It is much more expensive than you realize, especially if you are talking about high power transmission lines and not just burying lines to houses. My neighborhood has buried lines but the large 75-500KV lines are not only very expensive to bury, there is a heat dissapation problem, and wherever they enter or exit the ground, there has to be a large, ugly relay station. Japan is the only place that has buried a 500 KV line and that was for a very short stretch. I was involved in reviewing the Antelope/Pardee EIS for coming across Bouquet canyon. One of the alternatives the Forest Service made them look at was burying a section of the line for visual impact reduction. I left before they had a final decision (if one has been made). That is the only reason I know about all of the ins and outs of burying lines. Plus, in an earthquake, it will be much harder to fix breakage. I think it would be great if they buried all the "consumer" lines, but the high power lines is much more complicated.
