Will electric planes eventually replace fuel based aircraft ?
 

This article, although writing primarily writing about small aircraft 'replacing' cars, tells also about possible future developments on larger aiwcraft.

https://www.theguardian.com/sustaina...-in-our-cities

Personally, I don't believe this in the next two decades as I cannot imagine an electric aircraft to move 500 tons pax + cargo over 10000km within 12 hours. Jet-A1 has a much better energy density than the very best battery technology.

I rather believe in synfuel which is a Jet-A1 compatible fuel made chemically or biologically (with microbes) from exhaust gas (see www.steelanol.com), mostly water + CO2. The energy need to reprocess this will be mostly renewable.

That keeps aircraft running on high energy dense traditional fuel, which is however not 'fossil' anymore.

When fossil fuels like oil are gradually being phased out, there is a new potential for the also sunshine rich Middle East: produce synfuel using the copious amounts of solar energy available there.

Current technology batteries are pretty heavy in proportion to the available energy they can store. The ratio of inherent energy density to weight in Jet A is much better than current technology.

Until this ration gets much better for electricity storage media, I don't see much opportunity to move away from Jet A.

The world will change almost instantly when someone invents a better battery. Battery tech is holding almost everything back: electric car ranges, planes, effective solar, even mass energy production.

What we need is a chemically stable, deep charge battery that can run longer than current batteries by a factor of 100. They also need to be lightweight and smaller, and composed of materials that are not particularly difficult to obtain.

Other technology is way ahead of battery tech, and is just waiting for battery tech to catch up. We already have great electric cars, but their drawback is range and re-charge time...not to mention the weight.

Planes are perfect for electric technology because without carrying fuel they can massively increase their range and load capacity. I am sure both airlines and aerospace manufacturers are chomping at the bit to get a plane that is lightweight, long range and fuel free.

Battery technology has still very far to go.

Lithium-based batteries will probably never make their way into airplanes as the primary source of power/propulsion. A Samsung Galaxy Note 7 is dangerous enough to make airlines ban them altogether. Imagine, what would happen if the battery packs, powering a 747 over TPAC routes, would go up in smoke (or rather explosion).

With cars that's pretty much not a problem. In the case your EV starts bursting up in flames, you can stop and get out. Try that at >33,000 ft while flying at cruising speed.

The primary batteries for the B787 are lithium-ion batteries.

Maybe "eventually", but certainly not in 2 decades, or in our lifetimes, I suspect.

Yes, we need battery tech that is 100x better. Just like we need fully functional robots to do all of our work, infinitely clean air and water etc. I don't think battery tech is in any way "behind" - that assumes it "should" be somewhere way far ahead. Our knowledge of chemistry, physics, and the realities of both are what they are. I don't think anyone is slacking off looking for better batteries.

When I was studying Computer Science in the 80's the very idea that a passable video stream over a copper phone line was science fiction - both with bandwidth and the compression technology required at both ends.

Things have certainly changed, battery technology can't be so far behind.

No, there is no way this will happen. Not unless you significantly redefine what you mean by "passenger airplane" or "battery".

The energy densities of batteries (~1 MJ/kg) are simply orders of magnitude too low compared to liquid fuels (~50 MJ/kg). Perhaps they could get part of the way there by ejecting batteries out the back of the plane after they're used.

As green as I am, even I am quite pessimistic and skeptical of why airlines periodically try to experiment with biofuels - for publicity reasons or what not. Inevitably which get canceled after 12 months of halfhearted experiments. $23 per gallon doesn't make sense no matter how green you are.

I edited my post. I didn't mean electricity but power/propulsion.

I'd agree. No way unless/until denser energy storage as above come along. An it'll have to be denser than that as at least fuel is burnt off inflight and the a/c becomes lighter. Batteries weigh pretty much the same depleted or not.

The only other possibility is power generation in flight (think nuclear reactors). Not so far-fetched as some vision/variant of this idea has been around for longer than most people here have been alive (or even their parents).

That wil be a great safety hazard even more than a new nuclear power plant. The airspace full of potential nuclear bombs ? When the U-235 (with thousands of times more energy per kg than Jet-A1) reaches the critical mass when a plane crashes another Chernobyl accident might happen ?

Indeed, I am not the only one saying battery powered electric planes will not make it. Jet fuel is way denser.
That is why I am advocating synfuel: the non-fossil synthetic variant of jet fuel. Technically it is possible, but it requires mass production and much stricter laws regarding global warning by CO2 to make it feasible.

How's that different from stuffing aircrafts to the brim with batteries?

Batteries are not radioactive and that is the danger.

A nuclear explosion can't/won't happen. I'd imagine only nuclear fuel that will not result in a fission explosion will be used. What will more likely happen is contamination due to a crash and/or fire that sprays the nuclear fuel everywhere, or in your example, a reactor meltdown. Still pretty nasty so a reason why a nuclear aircraft is unlikely to ever be developed, let alone fly.

What is the cost, not just monetary but also energy, of making such fuel? I am not a physicist but I imagine you can't disobey the laws of thermodynamics or other laws of physics.

What is the energy density of liquid hydrogen or liquid ammonia compared to Jet-A?
Also, if you can find a way to store a lot of hydrogen/protons in a safe matrix at higher densities than the liquid itself, would be a breakthrough.

Contrary to the situation discussed here, with telecom there were not physical\chemical limitations with transmissions.

As it was correctly pointed, current limitation is with fundamental laws of physics and chemistry and with material science as well.

10x increase of battery density with the same weight would be sufficient to transfer most passenger cars to electric ones. But it won't be sufficient for heavy-duty trucks (25x increase required) and planes (50x increase required).

Considering battery efficiency\density increase in last 30 years, unless there are fundamental discoveries in physics\chemistry, chances that you will see electric power replacing fuel is quite slim in next 50-100 years.

About 3x for liquid hydrogen.
Anything colder than liquified natural gas is very difficult to handle and liquid hydrogen specifically is extremely dangerous. Ask SpaceX on that...
https://en.wikipedia.org/wiki/Liquid_nitrogen#Safety
https://en.wikipedia.org/wiki/Liquid...cal_properties
https://en.wikipedia.org/wiki/Liquid...gen#Properties

No I am not violating these laws. It costs energy to make synfuel as energy to be used plus the losses in the process has to be input. And I think that over the longer term (decades) I think it will be economically feasible to use renewable energy for powering this process. The sources are mainly water and CO2, so actually one is recycling CO2. Mankind will be forced to do this for survival on this planet.

Referring to the same online chemistry textbook I see however, your statement applies to mass. By volume however, compressed H2 gas is only 5.6MJ per liter while Jet-A is 37.4. Again, by volume, Jet-A1 is the most dense fuel.
H2 gas is very bloated in volume, so that requires monstruously large aircraft. LNG is even a better option, but far more flammable, so the sky is filled with flying bombs, just like H2 powered planes. Remember the Hindenburg airship in 1937 ?

On the environmental cost, I agree. On the economic and/or energy cost, I suspect it will cost more than 100% of energy produced. The question is if the solar or whatever renewable energy can be put to better use.

But in a 100% renewable only economy of the 2050s there is no choice for the energy source. That might result in far higher energy prices.

And, as said (unless a miraculous battery or hydrogen storage technology emerges), jet fuel has the best energy density, so there is no choice for another propulsion source.

And an economy without aviation is also impossible (unless for shorter distances < 500km which might be replaced by high speed train or Hyperloop).

I didn't say that they were. You said (correctly) that a nuclear reactor would be a great safety hazard. Well, stuffing a commercial airline to the brim with batteries is a great safety hazard too.

Look what happens to this (tiny) lithium battery

Then try imagining what happens if we don't have a few Wh (e.g the iPhone 5 battery has 5 Wh (14,000 mAh @ 3.8V) but a couple of GWh. (1 GWh = 1,000 MWh = 1,000,000 KWh =1,000,000,000 Wh)

At least the resulting contamination from a large lithium battery fire int likely to be anywhere near as toxic and devastating as radioactive material contamination.

I wouldn't want to be anywhere near either of the two catastrophic events though.

That's for sure, but that doesn't make Lithium batteries safer.

Indeed. But of course, a crashed plane with lithium batteries aboard isn't going to spread radioactive waste either.

Nothing different than a crashing planeload of Jet-A1.
Assume an aircraft loaded with 180 tons of fuel, that makes (180000 kg *43.7 MJ/kg) / 3.6 kWh/MJ = 2185000 kWh is indeed 2GWh.
The damage is not different from exploding Li-ion with the same capacity.

How about directed energy beams?
Instead of aircraft being burdened with carrying their energy source onboard, planes fly along prescribed routes populated with ground-based energy beam stations that continually shoot the planes with directed energy beams (insert magical process here) providing thrust and onboard power.
Similar to current-day VORTAC stations and published airways.

Are you writing this from Earth-616?

This! I get that batteries and synthetic jet-a and similar are going to be the next step. But surely we should also be thinking about inventing the next technology that will completely revolutionize traveling, in the same way that the internal combustion engine did to enable the car, or the jet engine did for planes?

If we are going to dream, let's dream big! Even heavier-than-air flight was once thought to be a magic process, now thousands of aircraft take to the sky each day.

Bring on the energy beams I say!

:rolleyes:

If the plane crash, he doesn't matter what happens: Both the passengers and the people on the ground will almost certainly perish. The batteries would however be a constant danger. A faulty battery cell could have horrible consequences.

Given how highly reactive lithium is, I wouldn't wanna sit on thousands of batteries, that are needed to generate the couple of GW/h needed for a flight. Filling up a plane with lithium batteries (which are considered to be so dangerous, that they may no longer travel as air freight on board of passenger aircrafts), seems to me to be equally idiotic than filling up an airship with hydrogen.

Add to that multiple other issues:

• Charging the batteries is going to take considerably more time. More time on the ground = Less money for airlines
• Maintenance of the batteries
• Lithium isn't in infinite quantities available
• Insufficent energy density
• Complexity of the system: You'll need to cool the batteries on the ground (e.g. LAS, DXB, SYD where temperatures are that friendly to batteries) and to heat batteries while airborne and on the ground in colder countries.

The same with fossil fuel.
But you are right: Li batteries are not an option at all.
The energy beams sound very science fiction to me. But maybe somday in the 2080s it might be feasible....?
Then a 'magic' battery technology which does not have the big disadvantages of Li batteries is more probable.
In the 1970s we also never thought that within 50 years an electric car was possible.

Which is way, the technology has to be further tested and developed in ground transportation.

There were electric cars as early as 1896. ;) But yes, nobody thought in the 70s, that we would see EVs that could rival many sports and supercars. Even in the 90s and the early 00s, when I thought about EVs, I thought about Milk floats. The Swiss towns Sass Fee and Zermatt have prohibited the usage of traditional engines have been using Milk floats as vehicles as early as 1951.

The rapid advances possible with computer tech and software have misled people into overestimating what is possible.

Putting video over a copper line is largely a software advance.

Getting heavy objects into the air and keeping them there is mechanics and progress will be incremental and slow by comparison.

Both are technology.

But here you are right as well: software technology is in many cases overestimated.
Currently, progress is not as fast. We still type with the same qwerty keyboard as in the 1860s. Since the flat screen, display technology is not gone so fast anymore the last 10 years as they still have glare problems in daylight and are not reflective.

But other technologies as well. In the 1970s, a permanent lunar base was expected around 2000, and manned flights to Mars were already done.

So, we really don't know how we fly in the 2040s and beyond. I bet the same jet engine technology, but with even less fuel consumption per passenger distance. And probably (partly) renewable energy.

Advances in data transmission - and computer techology, AFAIK, have not breached any laws of physics.

Alternative propulsion for flight still have hard and fast laws against them, of weight/mass, friction, thermodynamics, among many. It may be possible to develop a very energy-dense battery, and it may be possible to beam energy in waves, and it may be possible to make synthetic fuels relatively affordable but all those laws have to be observed.

I did observe with interest that NASA has supposedly proven in theory a rocket engine that defies Newton's 3rd Law of Motion.

http://www.csmonitor.com/Science/201...tion-or-sci-fi

A friend who's an engineer was convinced that data were being stuffed through phone wires far faster than the Shannon limit he'd learned in college allowed. He was forgetting that the limit he'd learned was for phone wires equipped with the chokes that Ma Bell used to install to reduce noise. :)

Data limits through copper might well have increased. But what really changed to allow video and audio was compression technology - i.e software solutions.

The incredible advances made through applying software solutions have led many commentators to be over-optimistic about material solutions.

Or, as Scotty allegedly said, "ye canna change the laws of physics".

I think it was some of each. My Google skills are failing me and I can't the reference, but I recall reading that the old 56.5 Kbps modems achieved something very close to the Shannon limit for the pre-1988 telephone network. The limit was relatively low because of load coils that acted as 3400 Hertz low-pass filters installed on the cables. Rolling out DSL involved removing the coils, leading to a new Shannon limit that's two or three orders of magnitude higher.

Once the physics and electronics are in place, it's up to the software to exploit them.

They advanced together ajGoes, so yes, some of each.

The Germans who invented mp3 (and AAC too, not lot of people know that) had to wait about 20 years for certain technical improvements and market conditions, like more widespread broadband and mass market mp3 players , before their invention really gained momentum.

So even that "sudden" revolution took about 25 years in total, and against a lot of resistance.

Part of their story told in the book How Music Got Free , which you have probably read. Well worth it if you haven't.

Or it took that much time for the technology to implement it to be developed?

There are a lot of inventions that are theoretically possible but engineering knowledge and material science haven't allowed their development to be economically (or technologically) feasible.

Though supermagnets have been commercially developed and are available, a lot of spinoffs from Strategic Defense Initiative (a.k.a. "star wars") R&D spending of the '80s still haven't been developed into commercial technology.

As for what the future could hold, think space elevator, or more appropriately for air transport, SCRAMjets.

The synfuel for aircraft is a step closer:

http://www.flyertalk.com/articles/fo...al-flight.html