The EMP threat isn't restricted to miles-long conductors. Seems like this solution would only address that narrow definition.
The complexity of DC-AC and AC-DC conversion is significant.
I'm suspicious that the article's author has shares in a company that is planning to push this solution. It might help but there will still be miles of above ground wiring at less than transmission-line levels that can pickup the EMP and wreck much of our semi-conductor containing stuff.
(speaking as an EE with some hands-on experience with EMP resistant equipment)