16 ms·

Skeptical about electric-powered planes

99 points by lxm 5y ago

evancoop 5y ago
The contrarian in this case would be making Elizabeth Holmes' argument "first they say you're crazy...the you change the world." Of course, the folks delivering such an argument are either peddling vaporware or actually on a path to changing the world. Sometimes, perhaps even the speaker does not know the side of the divide on which they fall?
lowbloodsugar 5y ago
"When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong." - Clarke, A.C. This guy isn't even a distinguished scientist. He's a just a bitter investor that lost money to a snake-oil start-up, and has a penchant for logical fallacies.
sokoloff 5y ago
I likewise don’t get the breathless exuberance over the prospect of electric airplanes. Weight matters a little bit in cars. Weight matters one hell of a lot in light airplanes.
- SuoDuanDao 5y ago
  I gather enough people would like to commute to climate-change symposiums via private jet without having their lifestyle choices made mockery of that they'd accept an electric airplane with all its drawbacks.
- kurthr 5y ago
  Fuel and Maintenance costs, they're about 10-20% and 30% of total costs (flight/ground crew, landing/taxes, and amortization make up much of the rest) respectively. Combined they are a huge portion of potential cost reduction.
  - jeffreyrogers 5y ago
    If it's too heavy to fly the cost reductions don't matter. There are no proposed designs that use batteries that can carry anywhere near the weight of the current generation of airliners.
    - kurthr 5y ago
      I don’t think that long range jumbo jets are the target here. I’m also doubtful that batteries will be the dominant power source. I think it’s speculative, but there are certainly DARPA funds/projects available, and they (and FAA) actually do care whether these can fly.
- cromulent 5y ago
  Because of this, there are a number of companies working on synthetic aviation fuel generated by renewables.
- kloch 5y ago
  This limitation will help motivate advances in battery tech.
bklyn11201 5y ago
For anyone else like me wondering why hydrogen is difficult for airplanes (not mentioned in the OP article): from https://www.bbc.com/future/article/20210401-the-worlds-first-commercial-hydrogen-plane https://www.bbc.com/future/article/20210401-the-worlds-first... -------------- Hydrogen has higher energy by mass than jet fuel, but it has lower energy by volume. This lower energy density is because it is a gas at typical atmospheric pressure and temperature. The gas needs to be compressed or turned into a liquid by cooling it to extremely low temperatures (-253C) if it is to be stored in sufficient quantities. "Storage tanks for the compressed gas or liquid are complex and heavy," says Finlay Asher, a former aircraft engine designer at Rolls-Royce and founder of Green Sky Thinking, a platform exploring sustainable aviation. And there are other challenges. The energy density of liquid hydrogen is only about a quarter of that of jet fuel.
- PostThisTooFast 5y ago
  Not to mention that compressing or liquifying gas takes a shitload of energy to begin with.
- ncmncm 5y ago
  Probably you will want liquified H2. So, we need volume manufacturing of aerogel, for the tanks. If we don't go to wholly new airframes, we will need to sling the LH2 tanks in nacelles under the wings, like the engines, because the needed tankage volume won't fit inside normal wings. (With a new airframe with more internal space, the tanks could be inboard, but maybe you don't really want big tanks of LH2 inboard.) The LH2 would be electrolyzed on demand at the airport, using power delivered by transmission lines from all over, banking LH2 when the sun is out or the wind is blowing, when it is cheapest. Once these planes start flying, it will become impossible to compete with them, because the smaller mass of fuel needed translates to substantially more freight, both total capacity per flight, and per unit-cost of fuel. But there are still things to work out, so there will be an interim need to synthesize jet fuel from atmospheric CO2 and H2, which should soon get cheaper than extraction. It would be helpful if somebody were to come up with a good use for all the waste oxygen everyone is going to be producing.
  - 5y ago
aplummer 5y ago
This is an industry we will be trying to improve for several hundred years from now at least. Very good chance electric airplanes are not feasible today, or tomorrow, but this is a long game. Maybe it won't be typical batteries, and very likely not lithium ion batteries.
- PostThisTooFast 5y ago
  I think it'll age pretty well. I want electric airplanes to be viable, but come on.
- theaeolist 5y ago
  In this case the game is not building 'electric airplanes' but 'better batteries'. If you have the power plant at a reasonable power output / weight building the airplane is not such a challenge.
LittlePeter 5y ago
I have mostly questions... Are we at the theoretical limit of energy density in current batteries? How much more progress can we make, in theory? Could it be that in 20 years we find drastically better materials for batteries? Materials which would make electrical flight feasible. Assuming high energy-density batteries are coming, shouldn't you start now with developing electrical airplanes to be one step ahead of competition?
- jareklupinski 5y ago
  jumping on with one more question: would there be an advantage to lining the wings/flat surfaces with solar cells and patching them into the powertrain, helping drive even higher efficiency gains during optimal weather?
  - dsign 5y ago
    I did the math for that one, though not exactly for an airplane, but for a boring land vehicle (think Ford Traffic). I assumed futuristic photovoltaics with 40% efficiency, a factor of 0.7 to account for angle-of-incidence inefficiencies, pretty much all of of the van covered in panels, for an area of about 16 square meters, similar to the wing area of a glider Schleicher ASW 22 (I couldn't find the wing area of a Cessna 172). The result I get is somewhere from 3 to 8 kilowatts. A quick search in the Internet shows that a typical car has engine power starting at 130 horsepowers, which is 95 kilowatts. A van the size of a Ford traffic probably uses twice as much, and the Cessna uses 132 kilowatts. So, no, I don't think we are getting aviation as it exists today with solar panels and batteries, but one hour twenty minutes in good weather will be enough for some recreational pursuits. I also did the math for sailplanes with solar panels. That looks better, if all you are looking for is activating the propeller for a small fraction of the total flight time, or having an aircraft that can go very slow (that, in fact, has been done). I'm just an amateur, but my opinion is that, without solving the energy density issue, about 98% of the aviation we enjoy today will be gone.
  - davedx 5y ago
    I spreadsheeted this out a few months back for a plane. It is absolutely not worth it.
thehappypm 5y ago
I don’t really buy the main counter arguments here. First, the current tech as stated in the article is short flights, like an hour. That’s actually a niche that’s already marketed—luxury flights to Martha’s Vineyard, Tahoe, Bar Harbor. People are already paying for these flights today. Second, the heat issue. Batteries do suffer from cold weather but if it’s an hour flight, with the batteries dumping their full charge, between thermal heating and simply insulating your battery it can stay warm.
- aaron695 5y ago
  > That’s actually a niche that’s already marketed So just for the rich, in luxury jets? I'm not sure you'd want such an expensive aircraft that can only do one hour, 20 mins. It's a crippled asset with a large cost. You need to chose, a plane for the people like a Cessna 172 or luxury jet style. Cessna 172 has the down time problem. 50 mins in the air. Hour to charge? (The article says 2 hours) These operations are pushing people through. You'd need two or three times as many planes. Luxury jet that's in part opulence, not sure who cares about making them electric. Going in the middle of these two is just a trick to make the situation hazy. But I also didn't get the heat issue or radio transmissions? Or why they couldn't Google a rubber band's specific energy. I do want a business model spec'd out. People say "flight schools", which is a bit like the disaster relief or for the military scam. Asset costs and labour and storage and down times to real life situations.
- HuShifang 5y ago
  I think this is the key here: conceptually, there may be some cognitive shear around the word "plane." In the near-term VTOLs aren't going to be airliners or, for that matter, flying cars. Cessnas and helicopters, though...
- jeffreyrogers 5y ago
  There's not really a viable path from those short flights to longer ones though and the hype of the industry is driven in part around electrifying airliners. And those short flights are a small fraction of airline emissions. I haven't run the numbers, but I don't think it can be more than a few percent. If a company or airline actually cared about reducing emissions from aviation they would look at using hydrogen like the Soviet Union did (I'm not talking about fuel cells, the jet engines used hydrogen as fuel).
leoedin 5y ago
It's not difficult to imagine electric training aircraft. In fact, they already exist - Pipistrel have delivered 111 of them (https://www.aopa.org/news-and-media/all-news/2021/january/27/pipistrel-electric-airplane-in-demand https://www.aopa.org/news-and-media/all-news/2021/january/27...). They have swappable batteries and can fly for about an hour. The total cost of ownership must be super low compared to gasoline engines - there's almost no moving parts, which means no costly engine rebuilds. I'm very, very sceptical of electric passenger aircraft, but I think it's almost inevitable that electric aircraft will start to dominate at the training and low cost end of the market.
- Animats 5y ago
  Training makes sense. As usual, range is the big issue. There was a steam powered aircraft, once, in 1938.[1][2] Looks like it got into the air, went around the pattern once or twice, and landed safely. Unclear what happened after that. The Smithsonian has a copy of the engine. [1] https://www.youtube.com/watch?v=J1tyRX3bXhg https://www.youtube.com/watch?v=J1tyRX3bXhg [2] http://rexresearch.com/besler/beslerst.htm http://rexresearch.com/besler/beslerst.htm
- clueless123 5y ago
  Agree with the big benefits for training, specially if you can swap batteries like you do with industrial drones. Other niche area where there would be a great benefit: Remote regions like the amazon jungle where a regular trip between villages (no roads what-so-ever) takes hours or days on small powered canoes vs 15 minutes when flying. Electric seaplanes would not only deliver basic modern services (Medical, Police, Business, etc) to these areas but it could do it without the need of shipping expensive fuel from far away.. Solar chargers would take care of that. ( maintenance would be easier too.. ) My small attempt at the technology :) https://youtu.be/zAwpi7VPQTk https://youtu.be/zAwpi7VPQTk
  - clueless123 5y ago
    And one more niche area.. Electric engines do not care about low oxygen, going up and down from coastal areas to high altitude Andes is economically achievable. Going from a place like Lima to Jauja in Peru can take 12 hours on a road, but barely 45 minutes by plane. An early attempt with a Pipistrel sinus motorglider * going back down to the coast requires very little engine time :) https://www.youtube.com/watch?v=UOB8yzieYcs https://www.youtube.com/watch?v=UOB8yzieYcs
mmmBacon 5y ago
I love this comment because it’s true of a lot of hardware startups I’ve seen lately. While they may not be very good at building airplanes, they are absolute savants at issuing press releases
jbuhbjlnjbn 5y ago
Did you know "avgas", short for "aviation gasoline", in its most common use, is still using lead as a countermeasure to engine knocking? It means, the aviation industry continues to poison the world by spraying lead in the form of exhaust gases everywhere. The sooner this is stopped, the better.
- upofadown 5y ago
  The article mentions this indirectly, but the leaded gas issue is actually orthogonal to the question of the practicality of battery powered aircraft. Aircraft can and do work without leaded gasoline. The unleaded aviation gas issue has already been discussed to death here. It gets brought up every time there is any reference to anything to do with any aircraft that runs off gasoline.
  - deleted 5y ago
    [deleted]
- JasonFruit 5y ago
  The FAA in the US just approved a list of about 600 aviation engines to use unleaded, so that welcome change is progressing.
- jeffreyrogers 5y ago
  Jet aircraft use jet fuel, not avgas. Avgas is really only used by small GA aircraft and the FAA recently approved many of them to use unleaded avgas.
- jessaustin 5y ago
  Leaded gasoline is bad, but the worst part about it was that its use was concentrated in cities. Dose makes the poison, and kids in cities were getting a lot of tetraethyllead from all the motorized vehicles driving around. That isn't an issue with avgas, which is typically used while flying thousands of feet above relatively unpopulated areas.
occz 5y ago
Good. With that out of the way, time to build some trains.
- golemiprague 5y ago
  The question is, can trains work on batteries or hydrogen or do we need the electric infrastructure, all those cables above it. Also, do we really need tracks? Can't we just make a dedicated road with self driving cars or buses, which is possible on a dedicated road even today?
- foobarian 5y ago
  And tracks too, don't forget the tracks! :-)
barbazoo 5y ago
I'm skeptical about 2.62 MB pages with dozens of ad/tracking dependencies for a 1700 word article.
PowerfulWizard 5y ago
I'm optimistic about electrical. Here is a high level analysis of power and energy density required for some electric vertical takeoff aircraft, compared to some existing batteries: https://www.pnas.org/content/118/45/e2111164118 https://www.pnas.org/content/118/45/e2111164118 (h.t. kittyhawkcorp twitter). The necessary power density is achieved, the energy density needs to improve by about 2x for these vehicles to attain their intended range. The article also compares the range and energy efficiency to electric and ICE vehicles, accounting for the distance reduction by flying in a straight line versus driving on the road. If I recall it doesn't apply any extra value for time savings. The overall energy used in flying could be as little as 2-3x the energy used driving a terrestrial electric vehicle. Combine that with vertical takeoff and no traffic and we're looking at something pretty compelling. And how much does it really need to cost compared for example to a Tesla? The weight will be more optimized and the safety regulations I assume are much sterner. The technical complexity seems similar but the volume will be much lower. I don't think it really works if you need a pilot's license so full autonomy is probably also a prerequisite for an everyday application. I think EVTOL will still be embryonic in 2 years, but impressive in 5 years.
- tsimionescu 5y ago
  Autonomous vehicles can't drive in a tunnel yet, and you're imagining flying autonomous cars in 5 years? Flying cars already exist, they're called helicopters, and they are not a promising consumer technology, and never will be. Flying heavy materials (such as human flesh and bone) is far too energy intensive and inevitably produces too much noise. It is also far too dangerous to become a consumer technology.
  - deepnotderp 5y ago
    1. Autonomy in the air is far easier than on the roads 2. Helicopters have a much lower L/D ratio in forward flight than the tiltrotors being proposed for eVTOLs.
    - tsimionescu 5y ago
      1. Yes, but autonomy in a fixed tunnel would be easier still, and yet the Vegas Loop is using human drivers. 2. Helicopters have the advantage of actually existing in many varied form factors and designs, in common civil use, unlike tiltrotors.
jeffrallen 5y ago
> In contrast, the internal combustion engine on a 172 makes enough heat to keep the cabin warm whenever needed Right, and it's always making that heat whether you need it or not. So it's a good thing your avgas has a shit-tonne more energy density than my batteries because you're going to need it to waste all that heat. Look, physics is physics, you can't cheat it. Which means pure electric is only good for short air trips (energy density), but there's plenty of room to make airplanes more efficient (internal combustion = waste machines). So those who are busy saying it's impossible should get out of the way of those who are doing it.
- ampdepolymerase 5y ago
  If you want to take a plane without constant heating, be my guest.
  - jeffrallen 5y ago
    My Zoe keeps my toes warm all winter long, and it does it 30 seconds after I turn it on in -20 c weather. My diesel needs 10 minutes to warm up the cabin. Heat pumps rock. Internal combustion engines suck. Fight me.
    - vondur 5y ago
      Heat Pumps work best above 40F (4C), and after that they are not very efficient. I don't believe that would be a good fit for an energy starved system such as an electric plane.
      - jeffrallen 5y ago
        > Heat Pumps work best above 40F [citation needed]
        vondur 5y ago
        For year-round heating and cooling comfort, heat pumps work great in areas of the country with moderate temperatures. This is especially critical during the heating season. Once the outdoor temperature goes below 25⁰ - 30⁰ F, a heat pump can continue to provide heat. However, it will use more electricity to do so, which means higher utility bills. This is because there simply isn’t as much heating energy available as the outdoor temperature drops and the system will work longer to achieve the same indoor temperature. That’s why many air-source heat pump systems are installed with a supplemental heat source. Source https://www.carrier.com/residential/en/us/products/heat-pumps/heat-pump-efficiency/ https://www.carrier.com/residential/en/us/products/heat-pump...
tylermauthe 5y ago
The arguments presented here are logically sound and I agree that we won't be replacing a Boeing 747 with electrical. I also agree there are a lot of companies (not just electric planes) fleecing investors for money for products they have no idea whether or not they can build but claiming they absolutely can; but taking risk is baked into the idea of investing and is why profit is justifiable for investors so I think this is a moot point. That being said, I absolutely think we will see EV planes in short haul -- and short haul flights are a HUGE source of emissions. This is good. Here's a link -- local seaplane company is moving it's fleet to EV planes and has been flying test flights for almost a year: https://www.harbourair.com/harbour-air-magnix-and-h55-partner-for-the-worlds-first-certified-all-electric-commercial-airplane/ https://www.harbourair.com/harbour-air-magnix-and-h55-partne...
- rvense 5y ago
  A number of years ago I read, I believe on this very site, that, in general, the main product of many of today's tech startups is no longer the product itself, but the idea of that product, and their customers are not the people who buy the actual product, but investors. And I think it's fair to say that investors are often easily affected by hype. It's probably a bit dismissive of the passion of many founders[0], but I have found it a useful perspective in many cases. [0] Honourable mention goes to the CEO of the ten-person company I work for. He really does believe in this ish.
- arbuge 5y ago
  Electric on short haul flights really doesn't make sense to me either in most real-world scenarios given the energy densities possible from current batteries. Although you may be able to pull off the flights themselves without any issues, you will be unable to use the plane continuously because of the time you will need between flights to recharge. Of course, in scenarios where the plane is in use for only a small fraction of the time, this isn't a problem, but that does not apply to most commercial situations The most realistic way to attain "green" flights seems to me to be some variant of a high energy density fuel such as hydogen produced from green electricity... so-called "green hydrogen". This also solves the range limitations of batteries, besides charging time. There are however significant problems with using hydrogen too, as other comments in this thread point out.
slownews45 5y ago
Pax airlines over oceans etc using batteries is a bad joke. It's pure garbage hype. Some fantastic value around reliability and maintenance (two huge issues in GA market) with electric. If EPA bans leaded fuels (which they should immediately) there may be additional demand here. But it's going to have to be SHORT flights - think 30 - 45 minutes. Even then the payload (useful) is going to be pretty poor I'd imagine.
JasonFruit 5y ago
There's an area of aviation where a lot of innovation could occur, and people are excited to do it — but the FAA is in the way. Ultralight aircraft, under FAR Part 103, are allowed to weigh up to 254 pounds dry, without fuel. Electric ultralights must weigh up to 254 pounds with batteries, which is practically impossible to achieve, so ultralight pilots who would love to be flying clean electric aircraft are using unreliable two-stroke engines that spew incomplete combustion products like there's no tomorrow. If the FAA would revise the regulations to exclude the weight of batteries, like it excludes the weight of ballistic recovery systems or floats, it would open up a field for innovation and might reinvigorate ultralight aviation, but the FAA doesn't want to even think about ultralights, and ultralight enthusiasts are worried that if they push matters the FAA will shut it down like they did ultralight instruction twenty years ago.
- orangepanda 5y ago
  Isnt it because fuel can be dumped in an emergency, if needed? Cant say the same about batteries.
  - jacobmarble 5y ago
    Ultralight airplanes, and any general aviation plane I know of, do not have fuel dump systems. In cases where a plane is too heavy to land, it will often circle for a few minutes to burn off excess.
  - JasonFruit 5y ago
    Not really an option for ultralights or most private aircraft.
  - jmnicolas 5y ago
    But what happens "magically" at 255 pounds of weight that it falls in another category?
  - dghughes 5y ago
    The risk is different a large volume of liquid that can spill and is volatile vs essentially a solid (yes electrolyte is liquid/gel).
alfor 5y ago
Not true at all: - no loss of power with insulated batteries - heat generated in battery pack and motor can heat the cabin with a heat pump - energy density in batteries is steadily increasing - price of batteries steadily decrease All of this would work with the tech from a current Tesla, but flight time will get acceptable in a few years. Car and truck are going to be 90% electric in a few years Planes are going to follow after, but not before.
zackbloom 5y ago
I'm much more excited about manufacturing gasoline using renewable energy and captured carbon. That would provide the energy density planes need while being legitimately carbon neutral.
- Ekaros 5y ago
  Near carbon neutral fuels look to me as reasonable solution. Specially if the production is something we could ramp up and down easily and fast with renewable supply of electricity. Ofc, efficiency isn't great, but still seems much simpler thing to solve.
jeffreyrogers 5y ago
The author of this piece[0] has a fairly strong background in starting and running companies, so his opinion is worth more than the average commenter's. [0]: https://commons.erau.edu/ntas-bios/27/ https://commons.erau.edu/ntas-bios/27/
- a-nikolaev 5y ago
  Here's a video that's making a basically the same argument (although with a more sarcastic tone) that electric batteries don't have a sufficiently high energy density to power an economically competitive plane https://www.youtube.com/watch?v=dMmaG_3NnGs https://www.youtube.com/watch?v=dMmaG_3NnGs
- nqzero 5y ago
  he writes: "watt/hours", so ymmv ...
davedx 5y ago
The author makes quite some big claims without any evidence, including that "Energy density in these batteries is quickly reaching its theoretical limit". This is misleading bordering on false. Companies like Enovix [1] and Sila Nano have commercialized pure silicon anode batteries for small devices with energy densities greater than the current generation of Li-Ion with graphite/silicon anodes. A whole host of companies are attacking the "battery energy density" problem from all sorts of angles (including Tesla - no mention of 4680 cells in the article, because that would undermine its premise). There is no law of physics saying "350 Wh/kg is the absolute upper limit". [1] https://assets.website-files.com/6023ee57b22bf2f0c312206d/611fc38d49e8a40bc05fee2c_Value%20of%20Energy%20Density_White%20Paper_0820.pdf https://assets.website-files.com/6023ee57b22bf2f0c312206d/61...
- whatever1 5y ago
  We can cite hundreds maybe thousands of references of experimental high density batteries introduced last 30 years. No luck getting them to large scale production.
- staplung 5y ago
  My understanding is that the 4680 cell doesn't have any better energy density than what Tesla is currently using (the 2170). Yes, it has 5x the energy of the 2170 but it's also 5.5x bigger in volume. In essence, the energy density of the cell has gone down, not up. The battery as a whole could still go up because bigger cells mean less weight in the steal casing, better packing efficiencies and the tabless-ness of the 4680 should allow more efficient thermals. I'm assuming that the claimed 16% improvement in range would come from that. The big improvement of the 4680 is the power (and manufacturing costs), not the energy. In any case, it's sort of a moot point if Tesla won't sell these batteries/cells to anyone else. Anyway, my take on the article was that the practicality of the electric airplane basically comes down to battery tech. If someone produces a dramatically better battery I assume that putting it into an airplane will be straightforward. So if you want to build an electric airplane what you should really be building is a better battery.
  - genewitch 5y ago
jillesvangurp 5y ago
Most electrical planes flying today will have around 160-200 wh/kg of battery. That's not a lot but somebody is buying them nonetheless. The reason for that relatively modest energy density is that anything flying and certified now would have entered the certification process many years ago. The question is not if those batteries can be improved but by how much. Tesla already has cars on the road with batteries doing better than that. Their upcoming 4680 battery cells will be around 380 wh/kg, apparently. Then there are several companies working on solid state batteries promising closer to 500-600 wh/kg. Sounds good? That's 2-3 x the range of electrical planes on the market now or very soon. There's nothing to be skeptical about here. Pretty much a done deal. With that type of battery, we'll be seeing planes do 400-800miles; possibly a bit more. If you think that's ludicrous, the Eviation Alice is currently pre-selling a plane that will do 440 miles. Apparently, they use 260 Wh/kg batteries currently. Upgrading to something with 500 wh/kg would pretty much get them close to a 1000 mile range. I consider 2x to be the minimum of what we can expect this decade. That's just a matter of updating these planes with batteries that are either already being produced or will be very soon. More a matter of when than if, really. These are first generation planes too. It's not a question of if they will improve but how quickly and by how much. Designs, engines, wiring, materials, etc. There still is a lot of room for improvements. Longer term, I'd say 4-6x current ranges should almost certainly be doable based on just battery improvements. My view: 4x would be disappointing. 6x is a good number to shoot for longer term and we can actually hope for more. Like 8-10x. But actually 3x current ranges would already be a game changer. We'll see.
- SECProto 5y ago
  Yes, this feels a bit like reading an opinion piece dissing on EVs in CarAndDriver 15-20 years ago. Of which there were many.
- bernulli 5y ago
  Range is one thing - what is the passenger capacity of these planes?
  - jillesvangurp 5y ago
    Wrong metric. Cost per passenger per mile is a better one. The reason big jets are popular is that jets burn lots of fuel, which is expensive. Bigger jets burn fuel a bit more efficiently so the cost per passenger becomes more reasonable. Big battery electric planes are likely not possible with current battery technology. But the good news is that small electrical planes are pretty cheap and the electricity is cheap too. So, instead of buying a big Boeing to save fuel, you could buy a few dozen smaller planes, fly to smaller airports that Boeing would not even be allowed to land, and drop passengers off closer to their destinations.
whiteboardr 5y ago
“Ultralight” and “electric” don’t go well together - and it will stay this way.
leoc 5y ago
Here's a half-baked idea. The big problem with many next-generation electric cells like lithium-airs is that they have a short lifespan, right? But aircraft, unlike domestic cars, already have a fairly intensive maintenance schedule. Might it be feasible to just completely replace the batteries a few times every year? Obviously the manufacturing cost of the batteries, net of whatever you recover from recycling them, would have to be not too crushing.
- ncmncm 5y ago
  You would swap out the batteries after every flight, and charge them while waiting for the plane to come back. Replacement is an inventory maintenance problem divorced from flight dynamics.
tehjoker 5y ago
While we're dreaming, I'm dreaming of fusion power or solar power being used to synthesize 100LL or Jet A from the atmosphere, but I'm not holding my breath. That would solve the climate issue though it wouldn't solve the air pollution problem.
- ncmncm 5y ago
  Jet A from solar has been demonstrated. And will be used in huge volume, for a couple of decades, as LH2 aircraft and infrastructure are built out.
savant_penguin 5y ago
Why do people seem to care about electric planes? If the fuel is synthesized through a clean process isn't an energetically dense fuel better?
- Tagbert 5y ago
  Seems like a pretty big IF there. What is the carbon net of that process?
  - ncmncm 5y ago
    Is zero good enough? The process would bank fuel produced using solar and wind during the parts of each day/night when each is cheapest.
alkonaut 5y ago
The busiest air routes in the world aren’t the transatlantic ones but short routes in Asia. If you could make a 30 or 50pax plane that could fly for 1 hour you could serve a lot of the busiest routes to/from Seoul, Taipei, Jakarta, Singapore, Bangkok. They are electric plane routes that aren’t replacing normal flights, they are replacing routes that should have been short-ish train rides (but weren’t, typically because of water). It’s crossings of very busy and narrow bodies of water between very populated areas. Replacing even one of those top routes with electric would be a huge success. Even if there is no viable path to 300 passengers or 8 hour flights, this has to happen.
- ZeroGravitas 5y ago
  Worth comparing with battery trains. Just a few short years ago these were considered impractical, people were waiting for hydrogen or complex electrification projects. Now, (thanks mostly to cheaper batteries) the numbers pencil out for longer distance transport (as long as you include carbon and pollution costs) but just having a bunch of batteries you can connect to the grid (and move around by rail) could possibly pay for the whole thing by itself. Combining the two is looking pretty sweet. For planes, I imagine the ability to use these to offset the emissions from longer flights will be a potential driver of adoption. I'm also surprised that assisted launch isn't talked about more, but maybe the physics just doesnt work out. Just saw a company that is trying to launch satelites by throwing them from the ground. The 10000G would kill humans, but is okay for other uses. Feels like they could possibly branch out to terrestrial cargo delivery.

99 points by lxm 5y ago

The contrarian in this case would be making Elizabeth Holmes' argument "first they say you're crazy...the you change the world." Of course, the folks delivering such an argument are either peddling vaporware or actually on a path to changing the world. Sometimes, perhaps even the speaker does not know the side of the divide on which they fall?

lowbloodsugar 5y ago

"When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong." - Clarke, A.C. This guy isn't even a distinguished scientist. He's a just a bitter investor that lost money to a snake-oil start-up, and has a penchant for logical fallacies.

sokoloff 5y ago

I likewise don’t get the breathless exuberance over the prospect of electric airplanes. Weight matters a little bit in cars. Weight matters one hell of a lot in light airplanes.

SuoDuanDao 5y ago
I gather enough people would like to commute to climate-change symposiums via private jet without having their lifestyle choices made mockery of that they'd accept an electric airplane with all its drawbacks.
kurthr 5y ago
Fuel and Maintenance costs, they're about 10-20% and 30% of total costs (flight/ground crew, landing/taxes, and amortization make up much of the rest) respectively. Combined they are a huge portion of potential cost reduction.
- jeffreyrogers 5y ago
  If it's too heavy to fly the cost reductions don't matter. There are no proposed designs that use batteries that can carry anywhere near the weight of the current generation of airliners.
  - kurthr 5y ago
    I don’t think that long range jumbo jets are the target here. I’m also doubtful that batteries will be the dominant power source. I think it’s speculative, but there are certainly DARPA funds/projects available, and they (and FAA) actually do care whether these can fly.
cromulent 5y ago
Because of this, there are a number of companies working on synthetic aviation fuel generated by renewables.
kloch 5y ago
This limitation will help motivate advances in battery tech.

bklyn11201 5y ago

For anyone else like me wondering why hydrogen is difficult for airplanes (not mentioned in the OP article): from https://www.bbc.com/future/article/20210401-the-worlds-first-commercial-hydrogen-plane https://www.bbc.com/future/article/20210401-the-worlds-first... -------------- Hydrogen has higher energy by mass than jet fuel, but it has lower energy by volume. This lower energy density is because it is a gas at typical atmospheric pressure and temperature. The gas needs to be compressed or turned into a liquid by cooling it to extremely low temperatures (-253C) if it is to be stored in sufficient quantities. "Storage tanks for the compressed gas or liquid are complex and heavy," says Finlay Asher, a former aircraft engine designer at Rolls-Royce and founder of Green Sky Thinking, a platform exploring sustainable aviation. And there are other challenges. The energy density of liquid hydrogen is only about a quarter of that of jet fuel.

PostThisTooFast 5y ago
Not to mention that compressing or liquifying gas takes a shitload of energy to begin with.
ncmncm 5y ago
Probably you will want liquified H2. So, we need volume manufacturing of aerogel, for the tanks. If we don't go to wholly new airframes, we will need to sling the LH2 tanks in nacelles under the wings, like the engines, because the needed tankage volume won't fit inside normal wings. (With a new airframe with more internal space, the tanks could be inboard, but maybe you don't really want big tanks of LH2 inboard.) The LH2 would be electrolyzed on demand at the airport, using power delivered by transmission lines from all over, banking LH2 when the sun is out or the wind is blowing, when it is cheapest. Once these planes start flying, it will become impossible to compete with them, because the smaller mass of fuel needed translates to substantially more freight, both total capacity per flight, and per unit-cost of fuel. But there are still things to work out, so there will be an interim need to synthesize jet fuel from atmospheric CO2 and H2, which should soon get cheaper than extraction. It would be helpful if somebody were to come up with a good use for all the waste oxygen everyone is going to be producing.
- 5y ago

aplummer 5y ago

This is an industry we will be trying to improve for several hundred years from now at least. Very good chance electric airplanes are not feasible today, or tomorrow, but this is a long game. Maybe it won't be typical batteries, and very likely not lithium ion batteries.

PostThisTooFast 5y ago
I think it'll age pretty well. I want electric airplanes to be viable, but come on.
theaeolist 5y ago
In this case the game is not building 'electric airplanes' but 'better batteries'. If you have the power plant at a reasonable power output / weight building the airplane is not such a challenge.

LittlePeter 5y ago

I have mostly questions... Are we at the theoretical limit of energy density in current batteries? How much more progress can we make, in theory? Could it be that in 20 years we find drastically better materials for batteries? Materials which would make electrical flight feasible. Assuming high energy-density batteries are coming, shouldn't you start now with developing electrical airplanes to be one step ahead of competition?

jareklupinski 5y ago
jumping on with one more question: would there be an advantage to lining the wings/flat surfaces with solar cells and patching them into the powertrain, helping drive even higher efficiency gains during optimal weather?
- dsign 5y ago
  I did the math for that one, though not exactly for an airplane, but for a boring land vehicle (think Ford Traffic). I assumed futuristic photovoltaics with 40% efficiency, a factor of 0.7 to account for angle-of-incidence inefficiencies, pretty much all of of the van covered in panels, for an area of about 16 square meters, similar to the wing area of a glider Schleicher ASW 22 (I couldn't find the wing area of a Cessna 172). The result I get is somewhere from 3 to 8 kilowatts. A quick search in the Internet shows that a typical car has engine power starting at 130 horsepowers, which is 95 kilowatts. A van the size of a Ford traffic probably uses twice as much, and the Cessna uses 132 kilowatts. So, no, I don't think we are getting aviation as it exists today with solar panels and batteries, but one hour twenty minutes in good weather will be enough for some recreational pursuits. I also did the math for sailplanes with solar panels. That looks better, if all you are looking for is activating the propeller for a small fraction of the total flight time, or having an aircraft that can go very slow (that, in fact, has been done). I'm just an amateur, but my opinion is that, without solving the energy density issue, about 98% of the aviation we enjoy today will be gone.
- davedx 5y ago
  I spreadsheeted this out a few months back for a plane. It is absolutely not worth it.

thehappypm 5y ago

I don’t really buy the main counter arguments here. First, the current tech as stated in the article is short flights, like an hour. That’s actually a niche that’s already marketed—luxury flights to Martha’s Vineyard, Tahoe, Bar Harbor. People are already paying for these flights today. Second, the heat issue. Batteries do suffer from cold weather but if it’s an hour flight, with the batteries dumping their full charge, between thermal heating and simply insulating your battery it can stay warm.

aaron695 5y ago
> That’s actually a niche that’s already marketed So just for the rich, in luxury jets? I'm not sure you'd want such an expensive aircraft that can only do one hour, 20 mins. It's a crippled asset with a large cost. You need to chose, a plane for the people like a Cessna 172 or luxury jet style. Cessna 172 has the down time problem. 50 mins in the air. Hour to charge? (The article says 2 hours) These operations are pushing people through. You'd need two or three times as many planes. Luxury jet that's in part opulence, not sure who cares about making them electric. Going in the middle of these two is just a trick to make the situation hazy. But I also didn't get the heat issue or radio transmissions? Or why they couldn't Google a rubber band's specific energy. I do want a business model spec'd out. People say "flight schools", which is a bit like the disaster relief or for the military scam. Asset costs and labour and storage and down times to real life situations.
HuShifang 5y ago
I think this is the key here: conceptually, there may be some cognitive shear around the word "plane." In the near-term VTOLs aren't going to be airliners or, for that matter, flying cars. Cessnas and helicopters, though...
jeffreyrogers 5y ago
There's not really a viable path from those short flights to longer ones though and the hype of the industry is driven in part around electrifying airliners. And those short flights are a small fraction of airline emissions. I haven't run the numbers, but I don't think it can be more than a few percent. If a company or airline actually cared about reducing emissions from aviation they would look at using hydrogen like the Soviet Union did (I'm not talking about fuel cells, the jet engines used hydrogen as fuel).

leoedin 5y ago

It's not difficult to imagine electric training aircraft. In fact, they already exist - Pipistrel have delivered 111 of them (https://www.aopa.org/news-and-media/all-news/2021/january/27/pipistrel-electric-airplane-in-demand https://www.aopa.org/news-and-media/all-news/2021/january/27...). They have swappable batteries and can fly for about an hour. The total cost of ownership must be super low compared to gasoline engines - there's almost no moving parts, which means no costly engine rebuilds. I'm very, very sceptical of electric passenger aircraft, but I think it's almost inevitable that electric aircraft will start to dominate at the training and low cost end of the market.

Animats 5y ago
Training makes sense. As usual, range is the big issue. There was a steam powered aircraft, once, in 1938.[1][2] Looks like it got into the air, went around the pattern once or twice, and landed safely. Unclear what happened after that. The Smithsonian has a copy of the engine. [1] https://www.youtube.com/watch?v=J1tyRX3bXhg https://www.youtube.com/watch?v=J1tyRX3bXhg [2] http://rexresearch.com/besler/beslerst.htm http://rexresearch.com/besler/beslerst.htm
clueless123 5y ago
Agree with the big benefits for training, specially if you can swap batteries like you do with industrial drones. Other niche area where there would be a great benefit: Remote regions like the amazon jungle where a regular trip between villages (no roads what-so-ever) takes hours or days on small powered canoes vs 15 minutes when flying. Electric seaplanes would not only deliver basic modern services (Medical, Police, Business, etc) to these areas but it could do it without the need of shipping expensive fuel from far away.. Solar chargers would take care of that. ( maintenance would be easier too.. ) My small attempt at the technology :) https://youtu.be/zAwpi7VPQTk https://youtu.be/zAwpi7VPQTk
- clueless123 5y ago
  And one more niche area.. Electric engines do not care about low oxygen, going up and down from coastal areas to high altitude Andes is economically achievable. Going from a place like Lima to Jauja in Peru can take 12 hours on a road, but barely 45 minutes by plane. An early attempt with a Pipistrel sinus motorglider * going back down to the coast requires very little engine time :) https://www.youtube.com/watch?v=UOB8yzieYcs https://www.youtube.com/watch?v=UOB8yzieYcs

mmmBacon 5y ago

I love this comment because it’s true of a lot of hardware startups I’ve seen lately. While they may not be very good at building airplanes, they are absolute savants at issuing press releases

jbuhbjlnjbn 5y ago

Did you know "avgas", short for "aviation gasoline", in its most common use, is still using lead as a countermeasure to engine knocking? It means, the aviation industry continues to poison the world by spraying lead in the form of exhaust gases everywhere. The sooner this is stopped, the better.

upofadown 5y ago
The article mentions this indirectly, but the leaded gas issue is actually orthogonal to the question of the practicality of battery powered aircraft. Aircraft can and do work without leaded gasoline. The unleaded aviation gas issue has already been discussed to death here. It gets brought up every time there is any reference to anything to do with any aircraft that runs off gasoline.
- deleted 5y ago
  [deleted]
JasonFruit 5y ago
The FAA in the US just approved a list of about 600 aviation engines to use unleaded, so that welcome change is progressing.
jeffreyrogers 5y ago
Jet aircraft use jet fuel, not avgas. Avgas is really only used by small GA aircraft and the FAA recently approved many of them to use unleaded avgas.
jessaustin 5y ago
Leaded gasoline is bad, but the worst part about it was that its use was concentrated in cities. Dose makes the poison, and kids in cities were getting a lot of tetraethyllead from all the motorized vehicles driving around. That isn't an issue with avgas, which is typically used while flying thousands of feet above relatively unpopulated areas.

occz 5y ago

Good. With that out of the way, time to build some trains.

golemiprague 5y ago
The question is, can trains work on batteries or hydrogen or do we need the electric infrastructure, all those cables above it. Also, do we really need tracks? Can't we just make a dedicated road with self driving cars or buses, which is possible on a dedicated road even today?
foobarian 5y ago
And tracks too, don't forget the tracks! :-)

barbazoo 5y ago

I'm skeptical about 2.62 MB pages with dozens of ad/tracking dependencies for a 1700 word article.

PowerfulWizard 5y ago

I'm optimistic about electrical. Here is a high level analysis of power and energy density required for some electric vertical takeoff aircraft, compared to some existing batteries: https://www.pnas.org/content/118/45/e2111164118 https://www.pnas.org/content/118/45/e2111164118 (h.t. kittyhawkcorp twitter). The necessary power density is achieved, the energy density needs to improve by about 2x for these vehicles to attain their intended range. The article also compares the range and energy efficiency to electric and ICE vehicles, accounting for the distance reduction by flying in a straight line versus driving on the road. If I recall it doesn't apply any extra value for time savings. The overall energy used in flying could be as little as 2-3x the energy used driving a terrestrial electric vehicle. Combine that with vertical takeoff and no traffic and we're looking at something pretty compelling. And how much does it really need to cost compared for example to a Tesla? The weight will be more optimized and the safety regulations I assume are much sterner. The technical complexity seems similar but the volume will be much lower. I don't think it really works if you need a pilot's license so full autonomy is probably also a prerequisite for an everyday application. I think EVTOL will still be embryonic in 2 years, but impressive in 5 years.

tsimionescu 5y ago
Autonomous vehicles can't drive in a tunnel yet, and you're imagining flying autonomous cars in 5 years? Flying cars already exist, they're called helicopters, and they are not a promising consumer technology, and never will be. Flying heavy materials (such as human flesh and bone) is far too energy intensive and inevitably produces too much noise. It is also far too dangerous to become a consumer technology.
- deepnotderp 5y ago
  1. Autonomy in the air is far easier than on the roads 2. Helicopters have a much lower L/D ratio in forward flight than the tiltrotors being proposed for eVTOLs.
  - tsimionescu 5y ago
    1. Yes, but autonomy in a fixed tunnel would be easier still, and yet the Vegas Loop is using human drivers. 2. Helicopters have the advantage of actually existing in many varied form factors and designs, in common civil use, unlike tiltrotors.

jeffrallen 5y ago

> In contrast, the internal combustion engine on a 172 makes enough heat to keep the cabin warm whenever needed Right, and it's always making that heat whether you need it or not. So it's a good thing your avgas has a shit-tonne more energy density than my batteries because you're going to need it to waste all that heat. Look, physics is physics, you can't cheat it. Which means pure electric is only good for short air trips (energy density), but there's plenty of room to make airplanes more efficient (internal combustion = waste machines). So those who are busy saying it's impossible should get out of the way of those who are doing it.

ampdepolymerase 5y ago
If you want to take a plane without constant heating, be my guest.
- jeffrallen 5y ago
  My Zoe keeps my toes warm all winter long, and it does it 30 seconds after I turn it on in -20 c weather. My diesel needs 10 minutes to warm up the cabin. Heat pumps rock. Internal combustion engines suck. Fight me.
  - vondur 5y ago
    Heat Pumps work best above 40F (4C), and after that they are not very efficient. I don't believe that would be a good fit for an energy starved system such as an electric plane.
    - jeffrallen 5y ago
      > Heat Pumps work best above 40F [citation needed]
      - vondur 5y ago
        For year-round heating and cooling comfort, heat pumps work great in areas of the country with moderate temperatures. This is especially critical during the heating season. Once the outdoor temperature goes below 25⁰ - 30⁰ F, a heat pump can continue to provide heat. However, it will use more electricity to do so, which means higher utility bills. This is because there simply isn’t as much heating energy available as the outdoor temperature drops and the system will work longer to achieve the same indoor temperature. That’s why many air-source heat pump systems are installed with a supplemental heat source. Source https://www.carrier.com/residential/en/us/products/heat-pumps/heat-pump-efficiency/ https://www.carrier.com/residential/en/us/products/heat-pump...

tylermauthe 5y ago

The arguments presented here are logically sound and I agree that we won't be replacing a Boeing 747 with electrical. I also agree there are a lot of companies (not just electric planes) fleecing investors for money for products they have no idea whether or not they can build but claiming they absolutely can; but taking risk is baked into the idea of investing and is why profit is justifiable for investors so I think this is a moot point. That being said, I absolutely think we will see EV planes in short haul -- and short haul flights are a HUGE source of emissions. This is good. Here's a link -- local seaplane company is moving it's fleet to EV planes and has been flying test flights for almost a year: https://www.harbourair.com/harbour-air-magnix-and-h55-partner-for-the-worlds-first-certified-all-electric-commercial-airplane/ https://www.harbourair.com/harbour-air-magnix-and-h55-partne...

rvense 5y ago
A number of years ago I read, I believe on this very site, that, in general, the main product of many of today's tech startups is no longer the product itself, but the idea of that product, and their customers are not the people who buy the actual product, but investors. And I think it's fair to say that investors are often easily affected by hype. It's probably a bit dismissive of the passion of many founders[0], but I have found it a useful perspective in many cases. [0] Honourable mention goes to the CEO of the ten-person company I work for. He really does believe in this ish.
arbuge 5y ago
Electric on short haul flights really doesn't make sense to me either in most real-world scenarios given the energy densities possible from current batteries. Although you may be able to pull off the flights themselves without any issues, you will be unable to use the plane continuously because of the time you will need between flights to recharge. Of course, in scenarios where the plane is in use for only a small fraction of the time, this isn't a problem, but that does not apply to most commercial situations The most realistic way to attain "green" flights seems to me to be some variant of a high energy density fuel such as hydogen produced from green electricity... so-called "green hydrogen". This also solves the range limitations of batteries, besides charging time. There are however significant problems with using hydrogen too, as other comments in this thread point out.

slownews45 5y ago

Pax airlines over oceans etc using batteries is a bad joke. It's pure garbage hype. Some fantastic value around reliability and maintenance (two huge issues in GA market) with electric. If EPA bans leaded fuels (which they should immediately) there may be additional demand here. But it's going to have to be SHORT flights - think 30 - 45 minutes. Even then the payload (useful) is going to be pretty poor I'd imagine.

JasonFruit 5y ago

There's an area of aviation where a lot of innovation could occur, and people are excited to do it — but the FAA is in the way. Ultralight aircraft, under FAR Part 103, are allowed to weigh up to 254 pounds dry, without fuel. Electric ultralights must weigh up to 254 pounds with batteries, which is practically impossible to achieve, so ultralight pilots who would love to be flying clean electric aircraft are using unreliable two-stroke engines that spew incomplete combustion products like there's no tomorrow. If the FAA would revise the regulations to exclude the weight of batteries, like it excludes the weight of ballistic recovery systems or floats, it would open up a field for innovation and might reinvigorate ultralight aviation, but the FAA doesn't want to even think about ultralights, and ultralight enthusiasts are worried that if they push matters the FAA will shut it down like they did ultralight instruction twenty years ago.

orangepanda 5y ago
Isnt it because fuel can be dumped in an emergency, if needed? Cant say the same about batteries.
- jacobmarble 5y ago
  Ultralight airplanes, and any general aviation plane I know of, do not have fuel dump systems. In cases where a plane is too heavy to land, it will often circle for a few minutes to burn off excess.
- JasonFruit 5y ago
  Not really an option for ultralights or most private aircraft.
- jmnicolas 5y ago
  But what happens "magically" at 255 pounds of weight that it falls in another category?
- dghughes 5y ago
  The risk is different a large volume of liquid that can spill and is volatile vs essentially a solid (yes electrolyte is liquid/gel).

alfor 5y ago

Not true at all: - no loss of power with insulated batteries - heat generated in battery pack and motor can heat the cabin with a heat pump - energy density in batteries is steadily increasing - price of batteries steadily decrease All of this would work with the tech from a current Tesla, but flight time will get acceptable in a few years. Car and truck are going to be 90% electric in a few years Planes are going to follow after, but not before.

zackbloom 5y ago

I'm much more excited about manufacturing gasoline using renewable energy and captured carbon. That would provide the energy density planes need while being legitimately carbon neutral.

Ekaros 5y ago
Near carbon neutral fuels look to me as reasonable solution. Specially if the production is something we could ramp up and down easily and fast with renewable supply of electricity. Ofc, efficiency isn't great, but still seems much simpler thing to solve.

jeffreyrogers 5y ago

The author of this piece[0] has a fairly strong background in starting and running companies, so his opinion is worth more than the average commenter's. [0]: https://commons.erau.edu/ntas-bios/27/ https://commons.erau.edu/ntas-bios/27/

a-nikolaev 5y ago
Here's a video that's making a basically the same argument (although with a more sarcastic tone) that electric batteries don't have a sufficiently high energy density to power an economically competitive plane https://www.youtube.com/watch?v=dMmaG_3NnGs https://www.youtube.com/watch?v=dMmaG_3NnGs
nqzero 5y ago
he writes: "watt/hours", so ymmv ...

davedx 5y ago

The author makes quite some big claims without any evidence, including that "Energy density in these batteries is quickly reaching its theoretical limit". This is misleading bordering on false. Companies like Enovix [1] and Sila Nano have commercialized pure silicon anode batteries for small devices with energy densities greater than the current generation of Li-Ion with graphite/silicon anodes. A whole host of companies are attacking the "battery energy density" problem from all sorts of angles (including Tesla - no mention of 4680 cells in the article, because that would undermine its premise). There is no law of physics saying "350 Wh/kg is the absolute upper limit". [1] https://assets.website-files.com/6023ee57b22bf2f0c312206d/611fc38d49e8a40bc05fee2c_Value%20of%20Energy%20Density_White%20Paper_0820.pdf https://assets.website-files.com/6023ee57b22bf2f0c312206d/61...

whatever1 5y ago
We can cite hundreds maybe thousands of references of experimental high density batteries introduced last 30 years. No luck getting them to large scale production.
staplung 5y ago
My understanding is that the 4680 cell doesn't have any better energy density than what Tesla is currently using (the 2170). Yes, it has 5x the energy of the 2170 but it's also 5.5x bigger in volume. In essence, the energy density of the cell has gone down, not up. The battery as a whole could still go up because bigger cells mean less weight in the steal casing, better packing efficiencies and the tabless-ness of the 4680 should allow more efficient thermals. I'm assuming that the claimed 16% improvement in range would come from that. The big improvement of the 4680 is the power (and manufacturing costs), not the energy. In any case, it's sort of a moot point if Tesla won't sell these batteries/cells to anyone else. Anyway, my take on the article was that the practicality of the electric airplane basically comes down to battery tech. If someone produces a dramatically better battery I assume that putting it into an airplane will be straightforward. So if you want to build an electric airplane what you should really be building is a better battery.
- genewitch 5y ago

jillesvangurp 5y ago

Most electrical planes flying today will have around 160-200 wh/kg of battery. That's not a lot but somebody is buying them nonetheless. The reason for that relatively modest energy density is that anything flying and certified now would have entered the certification process many years ago. The question is not if those batteries can be improved but by how much. Tesla already has cars on the road with batteries doing better than that. Their upcoming 4680 battery cells will be around 380 wh/kg, apparently. Then there are several companies working on solid state batteries promising closer to 500-600 wh/kg. Sounds good? That's 2-3 x the range of electrical planes on the market now or very soon. There's nothing to be skeptical about here. Pretty much a done deal. With that type of battery, we'll be seeing planes do 400-800miles; possibly a bit more. If you think that's ludicrous, the Eviation Alice is currently pre-selling a plane that will do 440 miles. Apparently, they use 260 Wh/kg batteries currently. Upgrading to something with 500 wh/kg would pretty much get them close to a 1000 mile range. I consider 2x to be the minimum of what we can expect this decade. That's just a matter of updating these planes with batteries that are either already being produced or will be very soon. More a matter of when than if, really. These are first generation planes too. It's not a question of if they will improve but how quickly and by how much. Designs, engines, wiring, materials, etc. There still is a lot of room for improvements. Longer term, I'd say 4-6x current ranges should almost certainly be doable based on just battery improvements. My view: 4x would be disappointing. 6x is a good number to shoot for longer term and we can actually hope for more. Like 8-10x. But actually 3x current ranges would already be a game changer. We'll see.

SECProto 5y ago
Yes, this feels a bit like reading an opinion piece dissing on EVs in CarAndDriver 15-20 years ago. Of which there were many.
bernulli 5y ago
Range is one thing - what is the passenger capacity of these planes?
- jillesvangurp 5y ago
  Wrong metric. Cost per passenger per mile is a better one. The reason big jets are popular is that jets burn lots of fuel, which is expensive. Bigger jets burn fuel a bit more efficiently so the cost per passenger becomes more reasonable. Big battery electric planes are likely not possible with current battery technology. But the good news is that small electrical planes are pretty cheap and the electricity is cheap too. So, instead of buying a big Boeing to save fuel, you could buy a few dozen smaller planes, fly to smaller airports that Boeing would not even be allowed to land, and drop passengers off closer to their destinations.

whiteboardr 5y ago

“Ultralight” and “electric” don’t go well together - and it will stay this way.

leoc 5y ago

Here's a half-baked idea. The big problem with many next-generation electric cells like lithium-airs is that they have a short lifespan, right? But aircraft, unlike domestic cars, already have a fairly intensive maintenance schedule. Might it be feasible to just completely replace the batteries a few times every year? Obviously the manufacturing cost of the batteries, net of whatever you recover from recycling them, would have to be not too crushing.

ncmncm 5y ago
You would swap out the batteries after every flight, and charge them while waiting for the plane to come back. Replacement is an inventory maintenance problem divorced from flight dynamics.

tehjoker 5y ago

While we're dreaming, I'm dreaming of fusion power or solar power being used to synthesize 100LL or Jet A from the atmosphere, but I'm not holding my breath. That would solve the climate issue though it wouldn't solve the air pollution problem.

ncmncm 5y ago
Jet A from solar has been demonstrated. And will be used in huge volume, for a couple of decades, as LH2 aircraft and infrastructure are built out.

savant_penguin 5y ago

Why do people seem to care about electric planes? If the fuel is synthesized through a clean process isn't an energetically dense fuel better?

Tagbert 5y ago
Seems like a pretty big IF there. What is the carbon net of that process?
- ncmncm 5y ago
  Is zero good enough? The process would bank fuel produced using solar and wind during the parts of each day/night when each is cheapest.

alkonaut 5y ago

The busiest air routes in the world aren’t the transatlantic ones but short routes in Asia. If you could make a 30 or 50pax plane that could fly for 1 hour you could serve a lot of the busiest routes to/from Seoul, Taipei, Jakarta, Singapore, Bangkok. They are electric plane routes that aren’t replacing normal flights, they are replacing routes that should have been short-ish train rides (but weren’t, typically because of water). It’s crossings of very busy and narrow bodies of water between very populated areas. Replacing even one of those top routes with electric would be a huge success. Even if there is no viable path to 300 passengers or 8 hour flights, this has to happen.

ZeroGravitas 5y ago
Worth comparing with battery trains. Just a few short years ago these were considered impractical, people were waiting for hydrogen or complex electrification projects. Now, (thanks mostly to cheaper batteries) the numbers pencil out for longer distance transport (as long as you include carbon and pollution costs) but just having a bunch of batteries you can connect to the grid (and move around by rail) could possibly pay for the whole thing by itself. Combining the two is looking pretty sweet. For planes, I imagine the ability to use these to offset the emissions from longer flights will be a potential driver of adoption. I'm also surprised that assisted launch isn't talked about more, but maybe the physics just doesnt work out. Just saw a company that is trying to launch satelites by throwing them from the ground. The 10000G would kill humans, but is okay for other uses. Feels like they could possibly branch out to terrestrial cargo delivery.