To decarbonize USA you could coat 25% of Nevada with solar PV, and this would require 140 billion xmc4200, as described below. Page 2 talks about solar on land, mass produces, with Xmc4200 every 2 square meters of land.
http://www.ma2.life/doc/research/ma2/BiPV_and_LiPV_Development_Initiative_Ma2.pdf
25% of Nevada is 280 billion square meters, so you would need 140 billion of the xmc4200.
One way to stop burning all CO2 in USA is to cover 25% of Nevada with solar PV (74K km2 land, 37K km2 PV) and then use the electricity to make H2 gas. This gas could then be transported throughout America to power vehicles, heat homes, and generate more electricity. The electricity generated would be ~3 times more than what America currently generates since this system would be replacing energy we currently obtain from burning natural gas, coal, oil, and gasoline (10.4K vs 3.8K TWhr/yr). The solar parts and labor might cost ~$3.7T ($150B/yr over 25yrs, $0.50/Watt, 7.4TW capacity). However, this does not include the following costs: electrolysis to make H2 (currently costly), transportation of H2, maintenance of solar, and land. This solves the following problems: US decarbonization, energy storage (H2 is storage), limited rare earth metals for many EV batteries (cars run on H2), significant electrical grid expansion (no longer needed), and disruption to communities from locally based wind/solar/nuclear. The disadvantage is cost -- consumers might see a doubling of energy prices, which is politically unacceptable at this time.
For calculations that show how this works with xmc4200, see the below spreadsheet. Click on topics in the 1st 30 rows to get to discussions on listed topic.
To discuss further, email me at gWeinreb@Manhattan2.org