(1) Conventional liquid petroleum production may have already come to a peak. Or maybe not for two or three decades. But that's not all that far away. Unconventional sources of petroleum are more abundant (tar sands and oil shales) but these are expensive and problematic to produce. So petroleum might be an ongoing problem.
(2) Done properly, nuclear could power our civilization for thousands of years. Big engineering challenges harnessing nuclear for transportation, however. Nuclear -> hydrogen? Battery-powered cars?
(3) Coal. Abundant. Very dirty. Can be converted to liquid fuel. (The details of how it's mined are rather ugly. I'm not sure I believe in human-caused global warming, but the climate science community seems to think it's a big problem.)
(4) Hydro is limited. Not a lot of suitable rivers are left undammed.
(5) Natural gas has reached peak production in North America, or so I've read. To keep domestic supplies high, it will need to be imported. Unfortunately, this requires use of liquified natural gas tankers, which are frightening targets for terrorists. Currently (if memory serves) there are only a couple of terminals in the US for this stuff.
May I add two more:
(6) Wind: Abundant, not very expensive to exploit. But intermittent, cannot be used beyond maybe 15% of electrical grid capacity because it becomes too difficult to control the power grid beyond that point.
(7) Solar: Abundant, but very expensive. Intermittent, so can only be used for peak electrical power generation. One good application is for people in remote locations. But not even the hippies at Sierra Club expect renewables to do more than maybe 20% of our power. They instead envision "efficiency" to solve our energy problem. I.e., we'll learn to do without energy.