Why fusion is impractical for energy?

Answer 1

"It would be very desirable to use nuclear fusion to produce power on Earth. The fuel source, the hydrogen in water, is highly abundant, and the process is very clean and environmentally friendly. The fuel supply for nuclear fission is not abundant, must be highly refined, and the process yields a great deal of dangerous byproducts. So definitely fusion would be a great way to produce power on Earth. Unfortunately, there are a couple of very big problems that may nuclear fusion completely impractical, at least for now. First, it takes very high pressures and very high temperatures to initiate a fusion process. Despite the aspirations of "cold" fusion proponents, temperatures in the order of billions of degrees are needed to start nuclear fusion. Although this can be achieved, it is difficult and certainly is not possible for any large scale commercial venture. The high temperature makes the whole thing exceedingly difficult to deal with, simply because there is no material that can be used to withstand such temperatures. And the process itself, once initiated, is likewise difficult to control. Minor examples of the fusion process have been achieved in laboratories, but nothing feasible for useful power. production."

http://www.mhhe.com/physsci/astronomy/arny/student/webtutor/solar_energy/questions.htm#answer1

Answer 2

Fusion is impractical for energy due to the immense ammount of energy produced in a fusion reaction. Fusion produces much more energy than a fission reaction. Due to this, it is difficult to harness the energy produced.

Answer 3

Despite experiments for many years, and building of expensive test rigs, nobody has yet made fusion work for more than a fraction of a second, and commercial operation is still many years away.

Answer 4

At this time there is no known method of constructing a controlled fusion reactor.