Thanks for that Fenton. However, it should be noted that our grid is not fully shielded. Yes we know it should be, but it's not, at least not yet. We have had problems with X type solar events when they are aimed at Earth and will continue to have these problem until we address the grid as a whole. A locally deployed EMP device would be much more powerful than the X type flare event that can give us problems now and could very well overwhelm a weakly shielded (and perhaps vital) portion of our electrical infrastructure.
Not near the disaster you see in the apocalypse movies, but still bad. However, many of the nations where we had boots on the ground are not even close to shielded, making EMP weapons an effective thing to develop.