Companies are lookinto building electric flights. For example, hundreds of them are building eVTOLs: electric vertical take-off and landing vehicles. It’s a horrible acronym for small aircraft that take off and land like a helicopter and fly like a plane.
I do not know when we will have an electric plane that travel from San Francisco or Europe to Japan?
Hesham
On Thu, Mar 30, 2023, 10:31 PM Alexander Pelov <a@xxxxxxx> wrote:
Dear all,Indeed "proportional" doesn't exclude a constant (Ax+B) - and the size of that constant compared to the rest should also be taken into account.But I'm all for looking at the real world and see the real impact - don't care too much for abstract gains.I found an interesting paper dealing with the Marginal Fuel Burn per kg transported over 1000 km."The opposite is also true: a reduction in weightby one kg saves ~ 0.02 to 0.03 kg of fuel per1’000 km"From what I found, a kg of kerosene is 1.22 liters and produces 3kg of CO2 on average.Transporting a 100kg weight over 1000km then produces 60kg-90kg CO2 emissions.For a round-trip Paris-Yokohama (9731km) that would be 1.2t-1.7t of CO2 per person. (And use 0.95t-1.4t of kerosene)Worldwide, the average person produces about four tons of carbon dioxide each year.To have the best chance of avoiding a 2℃ rise in global temperatures, the average global carbon footprint per year needs to drop to under 2 tons by 2050.So yeah, it turns out that the personal contribution - even if the planes are flying- is not negligible (at least for me).The IETF at the scale of the global population is of course not going to change much.But now I see the point that IETF's impact is NOT net zero if we do nothing about it (as I initially assumed).Cheers,
Alexander
Le mer. 29 mars 2023, 14:02, Andrew McConachie <andrew@xxxxxxxxx> a écrit :
On 25 Mar 2023, at 16:37, Christian Huitema wrote:
> On 3/25/2023 5:36 AM, Julian Reschke wrote:
>> On 25.03.2023 11:48, Andrew McConachie wrote:
>>> ...
>>> Trains and planes are fundamentally different in this regard,
>>> because
>>> planes calculate their weight at takeoff and only take as much fuel
>>> as
>>> they need. The amount of CO2 produced by a passenger plane is
>>> directly
>>> proportional to how many passengers it’s carrying.
>>> ...
>>
>> So a passenger plane not carrying any passengers is not producing any
>> CO2?
>
> I think Andrew erred when he said "directly proportional". As in many
> things, you can probably separate fixed costs and variable costs.
> There is a fixed cost to carrying the whole weight of the empty plane
> and the crew through the sky. There is also a variable cost based on
> the load of the plane, which for a passenger plane means the weight of
> passengers and their luggage. So yes, an additional passenger directly
> increases the fuel consumption of the plane -- but less so than if too
> few passengers lead the airline to fly fewer planes. And the "fewer
> plane" effect is entirely comparable to the "fewer trains" effect.
>
Your first sentence is correct. I erred in claiming direct
proportionality. My point is that a plane carrying more people uses more
fuel and thus produces more CO2. This is much less true for trains.
There are more direct consequences of individuals choosing to fly simply
because weight added to an airplane has a much greater effect on energy
consumption than weight added to a train. Things like luggage and
airplane meals add weight, which requires more fuel, which then requires
even more fuel. So there are direct consequences with actually boarding
an airplane more so than with trains.
Whether or not reducing the number of overall passengers has the same
effect on planes as it does on trains is a really complicated and
difficult question to answer. You get into stuff like futures pricing of
jet fuel and regulations governing rescheduling practices, etc. I
don’t think anyone on this list is qualified enough to answer this
question.
—Andrew
