I wonder how these grid interconnections would be at least partly secured against attack, by a nation-state and/or by terrorists — it seems like increased vulnerability should be a concern.
> What's particularly different about these compared to the thousands of miles of existing power and pipeline infrastructure?
Don't know; it just seems as though the greater the interdependency between geographically-separated modules in a system, the greater the chances that damage to one module can take down remote modules and perhaps even the entire system.
Example: Oceangoing vessels are generally designed with watertight compartments, so that damage and flooding in one compartment won't necessarily doom the whole ship — as happened to the Titanic, which sank in part because its transverse internal bulkheads didn't extend high enough to prevent seawater spillover from the iceberg-damaged sections to undamaged sections as the ship started to sink by the bow.[0]
Example: The Great Texas Blackout in February 2021 resulted in part from electrical power being knocked offline for some natural-gas compression facilities, which resulted in still-other electrical-generation facilities, powered by natural gas, failing for lack of fuel. [1]
Texas also had the problem that the grid was isolated. Energy consumption spiked in neighboring states as well, with some problems, but nothing as severe as Texas.
I suppose there can be a difference between interconnection and interdependence. Unnecessary interdependence creates the possibility of failure cascades, but interconnections can provide resilience without necessarily increasing the likelihood of problems.
I think the national security aspect can be mitigated by keeping many of the existing fossil fuel plants operational as an emergency backup, but not running them in normal circumstances.
