I do not know how much electrical power is produced worldwide through hydro but it must be substantial. In Denmark over 10 percent of power is from wind. There is no reason why this cannot be increased. In fact it could be argued that the sooner fossil fuels run out the better. By the way there are huge deposits of hydragas crystals that could be developed as a source of natural gas.
Geothermal power is also an underdeveloped resource in most areas.
If oil prices go to 30 or 40 dollars a barrel geothermal power would be economic even in areas such as Saskatchewan. Scrub and quick-growing wood is also actually a good source of heat plus the junk grows back very quickly releasing oxygen and using carbon dioxide. In Sweden garbage is a source of heat for some urban centers. By the by, old growth forests are the worst trees from the point of view of global warming. The problem with global warming is that it is difficult if not impossible to know if it is a long term trend or what its effects will be.