The hydrogen economy is a term for the role hydrogen as an energy carrier to complement electricity as part a long-term option to reduce emissions of greenhouse gases. The aim is to reduce emissions where cheaper and more energy-efficient clean solutions are not available. In this context, hydrogen economy encompasses the production of hydrogen and the use of hydrogen in ways that contribute to phasing-out fossil fuels and limiting climate change.
Hydrogen can be produced by several means. Most hydrogen produced today is gray hydrogen, made from natural gas through steam methane reforming (SMR). This process accounted for 1.8% of global greenhouse gas emissions in 2021. Low-carbon hydrogen, which is made using SMR with carbon capture and storage (blue hydrogen), or through electrolysis of water using renewable power (green hydrogen), accounted for less than 1% of production. Of the 100 million tonnes of hydrogen produced in 2021, 43% was used in oil refining and 57% in industry, principally in the manufacture of ammonia for fertilizers, and methanol.
