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447 points Brajeshwar | 5 comments | | HN request time: 0.001s | source
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zw123456 ◴[] No.37373433[source]
Also, don't forget about air travel, especially private airplanes, something that is on the rise (e.g Netjets). Often the virtues of world travel are extolled as a way to learn about the world and bring people together etc. Except, it's extraordinarily carbon intensive and honestly doesn't do any of that IMO. Sure, seeing the Patagonia in person would be cool and all, but if I actually cared about it, I wouldn't go. I would admire it from afar to help preserve it. It's time to start travel shaming and discourage people from flying around just to get a selfie.
replies(2): >>37373455 #>>37373599 #
Gud ◴[] No.37373599[source]
Electric airplanes are becoming a real thing, at least for regional travel.
replies(2): >>37373764 #>>37373919 #
1. dredmorbius ◴[] No.37373919[source]
For long-range high-capacity passenger (or cargo) travel, electric airplanes will always be a pipe dream. Battery storage capacities are too low, as well as lacking the fuel-burn-off characteristics of fuel-powered aircraft: half a long-range flight's takeoff weight is fuel, and for distances > ~3000 km, each passenger burns roughly their mass in fuel. The carbon dioxide emissions are actually greater than this as CO2 includes two oxygen atoms contributed from the atmosphere.

Mind that long-range flights are also overall more efficient,[1] as they have a longer low-fuel-burn cruise-phase, as contrasted with take-off and climb, which consume tremendous amounts of fuel.

For ranges at which electric-powered aircraft are applicable, ground-based transport (e.g., electrified, preferably high-speed rail) are even more optimal, though there are cases (e.g., inter-island travel, remote low-population regions) which might not suit those. Those tend to be outlier and marginal cases already, however.

________________________________

Notes:

1. On a fuel/passenger-km or cargo-kg-km basis. Though the large overall distance makes for prodigious fuel burn regardless.

replies(1): >>37382249 #
2. Gud ◴[] No.37382249[source]
I don’t know enough about battery technology to agree with you, but yes with current technology, >2000km flights look impossible.

But regional travel, less than 1000kms I suspect we’ll see within the next two decades or so.

replies(1): >>37401752 #
3. dredmorbius ◴[] No.37401752[source]
That's ... probably around the upper range limit.

One problem with electrified aircraft is that longer ranges probably translate to much lower speeds. Total mass is absolutely critical, so two of the biggest areas of research are likely to be materials (lightweighting the entire airframe) and automation (removing pilots and flight attendants). Given that electrified aircraft are already likely to be small (I'm assuming anywhere from two to perhaps 20 or 40 passengers), eliminating anywhere from 50% to 10% of the total payload mass will be a major consideration.

But you're still looking at a slow flight in a small plane at lower altitudes (and bumpier air), with minimum cargo or carry-on allowances. If there's no alternative ground route, or schedule flexibility is of the essence, that might be an option, but not especially fast or comfortable.

Looking through proposed aircraft, I'm seeing models designed for anywhere from one to 186 passengers (the last is considerably more than I'd thought viable, Wright Electric with a 335 mi (540 km) range). More likely to me are the Zunum Aero (12 passengers, 700 mi / 1125 km range) and Eviation (9 passengers, 100--600 miles). From: <https://www.cnn.com/travel/article/electric-aircraft/index.h...>

Zunum's ceased operations.

Eviation appears to be ongoing. From Wikipedia:

With 260 Wh/kg cells, the 900 kWh battery capacity (3,460 kg, 7,630 lb) is initially estimated to give the design a range of 540–650 nmi (1,000–1,200 km) at 240 knots and 10,000 ft (3,048 m).[6] This is anticipated to increase as battery technology improves.

<https://en.wikipedia.org/wiki/Eviation_Alice>

(Again, somewhat better than my expectations.)

A prototype has flown, and there are orders for at least 167 aircraft. Colour me surprised.

Eviation Alice is the only electric aircraft listed by Wikipedia to give passenger numbers:

<https://en.wikipedia.org/wiki/List_of_electric_aircraft>

replies(1): >>37403091 #
4. Gud ◴[] No.37403091{3}[source]
There is also Heart Aerospace which I consider to be the best contender for first commercial flight,

https://heartaerospace.com/

They are well funded and have customers lined up

replies(1): >>37413139 #
5. dredmorbius ◴[] No.37413139{4}[source]
Thanks!

Noting that the ES-30 claims 30 passengers and an all-electric range of 200 km, 20k ft. service ceiling. No top/cruise speed mentioned.

<https://heartaerospace.com/es-30/>