There are two priorities I keep in mind, when thinking about collapse-time technologies.
- Maintenance complexity, especially in long-run context.
- Shortening the supply chain.
When it comes to electric power generation and various types of generators, I am very reluctant to accept generators based on rare-earth magnets. First, they are "bloody metals" indeed, mined and refined with extreme hurt to the planet and people. Second, their delivery chain is long and quite centralised which makes them possibly unavailable in case of disruption of the logistic system. While we wait for the US-sponsored program to develop alternative materials, still we can explore two avenues of research:
- magnets recycling
- generator constructions that does not need such magnets.
The recycling topic deserves separate consideration, in respect to a hypothesis of the "scavengers civilisation" as the next stage of human history. Meanwhile, we can have a closer look at constructions, using much more sustainable ceramic (aka ferrite) magnets, or no magnets at all.
If we can develop a "DIY" technology to make ceramic magnets, we can combine it with designs from 19th and early 20th Century and create alter-futurist line of more collapse-friendly electricity generators.
which is more difficult to obtain, iron based materials for permanent magnets, copper for field coils?
I believe the answer will depend on local circumstances. The copper will always be needed - it is a matter of mix proportions. As long as we can keep the supply chain short-ish and local, we are good.