[dmitrygr]

I am aware of no energy storage system capable of absorbing 250000 Wh in under a second

[murderfs]

You just need to use a sufficiently large storage system. One of the proposals of Project Plowshare was to use underground detonation of thermonuclear weapons as a geothermal energy sources.

[lazide]

There is a huge difference between electrical energy trying to find its way to ground the easiest way possible (lightning), and a nuke.

For one, lighting can almost certainly find an easier path than into the battery.

For a nuke, the easiest path (once triggered) is to explode.