At this point in time, there exists no "green" energy that can provide enough reliable power for the nation at anywhere near a reasonable cost. Solar, wind power, etc., are all incapable of producing enough energy, and simply aren't reliable.
Furthermore, just about all of these "alternate fuels" projects are dead ends, since they consume way more energy that they produce by being burnt. There are some that may be promising, such as making ethanol from switchgrass, but that's a long ways away.
Also, most plastics are synthesized from petroleum, and trying to synthesize them from other sources is highly inefficient, and expensive. Good luck trying to manufacture the wide variety of polymers that this nation uses from something like soybean oil...
Fossil fuels are here to stay, and nothing will change that until some truly groundbreaking technology is developed.
I still get blank stares from people when I ask them how those Tokamak reactors (nuclear fusion) are doing... They don't seem to understand that they still can't reach the break-even point with those.