Is it feasible to have a vehicle powered by fuel that the vehicle produces within its self? This vehicle can be a land vehicle or an air vehicle if you want. It must be capable of transporting at least one person.


Must be self-contained within the vehicle Must be powerful enough to move the vehicle at 10km per hour Must not rely on outside resources such as oil or natural gas

Edits Can have a closed loop inside the vehicle if wanted

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    $\begingroup$ 😁 (a) perpetual motion machines can't (and don't) exist. (b) If one could exist (e.g., if someone could give you a credible answer), they wouldn't post it here, they'd be running to the patent office. The answer is, regrettably, no. Sorry. You'll just have to declare that the "097 Power Plant" simply exists, can do what you claim, and move on with your story. $\endgroup$ Jun 16, 2020 at 2:24
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    $\begingroup$ The Simpsons addressed this: "Lisa, in this house we obey the laws of thermodynamics!" $\endgroup$
    – user535733
    Jun 16, 2020 at 2:42
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    $\begingroup$ @user535733 so has xkcd: xkcd.com/2217 $\endgroup$ Jun 16, 2020 at 7:43
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    $\begingroup$ You could make a vehicle that runs on batteries, and have a solar panel to recharge the batteries. I would usually need a much longer charging time than running time. $\endgroup$
    – NomadMaker
    Jun 16, 2020 at 8:11
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    $\begingroup$ Does sunlight count as an outside resource? $\endgroup$
    – user253751
    Jun 16, 2020 at 18:58

10 Answers 10


According to your last sentence (before Addition), the answer is: no!

You describe a perpetual motion machine which shall produce something (usually energy, in your case especialy fuel) from nothing. That’s not possible, it would break more than one law of physics. If we take the last sentence word by word, even solar power is not allowed as it uses an external resource (sunlight). You could try it with some reactor-engines, but even those need external materials from time to time (and are bulky and not really suitable for a vehicle).

Even if you accept external energy (sunlight for example) but want to stay with fuel you would need a technology which allows you to transfer energy to matter (like star trek replicators). This technology doesn't exist and we don't know if it ever will.

If we want to stay with self-produced fuel, but accept external energy and harvestable (regrowing) ressources, btl-technology comes to my mind. The technology to transfer biomass (wood, straw, nearly everything from plants) to usable fuel is still in development and not efficient by any means at the moment, but if our technological know-how advances further we could reach the point where this would be A.) usable and B.) could get small enough to fit on a truck or something equally big. You won't have a vehicle with long distances between stops to reload material, but it would work and should meet your requirements.

(Little hint: if you don't stick to fuel it gets much easier, you just need a steam-engine. 'Fuel' is whatever is capable of burning and the only other thing you need to replenish often is water.)

  • $\begingroup$ For my last sentence I was meaning non renewable resources such as oil sorry about that $\endgroup$ Jun 16, 2020 at 4:46
  • $\begingroup$ I Edited my answer to meet the corrected requirements. Thats a big difference at last. ^^ $\endgroup$ Jun 16, 2020 at 5:07
  • $\begingroup$ You can probably make a steam engine have a closed water system, but then cooling the steam back down could be a problem. Just letting it escape makes cooling a non-problem. But I don't see why it couldn't be a closed loop in theory, with the only input being the fuel. $\endgroup$
    – kutschkem
    Jun 16, 2020 at 14:37
  • $\begingroup$ @Zeronineseven, please edit the question to reflect that. $\endgroup$
    – Matthew
    Jun 16, 2020 at 15:13

A steamboat fits the bill. You can cut the ships own structure to feed the furnace. This will move you over 10km/h and will last as long as there are superfluous parts in the ship's structure (i.e.: the ship can move without its roof).

Don't be mad at me. You wanted the vehicle to produce its own fuel. This is a self-destructive process for the vehicle. Otherwise you would be in violation of Thermo's 2nd and we would have to give you a ticket for it.

  • $\begingroup$ Just plant the hulk with willow withies and you get to move for another few hours in a few months. $\endgroup$ Jun 16, 2020 at 17:30
  • $\begingroup$ +1 for a clever use of sarcasm. I love it! $\endgroup$ Jun 16, 2020 at 22:51
  • $\begingroup$ You might have to give Black Holes a ticket too and I can tell you that I'm not going to try and ticket a Black Hole. $\endgroup$
    – Demigan
    Jun 17, 2020 at 8:14
  • $\begingroup$ Like in Around the World in 80 Days... $\endgroup$ Jun 18, 2020 at 0:28

Thorium Reactor

A company called Laser Power Systems are planning a car running on a compact thorium reactor, claiming that just 8 grams of thorium could power a thorium turbine car for a century. This estimate has been criticised - this feat would require no less than 80 grams!

We are, however, quite far from making this come true. We don't have any actual working thorium reactors yet, and the first ones are likely to be far too large for a car (though in theory, they can be made far smaller than traditional nuclear reactors. And then, of course, there is the need for shielding against radioactivity, where 1 cm of lead is required to just cut gamma radiation in half. Still, it is feasible with future technology.

  • $\begingroup$ Reminds me of the Ford Nucleon: en.wikipedia.org/wiki/Ford_Nucleon $\endgroup$
    – stux
    Jun 16, 2020 at 14:52
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    $\begingroup$ This answer violates "Must not rely on outside resources" it may be far more efficient than your standard ICE but you are still consuming resources to produce motion nonetheless. $\endgroup$
    – eps
    Jun 16, 2020 at 15:05
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    $\begingroup$ Indeed it does. It might be good enough to solve the OP's XY problem though. $\endgroup$
    – user253751
    Jun 16, 2020 at 19:59
  • $\begingroup$ @eps yeah but if human lifespan is shorter than the lifespan of the battery, does it matter? Without more context of what OP is really trying to accomplish, it can still be a viable solution and worth mentioning. $\endgroup$ Jun 16, 2020 at 20:54
  • $\begingroup$ @eps I'm giving this one a thumbs up. It may technically violate the OP's intent, but it spiritually meets the expectation by describing a power source that would outlast the driver and many of the mechanical components of the vehicle. The OP may need to change his world/story a bit, but it's great solution. $\endgroup$ Jun 16, 2020 at 22:50

Nuclear Battery

Whilst not actually generating the energy itself, a nuclear battery generates a constant trickle of energy for many years. This could in turn charge capacitors in the vehicle which would allow it to drive until the capacitors ran flat and then have to wait for them to recharge.

  • 1
    $\begingroup$ This is no different than a normal battery and violates "vehicle powered by fuel that the vehicle produces within its self" $\endgroup$
    – eps
    Jun 16, 2020 at 15:07
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    $\begingroup$ Well unless the OP invents perpetual motion, this is as close as they'll get $\endgroup$
    – Thorne
    Jun 16, 2020 at 22:55

A tiny white-hole inside your car.


While the consequences of white hole existance will likely throw most of our understanding of the natural laws in chaos, I doubt the general public would notice. We are causing time travel on a quantum level already and have theories that Black Holes break the conservation of information and energy and the world is still spinning so I guess a white-hole energy reactor wouldnt be much of a problem.

White holes are the theoretical opposite of a Black Hole. You cant enter them while matter and energy can only come out. So use one in your vehicle to generate the energy you need in any way you please.

Another alternative would be almost as magical: if you can control quantum fluctuations around a tiny Black Hole/kugelblitz you can control the amount of energy released per second (which is important as without it a Black Hole weighing 1 kilo would evaporate almost instantly in the form of a big radiation explosion). This allows you to power your vehicle for incredible amounts of time. You do have to make new BH's every now and then as its likely not possible to feed a BH that small even with light, which is weird in the case of a Kugelblitz which is a BH created by so much light energy in one tiny region of space it collapses in on itself.

  • Solar cells, batteries.
    Drive when the sun shines or as long as the batteries last.
  • Solar cells, electrolysis, fuel cell.
    Instead of batteries, use electrolysis to split water into oxygen and hydrogen. Use the hydrogen in a fuel cell and recover the water. The advantage over batteries is that this might feel more like "fuel," and there may be manufacturing efficiencies for large tanks vs. large batteries. The disadvantage is that gaseous or liquified hydrogen is awkward to handle.
    In all cases, the conversion will be less than 100% efficient. Put electrical power into an electrolysis system, pipe the hydrogen and oxygen directly into a fuel cell, and you will end up with less electrical power than you startet with. Same for batteries. So it is a good idea to use solar power directly in an electric drive as long as the sun is shining, and only go to power storage technologies when it is out and you need the reserves.
  • Wind generators and one of the above.
    Again you are dependent on outside power, in this case wind blowing, so storage technology is a good idea.
  • Muscle power.
    Muscle-powered vehicles can exceed 10 kph. There are even some aircraft. In this case the energy supply is in the form of food and drink for the operator.
  • $\begingroup$ No sun and no wind in the fog. $\endgroup$
    – user28434
    Jun 16, 2020 at 21:23
  • $\begingroup$ Solar, wind, and muscle all depend on outside resources (sun, air, food) and are excluded by the question. Frame challenge? $\endgroup$ Jun 16, 2020 at 22:52
  • $\begingroup$ @JBH, what I describe is outside, but not "outside resources such as oil or natural gas." $\endgroup$
    – o.m.
    Jun 17, 2020 at 4:21
  • $\begingroup$ Let's agree to disagree - your source fuel for solar power is sunlight (outside the vehicle), wind power requires moving air (outside the vehicle) and muscles require food production (outside the vehicle). If any of those three sources stop - so does your vehicle. nevertheless, I need to bow to whatever judgement the OP provides. $\endgroup$ Jun 17, 2020 at 13:48

Zero Point Energy

This in itself would not be exactly be self contained energy as I believe it draws energy from the quantum plane, but it would be close enough. That's at least what I know. More information here.

  • $\begingroup$ How would you extract energy from something when it's at the lowest energy level it can possibly be? $\endgroup$ Jun 16, 2020 at 21:13
  • $\begingroup$ The best estimates for the density of zero-point energy are that the entire Earth contains less energy than the equivalent of a liter of gasoline. $\endgroup$
    – Mark
    Jun 16, 2020 at 21:42

Consider a hydrogen modulated self regulating nuclear power module. It's purposely designed to be small, self contained, and self regulating. That means it doesn't need control rods or anything complex like current reactors do. As power output increases, the Uranium Hydride decomposes into Uranium and Hydrogen. It then loses its neutron absorption capability, and the reactor power drops on its own. It reaches equilibrium where the reaction is just moderated enough to keep going, with few moving parts. It is impossible for this design to meltdown, and will run for many years.

Current designs are about a couple meters in length, but could probably be made smaller. The fuel is not weapon grade, so tampering with it to get the Uranium would not yield bomb-making capability. The coolant is liquid bismuth, potassium, or lead, surrounding the reactor. This makes it very durable. If it falls off a truck for example, the case cracks, the metal leaks out and solidifies, making it hard to leak radioactive material. And for those concerned with safety of hydrogen in the reactor, it also works with Uranium Nitride and others, but Hydride is the most efficient.

This is all very viable with current technology, and is being actively developed (see Gen4 Energy for an example of a current design for a commercial reactor). Only approval by the Atomic Energy Commission is in the way of making these a reality.

As for performance, the original patent filing was for a reactor 1.5 meters in length, about 18-20 tons, and generates 27 megawatts of electrical energy. Even if you were to scale that down by a factor of 10, you'd still have a vehicle that could travel at any speed really, and you'd still have a ton of leftover power to add energy weapons, or whatever other electric or heat powered devices you need.

  • $\begingroup$ One crack in the confinement, a bit of oxygen, and BOOM. You'll need to evacuate the city around the accident afterwards. Hot hydrogen mixed with fissile material is a recipe for catastrophe, imho. $\endgroup$ Jun 16, 2020 at 20:38
  • $\begingroup$ If you scale it down by a factor of ten, do you still have sufficient mass to achieve criticality? $\endgroup$
    – jdunlop
    Jun 16, 2020 at 20:42
  • $\begingroup$ @cmaster-reinstatemonica The entire core is very small, and encased in a thick layer of lead. It's a very small amount of hydrogen, no more than the fuel itself. Besides, this isn't my design, it's a real thing, and the people are making it don't seem overly concerned with the very small amount of hydrogen in the core. $\endgroup$ Jun 16, 2020 at 22:03
  • $\begingroup$ And also, whoever down-voted it, really? For my first post on the particular exchange, with a design that would work perfectly as an answer to the question? It's almost ridiculously safe compared to current reactor designs; and I would like to point out that the question said nothing at all about safety, even though this is pretty safe. $\endgroup$ Jun 16, 2020 at 22:09
  • $\begingroup$ @jdunlop I'm not sure to be honest, but you don't have to scale it down. Leave it full size; it's heavy, 18-20 tons, but at full size you'll have 27 megawatts to play with, which is absurdly powerful for a vehicle, and still would weigh less than a tank. $\endgroup$ Jun 16, 2020 at 22:14

All the other answers are fantastic, but they're mostly ways to harvest a single resource, but there's a little considered aspect of the twin nuclear technologies which is criminally undersold IMO

That is that Fission reactors can produce fusionable materials, and that fusion reactors can produce fissionable materials

We don't have quite the technology to have an entirely-closed nuclear lifespan yet in the real world, but it is definitely a future feasibility, which means with a fictional efficiency improvement you could have a main reactor, which produces fuel to feed a supplementary reactor, which produces fuel for the main reactor, ad infinitum.

There would still be mass loss, from energy harvesting and byproducts (helium etc,) so you could have refuelling timelines tuned basically around the needs of the story depending on what specific tech you go with, but it would actually mean actually producing your own fuel onboard cyclically


  • 1
    $\begingroup$ The linked paper isn't saying that you can fuse things into fissionables and vice versa, it's saying that using a tokamak as a neutron source would mean that the fission reactor could use less optimal fuel, and that including heavy water in the blanket would produce tritium to improve the tokamak performance. It's not a closed loop, you'd still need deuterium and uranium inputs. $\endgroup$
    – jdunlop
    Jun 16, 2020 at 20:40
  • $\begingroup$ Fusing all the way up to even a light fissionable requires extremely high energies - not found (nor possible) in fusion reactors. $\endgroup$
    – jdunlop
    Jun 16, 2020 at 20:41
  • $\begingroup$ I probably should have been clear that the link was just for inspiration in the direction you could push sci-fi, but still basically realistic tech $\endgroup$ Jun 16, 2020 at 20:48
  • $\begingroup$ I got they impression they weren't looking for tech that exists now, but which could exist in a universe like ours $\endgroup$ Jun 16, 2020 at 20:49
  • $\begingroup$ Probably, but fusing elements into fissionable elements isn't something we're likely ever going to be able to do in a power-generation scale. Sustaining fission requires high-neutron-density elements, which require extremely high energy events (like neutron star collisions) to create. It's not a "we don't have the technology for this yet" situation, it's a "there's virtually no situation where this would be practical" situation. Direct matter-to-energy conversion would probably be more practical\achievable than fission/fusion in a cycle. $\endgroup$
    – jdunlop
    Jun 16, 2020 at 21:28

Assume that a hydrogen fusion power generator is developed sometime in the future, the goal of massive research programs.

Assume that smaller and smaller fusion power generators are developed over time.

So there will be fusion power generators that can fit into gigantic super ships, or maybe even smaller ships, And maybe spaceships, and maybe locomotives, and maybe cars, and maybe airplanes.

And maybe those fusion power generators will power electric motors to drive those vehicles.

Or maybe those fusion power generators will power fuel production plants which make chemical fuel for engines for the vehicle. Vehicles operating on Earth could take water, or water vapor in the air, and use electricity to split it into hydrogen and oxygen, and store the hydrogen and oxygen. And when enough is stored up the vehicle will be able to burn the hydrogen and oxygen, producing water vapor and energy to power motors such as internal combustion engines or steam turbines. If the water vapor is saved it can be split into hydrogen and oxygen over and over again.

And any decent sized tank of hydrogen for the fusion generator would contain enough hydrogen to last for years, decades, centuries, or millennia.

So whether this type of vehicle used the power of the fusion generator to power electric motors, or used it to produce hydrogen and oxygen to fuel chemical motors, it couldn't operate eternally but could be made self contained as far as fuel sources were concerned for years, decades, centuries, or millennia, assuming there were no mechanical problems.


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