What is "hydrogen economy"

n. A hypothetical future economy in which the primary form of stored energy for mobile applications and load balancing is hydrogen (H2), and, in particular, hydrogen replaces fossil fuels in automobiles.

The hydrogen economy is a proposed system of delivering energy using hydrogen. The term hydrogen economy was coined by John Bockris during a talk he gave in 1970 at General Motors (GM) Technical Center. The concept was proposed earlier by geneticist J.B.S. Haldane.

Proponents of a hydrogen economy advocate hydrogen as a potential fuel for motive power (including cars and boats) and on-board auxiliary power, stationary power generation (e.g., for the energy needs of buildings), and as an energy storage medium (e.g., for interconversion from excess electric power generated off-peak). Molecular hydrogen of the sort that can be used as a fuel does not occur naturally in convenient reservoirs; nonetheless it can be generated by steam reformation of hydrocarbons, water electrolysis or by other methods.

The spike in attention for the concept during the 2000s has been repeatedly described as a hype by critics, neutral observers and advocates of further research and development. Some small-scale initiatives from that period are still trying to enable hydrogen-fuelled land transport. However, this application faces many issues, given fundamentally low conversion efficiencies and competition from other sources.