Technically speaking, it's supposed to be 1.21 GIGAWATT.... or 1.21x10^9 or 1,210,000,000 watts (that's a Billion BTW)....
At 12V DC (such as in the ST) that would be approximately 100,833,333 Amps... Issac Newton be damned!
At 120V AC (such as in your home) that would be approximately 11,724,806.2 Amps (witha a power factor assumption of .86)....
This would require wire guage of huge proportions as the largest guage that I have data on only goes to 1,560 Amps, or about .0133% of that....
1.21 Gigawatts is a power (especially DC such as lightning) that would be nearly unmanageable....
Sorry to ruin a good movie with facts.... and a thread with a correction....