Future of transportation on Earth - Electric airplanes or Vactrains?

[szputnyik]

What do you think, which transportation technology would be more likely to become the standard form of long-distance terrestrial transport in the future?

Airplanes which have some way of storing or generating massive amounts of electricity, and using this to simply suck in and expel air through the turbines, creating thrust.

Or maglev trains, which run at hypersonic speeds in vacuum tubes with Martian atmospheric pressure.

The first option would require the invention of much higher capacity batteries or supercapacitors, the second would be possible with present-day technology, but the costs of constructing such a railway would be enormous. Perhaps we'll get the second one much earlier on the Moon or Mars, than on Earth, since no low-pressure tubes would be required there.

[peadar1987]

I'm guessing subsonic planes using turbofan engines like today, only powered by hydrogen, or synthetic fuels. It's easier to store energy that way than in batteries or capacitors.

[WestAir]

Unlike in the past, there's really no reason to transport goods or people any faster than a day. We have e-mail, text, video calls, et al to send information from London to New York in under 1/6th of a second. What reason is there to invent vactrains or super high speed transport, when it takes more energy to move these vehicles faster than the average train? Is the gain in time worth the loss in fuel? In todays world, many business leaders would say no.

One of the calculations pilots use to determine their "fuel efficiency" for the flight is literally "what do we gain by going faster?" If there are passengers who will likely miss their connection, they might be told to go faster. If there is senior crew onboard who get paid way too much per hour, they might go faster. Otherwise, there's really no point in burning the fuel. I imagine that business model will carry over into any future transportation technologies.

[peadar1987]

Unlike in the past, there's really no reason to transport goods or people any faster than a day. We have e-mail, text, video calls, et al to send information from London to New York in under 1/6th of a second. What reason is there to invent vactrains or super high speed transport, when it takes more energy to move these vehicles faster than the average train? Is the gain in time worth the loss in fuel? In todays world, many business leaders would say no.

One of the calculations pilots use to determine their "fuel efficiency" for the flight is literally "what do we gain by going faster?" If there are passengers who will likely miss their connection, they might be told to go faster. If there is senior crew onboard who get paid way too much per hour, they might go faster. Otherwise, there's really no point in burning the fuel. I imagine that business model will carry over into any future transportation technologies.

Unless we get to a stage where energy becomes ludicrously, unimaginable cheap, so fuel can be produced for next to nothing.

[Godot]

Vac trains were already planned for switzerland (although not of the Mag Lev variety but standard trains on rail ... just with evacuated tunnels through which they were supposed to move).

http://www.articlesextra.com/swiss-metro-alps-tunnel.htm

The biggest obstacle AFAIK still are the high costs.

Nevertheless IMHO this is a good means of transpotation for the future (no matter whether of the MagLev variety or Swiss Metro-like).

You don´t have any above ground railtracks that take away precious building space, it is clean and it is energy efficient.

[Idobox]

Electric planes don't make sense. Chemical batteries will forever be less energy dense than chemical fuels, and modern engines are already pretty close to maximum theoretical efficiency.

The main ways to improve would be new airframes with lower drag (flying wing, rhomboidal wings...), new fuels (hydrogen, biofuel, metal powders) or higher altitudes (less air, less drag).

Vactrains will not appear soon, but Maglev has a case for the mid future in densely populated areas. It doesn't make sense to make a NY-LA maglev, the infrastructure cost would be horrible, you wouldn't save time compared to planes and the USA doesn't spend money on trains, but for Tokyo-Osaka or London-Paris-Strassbourg-Berlin, it completely makes sense.

The thing is, airports take a lot of space, there are long delays at take off and landing, and they have saturation issues.

Concrete example: Marseille-Paris (I do that once in a while). It takes about 30 minutes of bus to go from the central station to the airport, I have to be there roughly 1h before the gate closes, then it takes roughly 1h to land in Paris, half an hour to get out of the airport, half an hour to go to the center. Total travel time, 2h30, closer to 3h in practice.

Now, the TGV takes 3h20 to do the same, I get much more comfort, and I'm allowed to bring a bottle of water or a bike with me.

And that's a 800km trip. For shorter trips, the train is way faster than the plane.

The main issue with train is capital cost: it's absurdly expensive to build tracks. So you need to have a lot of travelers (or care about CO2 emissions, I'm looking at you USA) for it to make sense. That's why high-speed trains are only found between large and close cities, and it's only where these high-speed lines are getting saturated that we will see faster trains.

In 2009, the Tokaido Shinkansen (TOkyo-Osaka line) transported 83 million passengers, which gives an average of 9400 passengers an hour, or a little more than 11 A380 per hour (assuming everybody in economy). The train in these conditions is not only cheaper and faster, but more flexible (a train every 5 or 6 minutes at rush hour). And it's not a surprise Japan is investing a lot in Maglev and wants to build a maglev line between the two.

Only when Maglev lines start to get saturated will we see serious interest in vactrains. The only economically viable reason to go that fast for a train is to transport more people.

[Caroliano]

Electric planes don't make sense. Chemical batteries will forever be less energy dense than chemical fuels, and modern engines are already pretty close to maximum theoretical efficiency.

What about beamed microwave power from space solar panels? Is that plausible? Elon Musk has talked that he wants to make a supersonic electric plane in the future, but never gave details on how that might be possible.

Also, there is the hyperloop idea, that is not quite a vactrain, as it needs a bit of air to work.

[sgt_flyer]

Well, Electric planes are being researched right now - Airbus e-fan - a two seater electric demonstrator already has an autonomy of 1hour at 160km/h. The electric consumption is estimated at 2€/flight hour.

Electric planes might not be a revolution regarding transport speeds / etc, but they could lower a lot airplane fuel costs. (Fuel usually account for around 30% of liners running costs) - no wonder airbus is want to try to make a regional passenger electric aircraft

Between high speed trains in partial vacuum and electric planes, i think industry will go after the thing that allows them to make money anyway (which one could depend on the local situation of course) if the need is to cross over large distances over easy land, electric planes would be the way to go. For zone in mountains, things might be different, due to the limits the mountains will create for planes. (Changing weather, etc)

Besides, we will need more and more advanced extraction techniques to get our fuels - which will lead to fuel costs increase (not accounting for other sources of fuel cost changes, like conflicts or political struggles), so electric transportation means will be more and more interesting

Edited August 22, 2014 by sgt_flyer

[K^2]

Electric planes don't make sense. Chemical batteries will forever be less energy dense than chemical fuels, and modern engines are already pretty close to maximum theoretical efficiency.

In pure weight ratio, maybe. But combustion engines are less than 50% efficient, while electric ones are well over 90%. Jet fuel is expensive. Electricity is cheap. Add to that various environmental concerns and related taxes, and while you'll never have airplane with chemical battery be lighter than a combustion fuel one, it can be cheaper to operate.

Also, who said we have to be stuck with chemical batteries? Nuclear Isomer Batteries research is advancing at a decent rate.

[Jouni]

Also, who said we have to be stuck with chemical batteries? Nuclear Isomer Batteries research is advancing at a decent rate.

That sounds like a really good idea. Let's have passenger planes with nuclear batteries big enough to store a few terajoules, capable providing power at a sustained rate of tens of megawatts. Aircraft hijackings should become more interesting, at the very least.

[cantab]

So the same kind of energy storage and power outputs as current planes have then. Those energies did indeed make aircraft hijackings "more interesting" back in 2001.

Anyway, advanced aircraft will always have the advantage that they're highly flexible and don't require massive infrastructure investment to go anywhere. Never mind vactrains and maglevs, electric aircraft could be a serious threat to conventional trains, which at the moment benefit from much cheaper fuel costs to offset the slower speeds and greater capital expenditure.

[K^2]

That sounds like a really good idea. Let's have passenger planes with nuclear batteries big enough to store a few terajoules, capable providing power at a sustained rate of tens of megawatts. Aircraft hijackings should become more interesting, at the very least.

Lets see... Which is safer? A battery made of material that's essentially inert, unless triggered by very intricate electronics, at which point it releases controlled and measured amounts of energy, or literal tons of jet fuel which contain exactly the same total energy?

Yeah, I'm going with nuclear isomer batteries as the safe alternative here.

[magnemoe]

Well, Electric planes are being researched right now - Airbus e-fan - a two seater electric demonstrator already has an autonomy of 1hour at 160km/h. The electric consumption is estimated at 2€/flight hour.

Electric planes might not be a revolution regarding transport speeds / etc, but they could lower a lot airplane fuel costs. (Fuel usually account for around 30% of liners running costs) - no wonder airbus is want to try to make a regional passenger electric aircraft

Between high speed trains in partial vacuum and electric planes, i think industry will go after the thing that allows them to make money anyway (which one could depend on the local situation of course) if the need is to cross over large distances over easy land, electric planes would be the way to go. For zone in mountains, things might be different, due to the limits the mountains will create for planes. (Changing weather, etc)

Besides, we will need more and more advanced extraction techniques to get our fuels - which will lead to fuel costs increase (not accounting for other sources of fuel cost changes, like conflicts or political struggles), so electric transportation means will be more and more interesting

Problem with electrical planes is that unlike cars the energy density is important.

You might get hybrid planes, makes a lot of sense for VTOL as you can power the lift engines from battery and the battery give an backup if the single turbine fails.

Vacuum trains, I'm not sure, the AVG and other high speed trains is +300 km/h, and unlike magelv or vactrains they can run on ordinary tracks.

This is important an rail line is a long single point fail structure at least unlike you have ways too route around, it can be so simple as use one track past the area where one track is down over to patch into another line until the problem is fixed.

In short I think its more cost effective to make standard high speed trains than going exotic even if cool.

(side note I want the elevators at the office to fall free the first half of the trip then do a 2g braking it would save time but more important it would be fun )

[Jouni]

So the same kind of energy storage and power outputs as current planes have then. Those energies did indeed make aircraft hijackings "more interesting" back in 2001.

The nuclear batteries would transform the plane from an 1-kiloton bomb into an 1-kiloton dirty bomb in a 9/11-type scenario. Even if you shoot the plane down before it can hit anything, you still have to deal with pretty significant fallout. Even in a more typical hijacking, you can't allow the hijacker to fly to Terroristan, because that'll give Terroristan access to a dirty bomb. (Of course, Terroristan Airlines already has those, so maybe it'll just strip one of its planes for spare parts.)

We know how to secure nuclear components against accidents. Securing them against deliberate abuse is a much harder task, however.

[K^2]

The nuclear batteries would transform the plane from an 1-kiloton bomb into an 1-kiloton dirty bomb in a 9/11-type scenario. Even if you shoot the plane down before it can hit anything, you still have to deal with pretty significant fallout. Even in a more typical hijacking, you can't allow the hijacker to fly to Terroristan, because that'll give Terroristan access to a dirty bomb. (Of course, Terroristan Airlines already has those, so maybe it'll just strip one of its planes for spare parts.)

We know how to secure nuclear components against accidents. Securing them against deliberate abuse is a much harder task, however.

I don't think you understand what a nuclear isomer battery is. It's completely inert if you aren't extracting energy from it. And when you are, it can only release energy in measured amounts. It would never turn the airplane into a dirty bomb. On the contrary, it would prevent energy release in case of a crash. That means far, far less damage to anything the plane hits, as well a much higher chances of survival to passengers in crew in event of an accident.

That's the same kind of conclusion-jumping that resulted in medical MRIs being called just that, instead of NMRI, which is the proper term. (Nuclear Magnetic Resonance Imaging) The word "nuclear" in the name doesn't mean danger of radiation.

[Kryten]

I don't think you understand what a nuclear isomer battery is. It's completely inert if you aren't extracting energy from it.

Nuclear isomers are radioactive by definition.

[K^2]

Nuclear isomers are radioactive by definition.

So is jet fuel. You are looking at something with half life of many decades, emitting relatively soft gamma radiation at a very low rate. It's inert compared to your fire alarm. It's completely inert compared to jet fuel. I stand by my statement.

[Jouni]

I don't think you understand what a nuclear isomer battery is. It's completely inert if you aren't extracting energy from it. And when you are, it can only release energy in measured amounts. It would never turn the airplane into a dirty bomb. On the contrary, it would prevent energy release in case of a crash. That means far, far less damage to anything the plane hits, as well a much higher chances of survival to passengers in crew in event of an accident.

I don't understand them, because I hadn't heard about them before, and the Wikipedia article doesn't tell anything useful.

Still, my main point was that an energy store with a significantly higher energy density than current fuels will be incredibly dangerous in wrong hands. You can't use them in civilian airplanes.

[magnemoe]

Lets see... Which is safer? A battery made of material that's essentially inert, unless triggered by very intricate electronics, at which point it releases controlled and measured amounts of energy, or literal tons of jet fuel which contain exactly the same total energy?

Yeah, I'm going with nuclear isomer batteries as the safe alternative here.

You are thinking normal batteries, not scifi high performance ones who have an energy density close to petrol. Petrol need oxygen to burn, you only get an explosion if you get gas mixed with air, else you get an fire limited to the surface area where its contact between fuel and air.

An normal battery works just as well in vacuum or underwater. If the energy density is as high as required (in the same magnitude as petrol) you have the risk of getting a chain reaction, a small part of the battery breaks down this releases energy, the energy will disrupt more of the battery making it fail catastrophically and this disrupt more of the battery, only real way to avoid this is to use a battery who need air or other gas to release energy. Other way is armor and blow out panels like on the M1 tanks armory compartment.

[K^2]

Still, my main point was that an energy store with a significantly higher energy density than current fuels will be incredibly dangerous in wrong hands. You can't use them in civilian airplanes.

You can get the same energy output from your house's power grid. I guess, we shouldn't connect houses to electricity. After all, it's dangerous in the wrong hands.

A nuclear isomer battery is inherently safer than any fuel or explosive, because it can only release its energy at some maximum rate. It can't go all at once. So you are inherently limited in any mischief you can cause with it.

Not only should we replace fuels in civilian aircraft with these. We should replace car batteries with these. Again, because they are far, far safer and far more difficult to misuse.

I don't understand them, because I hadn't heard about them before, and the Wikipedia article doesn't tell anything useful.

Yet, you were eager to jump in and make a comment about it. It's ok that you don't know something or don't understand something. And I'm always happy to explain what I can. What bugs me a little is when people charge into discussion when they clearly don't understand the subject. I just ask that you slow down and think for a bit, and maybe start by asking questions.

You are thinking normal batteries, not scifi high performance ones who have an energy density close to petrol. Petrol need oxygen to burn, you only get an explosion if you get gas mixed with air, else you get an fire limited to the surface area where its contact between fuel and air.

An normal battery works just as well in vacuum or underwater. If the energy density is as high as required (in the same magnitude as petrol) you have the risk of getting a chain reaction, a small part of the battery breaks down this releases energy, the energy will disrupt more of the battery making it fail catastrophically and this disrupt more of the battery, only real way to avoid this is to use a battery who need air or other gas to release energy. Other way is armor and blow out panels like on the M1 tanks armory compartment.

If you read the thread carefully, you'll see that I'm thinking nuclear isomer batteries. And everything you wrote doesn't apply to them. They have several orders of magnitude higher energy density, and yet are far safer than any chemical battery or chemical fuel, precisely because accidental or intentional catastrophic energy release is impossible.

Edited August 23, 2014 by K^2

[magnemoe]

I don't understand them, because I hadn't heard about them before, and the Wikipedia article doesn't tell anything useful.

Still, my main point was that an energy store with a significantly higher energy density than current fuels will be incredibly dangerous in wrong hands. You can't use them in civilian airplanes.

This, they don't have to be radioactive and would not be in any normal settings that is outside of deep space it would be not acceptable even for military uses.

Anyway, the problem with high energy density who don't rely on oxygen is that its hard to not make it an high explosive if handled wrong, know from experience that the difference between a pipe bomb and a solid fueled rocket is small (tried to make a pipe bomb as kid, hole for fuse was to large and it became an rocket who jumped from the pit we was setting it off to the pit we was hiding )

Skyjacking is deader than steeling cattle, not been much of it since 9/11 however the idea of using a private plane on autopilot would be an serious issue.

(This was covered in the Man-Kzin wars where humans on a Kzin occupied planet was not allowed electrical cars only the old fashioned ones with IC engines as the battery was too easy to convert to a bomb)

[K^2]

magnemoe, you just refuse to read on principle, don't you?

[Jouni]

You can get the same energy output from your house's power grid. I guess, we shouldn't connect houses to electricity. After all, it's dangerous in the wrong hands.

I don't know where you live, but where I live we can't get tens of megawatts from the grid without some heavy power lines.

If you read the thread carefully, you'll see that I'm thinking nuclear isomer batteries. And everything you wrote doesn't apply to them. They have several orders of magnitude higher energy density, and yet are far safer than any chemical battery or chemical fuel, precisely because accidental or intentional catastrophic energy release is impossible.

How do you know it's impossible? How many thousand engineer-years have been spent for trying to weaponize nuclear isomer battery designs that are known to be practical in megawatt/terajoule-scale?

Up until this point in human history, every single technology that can store large amounts of energy and release it reliably at a high rate has been successfully weaponized. Unless there is significant evidence to the contrary, the only sane assumption is that the same will hold for all future technologies as well. In this case, "significant evidence" means thousands of engineer-years of fruitless weaponization attempts, with a few hundred new PhDs as collateral damage.

[Tommygun]

Any kind of train and "rail/tube" technology will require a lot more expensive infrastructure than planes will.

So planes will have an advantage, but you will need a big jump in battery technologies to do it.

The major costs in building and maintaining the pathways a train needs will keep it used to only highly populated areas.

[Jouni]

Skyjacking is deader than steeling cattle, not been much of it since 9/11 however the idea of using a private plane on autopilot would be an serious issue.

There were a few quiet years after 9/11, but now the hijacking rates are back to normal. The latest case was a flight from Addis Ababa to Rome, which was hijacked to Geneva. It caused a bit of controversy in Europe, when it was revealed that the Swiss Air Force only operates during normal office hours.