There are about 1200 coal plants in the US with a nameplate generating capacity 390GW+-.
http://www.eia.doe.gov/cneaf/electricity/epav2/html_tables/epav2t23p1.html and
http://www.eia.doe.gov/cneaf/electricity/epav2/html_tables/epav2t45p1.html Coal plants average about a 79% capacity factor. The production by coal of 390GWx79% equals 308GW that we need to deliver to 'technically' replace coal - the worst offender for climate change and pollution bar none. That would be a total production of 2,698,080 TWh/year.
Lets leave natural gas and nuclear as is for the moment.
Current generation turbines are 1/5-2 MW onshore and 2-3.6MW offshore The onshore probably will be slow to achieve further increase because they are limited by the ability to transport the rotors overland. But the next generation of offshore wind farms are between 5-7MW per unit nameplate and can be expected to operate at 40+% capacity factor. Figure the build-out in the corridor Picken's speaks of to deliver about 30% capacity factor.
In near shore <50meter deep waters, and allowing exclusion areas for fishing grounds, beach replenishment borrow areas, avian flyways, shipping channels and visual buffering for the tourist areas, there is just off the coast of tiny Delaware enough room to place:
19GW with GE 3.6MW turbines
26GW with 5MW turbines (vestas?)
37GW with the RePower 7MW turbine
Using a capacity factor of 40% (it is actually estimated to be 44%) that yields:
7.6GW for the 19GW with GE 3.6MW turbines
10.4GW for the 26GW with 5MW turbines (vestas?)
14.6GW for the 37GW with the RePower 7MW turbine
So just off the 25 mile coast of little old bitty Delaware, we can get an output equal to between 7 and 14 nuclear reactors - with no waste storage problems or risks of proliferation.
As for finding the space for solar - why don't we start with roofs?
As of 2000 in the US residential sector alone there were about 83 million buildings with a combined square footage of roughly 170 billion square feet or 18 billion meters^2 or 1.8 billion km^2.
Using an average capacity factor of 14% against the average 1800Kwh/1m^2/year of sunlight gives us 252kWh/year/m^2.
18 billion meters X 252kWh =
4,536,000 Twh/year of actual production to replace the 2,698,080 TWh/year coal is presently generating.
And we can let the homeowners be responsible for cleaning them.
Finally, we add in storage through the batteries of V2G EV and similar battery packs for the home so that those majority of those 83 million homes are mostly self sufficient and there is also plenty of storage to maximize wind and large solar thermal arrays.
What is the rush to nuclear with its KNOWN pitfalls? Why not a goal like described above first and then see what the need for nuclear ends up being? Of the two choices, we are much better off in the long run (in money, energy security, national security, energy returned on energy invested and environmental footprint) to do this without nuclear if we can.
So again, what is your rush to promote nuclear?
Data on buildings drawn from
http://www.btscoredatabook.net/?id=search_table_title&q=Single-Family+Homes&t=5Tables 5 and 21