Hey,
you simply edit the "recipes.lua" in "prototypes/WindTurbine".
there you will find the following code:
ingredients =
{
{"iron-plate", 8},
{"iron-gear-wheel", 4},
{"copper-cable", 8},
{"iron-stick", 5}
},
edit it like this:
ingredients =
{
{"electric-engine-unit", 2},
{"iron-gear-wheel", 4},
{"copper-cable", 8},
{"iron-stick", 5}
},
and that's it! You done.