I posted this because of Sam's piece on Energy came on the heals of me listening to the organizer of the Survivor Library [1] on NPR this weekend. If the world experienced another solar flare on level with the Carrington Event [2], we'd be screwed.
In the US, bills introduced to spend the ~$3B to shield the power grid have died in committee several times. I'm not a survivalist / bunker builder, but it does seem like a relatively cheap insurance policy to guard against catastrophe.