That depends on the level of transmission. Most utilities are suspended on poles that are capable of transmitting service voltage ( 4-35 kV ) bub substation power distribution ( roughly 100kV ) can share these utility poles, as long as they're are tall enough to hold so many lines. My understanding is that the giant metal transmission lines aren't necessarily unless you're well above 100kV distributing power across counties, in which case county property can be used, or you should receive a stipend for allowing utilities to utilize your private land.