@Stephen challenging my statement that electricity does not gain value by being shared over long distances:
"In that case why are the electricity networks connected now? There must be some value in it or else no-one would do it. If what you said in this statement was even remotely true then the electricity grid would consist of isolated networks with no interconnectors.
Unfortunately reality contradicts this statement. Do you have an explanation for this?"
Sure. Please read carefully what I wrote. There is no increase in value for the product - electricity - when it is shared. There is often a reduction in COST for the producer / distributor.
Transporting electricity over a wire is generally cheaper than transporting fuel over other transportation networks. It is also true that concentrations of customers often prefer not to deal with the ugly parts of electricity production (large plants, huge piles of fuel, tall smokestacks dumping waste into the local atmosphere) so they push the production to a place where wires are the only method of transportation back to the customers.
The very first motivation for transporting electricity over long distances - selling motive power produced by a natural fluid flow in a geographically unique area to a large urban customer base that was not located near the fluid flow - was a case where moving electricity over wires was the the only way to get the electric power product to the customers.
If, on the other hand, it is possible to move fuel very cheaply and use it in pollution-free generators, it is often cheaper to put the fuel into generators close to the customer and produce the electricity locally. There is a quantifiable COST to moving electricity over a wire, both to pay for the capital and maintenance costs of the wire transportation network and because the wires charge a physical "toll" in the form of some amount of loss during the transportation.
If solar systems (panels, inverters, storage systems, etc.) were really cheap to install and could provide dependable electricity, people could generate power locally at a lower delivered cost than buying electricity delivered to them via a wire, assuming a system where the real cost of transporting that electricity is included.
If a series-produced, reasonably-priced generator uses an energy dense, emission-free fuel that rarely needs replacing, it can be placed near customers. If it is a well designed, reliable system, it might only need a rare backup that can be provided by using a couple of parallel generators with slightly more total capacity than needed for normal peak loads.
I can envision a reliable, affordable electricity system of isolated local grids with few interconnections and only rare transmission lines that happen to connect areas with abundant fuel or falling water with urban areas. I can imagine that future because I know there are very reliable local generation and distribution systems operating today on ships and submarines.
Combustion powered ships do not qualify because they are still tied to a fuel delivery network, but nuclear powered ships and submarines have fuel supplies that last for decades. Their cores essentially capital equipment that occasionally needs repair or replacement; the ships do not depend on consumables like hydrocarbon fuel.