How far has plasma physics advanced in the goal of creating a safe useful energy resource?

Answer 1

Power plants are 30 years away. If history is a guide, 20 years from now they will still be 30 years away. Researchers will never declare that it might take more than 30 years because they know it is a peculiar feature of human psychology to not really care much about what happens more than 30 years from now, and they will lose funding.

Answer 2

Look at this wiki:

http://en.wikipedia.org/wiki/Fusion_reactor