The concept of a "degeneracy generator" has been bothering me ever since I watched Gunbuster a while ago. Essentially, a degeneracy generator is a device that allows the production of a large amount of energy, apparently without an external source (According to 1:30 in the video above, its power output is 10²⁶ J/s or W). The OVA series does not attempt to explain the "scientific" principles behind such a device, other than the fact that it contains one or more black holes. Of course, I recognize the fact that anime physics is not "real" science and that there was probably no rigorous scientific principle behind this when the series was made, but after dwelling over it for a while, I came to the conclusion that it is in fact possible to create such a device with modern-day technology, with the exception of the method by which a black hole of sufficient size can be acquired.

Some brief points that allow for the capture of a micro black hole inside a confined space:

• Black holes can hold electrical charge.
  
• Charged objects can be held in place with a Penning Trap.
  
• Superconducting electromagnets allow for the creation of arbitrarily strong Penning Traps.
  

For the structual integrity of the containment apparatus to remain intact, the black hole must have a mass that is low enough to not exert significant strain on the surrounding equipment. A black hole which exerts a gravitational acceleration equivalent to Earth's 9.8 m/s² at a distance of 1 millimeter would have a mass of 1.468 x 10⁵ kilograms, which is about the mass of a Boeing 757. This black hole would have a schwarzchild radius of 0.218 zeptometers: less than the size of any known subatomic particle with nonzero volume. It represents a negligible risk if it were to escape from containment; the gravitational pull from the black hole would be nearly nonexistent at any macroscopic distance.

So a black hole is captured. Now what?

We know that black holes emit hawking radiation. Through the Stefan–Boltzmann-Schwarzschild-Hawking power law, we obtain a net energy outflow of ħc⁶/(15360πG²M²); under the condition that M = 1.468 x 10⁵ kg, the net amount of power expelled by such a black hole is 1.652 x 10²² watts. This falls short of the power of the generator presented in the Gunbuster OVA; such a black hole would produce about 1/23,200 of the power output of our sun. (Keep in mind that this is still more than the equivalent of 2 trillion times the power output of the largest nuclear power plant in the world.)

It is trivial to supply more mass to the black hole to compensate for this energy loss; simply physically inject more mass by sending it towards the black hole in a manner that does not disrupt its angular momentum. By "feeding" mass to the black hole at a rate equivalent to the speed at which it is losing mass, any loss in mass experienced by the black hole is immediately compensated.

The input is mass; the output is thermal radiation, which incurs a loss in the black hole mass as a result. Due to conservation of energy, this effectively allows us a method to obtain a 100% efficient process of conversion from mass to energy as described E=mc², by utilizing a micro-black hole as a conversion mechanism.

The generator can be "turned off" by reflecting the thermal radiation back to the black hole; most massive black holes actually gain mass since they absorb the cosmic background radiation and gain mass faster than they lose to hawking radiation, due to the fact that larger black holes emit less hawking radiation than smaller ones. ("The power in the Hawking radiation from a solar mass black hole turns out to be a minuscule 9 × 10⁻²⁹ watts.", as explained in the Hawking Radiation article.) By redirecting the emitted radiation back into the micro black hole, its mass loss is negated and the black hole remains at equilibrium with zero useful power output. Reducing the quantity reflected back into the black hole allows for the extraction of useful work (which must in turn be compensated by a "mass feed" to keep the mass of the black hole constant.) This mechanism can therefore allow the generator to be "partially on", or produce smaller units of power than that actually released by the black hole. Such a mode makes this generator more practical to use; after all, a device that constantly generates a huge amount of power even when idle is not especially useful for real-world applications.

So as far as I am able to tell, a degeneracy generator is not only possible, it is also practical as it actually will generate a large amount of power (albeit of a different magnitude than that of the fictional device depicted in the anime), substantially greater than that of any other technology now available to humankind. Additionally, such a reactor does not require expensive or rare isotopes of elements to function; plutonium-cycle nuclear reactors require an expensive fuel source, thorium-cycle nuclear reactors are not economically viable, while nuclear fusion reactors not only require rare isotopes like Hydrogen-3 and Helium-3, but also do not yet generate a net power yield. Degeneracy reactors can use any mass as the reactant and convert it 100% effectively to energy. No more landfills; garbage can be fed to a black hole and be turned into clean, pure energy.

So to the SENers who understand enough Physics to see any problems with this theory: Is there anything wrong with this idea? Will such technology become available within the foreseeable future and permit mankind access to exotic things like interstellar spaceflight with this newfound energy source? Will our civilization eventually run on this type of energy source? If there is anything I'm missing, please point it out, or if you don't see any, please feel free to discuss the possible ramifications of developing such technology .

Not a very far fetched idea, as far as the theory goes. Though the actuality of making such a black hole would be questionable.
While there is no question that there is 100% conversion from mass to energy, the fact that it converts its mass into thermal energy provides room for energy loss when we are trying to put that energy to use.
If containment field would be generated by a superconducting electromagnet you would be constantly using energy. (You would need to constant cooling of the conductors to maintain superconductivity, and that implies energy loss.) So if you were to turn the generator idle, you would probably be losing energy when it is idle. So it would be more ideal to use such generators for cities, planets, and other things that require permanent energy generation.
Not sure if the actual generation of such energy would make it possible for superconducting electromagnets to be nearby. It would rather be more logical to use plasma conduits for electromagnets, since they inherently require heat in order to be supercharged, and can be self-sustainable after black hole has been effectively trapped.

It does seem like you have given this a lot of thought.

By far the biggest practical impediment to creating such a device would be the creation an stable maintenance of a such a black hole. The idea of a singularity with a Schwarzchild radius so small strains credibility, and even if you had such a black hole, your Hawking radiation output of ~10²² watts requires a mass loss of 4x10⁵ kg/s as far as mass-energy equivalence is concerned. Feeding a hundred thousand kg per second into an object of size 2x10^-22 m without disrupting its angular momentum or a field containing it is, from the standpoint of all current technology, impossible.

Also consider that at such a rate, your black hole will lose its mass in Hawking radiation energy in about 200 ms. This is not a stable situation in any circumstance.

Ah, I have forgotten to calculate the rate of mass loss by such a black hole. How silly of me .

One of the restraints that I noticed when doing the calculations was that the power output is inversely proportional to the square of the black hole mass, but the Schwarzchild radius is proportional to only the first power of the mass. Therefore, larger power outputs are actually produced by smaller black holes with steadily decreasing gravitational attraction (which makes mass-feeding significantly more difficult).

Larger black holes are inherently more stable, but also produce much less power. I considered working backwards from the practical standpoint of mass feeding: from mass-energy equivalence, a 1 PW (10¹⁵ W) black hole generator loses about 11.12 grams of mass per second. Feeding this quantity of mass to a black hole seems feasible; when I calculated the mass of such a black hole, it turned out to be about 5.968 x 10⁸ kilograms (~600,000 tons). While this means that the black hole will be relatively stable in terms of mass loss, it still yields a Schwarzchild radius that is incredibly small: 8.86 x 10^-19 meters. Its gravitational pull is slightly stronger: the gravitational acceleration of an object near such a black hole would be equivalent to that of Earth's at a distance of 6.38 centimeters. Anything closer than that would be significantly attracted to the black hole and become assimilated (since it is after all not necessary to throw an object directly into the event horizon for it to be pulled in with significant force).

This throws a wrench into my plans: it is inconceivable to generate a field which exerts 6 billion newtons of force on this black hole to prevent it from falling into Earth due to Earth's gravitational pull on such a black hole; this large black hole also represents considerable risk when it escapes confinement. Such a system would necessarily need to be confined to an exoplanetary environment. On top of that, the power yield of 1 petawatt is not very large; mankind currently consume at a rate of about 1.5% of one petawatt, but the amount of solar energy hitting Earth every second is about 179 petajoules; this means we need 179 such petawatt reactors to equal the power output of an Earth-sized solar panel with 100% efficiency.

The problem that I can see is the fact that while mankind remains in the solar system, it is far more economically and technologically viable to construct solar harvesters (cf. Dyson sphere) than to create stable degeneracy generators. Perhaps these generators will only be practical for interstellar applications like spaceflight??

How do you convert thermal energy into movement in space? There's nothing to push off of once you're in space, so most heat engines won't work very well out there. I thought you had to eject matter out of the back of the ship to accelerate, but I there could be other ways I don't know about.

As far as I know, the only problem is actually creating the black hole. But of course, I'm not a physics major.

I don't know how else to put this, but creating the black hole is definitely not the only problem here.

For one thing, how much energy is it going to take to create an electromagnetic field strong enough to contain a 1.46*10^5 kg (approx. 322000lb) mass (from aristo's calculations), and according to the wikipedia page
What are we going to do with all that energy in 1 second? I don't know of any machine which can convert that much radiation/heat energy into useful electricity or anything in 1 second. On top of that, no machine has perfect efficiency, so there will be energy losses, and it probably takes a buttload of energy to make the black hole in the first place, so what's the net energy gain here? Plus black holes are dangerous, so you gotta get someone willing to take the risk to finance the damn thing, you gotta keep it hush hush so that governments dont try and get in your way, and you're going to have to make the black hole in a penning field to begin with to make sure it doesnt escape somehow, add up those joules/second + safety margin time, and DTBK mentioned:
And aristo mentioned some things so. Lots to think about.