Ocean-going ships could be powered by ammonia within the decade as the shipping industry takes action to curb carbon emissions.
The chemical - the key ingredient of fertilisers - can be burned in ships' engines in place of polluting diesel.
The industry hopes ammonia will help it tackle climate change, because it burns without CO2 emissions.
The creation of the ammonia itself creates substantial CO2, but a report says technology can solve this problem.
The challenge is huge, because shipping produces around 2% of global carbon emissions about the same as the whole German economy.
