Devin Lavign wrote:You could use 2 liter bottle vertical turbines like this
Building the "tree" structure could be done with scrap metal.
I'm not sure how to weatherproof the 2 liter bottle. I think maintaining the 2 liter bottles might out weigh it's purpose. Water is a whole other issue - how do you keep it out of the tunnel? I live in north Texas and our spring is brutal. We actually have a "hail" season. Durability seems to be the plague here.