Gaseous Hydrogen

In principle, hydrogen is an ideal vector for the transmission and storage of energy. One might imagine, in the post-fossil-fuel age, huge solar collectors and electrolysis plants located over large areas of desert. It would then be necessary to convey the hydrogen to market. The most obvious means would appear to be via pipeline. Indeed, as long ago as 1938, conventional mild-steel pipelines were installed in the Ruhr district of Germany to convey hydrogen between refineries and chemical works. The initial system was about 24 km in length and fed two plants. Since then, the grid has been expanded to a 210-km network that links four producers of the gas and thirteen users. It even crosses the Rhine in two places. The pipes are wrapped in bitumen and plastic, have diameters of 15 30 cm, and operate at pressures up to 1.6 MPa (16 atm.). Remarkably, no major accidents have arisen from escaping hydrogen or potentially explosive hydrogen-air mixtures. There is also a 170-km system in Northern France and a total of some 1500 km in Europe as a whole. North America has at least 700 km, and other smaller networks are in use in South Korea and Thailand. Clearly, the technology of transmitting pressurized hydrogen safely over considerable distances has been demonstrated and used commercially to supply gas for chemical processes.

Hydrogen as an energy vector is a rather different proposition since the distances involved are likely to be much greater and...