Diversity is the key to energy problems. In the end for our energy needs to be sustained it will have to come from multiple means. The thing here is many people seem to think in our search for alternative energy we need to find a solve all energy source. The thing is that would be a disaster in and of itself. What would happen is we would become too reliant on that source and when it causes problems humans would be saying "WTF are we going to do now".
Every energy source has it's downsides the reason for diversity is not to find a solve all solution but to use the advantages of one to cancel out or minimize the disadvantages of another.
example:
Wind does not blow all the time, but the sun shines quite a bit.
The sun goes down or hides behind the clouds, well the wind might still be blowing.
Both of thes take the drain off of oil and coal which can then in turn be used for something else and maybe even reduce the cost through reduction in demand, even if only by a small fraction.
The fossil fuel form of power generation will come to an end. The big question is when. There have been amny estimates and so far many of them have come and gone but should we wait until it becomes a real issue before we start working on alternatives. This where mankind as fallen on many things. We become too dependant on one thing until it runs out completely instead of thinking ahead and looking for a solution before it becomes a real problem.
Isy bring on the wind, solar, hydraulic, tides, geothermal, and whatever else they can think of, None of these systems will be anywhere near their peak performance if they are used for any real amount of time.