Put short, this is a serious matter, but not in the way it is presented here. It would be a herculean effort to take out 1 let alone the suggested 9. Especially in a coordinated fashion. EVEN IF it was achieved.. This would only cause localized issues. Not takedown. “THE GRID”
This is a much larger discussion but a few things to consider:
1. There is no singular "grid". It just does not work that way. There are thousands of generation and transmission companies throughout the US. They all maintain there own “grids”. There is connectivity to provide ways to connect grids to sell/buy/shed power. But these connections are controlled and can be simply… disconnected. 2. Without going on a major diatribe on the many different attack vectors and inherent vulnerabilities in the energy sector…. Suffice to say.. The easiest and most sure way to take out a transformer is physical. They would need to be destroyed or disabled. Digital/remote interference would require an immense effort and campaign… we are not talking breaching the 9 locations… we’re talking hacking millions upon millions of connected devices and coordinating load to take out a transformer or the grid as whole…. The coordination and effort necessary for either are staggering. 3. There are in fact spares and inventory… just not in the hands of the feds.