The fusion project that’s currently going on should take care of the long-term energy needs (50 years), potentially getting us to the Type I civ level. Thermal depolymerization is already used to generate oil from garbage, however, it is not presently cost-effective (you end up with $4.5 per gallon gasoline and thats with subsidies, and without taxes). It does have a lot of potential though. There are 2 pieces of the puzzle that would completely remove any US dependence on foreign energy: Yucca Mountain and EVs. Both are easily within reach, given even minimal politcal will. By the way, Israel is planning to convert 10% of all its cars into EV within 5 years.