        Wondering what kind of SuperCharger advances and developments there may likely be in 2-3 years, when Model 3 hits mainstream production…

      2. Pushmi-Pullyu says:

        Speculawyer said:

        “They require periodic hour long stops to recharge… something you don’t have to do with gas cars.”

        From what I’ve seen reported, the average waiting time when Supercharging a Model S is 30 minutes, with 45 minutes normally being the maximum. An hour wait would only be needed for someone who wants to charge that last few percent of capacity, which in most cases is a waste of time.

        1. Speculawyer says:

          Cool. Nice to know. And I hope people unplug and move on once the charging rate drops to allow the next person to charge.

    2. Bill Howland says:

      4500kw is just about the size for Priusmaniac….1500 volts @ 3000 amperes.\

      Perfectly doable except the $$$.

      Bateries and electronics would haveto get more efficient and much cheaper f or this to become an everyday occurance.

      1. Priusmaniac says:

        A bit late on the comments here, but since you invite my response, I would tell that 4500 KW is a bit higher than what I would expect. Considering costs, batteries and overall optimization I would say somewhere between 500 KW and 1000 KW. But on the voltage, yes 1500 V or 1600 V is very likely. That may sound a lot right now but it is a similar factor ten to the one the Tesla Supercharger was when the other ev where still charging at a maximum of 9 or 10 KW. In order to bring in that kind of power in a 150 KWh battery at 4C go 7C rates, electrodes are going to move back from more thickness to drastically more surface area. So that means the thinner the better but with a super high surface area. For charging the Tesla snake could be an option or a ground based system under the car which would have the advantage of doubling as a cheap set for widespread secured contact based automatic charging bumper spots at almost every parking place. Megacharger (1000 KW) would be at 1600 V and lower speed charge would still be at 400 V. For standard parking places it would drop to 230 V. So always two contacts but with a voltage adapted to the charger type. Security check would be using a Bluetooth connection and perhaps associated with the smart idea (originally presented by Richard Factor here http://www.priups.com/misc/contest-entry.htm ) of special switch under both wheels which requires several pounds of actuation force. But the alignment would of course be automatic and the contacts on the ground would be large inox ones on a plastic bumper to be somewhat above ground away from standing water. The car would have contacts on flexible support that bring them in smooth contact with the ones on the ground. A plastic brush like protection around the car contacts prevent outside interaction while charging. On a high voltage location a fast Dyson type dryer is removing any moisture before the start of the security check procedure and the following high power charging.

  3. Scott says:

    Yeah, buffering “supercharging” makes sense and all, but 99.9% of the time I could care less.
    I asked my neighbor if they thought the whole neighborhood could run their dryers at the same time. They thought “Yeah, no problem.” But when I asked if they thought everyone could charge their vehicle at night (at the same ratings) it seemed impossible.
    We have a long ways to go.

  4. Alaa says:

    And to think that they are Swiss!

  5. enerc77 says:

    Owning a LEAF for 6 month and 5000 km, I have never fast charged. Only charge at 3kW in the street or at home at 2 kW.
    With the 2015 LEAF, it’s difficult to cross 700 km especially in winter with heating. But when new EV generation with 250 km real range will come in 2017, I will only need two charges each way to go for holidays twice a year. That would be 8 fast charging a year.
    And I don’t mind waiting one hour resting every 2-3 hours of driving.
    For sure, fast charging is required to travel long distance. But I will spent less time in fast charging, than in fuel stations I used to.

    1. GSP says:


      Exactly this. With only 8 fast chargers per year needed for your driving, and zero weekly stops at a gas station, you are ahead in time (and money).


  6. ItsNotAboutTheMoney says:

    The real reason for buffering to have superfast charging is not about the grid, it’s about contention at on-the-road chargers. The faster you can go, the greater volume it can handle.

    And +1 on the nonsense of “overloading the grid”. You’ll only get overload if electricity pricing doesn’t encourage people to charge at night. We probably peak when the stove is on, not when the Volt’s charging.

  7. Anthony says:

    Eventually we’ll get to 20 minute charging from 0 to 80% that allows for 200+ highway miles (75MPH) in nearly all conditions. I think that’s where improving on those parameters will no longer return enough value to the user to make the investment worthwhile. Its long enough to grab a bite at a quick-service restaurant.

  8. scott franco says:

    “But such a quick charge would require 4.5 MW of power – equivalent to 4,500 washing machines. This would bring down the power grid.“

    No. Short of powering on an aluminum smelter, the power grid has plenty of headroom for industrial applications. The worst that could possibly happen is that charging stations would be limited to at or near industrial sections of town, hardly a big limitation.

    Go outside, look up at the power lines. Those top lines are typically 15kv or more for distribution.

    The worst power user here in Silicon valley was the Moffet field wind tunnel, which had its own power substation, and the operators of it were required to call the power grid operators and ask for permission to turn the wind generators on.

    Short of that, car charging is a flyspeck.

  9. Storky says:

    Is not heat an issue when fast charging?

    1. SJC says:

      Yes it is, but that won’t stop exaggeration.

    2. Pushmi-Pullyu says:

      Yes, but EPFL’s claim that a superfast charger for EV passenger cars would operate at 4500 kW (4.5 MW) is just silly. It’s entirely possible that EV heavy trucks or buses would need that much power, but those will be charged at the EV equivalent of truck stops, not the EV equivalent of filling stations.

      Currently (pun intended), Tesla Superchargers charge at the rate of about 150 miles in 30 minutes, at 120 kW. To get to 300 miles in 10 minutes would need 720 kW. (A gasmobile’s gas tank typically will take the car at least 300 miles, so that’s a useful target.) If you want to get down to a five minute charge, that needs 1440 kW. Still a long way from 4500!

  10. BraveLilToaster says:

    I’ve seen this come up a lot in the forums, people telling the world that EVs *need* to charge in 2 minutes flat or they’re useless.

    I can see that at the very least, they did the math that tells them they need to charge EVs at a rate of 4.4 MW.

    However, they’ve rather stupidly forgotten to bother with Ohm’s law: Power = Volts * Amps.

    So let’s take the Model S’ battery, at 375 volts. When nearly drained, it can charge at about 400 volts at a supercharger. So 4.4 Mw / 400 = 11,000 amps. Congratulations, you’ve *instantly* melted the charging cable and started an electrical fire! That is, if you didn’t just make the whole thing immediately explode!

    If we were able to somehow (magically) double the volts we can charge at, then we’re only halving the amps. 5,500 amps will still melt the cable, it just takes a few seconds to make it happen. To even get this to a manageable level of 1,000 amps, we’d have to use a voltage of 4400 volts. Or 10 times what the battery can take. Again, you’ve just started an electrical fire, this time by exploding the battery.

    You want to know what you really need to do? Stop being stupid and change the charging time from 2 minutes to 8. Now you’re charging at 1.1 Mw, and “only” 1100 volts, or nearly 3x as fast as a Tesla Supercharger can put power into a Model S without making it burst into flame.

    Now all you need to do is invent a battery that can simultaneously hold 70 kwh of electricity, accept a charge at a 3c rate on a frequent basis, and survive a bare minimum of 5,000 charges over its lifetime, all for less than $200 per kwh.

    I’ll wait here while you take care of that part.

    1. ffbj says:

      Very informative.

    2. Pushmi-Pullyu says:

      BraveLilToaster said:

      “Now all you need to do is invent a battery that can simultaneously hold 70 kwh of electricity, accept a charge at a 3c rate on a frequent basis, and survive a bare minimum of 5,000 charges over its lifetime, all for less than $200 per kwh.”

      Or, use a 140 kWh battery pack, accept a charge at 1.5c rate, survive at least 2500 charges over its lifetime… all at the very same per-kWh price, without even choosing cells optimized for high power (and thus fast charging). Since LG Chem is charging GM only $145/kWh for Bolt batteries (admittedly a sweetheart deal), a $200/kWh price seems quite do-able.

      It’s hardly realistic to expect future EVs will be limited to a 70 kWh battery pack. Gasmobiles typically have a range of at least 300 miles. To reliably go 300 miles at highway speed, the Model S would need a battery pack of at least 116 kWh. Adding 20% to allow for range degradation in very cold weather and/or some safety margin, that would be a 139 kWh battery pack.

      So yeah, in the future we most certainly will see EV passenger cars with 140+ kWh battery packs.

      1. BraveLilToaster says:

        Yes, and at even $100 per Kwh (a wildly unrealistic number right now and well into the future), a 140 Kwh pack comes out to $14000. Not to mention the weight and size of such a battery. Currently, 90 Kwh is the largest pack we can put into a car, period, and that’s with a “damn all considerations of cost” engineering limitation.

        Either way, the stipulation that EVs are useless until they can refuel at the rate of ICEs is still a stupid one. They’re trying to solve the wrong end of the problem. Norway and Denmark have already shown us that it’s an EVs initial sticker price that keeps people out of them, not any of their other limitations.

        1. Pushmi-Pullyu says:

          I agree that it’s completely ridiculous to claim that EVs will never sell well as long as they can’t be recharged as fast as a gasmobile can be filled up. As has already been said, most buyers choose on the basis of the entire package — not on the basis of a single variable.

          However, I take issue with this:

          BraveLilToaster said:

          “…at even $100 per Kwh (a wildly unrealistic number right now and well into the future)…”

          Let’s just say that those who know more about the subject than we do, don’t agree with your pessimistic opinion of the near-future cost of EV batteries. See here:

          “Tesla Projects Battery Costs Could Drop To $100/KWH By 2020”


  11. Speculawyer says:

    I’ve seen this article around and it doesn’t seem very informative. Yes, if we build really fast DC-chargers, we will need to have battery storage at such sites because the utilities are going to be a bit freaked out over such big bursty power draws. Duh.

    But they don’t address the other bigger problems such as the lack of standardized high-current charging port for cars, the lack of any car with a battery that could handle such high current, the need for really big thick charging cables, etc.

    1. Pushmi-Pullyu says:

      Speculawyer said:

      “Yes, if we build really fast DC-chargers, we will need to have battery storage at such sites because the utilities are going to be a bit freaked out over such big bursty power draws. Duh.

      Why? Many industries have “big bursty power draws”.

      It might be advantageous to install a modest power buffer at a superfast charge station, to avoid the most excessive of surcharges which electric utilities impose on industries for sudden spikes in power demand, but it’s not realistic to think you can supply a busy superfast charging station with high power by using a modestly sized electrical power hookup and a large battery buffer. If the station is busy, then that buffer will soon be exhausted.

      What’s really needed is the sort of high power hookup used by sizable commercial buildings, and many industrial buildings.

      1. Speculawyer says:

        And those industries pay big ‘demand charge’ fees that the utility uses to strength the grid at that point and add buffering.

        1. Bill Howland says:

          Which industries have “Big bursty power draws”?

          In my experience, the larger the industry, the more they avoid that.

          Or is it just what he thinks? Or what some idiot technical reporter said?

          1. Pushmi-Pullyu says:

            LOL! Poor Bill. He can’t imagine that anybody knows more about a subject than he does.

            Someone upstream already mentioned aluminum smelters. And some steel mills use electrically heated crucibles, too. Those would be two extreme examples of industries with intermittent very high power demand, but there are plenty of other industries, and even some large commercial buildings, which get hit with surcharges for power.

            If a superfast EV charge station is going to avoid such surcharges, it will need a battery buffer. I don’t have any figure for the size needed; that could use some discussion.

        2. Pushmi-Pullyu says:

          Speculawyer said:

          “And those industries pay big ‘demand charge’ fees that the utility uses to strength the grid at that point and add buffering.”

          Yup. Now we’re getting to the real issue of building superfast charging stations: The cost. Nobody who knows much about the subject will claim it’s gonna be cheap. Upstream in this discussion, Scott Franco said:

          “The worst that could possibly happen is that charging stations would be limited to at or near industrial sections of town, hardly a big limitation.”

          Unfortunately that is a big limitation, since what we need is a network of superfast chargers along all major highways, and eventually even minor highways. Running high tension power lines to all those rural locations is gonna be expensive. But as I see it, we have no alternative. Powering such stations with solar panels is a fantasy; you’d need a solar farm the size of multiple football fields to power an 8-stall superfast charge station, even on a bright sunny day. Even with such an installation, you’d still need that high-tension power hookup for cloudy days and night-time charging.

  12. Aaron says:

    I do like the idea of having the EV “fueling” stations also be buffers for the grid. This would also enable solar and wind to become a larger part of the equation.

    Still, at $250K for the batteries alone to buffer electricity, it is STILL cheaper to build than one hydrogen fueling station.

  13. Murrysville EV says:

    It’s easy to be critical of their research on an EV forum when most people here are driving short-range EVs they charge at home.

    The truth is that they’re right – the general public wants a quick fillup, and the longer-range EVs coming in the next couple of years will travel longer distances.

    This means people won’t be charging in their garages every single night. They’ll want to fill up somewhere on their journey, and it’s the constant PLANNING that distinguishes EV drivers from everyone else.

    The general public has more Planning Anxiety than Range Anxiety. When I had my Leaf, every. single. trip. was. planned. That is a very high barrier to entry for a buyer considering an EV for the first time.

    Tesla is now the best-selling EV for this reason: long range and a network of Superchargers remove nearly all of the planning that Leaf drivers are burdened with.

    Saying that “the public’s thinking has to change” is one reason why EVs struggle.

    1. Emmanuel Huybrechts says:

      The planning is only necessary because of the lack of good infrastrure. If you had as much DCQC locations as there are gas stations no planning would be ever necessary. Just go to the closest charging station when the battery gets low.

      It’s also a technology issue, the planning could also be taken care by computers.

    2. shane says:

      I think you’re right. When I rented a Leaf for a week, it was the planning that I didn’t care for. Around that time we had an emergency with a pet, that required much more miles than the Leaf would have covered. That, and frequent long distance trips (with pets, by car) drove us to choose the Volt (can’t afford a Tesla). I still think the best answer – until the charging structure is built out – is a 100-200 mi affordable BEV with a small genset (like i3 Rex, except bigger battery, and an ability to turn the generator on when you want – oh, and a respectable gas tank size)

  14. jmac says:

    The solution is inductive charging. Just put inductive chargers in many places. At work, the the Costco, your favorite restaurant, the football stadium, at work, in the garage, at the soccer field, at the city park, etc.

    If you need charging while you are out driving away from your home charger, just park over a charger while shopping or doing business. It’s all done without so much as lifting a finger Charging begins automatic when you park and you are automatically debited for the electricity. You spend ZERO time waiting for a so-called fast charger.

    Everyone constantly makes the mistake of modeling EV charging after the gas station model. Inductive charging eliminates the gas station stop altogether and pointless waiting at the electrical kiosk for 15-30 minutes while your car fast charges. I’d rather be inside TGIF Fridays eating while you are outside wrestling with a electrical power cord the size of a Boa Constrictor.

    Please throw away those 6″ inch diameter power cords immediately. You’re scaring me.

  15. jmac says:

    The people in this article at EPFL want you to follow the old gas station model where everybody MUST stop and quick fill at an official EFPL shipping container.

    Basically, EFPL wants to become the new Standard Oil where everybody is addicted to stopping at their new electric refueling station just like in the good old bad days of gas.

    Only now, EFPL plans to crack the whip instead of John D Rockerfeller, Exxon and OPEC. But, in reality, the EFPL plan is just the same old, tired gas station model dressed up in new clothes.

    As a result, inductive trickle charging while parked at Costco is not part of this Swiss companies business plan. On demand, dirt cheap, streaming internet movies from Netflix were not part of Blockbuster’s plans either.

  16. Nix says:

    I wish I could fill my gas tank that fast. But I have to drive to a gas station first, and that takes time (and gas).

    There are no gas stations directly on my daily driving route, and the closest station to my house likes to screw people with high prices because there isn’t another gas station nearby.

    So I get to go out of my way at least 10 minutes just to not get screwed buying gas.

    That’s what’s nice about having a PHEV. I can run on electricity most of the time, and just keep topped up with gas at my convenience when we’re also buying groceries.

  17. Bill Howland says:

    Well, I don’t know how they do things in Switzerland, but our washers in North America (except for large commercial jobs) don’t use 1000 watts. The largest machine ever made for residential use, a Norge 20 pound machine with 3/4 hp motor, used around 800 watts. Most used around 500, and my current General Electric draws between 125 and 300 watts.

    The Doctor’s other conclusions are equally suspect. Such as 11 kwh dump storage per car, including the high losses that a superhuge charge rate would incur in the car, when trying to eventually end up with 100 kwh into the car. If we’re not putting that much into the car, then there is no need for a 4500 kw charge rate. I’d be doubtful if the efficiency of a 45C charge rate would be higher than 50% – anyone who has seen other fast charging set ups sees the amount of heat coming from the apparatus – batteries included – both the supply batteries and target battery to be charged in the car. The amount of heat would be slightly under 7,600,000 BTU/Hour, or enough heat to run the boilers for a 6,000 seat theatre. This is the amount of heat from the activity of charging one car.

    So to repeat the punch line from a previous post, unless electronics and battery efficiency greatly improve (something which the Doctor could have no more of an inkling about what devices or modernization the future holds), I’d say people who want 4.5 Megawatt charging for their cars are in for a very long wait.

    1. Nick says:

      2kW is normal power for a washer in Europe. Keep in mind 230V, and cold water inlet only. Water is heated by the washer, up to 90C.

      1. Bill Howland says:

        OH ok, that explains it. Water heating in the states is usually very low cost, which is why it is almost universally centralized, having hot water distribution to almost all locations in a house. My water heating costs are 1/6 th my electricity cost, but some people with more efficient water heating than what I have pay only 1/7 th.

        Solar water heaters and/or ground water heat pumps are easily integrated into the states’ centralized hot water distribution systems.

        1. Bill Howland says:

          Speaking of low natural gas cost, in my current gas bill, by heat content, my marginal cost for gas, including taxes for last month was 1 1/5 cents per kwh. Electricity was 12 cents, so that means my gas cost for last month, for the same amount of heat value, was 1/10 th (!!!!) the cost of my reasonably low cost electricity.

          A note on the gas bill said, ‘energy prices can’t go any lower than this’. TOTALLY AGREE!

  18. Pushmi-Pullyu says:

    It’s hard to know if the laughable claims in EPFL’ ad are a result of ignorance, or a desperate attempt to sell a solution in search of a problem… or both.

    Tesla Supercharger already charge at a rate of up to 120 kW; no battery buffer needed. In fact, any sizable commercial building needs more power than this, and such power is routinely supplied by a typical utility.

    EPFL’s infographic claims:

    “Electricity, home charging: Most common method for today’s electric cars. Growing risk of overloading the electric grid due to increasing popularity and power requirements.”*

    Seriously, using the hoary old FUD about crashing the grid to promote a battery-buffered EV charger? How many years are we going to continue to be subjected to that cabbage?

    Reality check: Adoption of plug-in EVs will create no more additional demand on the grid than installing central air conditioners in the USA did, a couple of generations ago. Last time I looked, the utilities were able to keep up with the gradual increase in demand, and there is no rational reason to think modern electric utilities have suddenly lost the ability to increase capacity where necessary.

    *The text was cut off in what’s posted at the top of this article; I found the original and transcribed the full quote.