We're actually not that far off.

Right now, liquid fuels have about 10x the energy density of batteries. Which absolutely kills it for anything outside of extreme short hop flights. But electric engines are about 3x more efficient than liquid fuel engines. So now we're only 3x-4x of a direct replacement.

That means we are not hugely far off. Boeing's next major plane won't run on batteries, but the one afterwards definitely will.

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breve 2 hours ago | parent | next [-]

> Boeing's next major plane won't run on batteries, but the one afterwards definitely will.

Jet engines work better. Boeing's next major plane will have jet engines, just like their previous major planes.

Synthetic, carbon neutral jet fuel will be the future for commercial jets.

	▲	2 hours ago \| parent [-]
		[deleted]

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WalterBright 2 hours ago | parent | prev | next [-]

> So now we're only 3x-4x of a direct replacement.

The math leads out an important factor. As the liquid fuel burns, the airplane gets lighter. A lot lighter. Less weight => more range. More like 6x-8x.

Batteries don't get lighter when they discharge.

	▲	giobox 19 minutes ago \| parent [-]
		Not to mention that jet planes routinely take off heavier than their max safe landing weight today too, relying on the weight reduction of consuming the fuel to return the plane to a safe landing weight again while enjoying the extra range afforded. This trick doesn't work well with batteries either. The max safe takeoff weight for most jets significantly exceeds the max safe landing weight, which is harder to take advantage of with current battery tech the way you can with consumable fuels.

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rgmerk 32 minutes ago | parent | prev | next [-]

Hmmm. If we do simple extrapolation based on a battery density improvement rate of 5% a year, it takes about 30 years to get there. So it's not as crazy as it sounds - and it's also worth noting that there are incremental improvements in aerodynamics and materials so that gets you there faster...

However, as others have pointed out, the battery-powered plane doesn't get lighter as it burns fuel.

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capitainenemo 2 hours ago | parent | prev | next [-]

Well, there's also burning regular fuel in a fuel cell, a FCEV. That doubles the efficiencies over ICE, so I guess that bumps it back up to 8x away?

Given the great energy densities and stability in transport of hydrocarbons, there's already some plants out there synthesising them directly from green sources, so that could be a solution if we don't manage to increase battery densities by another order of magnitude.

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WalterBright 2 hours ago | parent [-]

> there's already some plants out there synthesising them directly from green sources

I didn't realize that a "green" carbon atom is different from a regular carbon atom. They both result in CO2 when burned.

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jeffbee an hour ago | parent | next [-]

Its the time shift. Burning a plant releases CO2 and it is still considered to be carbon neutral.

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TheSpiceIsLife 2 hours ago | parent | prev [-]

And, the two major byproducts of burning hydrocarbons are water and carbon dioxide.

Literally essential plant nutrients, essential for life.

Tangentially related, the 2022 Hunga Tonga–Hunga Haʻapai volcanic eruption ejected so much water vapour in to the upper atmosphere, it was estimated to have ongoing climate forcing effects for up to 10 years.

Water vapour is a stronger greenhouse gas than carbon dioxide.

And we heard precisely nothing about that in the media other than some science specific sources at the time and nothing on an ongoing basis.

From Wikipedia:

The underwater explosion also sent 146 million tons of water from the South Pacific Ocean into the stratosphere. The amount of water vapor ejected was 10 percent of the stratosphere's typical stock. It was enough to temporarily warm the surface of Earth. It is estimated that an excess of water vapour should remain for 5–10 years.

https://en.wikipedia.org/wiki/2022_Hunga_Tonga%E2%80%93Hunga...

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robertjpayne an hour ago | parent [-]

Please, the media didn't report on this because natural disasters affecting the climate is not controllable by humans and thus doesn't warrant a global effort to address unless it's so large as to be species ending.

Global warming is not fake, there's tons and tons of evidence it is real and the weather is getting more and more extreme as humans continue to burn petrol.

	▲	nandomrumber an hour ago \| parent \| next [-]
		Yes, and it doesn’t fit the narrative. We should be moving towards being able to terraform Earth not because of anthropogenic climate forcing, but because one volcano or one space rock could render our atmosphere overnight rather uncomfortable. You won’t find the Swedish Doom Goblin saying anything about that. > burn petrol. Well yeah, so making electricity unreliable and expensive, and the end-user’s problem (residential roof-top solar) is somehow supposed help? Let’s ship all our raw minerals and move all our manufacturing overseas to counties that care less about environmental impacts and have dirtier electricity, then ship the final products back, all using the dirties bunker fuel there is. How is that supposed to help? I mean, I used to work for The Wilderness Society in South Australia, now I live in Tasmania and am a card carrying One Nation member. Because I’m not a complete fucking idiot. Wait till you learn about the nepotism going on with the proposed Bell Bay Windfarm and Cimitiere Plains Solar projects. I’m all for sensible energy project development, but there’s only so much corruption I’m willing to sit back and watch. With the amount of gas, coal, and uraniam Australia has, it should be a manufacturing powerhouse, and host a huge itinerant worker population with pathways to residency / citizenship, drawn from the handful of countries that built this country. And citizens could receive a monthly stipend as their share of the enormous wealth the country should be generating. Japan resells our LNG at a profit. Our government is an embarrassment.
	▲	jeffbee an hour ago \| parent \| prev [-]
		Also some time after that other guy copied and pasted his canned Hunga remark into his big spreadsheet of climate denial comments the international community of climate scientists concluded that Hunga cooled the atmosphere, on balance. "As a consequence of the negative TOA RF, the Hunga eruption is estimated to have decreased global surface air temperature by about 0.05 K during 2022-2023; due to larger interannual variability, this temperature change cannot be observed." https://juser.fz-juelich.de/record/1049154/files/Hunga_APARC...

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TheSpiceIsLife 2 hours ago | parent | prev [-]

More accurately, the calculation needs to factor in the fact that battery weight doesn’t decrease as charge is used.

Commercial aviation’s profitability hinges on being able to carry only as much fuel as strictly[1] required.

How can batteries compete with that constraint?

Also, commercial aviation aircraft aren’t time-restricted by refuelling requirements. How are batteries going to compete with that? Realistically, a busy airport would need something like a closely located gigawatt scale power plant with multi-gigawatt peaking capacity to recharge multiple 737 / A320 type aircraft simultaneously.

I don’t believe energy density parity with jet fuel is sufficient. My back of the neocortex estimate is that battery energy density would need to 10x jet fuel to be of much practical use in the case of narrow-body-and-up airliner usefulness.

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abdullahkhalids 2 hours ago | parent | next [-]

An A320 can store 24k liters of fuel. Jet fuel stores 35 MJ/L. So, the plane carries 8.4E11 J of energy. If that was stored in a battery that had to be charged in an hour 0.23GW of electric power would be required.

So indeed, an airport serving dozens or hundreds of electric aircrafts a day will need obscene amounts of electric energy.

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WalterBright 2 hours ago | parent | prev [-]

You laid it out better than I. Thank you!

	▲	TheSpiceIsLife 2 hours ago \| parent [-]
		Thanks Walter!