Burning Questions About Hydrogen Wire

Scientists at Harvard have recently announced the long-sought creation of the metallic form of Hydrogen.  The last I recall reading about progress towards this goal, perhaps a decade ago, researchers were using diamond anvils.  Take two perfect diamonds, set them opposite each other, place the sample substance in between, and then squeeeeeeeze.  As it turns out they’re still using that same kind of apparatus with some refinements to make the compression surfaces more atomically perfect.

In the circles of material science this milestone really is a big deal.  The theoretical properties of metallic hydrogen are intriguing: room-temperature superconductor, super-high energy rocket fuel.  The article goes into some pie-in-the-sky speculative detail about what wonderful things could be done with this new substance, as most science articles are wont to do.

Let me just point out a couple of things:

  1. There is no theoretical means of mass production.  When these people talk about this room temperature superconductor revolutionizing energy storage and transmission, bear in mind that we have no idea how to scale up production to a level which would be useful or economical for anything other than special-purpose 1-off big-money project.  Think: military, or space exploration, or special-built supercomputer.
  2. Unlike most fuels we use metal hydrogen must have all its energy put into it.  Gasoline, in contrast, has a rather high specific impulse, but what makes it so darn attractive is that the energy is already present in the hydrocarbons we pump out of the ground.  With a few chemical tweaks we can modify it into a very useful fuel, but it is an energy source, whereas metallic hydrogen would be useful as an energy medium, i.e., a form of energy storage.  That is to say, the energy from metallic hydrogen will have to come from some other source and then be stored in the form of metallic hydrogen, but that energy has to come from somewhere else.  Therefore, it’s useful for rockets where volume and mass are at a premium, but very little else as compared to, for example, hydrocarbons.
  3. When considering the superconducting applications of metallic hydrogen, don’t forget the other potential use: high specific-energy rocket fuel.  Now consider the implication: superconducting metallic hydrogen wire would be made of rocket fuel.  We’re used to thinking of wiring as a fire hazard, but mostly because it can overheat and melt, and spark, and thereby set other things on fire, but hydrogen metal wire will itself burn enthusiastically.  Maybe not the kind of stuff you’d want anywhere near your person or things you care about.

So: Metallic Hydrogen.  Superfantasic as the fuel of the world’s tiniest spacecraft, but otherwise, well…  Not so great.