long the way disrupting “the electric power grid,
Idiots. Cyber Defence center of W*nksellence is more like it.
If a grid is under a successful nation state attack it is a DEAD grid. The key difference between a nation state and a K1DD10T in mom's basement is that the nation state can run the relevant computations for the failure modes and ensure that failure modes are destructive. The attack itself is only minutes by the way so by the time you know your grid is under attack the entire country is without leccy.
It is not that difficult - it is just the standard grid optimisation and balancing software run for a solution matching "slightly" different criteria from the normal ones. The end result is potential physical damage to key substations and more importantly generation capacity going into emergency shut down due to being cut-off from the grid by overload switches (with once again potential damage).
It is a bit harder today - the computation was in the realm of trivial if you had the right consumption data + topology in the days of resistive lights. Still doable if you are a nation state and you are really attacking at a level where you can disrupt it.
So if Russia (or any other nation state with similar resources) is whacking "W*nkillia"'s grid for real that grid is not getting up any time soon.
By the way, that does not mean that we should provide them with tools to do programmable load pulsing - namely hackable smart meters with built in switches.