The worst case scenario includes 200 or so nuke plants melting down when they can no longer maintain cooling. That alone should justify spending a little money to harden the grid. Everyone seem more concerned with an unlikely EMP attack which might or might not "break" the grid. I am more concerned about the certain to occur solar flare with will "break" the grid. Hopefully the flare will break someone elses grid and then maybe we will take the threat seriously.
At the flare's peak, the LAT detected gamma rays with two billion times the energy of visible light, or about four billion electron volts (GeV), easily setting a record for the highest-energy light ever detected during or immediately after a solar flare. The flux of high-energy gamma rays, defined as those with energies beyond 100 million electron volts (MeV), was 1,000 times greater than the sun's steady output.
The March flare also is notable for the persistence of its gamma-ray emission. Fermi's LAT detected high-energy gamma rays for about 20 hours, two and a half times longer than any event on record.
http://www.nasa.gov/mission_pages/GLAST/news/highest-energy.html