What Would it Take to Reduce US Greenhouse Gas Emissions 80% by 2050?

I investigate the cost and feasibility of reducing US GHG emissions by 80% from 2005 levels by 2050. The US has stated in its Paris COP 21 submission that this is its aspiration. I suggest that this goal can be reached at a cost in the range of $37 to $135 bn/year. I assume that the goal is to be reached by extensive use of solar PV and wind energy (66% of generating capacity), in which case the cost of energy storage plays a key role in the overall cost. I conclude tentatively that more limited use of renewables (less than 50%) together with increased use of nuclear power might be less costly.