There are 3 power grids in the US - East, West, and ERCOT (most of Texas). Taking out substations will work on a small scale, but the real target would be the grids themselves. They are being attacked every day, all the time by individual as well as state-sponsored hackers. Eventually someone will likely succeed on one of the grids - potentially taking out up to 1/3 of the country depending on which grid is hit.
That said, substations are still a target of opportunity. They would for example be an easy way to disrupt communications in a city/town before an armed attack.
As for the water treatment plants - it wouldn't take a bunch of them being attacked to do damage. If people start hearing water plants are being poisoned they will stop using city water, buy up every bottle of water they can find, and a lot of people will end up dehydrated due to paranoia of their water being poisoned (whether true or not).
If attackers went these routes I'd expect them to do it in the middle of winter when a lot of the country has frozen lakes, heating is absolutely required, and big events like the SuperBowl or NCAA Football playoffs are happening.
Part of my job when I was working as an NRC Cyber Inspector was to postulate attack scenarios on our nuclear plants so they could protect against those scenarios. That was pretty hard to do with the numerous systems each plant had, but it was actually a lot of fun. Especially when the plant leadership agreed with our findings and could fix the issues they didn't know they had. I miss that.
Edit - just thought of another issue if for example the West grid went down, or LA substations were attacked. Think how many Teslas could end up unable to make it home when all the charging stations are down. People either stranded at home of on the highway trying to make it somewhere safe. Yet another reason to avoid electric cars.
Good research on the numbers!
There are 3 power grids in the US - East, West, and ERCOT (most of Texas). Taking out substations will work on a small scale, but the real target would be the grids themselves. They are being attacked every day, all the time by individual as well as state-sponsored hackers. Eventually someone will likely succeed on one of the grids - potentially taking out up to 1/3 of the country depending on which grid is hit.
That said, substations are still a target of opportunity. They would for example be an easy way to disrupt communications in a city/town before an armed attack.
As for the water treatment plants - it wouldn't take a bunch of them being attacked to do damage. If people start hearing water plants are being poisoned they will stop using city water, buy up every bottle of water they can find, and a lot of people will end up dehydrated due to paranoia of their water being poisoned (whether true or not).
If attackers went these routes I'd expect them to do it in the middle of winter when a lot of the country has frozen lakes, heating is absolutely required, and big events like the SuperBowl or NCAA Football playoffs are happening.
Part of my job when I was working as an NRC Cyber Inspector was to postulate attack scenarios on our nuclear plants so they could protect against those scenarios. That was pretty hard to do with the numerous systems each plant had, but it was actually a lot of fun. Especially when the plant leadership agreed with our findings and could fix the issues they didn't know they had. I miss that.
Edit - just thought of another issue if for example the West grid went down, or LA substations were attacked. Think how many Teslas could end up unable to make it home when all the charging stations are down. People either stranded at home of on the highway trying to make it somewhere safe. Yet another reason to avoid electric cars.