re: DIY energy
im just researching at this stage. But i wondered what the chances were of using the added wind energy from driving to generate power back. I did a few calcs and figured if we could find robust enough kit, with say 1/2m diameter rotors strapped to the front of a vehicle (lower front im thinking here!), i worked out you could generate a good few hundred watts in an hour or two. Apparently – depending on design, the generation increases with the cube of the diameter (which is a pain!!) so like only big turbines are gonna do a good job… but an interesting thought anyways.