This week, researchers at MIT announced their designs for a new nuclear fusion reactor that apparently solves the problem that has made fusion unattainable: the issue of containment. It might put us closer to a vaguely affordable reactor that could cleanly power a small city, the MIT News Office reports.

Nuclear fusion, the same process that powers the sun, is the ultimate in clean, endless power. In theory, all it takes is the slamming together of two hydrogen atoms to release huge amounts of energy. The problem has always been containing the insanely hot plasma that comes with that release.

But thanks to advances in magnet technology, the MIT team has been able to produce a magnetic field strong enough to contain this plasma in a relatively tiny fusion reactor. To create the super-strong magnetic field, the new design coils up thin superconducting strips of commercially available rare-earth barium copper oxide.

Publishing their work in the journal Fusion Engineering and Design, the authors believe their “tokamak”(donut)-shaped fusion reactor could be realized in as little as a decade. That’s a huge claim, especially considering that the running joke among energy scientists is that nuclear fusion power plants are constantly 30 years away.

Currently, the world’s most powerful (and still theoretical) fusion reactor is the International Thermonuclear Experimental Reactor under construction in France, which is estimated to cost $40 billion to make. MIT’s little reactor, in contrast, is half the size and can produce the same amount of power at a fraction of the cost.

In nuclear fusion, as in life, bigger isn’t always better. Here’s a toast to the little fusion reactor that might.