american electric power is one of the largest electric utilities in the united states, delivering electricity to more than 5 million customers in 11 states. aep ranks among the nation’s largest generators of electricity, owning nearly 38,000 megawatts of generating capacity in the u.s. aep also owns the nation’s largest electricity transmission system, a nearly 39,000-mile network that includes more 765-kilovolt extra-high voltage transmission lines than all other u.s. transmission systems combined. aep’s utility units operate as aep ohio, aep texas, appalachian power (in virginia and west virginia), aep appalachian power (in tennessee), indiana michigan power, kentucky power, public service company of oklahoma, and southwestern electric power company (in arkansas, louisiana and east texas). aep’s headquarters are in columbus, ohio.