60 projectors at 26,000 watts each were synchronized to create a single seamless image with a resolution of 4592 x 2048 pixels on a 420,000 square foot surface. Wow.
"Presently, Hoover Dam can produce over 2,000 megawatts of capacity and a yearly average generation of 4.5 billion kilowatt hours"
2,000,000,000W capacity, but if the annual production is 4,500,000,000,000W then it's far short of the 17,520,000,000,000W max if it produced at peak for 365 days.
So really, the Hoover Dam averages 513,698,630W (arbitrary precision).
1,560,000W / 513,698,630W = 0.3% of the Hoover Dam typical production to power the projectors.