A wind turbine is an electricity generator that harnesses the power of the wind in order to generate electricity. They can be connected to multiple green energy sources, but their power must first flow through a Transformer before it can be used within your prison.
This item must be unlocked by completing the Green Energy Goal 1 grant.
Each wind turbine generates 75 unit of power regardless of time in a day, assuming weather is not enabled.
This works out to exactly 75$/day of profit from energy export via Power Export Meter (75 units * 24h * (500$/12000 units*h)), or 150$ if the Green Energy Goal 9 grant has been completed. That means a wind turbine will pay for itself after 2000/75 = 26 days (13 days if the grant was completed).