All of them are very expensive to install the machinery.
Nuclear energy has no particular negative effect while it's being
generated. But after the fuel is 'used up', and you can't get much
more energy out of it, it's still highly radioactive and dangerous to
people.
We still don't have a good, completely foolproof way to dispose of
the waste material, in a way that will protect people from it for as long
as it stays radioactive (can be thousands of years !).
