Re:Zero Emissions? (Score 1)

it is easy to replace the first stage with out-of-car hydrogen generation, if and when clean hydrogen becomes cheap and easy to transport.

That is of course the whole issue with the hydrogen cars. Manufactures can build small runs of hydrogen (be it ICE, ECE or fuel cell) cars as a technology showcase and to buy political/marketing points without having to worry the cars will actually be able to be fueled. Nocera at MIT and other have done great work to make certain non-fossil hydrogen production more viable, but this has not solved the practical aspect of hydrogen handling, storage and transportation. The construction of high temperature nuclear reactors will also enable thermal cracking of water.

Hydrocarbons are easy to store and transport and have a much higher energy density. Continuing development of biomass (especially algae based) and synthetic liquid fuels offers the ability to reuse most of the current national fueling infrastructure and still close the carbon cycle. There are other benefits as well. Algae reactors connected to smoke stacks absorb not only the CO2 but also nitrogen oxides. The pressed algae can be used as a non-fossil fuel based fertilizer.

Obviously hydrogen energy transport and fuel-cell vehicles hold some promise. But I am very concerned with the hype and almost religious defense of all things hydrogen "the ocean is full of hydrogen" especially when there are many other technologies that are closer or even in deployment that we can use right now.