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>Aviation Is on a Low-Carbon Flight Path Really? The article just says its author hope for a low-carbon future for the air transport, and mentions some tiny pl
by rcMgD2BwE72F 7y ago
>Aviation Is on a Low-Carbon Flight Path
Really? The article just says its author hope for a low-carbon future for the air transport, and mentions some tiny plans by jet makers and early startups to plan to 'hybridify' airplanes.
How much low-carbon would that be? As far as I could read, the author does not even try to evaluate that and blindly hope that it should be helpful, somehow. As if he can't bear flight shame, and tries to share/sell some "hope" to cope with that.
- ekianjo 7y agoThere's always the possibility of hydrogen-powered planes. https://en.wikipedia.org/wiki/Reaction_Engines_A2 https://en.wikipedia.org/wiki/Reaction_Engines_A2
- sokoloff 7y agoEnergy density of hydrogen by mass is excellent (about 3x that of gasoline/jet fuel), but much worse by volume (about 1/4 of gasoline/jet fuel). Finding a way to store liquid hydrogen in 4x the volume (plus any required cooling/insulation and safety systems) might be a challenge for long-haul flights.
- revax 7y agoAlso the production of hydrogen is far from being low-carbon. Yes there are some ways to produce hydrogen from electricity with electrolysis but at the moment 90% of hydrogen use natural gas or other hydrocarbons and release enormous amount of CO2.
- davedx 7y agoYou can say that about everything (except maybe nuclear) right now. This morning I had a discussion with someone on Twitter about windmills, and he said "yeah but they're still manufactured with carbon based processes, cement and steel are made using fossil sources". Hydrogen production can be clean though. https://www.cleanenergywire.org/news/hamburg-and-fukushima-cooperate-wind-power-and-hydrogen-production https://www.cleanenergywire.org/news/hamburg-and-fukushima-c...
- revax 7y agoIt can be, but it in fact not. And if it is, at what price? Don't misunderstand me, I want a low-carbon aviation, I'm all for it. But even if you cut the emissions by a factor 2 of each newer aircrafts, what's the point? The numbers of flights is expected to double in less than 20 years. Global emissions won't reduce at all. https://www.iata.org/pressroom/pr/Pages/2018-10-24-02.aspx https://www.iata.org/pressroom/pr/Pages/2018-10-24-02.aspx IMHO, we need more regulations (e.g. ban domestics flights if high-speed trains are a viable alternative) rather than technological solutions.
- netcan 7y agoThere needs to be some middle ground in these discussions. Yes, it's silly to ignore realities like "how was the electricity powering this car produced?" OTOH, since we're talking about potential future solutions to a hard problem (hard relative to cars, for now)... you kind of need to dismiss current issues if they're solvable to in theory. Price of electrolysis hydrogen now, when we're not using that much of it is not necessarily indicative of potential prices at scale. To me, I think we need to focus regulation that gets high potential technologies (eg electricity production and electric transport, atm) past the point on their learning curves where ordinary price economics and/or bans on carbontech can take over. The problem with marginal mitigation like discouraging flights or large ICE engines is that gains are one-off, and not en route to bigger solutions. I agree that commercial flight is a big problem. I'm just skeptical that carbon austerity can amount to more than a rounding error in the long term.
- hodgesrm 7y agoThe harder problem is selling hydrogen fuel to consumers.
- sambull 7y agoI was next to a hydrogen refuelling station yesterday at a shell station. It basically looks like they produce it on site with electricity and natural gas... the point is I couldn't order at a drive thru across a parking lot from the thing because it kept making like 15 second long whirlly/screeching pressure sound in some sort of regen cycle.
- growlist 7y agoAlso a lot harder to handle, and leaks are potentially far more dangerous. Kerosene won't even ignite with a naked flame held to it, whereas H2...
- anovikov 7y agoFortunately planes don't have much trouble with volume. Taking away a luggage compartment of a long-range airliner like 777 plus it's normal fuel tanks, for hydrogen, will result in at least a trans-atlantic range carbon-free plane. And people already more or less got over the idea of check-in luggage, due to fees.
- netcan 7y agoIf you adjust for the drag/energy required to carry more voluminous fuel... any idea how this nets out?
- simonebrunozzi 7y agoYou're correct, but the biggest problem in aviation is weight, volume is a distant second. Large planes can relatively easily get extra volume with a slightly different design, but too much weight just worsen everything.
- evgen 7y agoIncreasing volume is not really that easy. You are constrained by aerodynamics and any additional material required to contain an expanded volume adds weight in addition to increasing drag. There is a reason all planes look relatively the same, and it is not because we just happen to think it is a pretty shape.
- VBprogrammer 7y agoThe problems of using hydrogen are practically non-existent compared to the problems of using batteries. Even if you use half the interior volume of the aircraft for hydrogen storage you are still in the realms of it being economically viable (though still challenging). 1lb of jet fuel has roughly 5kwh of energy. Of course you are going to get less than half of that out as useful work. But an airliner can carry 300000lb of fuel. So as a first order approximation you are going to need 10000+ Tesla battery packs to do the same job.
- phkahler 7y agoHydrogen makes water when burned. Con-trails really need to be investigated for their effects on weather/climate. Coal fired plane might be better since CO2 is a much weaker greenhouse gas than water.
- davedx 7y agoGood article about this: https://www.newscientist.com/article/dn11652-climate-myths-carbon-dioxide-isnt-the-most-important-greenhouse-gas/ https://www.newscientist.com/article/dn11652-climate-myths-c...
- hwillis 7y agoThis comment is wrongheaded on several levels. 1: Jet fuel makes water when burned as well: by mass it is ~18% hydrogen, and by energy content it produces 55% as much water as pure hydrogen. The fuel itself is vastly less relevant than the amount burned. > Coal fired plane might be better since CO2 is a much weaker greenhouse gas than water. This is a fundamental misunderstanding of how atmospheric water works. 2. Water vapor -which is a gas- is effectively set; it cannot be affected by dropping water in the air. The amount of evaporated water is only affected by atmospheric temperature. 3. Liquid water droplets in the air are just clouds. Unlike water vapor, clouds are extremely good anti-greenhouse gases. They block visible light but allow infrared through. Seeding clouds with sulfuric acid is one of the suggested ways to fight global warming. 4. Contrails are made of ice crystals, not gas or liquid water. Ice clouds cause greenhouse forcing, but the destruction of ozone and other protective gases from high-altitude radicals in jet exhaust is generally considered a larger concern. 5. This is an area of active research, not something that is neglected. All climate research needs a lot more funding.
- phkahler 7y agoCon trail are formed when the water from combustion hits the cold surrounding air. They also grow under some conditions, creating more cloud cover.
- mtgx 7y agoOnly if you want mini-hydrogen bombs flying above your head every day with an order of magnitude bigger appeal to terrorists.
- davedx 7y agoYep! There's a team working on that in the Netherlands that I'm following: http://aerodelft.nl/project-phoenix/ http://aerodelft.nl/project-phoenix/
- throwaway5752 7y agoThis is more promising since it is a closed carbon loop and a drop in replacement without capex for retrofits: https://en.wikipedia.org/wiki/Aviation_biofuel https://en.wikipedia.org/wiki/Aviation_biofuel