From Iberdrola’s web
A simple introduction to green hydrogen by IBERDROLA, a leading Spanish utility pro-decarbonising our way of life: “Green hydrogen: an alternative that reduces emissions and cares for our planet”
Decarbonising the production of an element like hydrogen, giving rise to green hydrogen, is one of the keys as this is currently responsible for more than 2 % of total global CO2 emissions.
Replacing all grey hydrogen in the world would require 3,000 TWh/year from new renewables — equivalent to the current demand of Europe.