If nuclear fusion is so effective for powering stars why isn't it pratical for generating electricity in power plants?

Answer 1

Nuclear fusion in stars is quite slow; typically the star exhausts its entire fuel supply in millions, billions, or even trillions of years. To make it practical on Earth, temperatures and pressures must be achieved that are quite a bit higher than those in the cores of stars. But even the pressures and temperatures in the cores of stars are hard to achieve - we are talking about temperatures of several million degrees, as well as very high pressures. For example, no regular container can withstand such a temperature.