According to the  USGS U.S. Wind Turbine Database there are 58,449 turbines with a total rated capacity of 91,115 MW, providing 6.5 percent of US. Electrical energy.

Estimating the average percentage of electricity per number of turbines to double that to achieve 13% electricity from wind would require an estimated 116,000 Wind Turbines, To provide 50%  roughly 464,000 Wind Turbines would need to cover the country. 
These estimates  do not take into account that wind turbines, are getting larger and have increasing MW production per turbine, so the number of actual turbines would be less, but since larger turbines need more space and the footprint the total area impacted would be relatively the same, and it still provides an idea of the amount of land use and industrialization required.

Across the United States, workers are covering fields with solar panels, and big rigs are hauling massive turbine blades to wind-scoured ridgelines. This is what it looks like when renewable energy expands exponentially.

So where do we stand after accounting for all that growth? Well, some 17.6 percent of the country’s power now comes from renewables.

It’s mainly electricity generated by hydroelectric dams (6.9 percent). Even after all that massive growth, wind only provides 6.5 percent and solar 2.3 percent of our electricity. Renewables like biomass and geothermal generate the last 1.9 percent.
So we still have a long way to go. But consider this: If renewables sustain this rate of growth, the United States would be roughly on track to get all of its electricity from carbon-free sources by 2050. The question, of course, is whether that exponential growth can continue. The size of the job is staggering. Those solar-panel covered fields will have to be five times as big in 10 years, and 25 times as big in 20, and 125 times as large by 2050.
~ Via Solar and wind power has quintupled in a decade | Nathanael Johnson, Mar 19, 2019