Yah the wind is free, but those huge supremely sophisticated turbines are pricey as all get out.
Actually it's more complex than that.
Energy is Fungible.
An Erg of energy in East Bazoo produced by fairy dust and wishes (assuming that you can produce energy that way) will sell for the same same price that a similar quantity of energy produced elsewhere by oil, coal, gas, nuke, or any other source.
Reason: If the Irish are paying $10.00 for a gallon of fuel that high price controls the price I can get for my energy that I made from fairy dust and wishes. The economy is global and energy is fungible.