Much of the grid interconnects and redundancies we today take for granted were actually implemented during Dwight D. Eisenhower's administration. General Eisenhower was strengthening the country infrastructure to save us from the spectre of Communism. He built the Interstate Highway system, he implemented redundant power grid interconnects, and he surrounded this country with a ring of high power over-the-horizon radars and each major city got a ring of Nike missile bases around it for defense against Russian bombers and ICBMs. Six decades ago, we implemented the area interconnects with central control rooms. Sometime after that six of these area interconnects implemented another hierarchy of control in the Eastern Interconnect (Red). That was in the 1950s.
Then there were two interconnects, the Eastern and the Western, divided more or less along the Mississippi river. Some time after that the Eastern interconnect pushed past the river, Texas did it's own thing, and both the Eastern and Western interconnects pushed North into the Canadian provinces. Now we are in the 1960s.
This was the era of vacuum tubes, and did not include the ability to remotely sense power failures or remotely control switches and transformers. The utilities depended upon users to report power outages via telephone and then would dispatch linemen in trucks to troubleshoot and repair the distribution flaws. Eisenhower had had a hand in standardizing telephone hardware and putting 40 volt batteries at central telephone exchanges, so that communications were independent of the power grid even before cellphones.
The next move was made by the utilities themselves, who used the Federally-mandated power interconnects to implement an open power wholesale exchange, and began selling each other power futures and fixed price power contracts. In the process, the early and primitive controls of the power distribution were removed and central controls were implemented for each of the four zones above. The Eastern power interconnect took this up to another level, combining area interconnects into the super-area shown in red. Now we are in the 1970s.
Although they gained redundancies that compensated for the aging infrastructure, much of the equipment in the Eastern interconnect dates back to Eisenhower - or Edison/Westinghouse, if you ever visit Niagara Falls, you can see some of the early power plant stuff in the museum.
See what I am saying here, MD? The infrastructure that you believe we can "fall back on" simply does not exist any more. Power plants are only attached to the national grid. Cities and rural power administrations are only attached to the national grid. We CANNOT "fall back" to anything because it is NO LONGER THERE. If we wanted to re-implement the Edison/Westinghouse model of a central power plant surrounded by a web of power consumers, we would have to start by tearing down the existing grid, then building a new one with an entirely different distribution topology - and many more control rooms.
It just is not going to happen. You can live within sight of a functioning power plant, and freeze to death because you have no electrical power, because somebody stole a section of copper wire over the horizon, or an overloaded transformer burned and there is no available replacement.
The modern "emergency power" that is used when a large area transformer is being replaced or upgraded is to strategically spot large diesel generators in the 200-500 Kilowatt sizes around the area going dark. Then on a scheduled time in the wee AM hours, the cutover is made and the generators take over the blocks effected. Then some days or weeks later, the cutover to the new transformer is made. A key thing to understand is that all of the generator trailers combined, which are typically parked at a power substation, along with other trailers having transformers, typically have 5% or less of the capacity of that local power substation. They definitely do not constitute any emergency power supply that would ever power a normal residence in an emergency. Emergency services and government offices, yes. Your house, no.
You see what I am saying here? The control topology for the power grid is what it is, and it does not lend itself to easy or cheap reconfiguration. The redundancies that Eisenhower insisted upon, have been steadily whittled away by the rising demand for power and the reduced investment levels of power utilities. The utilities themselves lack a coherent goal, beyond profit. These utilities are a mix of traditional power companies (owning both power plants and distribution networks), other corporations (such as CALPINE) serving only the wholesale power market, and other utilities (some public, some private) which have no power plants, they only buy wholesale power and sell to retail consumers.
The model is that power plants feed the national grid, and the grid powers everything. That is all there is. If the grid goes offline, there won't be any segments alive - and I seriously doubt that we would ever make the investment to reconfigure to the Edison/Westinghouse model that you seem to have in your head.
What I think will happen to the grid is that the consumers will transform into micropower consumers. We will live in tiny super-insulated homes, use minute amounts of power, and use passive and active solar heat, plus a combination of every present power source we have and a few we cannot yet imagine. Current cities are obsolete, but new cities (arcologies is one name for them) will come about. Underground (or at least Earth-sheltered) living will become common. Green roofs will be the norm. LED lighting will be the norm. Organic LED HDTVs will be the norm. You will carry around a computer/phone capable of handshaking with every HDTV/PC Monitor nearby, and the worldwide network. The network capability in that telephone will include satellite connectivity, and national borders may disappear, I believe that we will organize ourselves into "virtual nations" all of which intermingle geographically. You will own a bike, and eat about 75% of what Americans eat today - which will still be an unhealthy amount of food.
There may be a power grid - with less than a quarter of today's grid capacity - but powered by fewer and fewer fossil fuel plants over time.
New world, but not so strange after all.
