[japanuspus]

Just wanted to add some basic chemistry information as background

Hydrogen (H) can be split from water (H2O) with a by-product of Oxygen (O). Hydrogen is hard to handle logistically (as discussed elsewhere in the thread), and the real idea in "Power to X" is to include Hydrogen in another molecule with better logistics. Main contenders are Ethanol (C2H5OH, alcohol), Methane (CH4, ~natural gas), and Ammonia (NH3).

Ethanol and Methane are by far the nicest products: already used as energy carriers, easy to handle, relatively non-toxic, but they have one problem: They require Carbon (C) to manufacture in addition to Hydrogen. Even with increased atmospheric CO2 levels, CO2 concentration in the atmosphere is only on the order of 400 ppm and extraction is expensive.

Ammonia (NH3) is synthesized directly from Hydrogen and Nitrogen (N) which is makes up 70% of the atmosphere. The Haber-Bosch process used for this synthesis is a cornerpiece of industrial chemistry.

[p_l]

Interestingly enough, at least in USA the proposed automotive hydrogen solution is one that reduces logistical problems by placing electrolysis equipment at filling stations - then you have reduced transport to just on-site piping and storage tank, and it makes sense to colocate charging of electric cars with hydrogen ones, as well as use demand-response for the stations (providing extra load balancing for the energy grid, which benefits renewables and nuclear alike)