We have a railroad wheel manufacturing plant close by, Amsted Rail Griffin Wheel. Toured that plant with a group of teachers, back in the 80's. The electrodes were not quite as large as the ones Crusty described, but they had to contact the power company before energizing them so the power plant was prepared for the sudden HUGE load increase. I cannot recall the number MegaWatts, but it was very impressive.

The sound when they were energized was intense.