At the time of the 2011 blackout , San Diego Gas & amp ; Electric ( SDG & amp ; E , a subsidiary of Sempra Energy ) was connected to Arizona by the Southwest Power Link , which is a single 500 kV power line ( the next year , SDG & amp ; E completed a second line , the 500 kV Sunrise Power Link which was under construction during the event but still , it only parallels the Southwest Power Link and connects back to it at Imperial Valley ; the remaining section into Arizona is still a single line ) .