One immediately reusable stock is found in discarded tires. Shred and burn at low temp (high enough to create steam for a turbine). Unfortunately the resulting smoke is toxic. The rubber itself melts down into an oily sludge that can be processed.

Bio-diesel is a fact. Cost about the same as regular diesel production(price at the pump minus mark-up and taxes). Since every BK, Mc'Ds, Wendys or greasy spoon produces five to ten gallons a day there is at least a small amount that could be made daily.

Compost heaps create methane gas it just needs to be tapped.

The thing I don't understand is why there aren't combined efforts. Line the natural gas electric plants with solarpanels. Use lightweight tubine fans in the exhaust stacks (won't get bird flocks in there). Instead of allowing the steam to escape the top of the stacks, let it condensate and run down to accumulating tanks which would flow to a hydropower turbine. Put the generating plants near the coal mines instead of shipping it all across the country (energy consumption that's unnecessary) (would work with superconductor wires).

I could go on...