We do need more transmission (another thing the White House is working on: https://www.whitehouse.gov/briefing-room/statements-releases...), but power import/export over long distances is already commonplace.
Edit: And if you really want to look to the future, you could read the proposal for a North American Supergrid: http://northamericansupergrid.org/
Anyway, the more important point is that we already have large regional grids across the country, and while it's obviously nice to have generation and consumption close to each other, it's not a requirement.
The numbers I quoted were just for NYC, and they weren’t adjusted for the winter sunlight problem. To power the entire metro area would likely require 40,000 acres. To cover the entire region likely 60,000 acres. This land does not exist.
It isn't that big an area in the scheme of things. If you try to find a single place for it it probably won't work of course, but it is a tiny little fraction of the developed land already devoted to New York.
New York State is 35 million acres. You don't think 0.2% of that, including rooftops of existing buildings, might be useable for solar/wind/battery storage? And again, NY already uses tons of out-of-state energy.
2) Rooftop solar
3) National grid improvements that make transferring power from renewable sources further away more efficient
4) There are massively huge areas of empty land within 100 miles of NYC. This map shows roughly the 100 miles west of NYC. Take note of all of that unused space, which is most of it: https://www.google.com/maps/@40.7560624,-75.4552232,170414m/...
Where are we going to build a solar farm to cover NYC, DC, and Philadelphia? There is 9 hours of daylight in the dead of winter, and it’s not exactly known for being sunny in January.
NYC alone needs 11,000 megawatt hours per day. My back of the envelope fermi estimate is a solar farm covering approximately 16,000 acres. Forget the metro area, that’s just for NYC. Probably double if you include the entire metro area.
You aren’t going to find that kind of land within 300 miles of NYC.