It was done in the late 1920s/early 1930s with the aircraft carrier Lexington, which powered Tacoma, WA, during a drought which affected hydroelectric generatio

It was done in the late 1920s/early 1930s with the aircraft carrier Lexington, which powered Tacoma, WA, during a drought which affected hydroelectric generation. The thing is that Lexington was very unusual for an American ship in having turboelectric propulsion, where the steam turbines were connected to generators which produced power for the electric motors which turned the propellers. Most US Navy steamships- including all of the modern nuclear-powered ones- use a mechanical transmission to connect their steam turbines to the propellers directly. They do run some generators from the turbines for so-called 'hotel load'- operating the ship's electrical systems- but the output of these is relatively limited. Some other countries' nuclear submarines do have turboelectric propulsion- I think the Russians have used submarines to power isolated Siberian cities in emergencies- and the USN's new Columbia-class SSBNs will. But the amount of electricity you could get from any current US Navy ship would be limited.