The grid very well may go down but unlikely to be an EMP. It will more likely come from cyber hacking. I read that there are 10,000 cyber attacks on our grid everyday. Sooner or later somebody is going to hit that magic combination.
There are attempts, sure. But with CIP in full swing across utilities it is impossible to get to SCADA networks unless your are strictly granted access. Only a saboteur that already works for a utility could cause havoc. The SCADA network is highly isolated. It would just be easier to have a four man team shoot up some of the heavy transformers (A test run was done in L.A. in 2015. The attackers had lots of time to shoot at the transformer. They also knew exactly how to disable alarms/alerts buy cutting the right fiber runs). That is where we are exposed.