Well, one watt of power is one joule of energy per second, so 1.21 gigawatts would be 1,210,000,000 joules of energy...would you feel safe with that sitting right next to you? I sure wouldn't!
(Interesting side note: I always assumed that in Back to the Future, actor Christopher Lloyd was mispronouncing "gigawatts" as "jiggawatts". It turns out that the scriptwriters had wanted to invent a totally nonsense unit of measurement; the script, allegedly, says "jigowatts," and it's just coincidence that it sounds like a mispronunciation of "gigawatts.")
