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the same power as is continually produced by the generators at Hoover Dam.

This is still scrambled. The sentence seems to be saying that the bomb yields as much ENERGY as Hoover Dam does in 24 hours, and that this figure would be 2 billion watt-seconds (joules). But since I don't know what the power capacity of Hoover Dam is, I can't say if this is actually what is meant.

Remember: Energy is what weapons blow stuff up with -- measured in joules, ergs, watt-seconds, and such things. Power is a measure of how fast something produces the energy.

You could produce 2 billion watt-seconds of energy from a hamster cage, but it would sure take a lot of hamsters!

This is still scrambled. The sentence seems to be saying that the bomb yields as much ENERGY as Hoover Dam does in 24 hours, and that this figure would be 2 billion watt-seconds (joules). But since I don't know what the power capacity of Hoover Dam is, I can't say if this is actually what is meant.

Here's what I think happened.

The writer apparently didn't know the distinction between power and energy. (Of course, were talking physics here, and I think she was too used to colloquial English!) Her source said to her that the weapon produces a peak power output equal to that of Hoover dam, which BTW is plausibly 2GVA (reactive gigawatts), and she mistakenly added the phrase "in 24 hours," seeming to bring energy into the description. Her source, if technically literate, could not possibly have meant the energy produced by Hoover in 24 hours.

Therefore, I focussed on the "2 billion watts" and discarded the "24 hours" as a red herring.

If the above scenario is correct, then the rewrite is too.

Remember: Energy is what weapons blow stuff up with -- measured in joules, ergs, watt-seconds, and such things. Power is a measure of how fast something produces the energy.

Quite true. However, these weapons, and lasers for that matter, depend on delivering a small or moderate amount of energy in a small space or area and in an extremely brief period of time. Come to think of it, the same is true of a bullet, but with a less extreme brevity of energy delivery.

You could produce 2 billion watt-seconds of energy from a hamster cage, but it would sure take a lot of hamsters!

Or one hamster running continuously for 633.76 years. Although the energy output of Hoover dam per day is actually 86400 * 2GW-seconds, or 172.8 terawatt-seconds (joules), so to match Hoover's daily energy output our poor hamster would actually have to run 54.76 million years.

BTW, I guess I'm an expert; I once kibbitzed on the design of a hamster-powered electrical generator and provided the firmware for its odometer. <>==<)B^)

This is a typical case of a reporter over-simplifying a technical term. These weapons typically have output energies in the tens of megajoules. Let's say that a particular device has an output of ~50 MJ. If that energy is dumped in ~25 milliseconds, then the power (joules per second) is ~2 GW. Thus a more impressive, and clearer, way of stating the device's output would have been to say that "It produces in 24 thousandths of a second what the Hoover Dam produces in 24 hours." (But that would require the Liberal Arts major who wrote the piece to have more than a passing understanding of the science involved!)