For two weeks last spring, hackers wormed their way inside a computer system that plays a key role in moving electrical power where it is needed around the state. The computers belong to the California Independent Service Operator, an agency that oversees much of the state's electricity transmission grid--including the massive complex of power plants and transmission lines. Cal-ISO patched the flaw that allowed hackers to roam through portions of its network before power supplies were affected. But the episode sent shock waves throughout the energy industry.
The crux of the issue is that the system is vulnerable - recall 2003 when a single tree branch killed power across several states for a week? That is not indicative of a healthy and robust grid system. And if the system is that vulnerable to an accident what would happen if somebody with malice aforethought (and a degree in EE) decided to spice things up a bit?
Unless the utility companies make explicit plans to correct things a macro-catastrophe is inevitable. Personally I think that a solar storm is more likely than a terrorist attack but it *WILL* happen and tens of millions of people will lose their grid indefinitely (probably several years to restore full access). (I further predict that the system will be rebuilt to the old specs because it will be cheaper and easier to do it that way, flushing an opportunity to build a hardened grid).
This is your transformer. (note that this company claims to be able to repair your transformer in less than 30 weeks - that means that)
This is your transformer after a solar storm. Yes, the sun did this.
This is the transformer with which most geeks are more familiar.