I don't believe you. Find me an EV truck that any company has fielded in the past 20 years that has less than 10km range.
Also you're comparing a prototype to a mature technology. One might as well note that early automobiles had less range, lower speed, worse reliability, and higher cost than horses. And unlike horses, automobiles require infrastructure such as roads and gasoline stations. All of those things were true at the time, but horses couldn't be improved upon and automobiles could. Now we're in the same position with respect to gas vehicles vs electric vehicles.
Battery technology is improving at an impressive rate. Energy density has doubled since 2010. Price per kilowatt-hour is 1/9th what it was a decade ago.[1][2] These advances have made EVs competitive on the ground. It's quite likely that improvements will continue and EVs will become competitive in the air. EVs have lower refueling costs, lower maintenance costs, and are simpler designs (making them cheaper and safer). We already have battery-powered commercial drones. Human flight is more conservative when it comes to adopting new technologies, so it'll probably take longer for EV planes to become widespread. But long term? I would bet on EV planes replacing regional jets.
1. https://cleantechnica.com/2020/02/19/bloombergnef-lithium-io...
2. https://www.statista.com/statistics/883118/global-lithium-io...
Energy density of batteries are around 1/40th of that of kerosene (0.9 mj/kg vs 44mj/kg) so we are talking 44x the energy density we need to make up for to get perfect parity. From what I can find I’ve seen 35% thermal efficiency for modern airliners and I believe 95% for electric motors. Ok so this means we can reduce the density gap required for parity to just under ~ 44/2.5 so ~18/19 mj/kg? (I’m doing this in my head so it’s rough). Rough calls show we need batteries with 20x the capacity to replace what we have right now with electric alternatives. While the gains in battery densities have been impressive we need to keep these gains in mind that we need to be making much bigger gains for this to become a reality. Personally I don’t see it being feasible for a very long time given the progress and I believe we’re better off taking fewer unnecessary flights than hoping on some miracle battery breakthrough
(Edited for clarity)
- Fuel has no structural strength. Batteries are rigid and can double as parts of the airframe, saving weight.
- Combustion engines are complex and expensive. This precludes mounting a dozen tiny engines on a plane and integrating them at just the right spots. Electric fans are cheaper and easier to integrate into the airframe, reducing drag. This also helps with engine-out capability. If you have two engines and one fails, you've lost half your thrust. If you have 36 engines and one fails, you've lost 3% of your thrust.
- Air becomes less dense with altitude. This reduces drag, but it also reduces the power of combustion engines. Electric aircraft don't need oxygen, so their power remains the same at altitude. There are losses due to the fan having to rotate more to move the same mass of air, but in general, electric aircraft become more efficient at altitude.
- Electric fans respond much faster to throttle inputs and are easier to gimbal than combustion propellors or jets. This allows designs with reduced or even eliminated control surfaces. The lack of rudder and elevator reduces drag, allowing for greater range.
That last trick might sound insane for human-rated aircraft, but there are already flying prototypes that use this approach.[1][2]
Be patient, we'll figure something awesome out.
BMW and the SCHERM Group have put a massive 40-ton EV into service for a one-year pilot. The Terberg YT202-EV electric tractor will travel a 2 km route eight times a day between the SCHERM group logistics center and the BMW plant in Munich, transporting vehicle components such as shock absorbers, springs and steering systems.
The standard tractor has two batteries (112 kWh), and a third battery can be fitted for extended operations. It is equipped with a 138 kW, 720 N·m Siemens motor and an Allison 3000 transmission. Top speed is 25 mph.
The YT202-EV has a range of up to 100 kilometers (62 miles), theoretically enough for a full production day. BMW says it will be charged exclusively with renewable electricity, and will save 11.8 tons of CO2 annually compared to a legacy diesel truck.
https://chargedevs.com/newswire/bmw-tests-40-ton-electric-tr...
83.1 km = (112kWh x 80% x 25 mph x 1.6 km/mile x 80%) / (138 kW x 25%)
Will you grant double digit km range? Still two orders of magnitude lower than a fuel-based truck in commercial operation?
150 gallons * 7 mpg = 1,050 mi / 1,690 km.
Petrochemical fuels afford a near unbeatable energy/volume and energy/mass density. The best theoretical battery might attain 1/10th this, practical batteries are nearer 1/100th, if that. A ~100 kWh battery holds the equivalent of 2 gallons / 8 litres of petrol or diesel.
Electrics have advantages of vastly more efficient potential-to-kinetic energy conversion (90%= rather than 30% for an ICE), a more efficient drivetrain (often in-wheel motors), and regenerative braking. Air and tyre drag are equivalent for both domains.
Capacity, energy management, and recharge access are all there is.
Two-order-of-magnitude improvements in any non-informational domain are both very hard-won and utterly transformational. Commercial passenger aircraft are ~2 orders of magnitude faster than walking. A semi-trailer has ~2 orders of magnitude more cargo capacity than a man with a wheelbarrow.
Getting two orders of magnitude out of long-haul road-based heavy-cargo EVs is a very tall order. Mains-fed electric trainsets would be a far more likely technology, and are extant and commercially proven
As others noted, we’ve just started taking a serious interest in renovating rechargeable batteries for this use. Lots more can and will be done once the political will is there.
Diesel engines tend to be more efficient the larger they are, with marine engines hitting 50% in fixed speed applications.
Passenger cars net about 90 or so, for a high-efficiency vehicle, gross vehicular weight, at full capacity.
Assuming 140,000 lb GVWR and 7 mpg, I compute 490 ton-mpg. That's roughly equivalent to numbers given for rail ("move one ton of freight one mile on a gallon of fuel), and is likely high, though 100-250 ton-mpg seems likely.
This is not net cargo efficiency, where that rail number may come from. But gives a sense for numbers.
> In 1937 they produced a ride-on four wheeled vehicle, suitable for a payload of 8–10 cwt (410–510 kg) and with a range of around 35 miles (56 km)
That’s probably why milk floats could go so far at the time despite obviously inferior battery technology; milk floats didn’t go very fast.
Generally speaking, the solution for car troubles is to reduce the scope that cars and trucks are used to solve transit problems. Road damage due to semi trucks? Build more freight rail! Inner city congestion? Add a subway! Long commutes? Build more housing, and if that doesn’t work add dedicated commuter rails. Too much air traffic? Offset local flights onto high speed rail to free up room for long distance flights.
A slow, economy cruise setting in a Cessna 172 is a 45% power setting - ~80 hp, and climbs will be at full power (180 hp).
On the other hand, you might only need ~20 hp to maintain 65mph on a level road in a sedan; and most people never use anything like the full power of their cars for more than seconds at a time.
Luckily the high power level is maintained at reliably high speed [0], ensuring airflow for cooling.
Even better, aircraft by its very long-range nature will have much larger battery:engine ratio. For example this 2018 article [1] discusses airplane with 9x the Tesla's battery capacity and 3x the Tesla's engine power, in other words, its batteries would need to handle only 1/3rd electrical load as much at peak load (per unit). The lower power density[2] of the battery pack again provides for easier cooling; perhaps even passive cooling or air cooling instead of forced liquid cooling. Whereas Tesla's sustained performance is limited by battery pack thermals.
Lastly, it's worth noting the ICE aircraft engines are "overbuilt" as compared to the roadgoing ones, mostly for sake of reliability.
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[0] aside of the engine run-up and initial acceleration, but both of those are short anyway
[1] https://news.ycombinator.com/item?id=18602771
[2] not to mix it up with energy density
Long-haul alt-energy aircraft utilise very low airspeed (low drag), extreme mass budgets (they're wonders of materials and structural engineering), and altitude profiles (potential energy0 to manage overall energy budgets and use.
While that is true of jets optimized for altitude, small piston aircraft (cessnas) do not burn nearly that much fuel on takeoff. Small aircraft can generally do a dozen or more takeoff/landing cycles on a single tank.
Range is ~615 miles at 39 mpg highway.
Passenger and cargo capacity is another 1,500 lb on top of this, give or take.
This is far lower than any conventional aircraft, though a few ultralights might compare.
The Cesna has a 140 mph cruise, a bit over double that of the Camry on highway, but that still means 20 lb at equivalent distance for the car, less than half the light plane.
Aircraft are fuel burners.
(Agreeing, just giving land-travel equivalent.)
Top Gear did an amusing test where they had a Toyota Prius drive flat out around a track, with a BMW M3 (a larger, heavier sports sedan) keeping pace with it.
Over the course of the test, the Prius returned 14.3 miles per gallon; and the BMW M3 achieved 16.1 - despite the fact the BMW has a 4 liter turbocharged, six cylinder engine vs. the Prius 1.5 liter, four cylinder.
I don't see your point however - what I'm saying is that at 130kmh (standard motorway speed in most of europe) a 70-90hp subcompact (by far the most common car in europe and the world in general) is running at above 80% max power (testified by the fact that as soon as there's a significant incline their speed will fall back to 110-120). So running long times under heavy engine load is quite normal for cars
Air resistance vs not having enough air to push.
Basically - you can design the prop for high altitude, but then takeoff is gonna not be great. You could design a variable prop system (or even have 2 different ones?) but then weight / complexity.
His plane is VTOL so the overpowered engines for supersonic will work well for liftoff.
I don't know how much weight a anti-ice/de-ice could add.
My point was only that once you think about it and redesign everything around the new constraints, you can come up with things that we don't yet think about.
Battery EV trucks (lots of prototypes and maybe even low volume production going on, from Tesla to Daimler) regularly get multiple hundred kilometers of range and 1000km isn’t at all unreasonable although 500 miles is probably the sweet spot in the near term to avoid reducing available payload (any greater range has diminishing returns due to regulatory requirements for rest stops). And that’s without advanced chemistries that you can get now at low volumes like metal anode or lithium-sulfur which double the specific energy and allow double the range (to say nothing of lithium-air, which is easily over a decade away from practical use but would eliminate the disparity in useful specific energy between battery-electric and hydrocarbon combustion in almost all cases—rocketry and munitions being the major exception).
EDIT: Daimler has delivered some 300-400km range electric Freightliner semis for customer testing already: https://electrek.co/2020/03/04/daimler-electric-freightliner...
Ideally, aside from parasitic losses, shouldn't decelerating pay joules?
A few years ago an electric bus hypermiled to get some ludicrous range. Turns out the trial stripped all spare mass from the rig (seats, other interior), pumped tyres to munition-rated pressures, hugely oversized the battery, and held a constant speed of about 24 kph (15 mph).
https://www.latimes.com/business/autos/la-fi-hy-proterra-ran...
(The article, as with most, reveals no test conditions though does at least note "a Proterra spokeswoman said they won’t reveal the test bus speed".)
In production, range claims seem to be about 1/3 this.
Typical city busses stop every block or two, accelerating to about 40 kph, then braking, every 60 seconds or so.
Both mileage and wear and tear suffer immensely.
A big part of this is wind resistance; as you know wind resistance increases with the square of the speed, so going 60MPH is going to cost quadruple what it costs to go 30MPH, and presumably "city" driving doesn't go much higher than 30 MPH.
Battery powered trucks that you can buy today from the likes of Scania/Daimler has a range of 200+ km. Not some prototype but currently in production for delivery next year.
Sure, it's not 1000 km, but that single digit km is off by two magnitudes.
Unless I'm mistaken? Can ducted fans match the speed of a jet engine?
https://youtu.be/MBItc_QAUUM?t=2422
- Going higher
- Using gravitational energy on the second half/landing part of the journey. Like a car going down hill.
- Making use of the higher power density of the engines
- (Doesn't mention this, but using batteries as structural elements)
I also think that this:
"Prandtl Wing Minimum Drag Update" - Al Bowers (Chief Scientist at NASA) would be a key technology
https://www.youtube.com/watch?v=bCwtcDNB15E
A new type of wing and maybe more importantly a new type if turbine fan.
Note that airplane fuel has significantly higher power density than an electric battery (~40x as much, see https://www.theverge.com/2018/8/14/17686706/electric-airplan...), so no EV will ever be able to achieve the same range as an ICE plane, ton-for-ton.
No. If you think that you didn't get his point.
- Fuel is not structural in a plane. Only fuel tanks.
- ICE are only optimally efficent at a particular height.
- ICE can not convert gravitational energy into fuel.
- ICE vehicles have a lower power density and are bigger. Making it harder to gimbals them for VTOL. This is a cause of huge issues with military VTOL.
> EV will ever be able to achieve the same range as an ICE plane, ton-for-ton
And they don't have to to beat ICE in the market.
2) Irrelevant. They're still more efficient than EV planes at any height, so comparing the relative efficiency of ICE to itself is pointless.
3) Neither can EV planes, unless someone has discovered how to turn gravity into electricity without water and a massive turbine.
4) ICE vehicles have higher power density (see previous Verge link, also https://www.topspeed.com/cars/warp-coils-seem-closer-to-real...). It's not even close. 43x-100x the power density of batteries, depending on the type of fuel and the type of battery. ICE vehicles are bigger because they are used to carry more things and people: hundreds of people or hundreds of tons of cargo on trips that can go almost halfway across the world without stopping. In contrast, an EV plane can currently carry itself, a pilot and a passenger, for almost long enough to get from LA to Fresno. (No EV currently on the market can even make the trip from LA to SF.)
And they don't have to to beat ICE in the market.
You're right. EVs will never be able to compete at the ranged market; they'll be limited to short-range hops. This means they won't be a viable option for the corporate/personal jet market beyond limited hobbyist use.
2) No, that is just flat out wrong. EV are more efficent, its not close. And they don't have 1 hight where they have the best efficency.
3) Yes they can. Have you ever driven an EV?
Its seem that you are just otherly clueless and seem to simply deny the existens of proven technology so there is no point in this argument.
Range is quite another issue. A Cesna 172 has a 1,289 km range, four times the Rolls-Royce prototype, and carries more than just the piolot and fuel.
https://en.wikipedia.org/wiki/Cessna_172#Specifications_(172...
For both land and air, total payload is another hard limit. Tesla achieves admirable results for a passenger vehicle by using high energy/volume and energy/mass batteries integrated into the vehicle structure itself. Battery EV trucks have had range limits of measured in single-digit kilometers. Their fuel-based counterparts exceed four digits (1,000 km). Accellerating, decellerating, and managing mass costs joules.