They said for years that fusion power plants would be operational within ten to twenty years. As those ten to twenty years have gone by several times (sound familiar anyone?), they've stopped saying it.
The problem with fusion reactions, is that here on Earth we need to make it far hotter than the inside of the sun to make the same reactions occur, as we are not in the middle of a star with fantastically high levels of pressure that allow fusion to take place at a lower temperature (think pressure cookers).
We are talking hot enough to melt anything... so they have to contain the plasma in magnetic fields, in a big ring-donut piece of kit called a tokomak I think.
At the moment, initiating a fusion reaction takes more energy than can be got out of it, because of the need for such super high temperatures and because of the very very strong magnetic fields that need to be generated. The equipment isn't good enough, yet, to sustain the magnetic containment long enough to make it past the 'break even point' in terms of ebnergy in vs. energy out.
Once you did achieve self-sustaining fusion reactions you could get energy from, essentailly you have solved a lot of problems in terms of power. A powerplant would need shielding, but other than the shielding becoming radioactive over time (from memory), there are no nasty problems with radioactive spent fuel, as the spent fuel is helium, which might make your voice squeaky if you inhale it, but is otherwise a nice unreactive gas. And if it went wrong, just venting the plasma would induce an instant shutdown.
Although fission power has received a bad press, what is often ignored is that it is actually better for the environment than anything short of hydroelectics, solar power, geothermal power and wind power. In fact, if you take into account the environmental damage done by many hydroeletric projects (making huge dams and flooding valleys), and the size of the arrays needed for wind turbines and solar power cells, there's a strong case for saying that fission power is only beaten by geothermal and sea-based hydroelectric and wind power projects in terms of environmental impact PROVIDED NOTHING GOES WRONG.
When something goes wrong, fission power stations are potentially very environmetally damaging. However, in a accident free life-time, a coal powered power station, for example, releases far more radioisotopes into the atmosphere than a nuclear power station.
It is possible that fusion is a blind alley, and that quantum energy generation (zero-point energy) will actually be practical before fusion power, but it's still not known if quantum energy generation is actually anything other than an intrieguing possibility.
