I think the Windmill's info box about it's power production is out of date
QuoteInput
Output 0-4 EU/t (varying)
Storage -
However lower on the page it says
Quote- If a wind mill produces more than 5 EU/t, it has a chance of breaking. If a wind mill's effective height is no more than 80, it cannot break.
If the output is only 0-4 how can it ever break?