As oil is depleted over the coming decades, its price will rise exponentially. Natural gas is a popular fossil fuel because it burns cleanly. Natural gas from the Gulf Coast comes up the slowly expanding pipeline system to a new generation of efficient gas turbine generators. But the pipeline system is expanding much more slowly than demand and natural gas prices will climb steadily with increasing scarcity. To complicate matters, all fossil fuels release carbon dioxide that may be limited by international agreements on global warming.
Nuclear reactors run on cheap uranium but nobody knows what to do with the radioactive waste.
The nuclear generators in use are getting old and no new ones are being built or even planned. Hydroelectricity has been an energy source but now the only talk is about which dams to tear down. Nobody knows, but be wary of any proposed government solution. Remember also the price caps on gasoline during the OPEC oil embargoes of the 1970s and the long lines at the gas pump. There are thousands of people working in the increasingly competitive energy industries trying to innovate, improve technology, and develop cheaper and more efficient energy systems.