What would happen if you used antimatter as a energy source?

If we had anti-matter to collide with matter it would provide a lot of energy using very little mass. That would make it a great rocket thrust device (if we could convert our maybe solar energy into anti-matter, we could put it in a gas tank and use it in a space vehicle). But two caveats. The energy would be in the form of gamma radiation. So it would be “dirty” in the same way as non-neutron producing nuclear fusion designs like tri-alpha’s (that is, it would have radiation warnings, require shielding and the gamma radiation could activate material around it, although gamma activation is less of a problem than neutron activation).

The other problem is that it wouldn’t “provide” energy in the way that coal or uranium or the sun provides energy. Anti-matter doesn’t exist in nature in a way that we can gather it. To get energy from anti-matter, we’d first have to expend more energy to create it. So anti-matter will almost certainly one day be used as a way to store and use energy, but it will never be an energy source to gather from nature and create energy for us in the manner of burning fossil fuels.

(Just in case the question is a sci-fi how-are-we-to-generate-energy-in-an-interstellar-age? I’d point out that if you think of the earth as a tiny dot circling a distant beach-ball sized sun, think of how little sunlight is going to hit the Earth as a fraction of total solar energy. Now imagine solar farms up close to the sun. They could easily collect many times that much energy (clean as can be). The sun produces a virtual infinity amount of energy (compared to mankind’s use on Earth) and throws it away into deep space. So it is entirely credible to image solar farms near our star collecting energy and creating anti-matter, or mini-black holes which subsequently evaporate, as means of creating all the energy we’d need to power star ships and such.)