There are NO errors in the math; but, the avoidance of the required landmass for an all-propeller-driven electric supply system is being totally ignored by all the wind-proponents.
Consistent with the claims of 150 miles-per-gallon carbureators (if only the taxpayers would supply the R&D funds to develop it), wind proponents can't compete without subsidies, no matter how they claim they have the answers to energy-independence.
Your 300 mile figure is totally wrong, as I showed.