I'd like to believe there are these enormous laser set ups and rather than coming from a power station, there's just a guy putting a duracell AA battery into a slot to fire it up.
Yeah, that would be comical. Deserves to be in an Austen Powers kind of movie.
In reality, they're probably using some kind of awesome capacitor that can dump a PW of energy in a minute amount of time. Not a lot (relatively) in terms of raw joules, but it's very hard to deliver that energy fast enough without burning something.
1 Peta-watt: 1,000,000,000,000,000 watts.
But, they only need it for a pico-second!
Works out to less than a watt-hour, if my maths is correct.
1 AA battery can slowly give you 3 watt-hours, but it can't give 1,000,000,000 amps at 1,000,000 volts for ANY length of time.