A 100 foot wire in a horizontal configuation will pick up something like 1 microwatt. With most towers standing that high I'm sure there would be additional voltage. Not much mind, but a small amount. It's not that it's a huge amount but every little bit! But what about the towers being covered with solar cells? It's not like they would take up more space than the tower's skin already does. I'm not sure how much it might add but with 100 towers...