Re:Aren't these windmills.... (Score 2, Insightful)

Aluminum doesn't get used just once. Running a windmill doesn't cause the Aluminum to degrade back to Bauxite. When you build something out of Aluminum, a large percentage of your raw material is recycled. When the windmill wears out and is torn down, the metal will be worth a lot and will be reclaimed. Recycling Aluminum is highly profitable, and large chunks of aluminum always efficiently salvaged.