13 ms·

I would've thought that the main challenge is the density of energy storage. It's hard for a battery to beat kerosene. The article mentions the industry took a

I would've thought that the main challenge is the density of energy storage. It's hard for a battery to beat kerosene. The article mentions the industry took a hit during Covid. It's interesting to note that a company like Air Lease Corporation (which buys aircraft and leases it to airlines) basically soldiered on unaffected by the pandemic [https://valustox.com/AL https://valustox.com/AL - there's a big dip in profit a year ago, but that's due to the Russian war sanctions].

anon84873628 3y ago
Plus burnt jet fuel weighs nothing, whereas a spent battery weighs the same as a fully charged one. It seems there needs to be a radical price difference between electrical and chemical energy before the virtues of the rocket equation are overcome for airline travel.
- Ekaros 3y ago
  Considering just how cheap renewable energy can be, even poor efficiency might not matter. If you have process that can be scaled by supply of cheap electric power, it could work even if there is inefficiencies in process and in use.
  - wayfinder 3y ago
    It's not generating the energy -- it's storing it. Fossil fuels are massively more energy dense than our current electric batteries. Fossil fuels are literally dead animals pressurized by Earth... all that energy went into the fuel. Planets work on massively larger scales of energy than human society right now and we're using stored energy created by planets to fly.
    - sokoloff 3y ago
      > Fossil fuels are literally dead animals By mass, fossil fuels are mostly from plants, algae, and bacteria rather than animals.
    - lovecg 3y ago
      The energy is not exactly stored in the fossil fuels directly. Indeed you have to put in extra energy to break those bonds - pulling atoms apart is work. The “stored” energy comes from the fact that long time ago various processes split various compounds into two components, A and B. And putting them back together makes them snap like magnets with enough force to release some extra heat. We call A “fuel” since that’s the part that’s somewhat difficult to come by. We often forget about B altogether as it’s literally all around us. Fossil fuels are fundamentally efficient for flight since the oxygen is something you don’t have to carry around with you (unless of course you’re going to space).
  - Manuel_D 3y ago
    It's not a matter of electricity cost, it's a question of watt hours per Kg. A battery powered plane cannot fly far, no matter how cheap electricity is, because the energy density just isn't there: https://en.m.wikipedia.org/wiki/Energy_density#/media/File%3AEnergy_density.svg https://en.m.wikipedia.org/wiki/Energy_density#/media/File%3...
    - Ekaros 3y ago
      I'm really talking about synthetic fuels made using electric energy.
      - itsyaboi 3y ago
        Traditional fuels would also benefit from the cost savings of cheap renewable energy.
    - thinkcontext 3y ago
      Don't forget watt per volume. H2 has great w/kg but poor w/liter.
- 8note 3y ago
  A spent battery doesn't weight anything if you drop it once it's done; similarly the spent fuel has weight if you have to store the hot gasses after burning. Turning a fossil fuel based plane carbon free has the same weight problem
  - otterley 3y ago
    Are you seriously suggesting that airplanes could just drop batteries weighing tons while flying across the sky?
    - barelyauser 3y ago
      Since this is HN, he probably is. And not only that, he is probably going to select this as his hill to die on. Good luck.
    - teeray 3y ago
      Filled with toxic substances, no less. There’s probably some treaties that would frown upon that.
    - FredPret 3y ago
      It'd go over as well as a lead... acid battery
    - hef19898 3y ago
      Li-Ion batteries at that! Ibdon't see any reason why regulator wouod object to that. Also, those batteries cost close to nothing, so yeah, just use as consumables...
    - lewispollard 3y ago
      I think the point was that the only reason burned fuel weighs nothing is because we throw out the waste into the atmosphere.
- panopticon 3y ago
  > a spent battery weighs the same as a fully charged one A Tesla's battery pack weighs ~3.2 nanograms less when it's fully depleted. Think of the weight savings with a bigger battery pack for a plane! /s
bluGill 3y ago
The article doesn't mention that, but I'm sure that is the root. Electric planes might make sense for short trips - a handful a enthusiasts fly to work every day (they live at/near an airport and work at/near an airport) instead of driving. A handful of rich people will hire an airplane (or helicopter) to get around cities faster. Some cross water transit is served by short haul flights (ferries are cheap, but boats are slow because of physics). However these are tiny niches and don't cover much air travel. In general air travel doesn't make sense unless your trip is 1500km or more, and the weight of batteries needed for those trips just doesn't make them possible. We know how to make zero carbon jet fuel today using WWII technology (which has been improved on since, and can be improved). The hard part is cost: synthetic fuel generally costs 4 times as much as pumping oil. (synthetic fuels normally use coal or natural gas for the energy but the process would work with renewables). Still this is very promising: we know from experience it scales up to produce very large volumes of great fuel, and there is reason to think we can make it better/cheaper.
mschuster91 3y ago
> It's interesting to note that a company like Air Lease Corporation basically soldiered on unaffected by the pandemic Because governments bailed out airlines so that leasing companies wouldn't go default which would then have caused the banks to get into trouble. It's ~180 billion dollars each year just for new airplanes - with ten or fifteen years worth of active contracts, a collapse of the industry would have let the 2008ff crisis look harmless. [1] https://www.statista.com/topics/3877/aircraft-leasing/ https://www.statista.com/topics/3877/aircraft-leasing/
- FredPret 3y ago
  Absolutely wild how much machinery we have flying around
  - mschuster91 3y ago
    Yeah, and these things cost a ton of money - around 200 million $ for your average Airbus A320. If you now ask yourself, hey how are airlines making money, the answer is: they aren't, the money all comes from frequent flyer programs [1] - it's gotten so ridiculous that the value of many airlines has shrunk to less than their FFP programs are worth and they are loss leaders [2]! Barely any airline actually has physical or real estate assets any more in their own name. It's all leased, rented or otherwise not on their books anymore, which was contributing to how badly airlines were losing money during COVID. [1] https://www.theatlantic.com/ideas/archive/2023/09/airlines-banks-mileage-programs/675374/ https://www.theatlantic.com/ideas/archive/2023/09/airlines-b... [2] https://happyrichadvisor.com/loss-leaders/ https://happyrichadvisor.com/loss-leaders/
    - okay0 3y ago
      No one is paying 200m for an a320
      - hef19898 3y ago
        Don't you say!

anon84873628 3y ago

Plus burnt jet fuel weighs nothing, whereas a spent battery weighs the same as a fully charged one. It seems there needs to be a radical price difference between electrical and chemical energy before the virtues of the rocket equation are overcome for airline travel.

Ekaros 3y ago
Considering just how cheap renewable energy can be, even poor efficiency might not matter. If you have process that can be scaled by supply of cheap electric power, it could work even if there is inefficiencies in process and in use.
- wayfinder 3y ago
  It's not generating the energy -- it's storing it. Fossil fuels are massively more energy dense than our current electric batteries. Fossil fuels are literally dead animals pressurized by Earth... all that energy went into the fuel. Planets work on massively larger scales of energy than human society right now and we're using stored energy created by planets to fly.
  - sokoloff 3y ago
    > Fossil fuels are literally dead animals By mass, fossil fuels are mostly from plants, algae, and bacteria rather than animals.
  - lovecg 3y ago
    The energy is not exactly stored in the fossil fuels directly. Indeed you have to put in extra energy to break those bonds - pulling atoms apart is work. The “stored” energy comes from the fact that long time ago various processes split various compounds into two components, A and B. And putting them back together makes them snap like magnets with enough force to release some extra heat. We call A “fuel” since that’s the part that’s somewhat difficult to come by. We often forget about B altogether as it’s literally all around us. Fossil fuels are fundamentally efficient for flight since the oxygen is something you don’t have to carry around with you (unless of course you’re going to space).
- Manuel_D 3y ago
  It's not a matter of electricity cost, it's a question of watt hours per Kg. A battery powered plane cannot fly far, no matter how cheap electricity is, because the energy density just isn't there: https://en.m.wikipedia.org/wiki/Energy_density#/media/File%3AEnergy_density.svg https://en.m.wikipedia.org/wiki/Energy_density#/media/File%3...
  - Ekaros 3y ago
    I'm really talking about synthetic fuels made using electric energy.
    - itsyaboi 3y ago
      Traditional fuels would also benefit from the cost savings of cheap renewable energy.
  - thinkcontext 3y ago
    Don't forget watt per volume. H2 has great w/kg but poor w/liter.
8note 3y ago
A spent battery doesn't weight anything if you drop it once it's done; similarly the spent fuel has weight if you have to store the hot gasses after burning. Turning a fossil fuel based plane carbon free has the same weight problem
- otterley 3y ago
  Are you seriously suggesting that airplanes could just drop batteries weighing tons while flying across the sky?
  - barelyauser 3y ago
    Since this is HN, he probably is. And not only that, he is probably going to select this as his hill to die on. Good luck.
  - teeray 3y ago
    Filled with toxic substances, no less. There’s probably some treaties that would frown upon that.
  - FredPret 3y ago
    It'd go over as well as a lead... acid battery
  - hef19898 3y ago
    Li-Ion batteries at that! Ibdon't see any reason why regulator wouod object to that. Also, those batteries cost close to nothing, so yeah, just use as consumables...
  - lewispollard 3y ago
    I think the point was that the only reason burned fuel weighs nothing is because we throw out the waste into the atmosphere.
panopticon 3y ago
> a spent battery weighs the same as a fully charged one A Tesla's battery pack weighs ~3.2 nanograms less when it's fully depleted. Think of the weight savings with a bigger battery pack for a plane! /s

bluGill 3y ago

The article doesn't mention that, but I'm sure that is the root. Electric planes might make sense for short trips - a handful a enthusiasts fly to work every day (they live at/near an airport and work at/near an airport) instead of driving. A handful of rich people will hire an airplane (or helicopter) to get around cities faster. Some cross water transit is served by short haul flights (ferries are cheap, but boats are slow because of physics). However these are tiny niches and don't cover much air travel. In general air travel doesn't make sense unless your trip is 1500km or more, and the weight of batteries needed for those trips just doesn't make them possible. We know how to make zero carbon jet fuel today using WWII technology (which has been improved on since, and can be improved). The hard part is cost: synthetic fuel generally costs 4 times as much as pumping oil. (synthetic fuels normally use coal or natural gas for the energy but the process would work with renewables). Still this is very promising: we know from experience it scales up to produce very large volumes of great fuel, and there is reason to think we can make it better/cheaper.

mschuster91 3y ago

> It's interesting to note that a company like Air Lease Corporation basically soldiered on unaffected by the pandemic Because governments bailed out airlines so that leasing companies wouldn't go default which would then have caused the banks to get into trouble. It's ~180 billion dollars each year just for new airplanes - with ten or fifteen years worth of active contracts, a collapse of the industry would have let the 2008ff crisis look harmless. [1] https://www.statista.com/topics/3877/aircraft-leasing/ https://www.statista.com/topics/3877/aircraft-leasing/

FredPret 3y ago
Absolutely wild how much machinery we have flying around
- mschuster91 3y ago
  Yeah, and these things cost a ton of money - around 200 million $ for your average Airbus A320. If you now ask yourself, hey how are airlines making money, the answer is: they aren't, the money all comes from frequent flyer programs [1] - it's gotten so ridiculous that the value of many airlines has shrunk to less than their FFP programs are worth and they are loss leaders [2]! Barely any airline actually has physical or real estate assets any more in their own name. It's all leased, rented or otherwise not on their books anymore, which was contributing to how badly airlines were losing money during COVID. [1] https://www.theatlantic.com/ideas/archive/2023/09/airlines-banks-mileage-programs/675374/ https://www.theatlantic.com/ideas/archive/2023/09/airlines-b... [2] https://happyrichadvisor.com/loss-leaders/ https://happyrichadvisor.com/loss-leaders/
  - okay0 3y ago
    No one is paying 200m for an a320
    - hef19898 3y ago
      Don't you say!