The current state of hydrogen production and markets is reviewed. The price of captive hydrogen is reconciled against the market prices of ammonia and natural gas. The present world hydrogen production of 70 million tonnes per year is shown to be 98% “gray”, meaning made by steam reforming with concomitant production of CO2. The remaining 2% is electrolytic “green” hydrogen generated chiefly as a byproduct of chlor-alkali manufacture. The present production of “blue” hydrogen, made by sequestering the CO2 of “gray” hydrogen, is shown to be negligible. The cost of “green” hydrogen made for energy storage solely is shown to be 3–5 times higher per delivered energy unit than “gray” hydrogen, due chiefly to the cost of the electricity used. The underground CO2 sequestration practices required for making “blue” hydrogen are reviewed and shown to have capital cost issues that cannot presently be addressed except with Enhanced Oil Recovery revenue or subsidies.
Machinery and Energy Systems for the Hydrogen Economy, Volume , 1 January 2022,