Originally Posted by
isuzurover
The big issue is baseload power. At present, fossil fuels (coal or gas) or nuclear provide almost all the world's baseload power.
Some "green" options like geothermal, ocean swell/tide, solar thermal + storage, etc... can provide baseload power as well, but the technologies are either experimental, very expensive, or the sites where they can be implemented viably are too few and far from the demand. Plus for all apart from Geothermal, a few days with no wind or sun will mean no power.
However, a lot of the issues can be overcome by better grids and smarter power management. It is usually windy or sunny somewhere. The middle of Australia has over 300 sunny days a year...