[leymed]

My point is hacking into home PV inverters doesn’t affect grid stability, you can’t penetrate into grid in that way. At worst we’re talking about losing power for a short time at those homes. When the demand is planned for a region you specifically exclude PV for load flow studies.

[BlueTemplar]

Why for a short time ? And this sounds reckless if most of your load flow is PV ?

[leymed]

Those are actually good questions.

Engineering grid and PV installations acknowledge that the generation may be lost, so you are having contingency plan by means of transferring or picking the load. You're going to lose power for short time if you didn't do this properly.

Actually due to the nature of PV generation, no sun no generation, it is reckless to just rely on PV. If sun is shining that is great, there'll be generation. However, daily peak consumption coincides with less day light. So during planning the target is the extreme cases (statistically estimating demand), in other words you do load flow studies for extreme cases. This helps to see your capacity limits.

In parallel to this you should consider electric grid as a layered system. PV generation at house is the lowest level, so less impact. So when it is lost, or neighborhood or town lose PV generation it will impact nearby station, which is couple MW if not kW. So when you lose PV generation and you planned your system for extreme case, higher level of generation or substation will take control of it.

Losing GW solar does not mean you're losing that amount power in small geographical region. You have to divide that into so many small parts. Also, PV generation at GW level is too high for small region.

Hope this explanation helps. It is because how power flows, governed by rules of physics. Bottom line, if hacker wants to affect a grid they should target higher level of grid, PV panels on the rooftops will not help their cause, they are end of line.