A net zero emissions global economy by 2050 will be dominated by renewable electricity, mostly solar and wind power, and electrification of end-uses. Low-carbon hydrogen, ammonia and synthetic alcohols and hydrocarbons will complement electricity in some areas where electrification is difficult, mainly chemicals, steel making, aviation and maritime transportation, perhaps range-extenders for some ground transports. They will also serve as an additional flexible resource to achieve the decarbonation of the power systems, with transport and storage abilities.
Of these, hydrogen and ammonia offer the advantage of not containing carbon, while others have higher energy density. Low-carbon hydrogen and thus ammonia will be produced mostly from steam methane reforming with carbon capture and storage, methane pyrolysis and water electrolysis with low-carbon electricity. The temporary scarcity of low-carbon electricity raises issues relative to the timing of deployment. Chemicals, shipping and electric systems will be the largest consumers of low-carbon ammonia.