The only reason they let water out of the Hoover Dam is for the little fishes to swim downstream, and for downstream water rights. The electricity, while a wonderful resource, is a free bonus when available. Originally Posted by DSK"Hoover Dam generates, on average, about 4 billion kilowatt-hours of hydroelectric power each year for use in Nevada, Arizona, and California - enough to serve 1.3 million people. From 1939 to 1949, Hoover Powerplant was the world's largest hydroelectric installation; today, it is still one of the country's largest."
https://www.usbr.gov/lc/hooverdam/faqs/powerfaq.html
Unless the law has changed only government owned electrical systems can purchase electricity from Hoover Dam, since it is also "Government owned." It's been awhile, but I believe LA was a municipal owned system and could purchase from Hoover.
As I mentioned a problem with Hoover is Lake Mead is "drying up"!
The white rock ring shows how much it has fallen.