...is nominally water are absurd.
Among the horrible physical properties are these: The second lowest critical temperature (33K) of any gas except helium, incompatibility with many metals, an extremely low viscosity, a positive Joule-Thompson coefficient over parts of the temperature range, a trivial heat of vaporization, and low explosive limits, and very poor thermodynamics represented by the environmental cost of production.
The popularity of the hydrogen fantasy, which is well over a half a century old, is a dangerous affectation, wasteful exercise that has been sold to the public at the expense of humanity.
To my way of thinking, it's a disgusting shell game being sold by fossil fuel interests to divert attention from the realities of their industry.
Hydrogen is a valuable captive commodity; it is essential for the world's food supply when used in the Haber-Bosch process to manufacture ammonia, and important in many industrial processes, including, interestingly, oil refining to make gasoline. In theory it can be utilized to make any component of petroleum using the Fischer-Tropsch process which was industrialized by two very awful countries, Nazi Germany and Apartheid era South Africa using hydrogen generated by the steam reforming of coal.
It can also be used to make relatively clean fuels, methanol and the wonder fuel DME (dimethyl ether) which is an easily liquified fuel that can displace all petroleum fuels, dangerous natural gas, and LPG, propane and, in fact, many refrigerants. (It is chiefly manufactured as a propellant in spray cans to displace CFCs.) The hydrogenation of CO2 to make DME would in theory allow for an industrial closed carbon cycle, the thermodynamics of direct air capture of CO2 notwithstanding.
The only sensible and sustainable way to make hydrogen cleanly is by thermochemical hydrogen cycles such as (my favorite as it's amenable to flow chemistry) the SI cycle. A lot of bullshit is handed out about these kinds of thermochemical processes using solar thermal energy, which is unsustainable, but I frequently read these papers because they are easily modified for a nuclear setting. A nuclear setting would allow for process intensification by which high thermodynamic efficiencies may be obtained, raising the thermodynamic efficiency of nuclear plants, now generally on the order of 33% for Rankine plants and only slightly better for Brayton plants, to levels that I crudely calculate to exceed 70%, even approaching 80%.
Hydrogen has no valid use in any consumer setting, and again, to make the point clearly, pushing it is a shell game to do what so called "renewable energy" is doing, to divert attention from the use of dangerous fossil fuels through diversionary advertising coupled with unconscionable soothsaying that is worthy of cheap tarot card readers working at the Jersey shore, but an expensive waste for all humanity, and indeed, all living things.
What's happening in Santa Cruz with respect to hydrogen buses, in a State wholly dependent on dangerous natural gas, with its last nuclear plant in danger of being shut in a paean to ignorance, is a disgrace. It is an effort to portray doing nothing other than making things worse as doing something positive, in short promoting a lie. It's garbage thinking, shallow and dishonest.
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