released hydrogen fuel cell cars commercially, with manufacturers such as Toyota and industry groups in China planning to increase numbers of the cars into the hundreds of thousands over the next decade. Current hydrogen market Hydrogen production globally was valued at over US$120 billion and is expected to grow over 5% annually through 2028. This market demand is usually met by pyrolysis of hydrocarbons to produce the hydrogen, which results in emissions. fertiliser production and oil refining are the main uses. About half is used in the Haber process to produce ammonia (NH3), which is then used directly or indirectly as fertilizer. Because both the world population and the intensive agriculture used to support it are growing, ammonia demand is growing. Ammonia can be used as a safer and easier indirect method of transporting hydrogen. Transported ammonia can be then converted back to hydrogen at the bowser by a membrane technology. The other half of current hydrogen production is used to convert heavy petroleum sources into lighter fractions suitable for use as fuels. This latter process is known as hydrocracking. Hydrocracking represents an even larger growth area, since rising oil prices encourage oil companies to extract poorer source material, such as oil sands and oil shale. The scale economies inherent in large-scale oil refining and fertilizer manufacture make possible on-site production and "captive" use. Smaller quantities of "merchant" hydrogen are manufactured and delivered to end users as well. almost (96%) all hydrogen production is from fossil fuels, and emits 900 million tonnes of carbon dioxide per year, a figure theoretically corresponding to 163, but in fact to only 90 million tonnes of dihydrogen per year. The large market and sharply rising prices in fossil fuels have also stimulated great interest in alternate, cheaper means of hydrogen production. Green hydrogen, from electrolysis of water, is a more economical means of energy storage to address renewable energy intermittency in terms of capital expenditures than pumped-storage hydroelectricity or batteries. Consumers The two major consumers are oil refineries and fertilizer plants (each consumes about half of all production). Production, storage, infrastructure , more than 95% of global hydrogen production is sourced from fossil gas and coal without carbon abatement. Color codes Hydrogen is often referred to by various colors to indicate its origin. As shown below, some production sources have more than one label with the more common listed first. Although the usage of