The only way I can conceive of this to work would be a device that uses the radiation of the accretion disk of the blackhole as a powersource.

To some extent you can use gravitational slingshots, too.
* Not with a black hole that is stationary relative to you.

Can't you use the intense hawking radiation of a micro black hole? Feed it matter in a continuous stream, harness the radiant output?
* Essentially the same thing as the accretion disk radiation mentioned above

Except for:
* miniscule vs massive
* unstable vs stable
* have to force-feed it vs let it feed
* blow up your solar system vs suck down your solar system
* 100% conversion vs 90% conversion

I'm not even sure what size a black hole would have to be to generate useful energy through Hawking radiation. And what lifespan it would have left if its matter stream were interrupted. For all I know, it might be too small to suck down a proton and blow up within a microsecond.

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Sounds like fun!

Assuming the placement of various devices around this object isn't a problem, which it shouldn't be --you just keep them far enough away, or orbiting around it fast enough, yadda yadda... there are a few obvious problems:

* you and all your equipment will be subject to bombardment from objects pulled in by the hole
* you and all your equipment will be subject to bombardment from the radiation and more especially, the EM field produced by the hole
* you and all your equipment will be subject to any number of other effects we don't currently know about
* if the black hole is big enough you'll either be forced to follow ''it'' where it wants to go or you'll be using a good portion of the energy it generates for you to move it anywhere
* all the other automotive companies are going to be pissy about it
* one or more people (or AIs at this point) will claim you're infringing upon one or more SubmarinePatent''''''s from several hundred years ago
* god help you if that hole plays its race card ("I will NOT be oppressed!")

Also, I'm thinking this page needs a related page called OneHundredAndOneUsesForBlackHoles.