Breath on the Wind
Are you are asking about a presently existing land mass or a political construct on that area of land. It is entirely possible that neither could exist in their present form. All it would take is for the super volcano in Yellowstone national park to erupt sometime in the next 1000 years. Scientists say it could erupt at any time and some of the land has risen over 10" in recent memory.
If it would erupt it might be an extreme form of "population control." The resulting global blackout may also make solar power lose some of its luster. Increased acid rain may also be a result of such catastrophe but wars over remaining resources are only a 50 50 chance.
odd
The USA likely will not exist as a political entity. It will probably be geographically divided, perhaps East-West along the Mississippi, with union or encroachment by Mexico. Canada might be a thing of the future past as well since they have not the population or army to defend themselves from civil and political problems from it's southern neighbor. (Quebec might become it's own nation).
Kano
Well it wont be solar powered, solar power can only amount to 15% of the power supplied to the grid, anymore than that destabilizes the grid.
Oscar
Sorry but all the crystal balls are on the fritz. Anyone's guess is as good as anyone else's. And it isn't an either or question. More like an unlimited multiple choice.
?
Watch the pilot episode of Futurama, and then you'll know.