Home > Economics - General > Drones (the good kind)

Drones (the good kind)

May 8th, 2017

It’s now pretty clear that renewables can replace fossil fuels in their main uses, electricity generation and land transport, at a very modest cost or, as appears to be the case for electricity, with a cost saving. But that still leaves room for doubt over whether the economy can be fully decarbonized in time to hold CO2 concentrations to 450 ppm or below. Among the big gaps are air and sea transport.

I’ve tended to argue on the basis of the idea of induced innovation that, since there are plenty of possible options, at least one will work out, given some incentives to reduce CO2 emissions. That’s proved true for electricity (solar and PV worked, while other promising contenders like geothermal and Gen III nuclear haven’t), and more recently for storage. But it doesn’t seem to satisfy everyone.

So, I was struck to realize that drones (which I’ve always thought of either as toys or as particularly nasty weapons systems) may be on the way to displacing a good deal of air and sea freight transport in the relatively near future. Initially at least, the bigger ones are likely to use conventional engines, but with greatly reduced fuel costs, as with this proposal. But it’s easy to imagine a version that carries its own solar PV system being developed in the future – possibly slower but even cheaper than the current verison.

Moreover, the size and capacity of battery-driven electric drones is increasing all the time. The current leader appears to be the Griff 300, which can (as the name indicates) lift 300kg, including its own weight of about 65 kg. Apparently there is a Griff 800 either released or in the works. At least to my understanding, there’s no fundamental scaling limit here, although there will obviously be plenty of technical challenges. On the other hand, with batteries getting lighter every year, performance can be improved over time without any significant change in design.

None of this deals with passenger air travel which looms larger in the culture wars over energy policy that its objective significance as a source of emissions justifies. But again, in the absence of fundamental limits (the kind that apply, for example, to carbon capture and storage), a sufficiently strong incentive will in all probability bring forth a solution.

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  1. Ronald B
    May 8th, 2017 at 17:52 | #1

    The economics of electric flight aren’t nearly as bad as a casual look at the specific energy of kerosene (plane fuel) and even the best available batteries today suggest.

    Using electric motors instead of kerosene engines gives the advantages of lower fuel cost, higher safety, and very importantly longer life and lower maintenance. Electric plane motors are also a lot lighter per kilowatt of output which helps offset the extra weight of batteries.

    For these reasons, despite their currently limited range, electric light aircraft could pay for themselves and larger electric powered planes could potentially be used for short distance flights.

    Another use of electric motors in flight is hybrid planes. Airplanes need a huge amount of power to take off. They also need power available if something goes wrong during landing and they need to pull up.

    Light weight electric motors could supply power during take off and if needed during landing. This would allow kerosene powered engines to be smaller, lighter, and more fuel efficient. Note that some hybrid concepts have drag issues that may need to get sorted.

    Solar power could potentially supply some power to a plane, but for anything more than a single seater plane it would be fairly insignificant. As planes get larger, the kilowatts of power they require increases much more rapidly than their surface areas.

    There are clear paths to how all electric and hybrid electric flight can be developed. But simply using kerosene and then removing the CO2 released from the atmosphere and sequestering it is definitely an option.

  2. suburbanite
    May 8th, 2017 at 19:27 | #2

    What about dirigibles? They might be completely impractical but they look cool and have a steampunk appeal.

  3. Ronald B
    May 8th, 2017 at 19:44 | #3

    Can’t do dirigibles. If we did, no one would be able to tell if they were in an alternate universe or not.

  4. Mark
    May 8th, 2017 at 20:40 | #4

    @Ronald B but all that amber would still give the game away.

  5. May 8th, 2017 at 21:27 | #5

    Without contradicting John’s general reasoning, it seems to me that the best dollars in abatement in this area are likely to be in biosequestration using algae.

    Yes, you could certainly decrease the amount of fuel needed for light aircraft by resort to hybrids, but ultimately I suspect FHC long haul passenger aircraft will be around for some time. We need to find a secure way to offset their emissions.

  6. Tim Macknay
    May 8th, 2017 at 22:01 | #6

    @suburbanite
    I’ve always had a soft spot for huge, prop-powered flying wings with ballrooms and jazz bands, a la Hugo Gernsback.

  7. plaasmatron
    May 8th, 2017 at 22:14 | #7

    The airlander 10 is close to production after a few hiccups along the way. Seems pretty cool, based on hybrid design of an airship shaped like a wing.

    en.wikipedia.org/wiki/Hybrid_Air_Vehicles_HAV_304_Airlander_10

  8. May 8th, 2017 at 23:41 | #8

    The fight in the USA to save ARPA-E is important, as it’s about the only public agency ready to consider off-the-wall ideas. These are no longer needed for electrical generation, but are for the transition in transport and – very important – for future giga-scale sequestration. The criticism indeed is that ARPA-E has played too safe compared to its famous DARPA progenitor. Its failure rate should be much higher than it is. But it does use a similar process: including competitions, and SFIK a willingness to back talented individuals rather than people who can put together a shiny business plan. The generally admirable German Fraunhofer network does not work this way. Nothing the EU puts together is free of stultifying multilingual red tape.

    Contributions to the mad inventor file: airships as recharging stations for electric airliners, and an h/t to an Australian inventor proposing to use tethered solar-powered hot-air balloons for generation.

  9. Moz of Yarramulla
    May 9th, 2017 at 07:21 | #9

    @suburbanite

    Any lighter than air craft has the basic problem that the lift to drag ratio is about half for air compared to water, even before the 1000:1 lift ratio makes vessels and hence ports unwieldy.

    https://sustainability.stackexchange.com/questions/2425/how-sustainable-are-cargo-airships-compared-to-current-cargo-shipping-methods/2426#2426

  10. May 9th, 2017 at 08:04 | #10

    ” …fundamental limits (the kind that apply, for example, to carbon capture and storage ..”
    Please explain. Is this a general proposition for sequestration, or limited to the failed efforts at CCS designed to save coal power stations? There are physical and biological constraints on say reafforestation, because trees can only grow so fast (though there is room for GM here) and you run out of land with sufficient rain that you can spare from crops. But what are the physical limits on geophysical techniques like carbonation of basalts and olivine weathering? There are fantastic volumes of both types or rock, teratonnes.

    It is really important not to allow the failed project for face-saving power-station CCS to discredit the search for an effective and affordable set of technologies for true carbon sequestration. TINA, since the 1.5 degree carbon budget will be overshot for sure, and we don’t know if even that is safe.

  11. Moz of Yarramulla
    May 9th, 2017 at 09:57 | #11

    James Wimberley :
    But what are the physical limits on geophysical techniques like carbonation of basalts and olivine weathering?

    Just like politics, the limits are about the cost of access. How do we expose the rock to CO2, and what are the costs – are they just energy, or are there also social, political, financial, ecological costs?

    Energy costs tend to be obvious, we just add up all the energy used to make and operate the equipment and there you go. But as with CCS, at some point the energy required exceeds the energy obtained from the process you’re trying to clean up. Which may not matter, we may be concerned with net greenhouse gas emissions and as long as they’re negative we might decide to accept the energy losses.

    If we can just pump liquid CO2 into basalt and it gets soaked up, that’s very cool. But if the volume of the rock changes and we start getting earthquakes that gets tricky. If instead we have to dig the stuff up and shake it or crush it, even worse – we’re going to need some dirty great open cut mines. Where is the basalt? Can we really just bulldoze the overburden off Belgium to expose the basalt, or will the Belgique object to their country being pushed into the sea?

  12. John Quiggin
    May 9th, 2017 at 10:14 | #12

    @James Wimberley

    I was only referring to CCA and power stations, where there are physical lower bounds on the proportion of energy needed to capture the CO2 and on the compressibility of [email protected] The bounds on afforestation are much less severe. I’ll look into the geophysical ideas, maybe you could give me a link.

  13. Andrew Dodds
    May 9th, 2017 at 19:55 | #13

    @Moz of Yarramulla

    For CO2 in basalt, there are huge formations of the stuff under the UK continental shelf (it has to be drilled through to get at some oilfields underneath; dates from the Atlantic opening around 60ma).

    The energy requirements involved in getting it there and injecting it would be high. But being offshore, any earthquakes from volume changes would not be noticed.

    Obviously direct exposure through open cast mining would not work.

  14. Hal9000
    May 9th, 2017 at 22:10 | #14

    @Moz of Yarramulla
    I’ve always thought combining pilotless drone technology with dirigibles has a great deal to offer in replacing small cargo transport, which occupies a great deal of road transport movements at present. There is also no reason with contemporary materials that hydrogen could not again become the buoyancy gas. It’s way cheaper than helium and super-abundant. The Hindenberg burst into flames on account of its doped fabric envelope, not because of the hydrogen.

  15. Joe
    May 10th, 2017 at 02:13 | #15

    Readers may find the website http://www.withouthotair.com useful. There is also a free textbook available.

  16. Moz of Yarramulla
    May 10th, 2017 at 08:07 | #16

    Hal9000 :
    @Moz of Yarramulla
    I’ve always thought combining pilotless drone technology with dirigibles has a great deal to offer in replacing small cargo transport, which occupies a great deal of road transport movements at present.

    Please read the stackoverflow link. For short distance low weight transport lighter than air craft have the problem that they’re expensive, complex and fragile compared to trucks, but also harder to operate and much more vulnerable to weather. If those problems can be solved you’re left with the same cost vs speed tradeoffs as helicopters have, but hopefully at a lower price point. But price is not the main reason helicopters are avoided for urban lift operations. Think about hiring a small crane for a single lift, like getting a new commercial aircon up an apartment building. $5000+ for the crane and likely you need to close a road for a while to do it which means permits and faffing about with traffic controllers and you’ll end up with 10-20 people on ste. Or hire a helicopter for a similar price but no road closure and done in under an hour. Why don’t people do that?

    Think about the fun of navigating a 10,000kg load attached to an airship between tall buildings on a windy day. Remember that 1 cubic metre gives about 1kg of lift, so that airship will be at least 30m diameter which is wider than most roads. So the delivery will probably involve winching the load down 30-50m while rapidly compressing the lift gas as the load is removed (I don’t think “load replaced by ballast water” is a practical model for competing with truck deliveries). There’s a whole lot of minor details to be solved.

    For deliveries less than 2-3 tonnes you’re competing with vans not trucks. Vans cost $5000-$100,000 and any monkey can drive one (observation suggests many monkeys do). Competing with minimum wage drivers using cheap vehicles on existing infrastructure is going to involve a revolution, not using the magic of computers to navigate giant balls of gas between power lines on windy days.

  17. derrida derider
    May 10th, 2017 at 10:00 | #17

    As usual we’ve wandered OT (our host is blessed with some fine commenters, but he must feel that keeping them even approximately on topic is like herding cats). Never mind, ’tis pleasant to dream of sipping champagne while flirting with an elegant fellow traveller in the spacious lounge of the New Hindenburg.

    I think the final nail in the coffin (hole in the gas bag?) for cargo blimps will be driverless planes, helicopters and trucks. Everything Moz says then gets multiplied times ten.

    Less OT – yes, the fundamental physics of capturing and compressing CO2 for sequestration means it must waste an awful lot of energy, which means it must cost a lot. Life would be so much easier if we could just find a way to repeal the second law of thermodynamics.

  18. Hal9000
    May 10th, 2017 at 10:25 | #18

    @Moz of Yarramulla
    I sspect Prof Q will shortly banish this discussion to the sandpit, however I’ll make the following points…
    “I don’t think “load replaced by ballast water” is a practical model for competing with truck deliveries”
    This is a wonderful example of a straw man argument. I may borrow it when talking to students about fallacies.
    “For deliveries less than 2-3 tonnes you’re competing with vans not trucks.”
    This is surely a distinction without a difference. Most of the commercial delivery vehicles I see queuing at my local shopping mall each morning or delivering groceries or appliances in the suburbs would be described by your average citizen as ‘trucks’. You require at least a Light Rigid truck licence to drive one.
    “any monkey can drive one ”
    The people driving them require to be paid. This is surely the point of drones for delivering goods. Much the same arguments were mounted about automation in the warehouse trade. This is not a trite point, since the trend is clearly towards automation of all inventory, storage and delivery processes.
    “Competing with minimum wage drivers using cheap vehicles on existing infrastructure is going to involve a revolution”
    Not unlike the revolution required to, say, replace horse-drawn vehicles and fast ocean liners with motor vehicles and passenger aircraft. Or, more to the point, the one required to decarbonise the economy.
    “using the magic of computers to navigate giant balls of gas between power lines on windy days”
    A remarkably similar contemptuously dismissive statement to the ones made by Barnaby Joyce on the reasons why renewables can never replace coal – they don’t work when the sun don’t shine and the wind don’t blow, unlike reliable ‘base load’ coal. The good Prof Q has dealt with these arguments time and again. Are masses of aerial power lines distributing base load power from giant coal fired generators to be a permanent feature of our cities? Must more and more of our urban environment forever be given over to roads? Are existing ways of doing stuff immutable?

  19. Peter T
    May 10th, 2017 at 11:35 | #19

    Maybe drones can deliver small loads short distances (if the control technologies can be highly automated. And this involves controlling many fast-moving objects in tight space with fairly high safety requirements). In this way they would replace Aus post vans.

    Sea cargo? No way. Containerised shipping in large vessels is astonishingly energy-efficient and low staff cost (around 15 crew to operate a 10,000 TEU ship). Containers move like bytes through a packet-switching network that makes use of every available bit of physical bandwidth. Air cargo is nearly as good.

  20. May 10th, 2017 at 12:26 | #20

    @Moz of Yarramulla
    There has IIRC been a successful small trial of injection of CO2 into basalt in Iceland. The carbon is fixed chemically by turning magnesium silicates like olivine into magnesium carbonates. Olivine weathering has similar chemistry but a more indirect path: expose olivine-rich rocks, preferably ground up, to the weather for carbonation; bicarbonate ions are washed into the ocean, where they are taken up by corals and diatoms and form carbonate rocks on long timescales. Olivine is the most common mineral in the lithosphere so it’s impossible to run out of it.

    These ideas need some of the money wasted on power station CCS. I’ll try to run down some links for JQ.

  21. May 10th, 2017 at 12:39 | #21

    @derrida derider
    Energy is the one thing we don’t have to worry about, at least for processes we can interrupt. In an electrical grid mainly run with cheap wind and solar, there are bound to be enormous volumes of electricity with no commercial demand that can be made available at irregular times for the cost of transmission. Thermodynamic inefficiency is not relevant if energy is free.

    The normal demand for electricity is incidentally very satiable. Even at a zero price, it’s useless by itself, and needs complementary inputs in the form of appliances and machines, which involve scarce resources.

  22. Jim Birch
    May 10th, 2017 at 12:45 | #22

    Agreed, containerised sea cargo is incredibly cheap. I can’t imagine a drone could compete on price although it might compete on speed and delivery site flexibility. I did this BOE calculation recently:

    A 10,000 TEU container ship costs like $M 120, annual depreciation like $M 20 on like 10 year life.

    Operational costs of about $9 million per year, fuel (46%) and port charges (21%) This gives annual operating costs of about $2,314 per TEU.

    One container (TEU) holds 50,000 bananas so a 10,000 TEU ship holds like half a billion bananas.

    $2314 / 50000 bananas / 25 two-week trips per year = 0.2 cents per banana transported

  23. Jim Birch
    May 10th, 2017 at 12:47 | #23

    I also learned that banana is also a temperature in the shipping trade. Cool but not frozen.

  24. derrida derider
    May 10th, 2017 at 14:08 | #24

    Hal9000, I can’t see why we can’t combine the Deputy Prime Minister’s excellent suggestion with the transport of the future. Let’s put our power stations in giant dirigibles floating above our cities, attached to earth by a coal slurry pipeline that doubles as the means of providing water ballast. No need for any National Electricity Market then – if one part of the country is a bit short of electricity we just load it up on coal and float it over to them. And think of the way it will spread life-giving CO2 evenly over the country so all the farmers benefit; we really will become the food bowl of Asia.

    Of course, in deference to our great visionary the first city to benefit from this nation building scheme that will surely make us the clever country must be Armidale …

  25. Moz of Yarramulla
    May 10th, 2017 at 14:44 | #25

    Hal9000 :
    “I don’t think “load replaced by ballast water” is a practical model for competing with truck deliveries” … This is a wonderful example of a straw man argument.

    I was attempting a practical objection. But since I’m apparently very slow today, can you explain it for me? How does the airship reduce lift when unloading cargo? The two means I’m aware of are reducing volume and taking on ballast, and since venting is out of the question compressing the lift gas seems like the only way to do that. Otherwise letting go of the load will be following by a sudden increase in altitude.

    Airships now typically aim at bridging the gap between helicopters and trucks – carrying oversize or overweight objects more cheaply than trucks while carrying more, further than helicopters can. Those 100+ tonne lift capacity dirigibles you see on the gee-whizz sites do exactly this (eg VariLifter, CargoLifter). Instead of dismantling the “thing” into 40 tonne chunks or moving along major roads at walking speed in one chunk, just airlift it in a straight line. It’s faster and easier than the very specialised heavy lift trucks so it doesn’t have to be cheaper.

    Most of the commercial delivery vehicles I see

    Excellent, so we’re talking airships with a load capacity of 20-40 tonnes, so a diameter of 30-50 metres. Which means my point about safety and operating altitudes seem relevant, albeit you haven’t been able to respond to them.

    When one crashes, we will have a large aircraft hitting the city from a fairly low altitude, but there’s still going to be a loud noise and unhappy people.

    “using the magic of computers to navigate giant balls of gas between power lines on windy days”
    A remarkably similar contemptuously dismissive statement to the ones made by Barnaby Joyce

    Please, can you actually address my points? I know snorting derisively makes good entertainment, but this is nominally a forum for discussions. To me a 30 metre diameter balloon full of helium or hydrogen is a “giant bag of gas”, and there are overhead power lines all over Australian cities. While powerlines might go away in the foreseeable future that won’t be soon. People keep suggesting this, but costs on the order of $50 billion keep coming up too. So “foreseeable” does not mean soon, and you seem to be talking about drones as a solution for the next decade, not the next century.

    And power lines are a real problem right now. The very first question a crane operator will ask is “where are the power lines”. Trucks have a less severe version of the same problem every time they visit a residential location. Can’t use the crane on the truck, can’t lift the bed, sometimes can’t even get onto the property because the lines down the side of the road are only 4-5m off the ground.

    Look, I get that new technology is cool. I would quite like a flying car. I just don’t see it happening any time soon.

  26. Ronald B
    May 10th, 2017 at 14:45 | #26

    There have been plenty of suggestions for non-biological sequestration of CO2 directly from the atmosphere. For example, extremely reliable katabatic winds in Antarctica could be used to generate electricity that is then used to freeze CO2 out of the atmosphere which is stored as dry ice in giant pits or a convenient valley and kept solid with a steady trickle of liquid nitrogen.

    But, I have never seen a serious suggestion that can compete on cost with biological methods. This doesn’t mean they never will, but I’m not optimistic about it happening any time soon.

    Of course, there is over lap between the two. CO2 from fermentation could potentially be stored geologically or converted into carbon ash via the application of very large amounts of energy.

  27. Peter T
    May 10th, 2017 at 15:34 | #27

    @Jim Birch

    I won’t argue with your numbers, but in practical terms 10 years ago it cost around $1500 to ship a container from Japan to Australia, and over half that cost was wharf handling, local transport, brokerage and other admin fees and government charges. The cost is so small that they ship frozen fish from Scotland to China and then back after processing to save money on wages – and are still ahead.

  28. May 11th, 2017 at 01:09 | #28

    @Peter T
    Shipping has up to now had a free pass on its carbon emissions, and on air pollution from tunning marine diesels in port. The comparison with alternatives should be made using a virtual carbon price, say $100 a tonne. I suspect that shipping in containers would still win, but less dramatically than now.

  29. Hal9000
    May 11th, 2017 at 12:31 | #29

    @Moz of Yarramulla
    It depends what you mean by ‘soon’. Climate mitigation policy already assumes a time horizon of 30-50 years. The Adanis plan to have their mine producing for 70. I don’t see any innovation making serious inroads for at least a decade. No doubt it would start in areas and for applications where it could operate despite legacy technologies in the first instance.

    I really don’t think I have to solve all the engineering issues in order to make the argument. This is the same nonsensical line followed by the nuclear lobbyists wrt renewables – every conceivable engineering problem apparently has to be solved before you can begin to consider alternatives. The main issue, surely, is that zeppelins require no energy whatever to remain aloft, whereas other technologies use vast amounts of energy to do just that. Hovering with a dirigible is in principle easy and cheap. The engines fail on a heavier-than-air craft and it crashes to the ground at the speed of a high category cyclone. Engines fail on a zeppelin and it drifts along relatively harmlessly. Surely they’ll be bigger than equivalent trucks, but then trucks operate on two dimensional surfaces while aircraft operate in three – much more space.

    Your concerns re power lines etc I’ve addressed earlier. I’m assuming these technological relics will cease to be the problem you believe they always will be, just as the pressing need for motor vehicles to avoid frightening horses ceased to be a major issue on our roads in another era.

  30. NME
    May 11th, 2017 at 15:25 | #30

    Hydrogen fuelled jet engines are another interesting possibility, though a quick google shows aviation industry interest fell away about 5 or so years ago, due to issues with the lower energy density of liquid hydrogen, and the cost of producing hydrogen (primarily from traditional fossil fuels). Falling renewable energy costs, together with a tax disincentive on fossil fuels in future, could renew interest in the possibility of hydrogen electrolysis from (sea)water, perhaps. It’s at least a technically feasible solution.

    There were also some interesting pilot projects using sails (more like high altitude kites) on modern cargo ships, which seemed to be achieving large fuel economies. But that seems to have died away too.

  31. Ronald B
    May 11th, 2017 at 20:22 | #31

    I probably should mention that high speed rail can substitute for flight. This includes various vactrain proposals such as the Tesla Hyperloop or the Edison Sucktube.

    But there is no need for fancy vacuum trains. Just a fast train can be faster than a plane on account of how trains take people to where they want to go while planes take people to airports.

  32. Ronald B
    May 12th, 2017 at 10:50 | #32

    The marginal cost of batteries is now low enough for them to replace petrol, diesel and LPG for most private car use. While it costs a huge amount of money for LG Chem, Panasonic, and others to set up their massive automated production lines, the cost per cell is reasonably low and quality is continuing to improve. This means reduced demand for oil. New car sales in Norway are already 30% electric. The majority of that 30% are all electric with the rest being plug in hybrids.

    It doesn’t take much of a contraction in demand to crash oil prices, So with an oil price that may be $10 a barrel or less, aviation is probably going to continue to use kerosene derived from oil and if they are required to they will offset CO2 emissions by investing in renewable energy to begin with and later by directly removing CO2 from the atmosphere.

    It will probably be a cheaper option to use kerosene and then grow biomass and sequester the carbon in it than it will be to grow biomass and then turn that biomass into aviation biofuel, at least in the short to medium term.

    Note we may see one more big run up in oil prices due to the fall off in investment in new wells before expanding electric car use drops demand and prices. I am not predicting permanently low oil prices from now on.

  33. Tim Macknay
    May 12th, 2017 at 12:28 | #33

    Yara Birkeland is building the first fully battery powered, autonomous container ship. It’s intended for relatively short distance, local use. I suspect battery technology isn’t up to ocean crossing (yet).

  34. Ikonoclast
    May 13th, 2017 at 05:53 | #34

    @Tim Macknay

    Machine design becomes so rational without the need to cater to superfluous humans. Skynet will soon realise this. 😉

    More seriously, unemployment on a scale never seen before will soon become the norm. Imagine a world where all drivers, captains and crews on land, sea and in the air are no longer necessary. This cannot be more than twenty years away for most applications and ten years for some.

    I can see the day arrive when robots will replace the trades. Today’s overpaid, under-skilled tradespeople are likely to be the last generation of their kind.

    This all raises the issue (and J.Q. has raised it) of how do people live with no income? Unless guaranteed and inalienable ownership rights to a certain amount of social and machine production come with citizenship itself, then we will see the most unequal society in history. Of course, the elites might decide the masses are unnecessary at all, which in a sense we would be. Are there any good depopulation conspiracy theories doing the rounds these days?

  35. Peter T
    May 13th, 2017 at 09:41 | #35

    @James Wimberley
    James

    Shipping has an enormous efficiency advantage relative to any other mode of transport. Any carbon price that affected shipping would affect other modes more – and air most of all.

  36. Ronald B
    May 13th, 2017 at 11:50 | #36

    Peter T, rail can beat shipping on energy per tonne-kilometer if it takes a shorter route. I also think it would be less affected by a carbon price, given the horribly low efficiency of most existing ship engines. But air freight does use about 35 times as much energy as rail or sea transport per tonne-kilometer, so that is quite a difference.

  37. Ronald B
    May 13th, 2017 at 13:29 | #37

    Yeah, the first sentence of my previous comment doesn’t actually make sense, but I am confident people will understand what I was trying to say.

  38. derrida derider
    May 15th, 2017 at 20:08 | #38

    Peter T, modern commercial flight averages about 3l/100km per passenger – much more CO2 efficient than cars. See https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft .

    As the article notes, modern planes are about twice as fuel efficient as the first commercial jets (and about five times as efficient as Concorde). Price signals take time to work (long run elasticities are generally much larger than short run ones) but they do work.

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