The pilot's selection of an inadequate takeoff site that did not allow sufficient horizontal clearance from obstacles in the takeoff path, and, his failure to ensure that all burners were connected to fuel sources, which reduced the available climb capability of the balloon. Also causal was the pilot's failure to activate the emergency vent panel and land prior to contact with the power lines, and, his use of an unapproved aluminum fuel tank, which ruptured during the power line contact and ignited a fire. A factor in the accident was the pilot's failure before takeoff to use pibals to quantify the wind speed.