Nothing I can find about the process itself speaks to it being any less arduous than creating an entire power station & electric grid just to create aluminum. The process the characters in this chapter are speaking to was discovered by individuals in a laboratory setting, and while they were working in at milligrams of produced aluminum, the chemical nature of the method means that the hardest part would be sourcing materials.
Maybe I need to keep digging, but comparing that to designing power stations, building said power stations, and then fueling those stations to create electricity to then utilize a more modern method of manufacturing sorta feels like building the Apollo Program because you want to invent Velcro.
And even then - we don't know the scale of output that Cohen desires. If she only wants a couple tons of aluminum, maximum--especially with how recyclable it is--then going to such lengths would be sort of counterintuitive, unless there were set agendas for using all that power and infrastructure outside of the aluminum process. As she's the only person in this setting who wants the metal, and she's a noted People Hater who prefers her isolation, setting up a power grid for just herself when the output to produce aluminum could also simply power the nearby city feels like the sort of endeavor she'd actively avoid.
But at the same time, simply saying "she's a genius craftswoman, so just give her the basics and let her loose" is more hand-wave-y than what the author actually went with, I'd argue.
A hydro electric station needs about seven different elements which they should be capable of producing as shown by their car production. This is assuming that they already have the precision manufacturing capability to build surface plates which are the origin of mechanical precision using the three plate method. And then can use that to build a lathe, a mill and hole boring machines such as drills and other types of metal cutting machines, to make larger machines and also standards of length and angle.
Keep in mind many of these early machine shops/factories were located next to a river which they would build a small dam on and then have a waterwheel power a huge overhead shaft that distributed power throughout the factory. So you dont even need electric motors for production
Which they are already able to produce as shown by their production of vehicles which require all of the components to make their parts
A hydroelectric station needs
A dam to hold the water
A chanel made to bring the water to the water wheel
A Water wheel
A shaft to hold that waterwheel
Bearings (wood) (bearings in many hydroelectric stations are made out of wood, specifically lignum vitae, or sugar maple as it's just the best bearing material when using water as a lubricant)
The clearly are advanced past this step as shown by their cars which need higher quality ball bearings for packaging
A shaft going to an electric motor/generator
And an electric motor(they already have bearings and copper wires which is the hard part.)
And then you need
