Where 3000MPG+ Cars Come To Compete: The Ecomarathon

Every year teams from around the world come together for the Ecomarathon, an event (ironically put on by Shell) that tasks teams from high schools and universities with creating energy-efficient electric, gas, and hybrid vehicles. This year’s competition was held in Detroit, so I headed over to check it out.

vehicle-blurThe event has two categories that vehicles compete in: prototype vehicles that compete for the highest fuel efficiency and “urban concept” vehicles that are more focused on normal driving environments and look slightly closer to street-legal vehicles. Cars in both categories can be fully electric or powered by gas, diesel, compressed natural gas, or other alternative fuels. Vehicles drive around a 0.9 mile track that weaves through downtown Detroit and the efficiency of each vehicle is measured as they complete a fixed number of laps around the track.

supermileage-workingEven though many of these teams are backed by universities with hefty amounts of funding, the skill sets of individual team members have a huge impact on a team’s success. I talked to a team from Ohio whose electric vehicle team was made up entirely of mechanical engineers — and they were actually able to put together a fully functional vehicle.

The Ecomarathon requires each electric vehicle to have a custom-designed motor controller, which was a big challenge to a group with both limited time and little electrical experience. To get something up and running as quickly as possible, the team took an Arduino and hooked it up to a bunch of parallel FETs which are PWMed to control their drive motor. Unfortunately their simple design ended up frying a bunch of FETs during competition, probably due to inadequate gate drive. Nevertheless, the team was able to get their car working before the end of the competition and ended up in 11th place with a power consumption of 109km/kWh.


In contrast, some other teams had pretty impressive electronics; custom vehicle controllers built around microcontrollers, and quite a few that interfaced to phones or Android tablets to display live data over Bluetooth or USB. A couple of teams even had web interfaces that displayed live telemetry from their vehicle.

Despite all of the fairly sophisticated electronics, most of the vehicles are based around single-cylinder gasoline internal combustion engines, and most use a commercial engine controller.

steering-columnMost teams start out with an off-the-shelf lawnmower engine or something similar in size. Some teams just run the engines stock, while others add mechanical or electronic fuel injection and fabricate their own cylinders and pistons. Teams with stock engines often perform surprisingly well, since a ton of efficiency is gained and lost in the aerodynamics of the car alone.

The construction of each car varies quite a bit: some cars have simple designs around tubular metal frames, while other designs are elaborate composite layups with carbon-fiber roll cages and supports. Some cars have automotive-quality paint jobs, while others have a pretty rough finish. Regardless of the outside appearance, nearly every car I looked at had some sort of awesome hacked-together last-minute fix (note the pop can in the image below).


Most of the prototype cars have extremely aerodynamic body shapes, which the students spend a ton of time simulating to make sure they are as efficient as possible. One of the biggest sources of drag for the vehicles is the wheels, so many of the vehicles have aerodynamic covers over the wheels, or actually move the wheels inside the car. Each team had their own take on body design, and most designs were really unique.

Even though these prototype cars aren’t anything close to what you might see on the road, this competition brings students together to research and create energy-efficient mechanical and electrical designs. The designs might not directly translate to vehicles on the road in the near-term, but I’m sure the students will use their the skill and passion for engineering and hacking to make the vehicles of the future even more awesome.

Want to check out the scores from the event and see what schools competed? Head on over to the results page.

65 thoughts on “Where 3000MPG+ Cars Come To Compete: The Ecomarathon

  1. These vehicles mainly use the pulse and glide strategy, which means they try to find where the up and downhills of the track are and coast as much of the way as possible.

    That’s why they don’t much put much care on the engine which only sees action for a handful of seconds per lap – they put more effort on the wheels, bearings and aerodynamics, and driving strategy because it offers a bigger return of investment – and simultaneously puts the vehicles further and further away from anything you could actually and meaningfully drive.

    It’s a pity, because the whole competition is a kind of smoke and mirrors. The idea behind it is to compete in fuel economy, but really they’re just avoiding the whole problem.

    1. Except that the pulse and glide works. I use it (minimally, albeit I do use it) to maintain approximately +2-4mpg on my commute daily.
      I drive a 1.0 Geo Metro (WOOT!)

      1. +2-4 mpg is really too small a difference to really measure from all the other things that affect your mileage. It’s the kind of measure that fuel saver scammers use, because people are convinced it works because they see a temporary improvement over whatever reason.

          1. Yes, because they’re very practiced at it, driving vehicles designed explicitly for gliding and pulsing, iterating over the same track in the same conditions to continuously hone their skills and craft.

            Not ordinary sunday drivers trying to guesstimate whether their efforts are making a <10% difference in their driving when they could just as well be making it worse.

          2. One of the problems in trying to measure your fuel mileage is that fuel density changes by temperature, so a gallon at the pump isn’t necessarily the same amount of energy.

            The amount of fuel you actually get changes about 2% between winter and summer, so if you’re driving a Geo Metro which is expected to get 53 MPG, you can expect +-1 mpg just by the temprature of your fuel. However, the fuel itself isn’t necessarily the same blend and so you may see +-1 mpg differences simply because the energy content is different to start with. Then there’s weather, traffic, your mood which affects your driving… You need to follow your mileage over a very long time, a year or longer, meticulously, before you can make claims of changes at <10% magnitude – but most people won't.

            What really happens is, people go "Well I suppose I was doing 50 mpg before, but now I'm doing 54. That's an improvement! These fuel line magnets really work!"

          3. I would say that even an ordinary Sunday driver can become very experienced at driving their standard vehicle in a way which improves their fuel economy (FE) significantly. Getting immediate feedback is cheap & easy (e.g. $15 Bluetooth OBDII dongle & free Torque app if you have ’96 or newer cars, if it’s not already part of a built-in display) and tracking tank-to-tank fills will help to calibrate the immediate readings. In my case, I can now improve the FE in my ‘normal’ car by 40 – 50% vs my wife in the same car. Granted, not the same weather, traffic, route, etc., but it’s been consistent over various routes for the past ~5 years and ~65K miles that I’ve tracked it.

        1. 2-4 is only if you aren’t even trying.

          My family periodically hypermiles, effectively driving like a complete dumbskull in order to squeeze every last ounce of the gasoline. Using a stock 2009 Honda Fit (advertised 35 MPG, highway), my brother routinely gets 42-45 MPG. Another co-worker’s family member makes extra efforts and routinely receives around 48 on trips. http://imgur.com/ChKVRBm

          On my Toyota Tacoma (advertised 25 MPG), when I make specific efforts, though not as OCD as my brother, I can get 30-31 MPG over the course of a tank… and that’s still got some city driving in there.

          Being obnoxiously slow to accelerate, slowing down going up hills, coasting, timing red lights from 1/2 mile away, avoid cruise control unless on perfectly level ground (okay, and don’t turn on the A/C or more than crack the windows). On /conventional/ vehicles, the car matters a good bit less than how neurotic the driver is.

          1. +2-4 mpg for a car that gets 35 mpg is a proportionally larger difference. It’s a significant improvement in a Toyota Tacoma, but only statistical noise in a Toyota Prius.

            And driving 10 mph below the speed limit saves you a lot more, but that’s just the point. In order to save fuel like the ecomarathon drivers, you have to start driving like a complete dick.

          2. This is kindof why I wish these races were more automated – or at least, that the driver was standardized between vehicles. It’d be really interesting to see the cars attempt to optimize the efficiency themselves: if the goal is really to optimize the fuel efficiency, a processor could keep the engine’s load at optimum a lot more efficiently than a person could.

            Of course, it’d also be interesting as hell to see someone attempt to drive a car whose throttle is being controlled dynamically outside of their control.

          3. Try going down the route of the ecomodder.com crew. Heavyly modified bodywork and eco driving. I get the feeling it’s almost a ‘sport’ to them. Hats off to them!

          4. You’d probably get better mileage from not driving a truck everywhere. You might save enough, getting a really efficient car, to pay for the car. For some reason European / non-USA cars tend to have much better efficiency. Actually the reason is fuel prices, but you knew that.

            Get a vehicle that suits your needs with efficiency as the most important thing. If you want to save fuel.

      2. One of the reasons why the ecoracers use pulse and glide is because an otto engine is most efficient at open throttle. They pulse the motor at 100% load for a couple seconds to gain speed or climb a hill, and then disconnect it from the drivetrain and shut it down.

        That’s generally not a feasible way to drive in a regular car. To do exactly what they do would mean throwing your car in neutral at the exit ramp and turning the motor off, then bump-starting it at the last possible moment when you need to accelerate again.

        1. > That’s generally not a feasible way to drive in a regular car.
          I guess you excluded hybrids from your set of ‘regular cars’ then. It’s not exactly how the Prius works, but an approximation and other hybrid cars could work like that.

          1. Not really. Especially the Prius does not work like that. Recharging the battery loses 30% of the energy on the round-trip, so toggling the engine on and off between full power and no power makes no sense and just causes undue damage due to thermal cycling. When the car is going forward at a steady speed, the engine is on all the time.

            You also need the engine running to provide heat to keep the windows clear and the passengers comfy.

          2. Actually I was using the wrong comparison.

            I should have said, the way you drive the ecomarathon cars is like accelerating to 100 mph on the freeway, then coasting down to 10 mph before bumping the engine back on with your gas pedal jammed hard on the floor. You’d go roaring back to 100 mph and throw the engine off, and rinse and repeat.

            It would be impossible to actually drive like that. Aside from being incredibly uncomfortable, it would break the car in a matter of miles because it’s simply not designed to do that.

          3. I have a friend who worked in russia for a while and he said his driver drove exactly like that everywhere they went. He had to get used to it to get over the motion sickeness of driving from 0 to 100mpg and having the engine slowing down until they hit 0 again and doing it all over

        2. Except, I drive an ’04 C230 2 door 6-speed. “Disconnecting from the drive train is fin and all, put simple coming off the accelerator downhill is sufficient for me to average 25mpg on my 24 mile commute averaging about 27 mph with about 1/3 of the trip dedicated to lurch and go traffic. Measured based on the active mpg calculator on my dash, which I’ve found accurate. I’ve also done the commute will throwing it in neutral downhill and the delta between 6th gear downhill and neutral as it relates to mpg is almost insignificant. It’s certainly never more than a 1mpg difference. So I’d challenge your assertion that pulse and glide is not a feasible way to drive in a regular car. I do however agree that “turning the motor off” is not a reasonable way to drive. (Obviously feasible because people do it)

          1. “the delta between 6th gear downhill and neutral as it relates to mpg is almost insignificant. ”

            That’s because the engine stops the fuel feed when it’s being turned by the wheels, while putting the car on neutral will keep feeding fuel to the engine to keep it idling. Either way you’re losing energy – coasting downhill on the gear slows you down.

            If you wanted to do like the ecoracers, you’d put the gear in neutral and turn the engine off entirely when coasting. That means all off – power steering, assisted brakes, AC, fans, lights, everything, then bump it back on at the foot of the hill.

    2. I wouldn’t call it “smoke and mirrors” – it’s a learning experience to get students a practical feel for what really causes losses in cars, like aerodynamics.

      Practically, you’re not going to be able to have teams improve engine (thermal) efficiency significantly. That’s just not possible for a college-type team. And yes, improving aerodynamics at low speeds is also a bit goofy, since those improvements don’t really translate to higher speeds like you’d want. But I agree, it’d be nice if the competition tried to push away from “driving strategy” benefits, since that’s not really engineering.

      1. That’s true. It’s a valuable engineering challenge.

        My point is that they aren’t addressing the actual economy and efficiency of the power source, with many of the teams using just off-the-shelf parts. It’s not really an “eco” marathon, but more about who can make the most aerodynamic soapbox racer. The letter of the law is to race vehicles using minimum energy, which they do, while the spirit of the game is to address future sustainability and energy use, which they don’t.

        1. I was in a shell eco marathon team, a few years ago.. a very small team, with very low budget.

          I can assure you that both the full body design and the core engine design were taken into account
          by the team of engineering students.

          Sometimes, some years, this was leading to catastrophic failures, due to poor design. But if most teams use *some* off the shell parts, most teams also use innovative custom parts and design.

          1. Were you allowed to insulate the engine and heat it up before the race to prevent heat loss in the cylinder to keep the thermal efficiency up?

            When the motor runs in short pulses, it goes cold and the efficiency on restart is horrible because you have to run it rich and all the optimizations are thrown out of the window. That’s why there’s little point in putting too much effort on the engine, and more point in using the engine as little as possible.

          2. As far as I saw other implementations, none of them were doing engine insulation.
            I saw that lot of work was being done on the engine cartography and engine control chip, however (but that was more interesting to me since it was more in my skills area, so my opinion is biased on this).
            It was not exactly short pulses but maybe 3 or 4 short “engine on periods” for every lap (I depends on the circuit, of course).

            The competition rules explicitely forbids some sort of cheating where by using short starter pulse only, the engine starter with the battery would provide more energy that the fuel itself (I don’t remember how it was done, maybe using some sort of indicator when you start the engine).

      2. Take for example, the news at the Ecomarathon website:

        “Competition Day 1
        High winds send practice runs indoors”

        These cars are so specifically engineered for certain external conditions that they won’t even go outside of that – they lack the engine power to drive into the wind, and their whole strategy is ruined even if they did.

        That’s how far removed from reality the competition is. One can ask, are economic cars only supposed to be driven in fair weather?

        1. That’s a good point. The Vetter Challenge tries to make more practical eco vehicles. The vehicles have to be able to carry several bags of groceries, they have to keep a certain pace, and the tracks are often windy.

        2. It seems more likely that the high winds would impact steering or even just impact the numbers enough that comparing to previous years would be impossible. If the goal of this is to continuously improve on previous designs, they need to keep things at least somewhat consistent to be able to tell if they’ve achieved that

          1. I suppose, but they’re designing a more and more specific white elephant. Aerodynamics is already quite understood, the application of it to go-karts isn’t really something the world needs.

          2. A “car” that is designed to coast half a mile down from 20 mph on level ground can’t tolerate any wind. A gentle breeze for a headwind will halve the mileage.

  2. The single biggest fuel efficiency you can gain is to drive less. While I’m all for efforts to try to squeeze every last MPG out of cars, it seems like a better use of brainpower would be for them to figure out how to have fewer people in fewer vehicles.

  3. They need to report miles per pound or kg of fuel. We should all be buying by weight, not volume. It isn’t exactly a scam, but it is misleading, as the government (in the US) mandates various amounts of lower density alcohol depending on season and region. Hmm. Yeah, it is a scam.

  4. A surprising amount of negativity here, in response to clever people really working hard to achieve something new: “Smoke and mirrors”, “driving like a complete dick” etc. The concept “obnoxiously slow to accelerate” in many cases only has meaning in the context of traditional drivers who race from stoplight to stoplight, or to catch up with the bumper of the next car. I would be happy with cars just having a “go” switch, that you press and it accelerates smoothly to the legal speed, or appropriate speed given the distance to the next stoplight. This, of course, is all coming, with adaptive cruise control, V2V connectivity and increasingly automated vehicles that coordinate speeds in heavy traffic to smooth flow (and increase average traffic throughput). The other reason these hyper-MPG vehicles are so efficient is that they are small and lightweight. Why does the average American, even if we are overweight, drag an average of 2 TONS of metal around with him when driving (http://www.nytimes.com/2004/05/05/business/05weight.html). Well, we know the reasons why, but it does not have to be that way.

    1. You need to keep a certain pace and speed in traffic or else you’re just blocking everyone else and causing more wasted fuel because by accelerating slowly, you slow down the average speed.

      Typical small economy cars get their best mileage around 35 – 45 mph, and their fuel economy becomes horrible if you’re forced to drive slower than 25 kph. Going slow actually has a greater impact on fuel waste than going fast.

    2. When you can telecommute and stuff is delivered to you by drone, you won’t need a car at all. But that is you. I like 350 to 500 HP to cruise the rolling hills of the Palouse. Until fast planes get cheaper anyway. These contests are fine as engineering challenges. Thinking they go beyond that is kind of silly. They might even be detrimental in that they encourage a minimum energy use existence. I would much much prefer an energy rich culture with wide open choices for everyone. Efficient and high capacity power source contests I think lead to envisioning a better future.

  5. The electric car isn’t anymore energy efficient than the ICE car of the same weight. Still requires the same amount of energy to to do the same work. Given the massive amount of technology built into cars today, they’re barely make better gas mileage than cars from the early ’80’s. The automotive industry reached the point of diminishing returns about 30-35 years ago in the mpg dept. Doesn’t matter who builds it either, the laws of physics and thermodynamics can’t be broken. If we’re going to reduce energy consumption for privately owned vehicles, they’ve got to be lighter and more aerodynamic but to really reduce overall consumption, smarter road systems look far more promising ie speed limits based on traffic conditions tied to intelligent cars. Most US cities currently lack the population density to support the investment of building or expanding mass transit systems economically. Besides the car is so 20th century, I want my damn privately owned flying vehicle aka the flying car which would end the need for costly highway systems!

    1. I would disagree with a few of the points you make… Yes, it takes the same amount of kinetic energy to move equally massive ICE or electric cars. but that’s not how you measure efficiency. Combustion engines are limited in their efficiency of turning fuel (chemical potential energy) into movement (kinetic energy) by physics to between 40-60% based on the engine design. A decent electric motor which converts battery power (chemical potential energy) or hopefully soon supercap stored energy (electrical potential energy) into movement can be upwards of 85 or 90% efficient. You could also note that most electric cars use simplified drivetrains (no transmissions) which can account for up to a 20% efficiency drop between the motor and the wheels.
      As for your thoughts on ICE design since the 80’s, i would ask you how many mid-range sedans in the 80’s were making over 200hp? Probably not many. And how many of those would be near 30mpg? Even fewer. And what about the extra mass on current cars due to increased safety regulations? Just because there isn’t a huge increase in mpg does not mean there has not been a massive advancement in ICE technology.

      1. I had a 1956 Alpha Romeo Spyder. 40 MPG highway and plenty quick. Probably in the size/weight class of those hampster cars of today – maybe heavier. Small displacement high rev engine like modern cars (or any Ferrari). The weight, size, and mileage of modern US cars has more to do with Ralph Nader than anything else.

        1. Disagree that weight, size (and therefore FE) have more to do with Nader than anything else. It has a lot more to do with consumers who want fast (and quick), comfortable, quiet, and roomy vehicles… hence the move to V8-powered SUVs with AC, seat warmers (and coolers), electric windows & locks, 90 speaker entertainment systems with a separate hi-def video screen for each of the 7 passengers, etc, etc. And yes, more safety equipment too. But safety is at the bottom of the top 10 reasons buyers choose a car, according to J.D. Powers.

          Note that the Smart ForTwo (I think that’s representative of the ‘hamster cars of today’), which is about the same HP and weight as the Alpha Romeo, is rated for 41mpg highway which *includes* AC, high speed, and cold temp tests. The 1956 Alpha Romeo did not have an EPA rating for FE, so no way to compare even the ‘old’ EPA ratings to the current Smart ForTwo ratings. Personally, I’d prefer the Alpha Romeo though if I was doing a daily commute or driving long distances, I’d prefer neither and go for something else that is more comfortable and gets greater than 40mpg freeway.

          1. The Nader effect was a by-product of safety rules. (Well, he personally ended the experiment with air cooled economy van/car for US makers). It killed the station wagon. To get station wagon utility, vans and SUVs were built to qualify under truck rules and use track frames, thus their size and construction. Toyota mechanics all call a 4Runner a truck. It was the only option for consumers who needed the seats for family or room for cargo.

            I had a 1968 Ford Country Squire station wagon that could hold full sheets of plywood with the seats down and 7 or 8 boy scouts and all their gear for a 100 mile hike and power over mountain passes with no problem – Ford 390 with automatic. No bottoming out of the suspension and good handling. Seat belts for everyone. Also had power windows and rear window. Best car ever. Remember, cars made then were expected to rapidly accelerate from a standing start to freeway merging speed, which was posted 70, and traffic was often faster. Interstate cruising was around 85-90. Cars from the 80’s aimed at President Carter’s 55mph. Even a BMW 325i from the 80’s does not like going over 90.

            I don’t think all the interior comforts and media options have much to do with weight. Also consider that current productions cars go 300 to 500,000 miles with almost no maintenance and tires are good for 3 or 4 times the distance compared to the 50’s/60’s. Total cost of production+operation in material and energy has to be way smaller than a 60’s car. I wonder what the lifetime “footprint” of a 2015 M5 or 4Runner, etc. is compared to a Chrysler station wagon from 1970? Besides, I have no interest in MPG. It is pounds burned per day that counts. Everyone in my city can drive Cadillac Eldorados for all I care. If there is a competition about emissions, the 60 mile commuters in Prius’s will loose to the SUV driver who picks up the kids at school.

          2. Sorry, not quite getting your points…

            >>The Nader effect was a by-product of safety rules. … It killed the station wagon.
            Err, what? The station wagon was killed? By what, safety rules? I thought it was the supreme ugliness of the Big 3’s products that killed ’em, since I still see Mercedes, BMW, VW, Subaru wagons out there…

            >> I don’t think all the interior comforts and media options have much to do with weight.
            Hmmm… OK, next time you have a chance, try pulling out a seat from an SUV (or car) which has ~6 motors for the various adjustments plus seat warmer and butt cooler and a video screen in the backrest. You’ll quickly realize you need an engine lift to get the damn thing out because it weighs somewhere in the neighborhood of a well-fed passenger. Well, maybe not that much, but double if not triple the ~35 lb seats I had in my 240Z. Then there is sound deadening, thicker glass, motors for the hatch, sunroof, cupholder, etc., wiring to power all those doodads… ya, the weight’s gonna add up. Obviously not a significant portion of the vehicle weight, but it could still get into the double-digit percent range, vs safety equipment which is under 5%.

            The rest rambles a bit too much to follow… :)

          3. Yeah, there are sort of wagons out there now after a very long absence and they are from outside the US. I don’t know if they qualify as cars or as shrunk down truck/SUV rules. I’m sure I can’t get anything big in a Subaru. [68 Ford https://www.flickr.com/photos/coconv/6523771653/?rb=1 Great visibility too (Have you tried see out of a new FJ Cruiser?). Back door is tail gait or swing out depending on the handle you use. All seats but the front fold into a completely flat floor.] To understand the Nader Effect you have to look at US regulation from “Unsafe at any Speed” to 1985. Yes, it isn’t all Nader, but he really got the ball rolling. It is not like we were not going to make improvements without the big advocate groups, just at a realistic engineering rate.

            Europe is full of wagons and they never became unpopular. I think any German parking lot is at least half wagons. In the US the minivan (a truck) moved into the wagon space, but they and SUV’s don’t drive like a wagon, which has the more sure handling of a car.

            1972 introduced insanely ambitious emissions standards and ended the muscle car and big engine performance (except for trucks) and the full size wagons need the torque when loaded. People used them like a pickup ruck. It was a mess. Meeting newly imposed emission standards required a (big) grab bag of add-ons and hacks that made the large engines look like a huge mass of hoses and wires, any one of which will screw up the thing if it gets out of adjustment. Today’s V8’s are awesome and would be a great fit in the full wagon style.

            Sorry about the rambling. The topic covers a really broad spectrum.

      2. Electric cars have problems with how the electricity is generated and the energy needed to manufacture their specific parts. The average grid loss is around 7% and the Energy Stored on Energy Invested (ESOI) of lithium batteries is around 10:1. The round-trip efficiency of the charger-battery-inverter system is around 85% and gets worse with quick-chargers. The efficiency of a direct-drive transmission is around 75% over the typical range of driving speeds because motor efficiency varies depending on running speed, reaching the top 97-98% range only at the nominal top speed.

        That considered, the actual source-to-wheel efficiency of an electric car is around 55% which is further reduced by considering that the average grid electricity source is currently between 30 – 60% efficient. In terms of primary energy, the electric car uses just as much if not more energy than the internal combustion engines.

        There’s a LOT of smoke and mirrors with electric cars.

        1. Let’s not add to the smoke here… If you are going to call out the source to wheel efficiency of an electric vehicle, then you also need to indicate the source to wheel efficiency of the ICE vehicle… without that, the claim that the electric uses as much or more energy than the ICE doesn’t stand.

          Efficiency (and emissions) of the electric source depend entirely on how the electricity is generated. Coal is ~33% efficient and produces fairly high emissions. Natural Gas is ~45% efficient and produces fewer emissions than coal. Hydroelectric is ~90% efficient and produces effectively no emissions. So if you live in the midwest where coal is king, you’d probably be serving the environment better by driving an ICE vehicle. But out northwest, where there is a mix of natural gas, hydro, nuclear and renewable, an ICE vehicle efficiency and emissions cannot come close to an EV.

          The manufacture of ICEV vs EV is another story and adds to the complexity. However, once built & bought, the EV has the added advantage of potentially becoming more efficient and generating fewer emissions, without any modifications to the vehicle itself, through the gradual replacement of older, dirtier power plants with newer, cleaner versions (or through the upgrade of existing power plants to make them cleaner).

          1. The source efficiency of, say, diesel fuel is around 80% which largely compensates for the lower efficiency of the engine.

            Appealing to the high efficiency of hydroelectricity or other existing energy source is a red herring, because electric vehicles represent a net increase in electricity demand, and that net increase is met with increased consumption of coal, oil and natural gas. Yes, renewables help somewhat, but they need to be supported by fossil fuels in the most inefficient ways (peak following powerplants), so the point is moot.

            It’ll take decades to clean up the grid to the point that it makes more sense to drive electric cars.

          2. To wring it out of iron:

            if you live next to a hydroelectric plant and recharge your electric car using their zero pollution energy, the plant can sell that much less electricity to someone else, who then fires up a gas turbine to fill the gap. It’s a zero sum game. Adding any demand on the grid will see an increase in the use of the cheapest available source of energy, which is coal and gas.

          3. A couple of things that you’re leaving out:
            >> The source efficiency of, say, diesel fuel is around 80% which largely compensates for the lower efficiency of the engine
            This still doesn’t give a good comparison, so I checked. Found a few reports that give Well-to-Wheels energy cost per mile for a variety of vehicle types:
            * Gasoline ICE Vehicle: 6,000 BTU/mi
            * Diesel ICE Vehicle: 5,500 BTU/mi
            * CA-based Electric Vehicle: 2,500 BTU/mi
            * US-average Electric Vehicle: 3,000 BTU/mi
            So comparatively, the ICEV requires about twice as much energy to move a mile than an EV, accounting for the efficiencies (or inefficiencies) of the entire Well-to-Wheels path. No red herrings.

            >> … the plant can sell that much less electricity to someone else, who then fires up a gas turbine to fill the gap
            If no one needs the excess electricity, none will be sold and no one will fire up a gas turbine. Meaning that if the electric vehicle is charged during non-peak hours, the electric company can sell the electricity they are generating rather than getting nothing for it. There is no equivalent for an ICEV.

            >> Adding any demand on the grid will see an increase in the use of the cheapest available source of energy, which is coal and gas.
            Let’s assume EVs are charged during peak electric consumption hours, which requires firing up a gas turbine to fill the gap. It certainly is a possibility, even very likely. Still it is not a zero sum game. As seen by the BTU/mi numbers above, running the NG turbine will be significantly more efficient than using an ICEV. Yes, the California BTU/mi may go up, but unless CA starts going to coal as well it would not even go as high as the US-avg BTU/mi. So still better off going EV.

            >> It’ll take decades to clean up the grid
            Probably. But it will happen, a bit at a time. And each incremental improvement toward the full cleanup will benefit every EV already on the road in the area where the grid cleanup is happening. For example, using solar to manage the peaks during the day and nuclear to supply steady state demand. Of course will still need a way to fill peaks, and so will still need gas turbines (or similar), but the improvement of the energy cost per mile and emissions per mile for each EV already on the road would be incredible. On the other hand, even if there is a significant improvement in the Well-to-Tank efficiency for getting ICE fuels to the vehicles, there would be minimal impact on overall ICEV efficiency or emissions because Well-to-Tank is relatively small for ICEVs.

            There is still a place for ICEVs but based on the numbers I found, it seems very unlikely they will ever approach the Well-to-Wheels efficiency of today’s EVs.

          4. >Meaning that if the electric vehicle is charged during non-peak hours,”
            >the electric company can sell the electricity they are generating rather than getting nothing for it.”

            Utilities turn their powerplants down for the night. They’re not generating electricity for nothing.

            And for hydroelectric plants, the energy they make is from the flow of the river, averaged over time. They fill up during the night and empty out during the day, so more for you means less for someone else regardless of when you recharge your EV.

            >Let’s assume EVs are charged during peak electric consumption hours, which requires firing up a gas turbine to fill the gap. It certainly is a possibility, even very likely. Still it is not a zero sum game.

            You’re making the assumption that the peak load following turbine is efficient. It’s not.

            Besides, the estimates for EV mileage are greatly exaggerated in these calculations, usually assuming the theoretical or manufacturer reported mileage, which are frankly a lie. You can easily double the energy use going from say California to New York because it’s not always warm (lower air resistance, no heater), or dry (lower rolling resistance).

          5. The problem with peak power production with gas turbines (CCGT) is this:


            For a 1 hour peak pulse operation, the efficiency of the facility will be about 25-27% and on top of that you get the grid loss, the recharger loss, the battery loss, the inverter loss… the well-to-wheel efficiency is just abysmal.

  6. It reminds me good memories of the Shell Eco Marathon at the Nogaro Circuit, (Gers) France.

    14 years ago it was still the same challenge and the same techniques, good moments, good music, good engineering team, a must for students team (read here: some students in mechanical engineering are required, though) in search of a good extra scholar project.

    nb: The “fuel efficient” Volkswagen XL1 really looks like some of the most successful prototypes that can be seen at the shell eco..

  7. “I talked to a team from Ohio whose electric vehicle team was made up entirely of mechanical engineers — and they were actually able to put together a fully functional vehicle.”

    I found this slightly offensive, and I’m not even a mechanical engineer. As a comp sci graduate working at an aerospace company I learned more programming skills from the mech e who was in charge of the project than I did from any of the rocket scientist CS people.

    1. +1
      As a Computer Engineer I learned more HDL on the job from a Bio-Mechanical Engineer than anyone else. And I’ve worked with one of these teams from Ohio in the past, and some of the Mechanical Engineers were only ME because they weren’t allowed to double and/or triple major in different engineering fields.

  8. “team was made up entirely of mechanical engineers — and they were actually able to put together a fully functional vehicle.”

    Ouch. If I were a mechanical engineer I might be offended.

  9. You guys should come check out the SAE Formula Hybrid competition in New Hampshire this year. It’s another one of the SAE Collegiate competitions and is widely regarded as being the most difficult one. It’s pretty much mini Formula 1 in that the cars have an electric system as well as an IC Engine. It’s an absolutely incredible competition! I’ll actually be there with my school’s team (MSOE) this year.

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