Please answer a question about the following article about Renewable energy commercialization:

As of 2014, the wind industry in the USA is able to produce more power at lower cost by using taller wind turbines with longer blades, capturing the faster winds at higher elevations. This has opened up new opportunities and in Indiana, Michigan, and Ohio, the price of power from wind turbines built 300 feet to 400 feet above the ground can now compete with conventional fossil fuels like coal. Prices have fallen to about 4 cents per kilowatt-hour in some cases and utilities have been increasing the amount of wind energy in their portfolio, saying it is their cheapest option.

How is the wind industry in the USA able to produce more power at lower cost?
by using taller wind turbines with longer blades