The size and number of turbines is irrelevant: bigger turbines have to be spaced further apart, so no gain in average power output per sq km of wind farm.  Onshore wind farms have average output of about 2 MW/sq km, so to replace a 1.5 GW nuclear plant (occupying about 1 sq km) with wind farms you need about 750 sq km of land without trees or buildings.  This doesn't allow for the extra generating capacity and pumped storage in mountain reservoirs that you'd require to maintain baseload on calm days.