Sep 8, 2022
Green, blue, yellow or grey: hydrogen gives us a hard time!
Learn about all hydrogen colors!
good and bad hydrogen?
Manufacturing hydrogen secrets
If you follow us on our blog, you know that to analyze new energy environmental impact, you must analyze its emissions from well to tank (before its use), then from tank to wheel (during its use), and finally from wheel to recycling (after its use).
Today, we are interested in hydrogen energy (which is actually an energy carrier and not energy in itself) which is increasingly presented as the cleanest for our engines.
Indeed, when used (from tank to wheel) as fuel to generate electricity through a fuel cell, this gas only emits water vapor.
But what about from well to tank? Hydrogen does not exist in its current form on Earth, although this is the most abundant element in the universe. It must be created. The hydrogen creating process will determine its color.
Green, grey, blue and yellow hydrogen: what are we talking about?
- Green hydrogen is produced by water electrolysis from electricity derived solely from renewable energy;
- Grey hydrogen is produced by thermochemical processes using fossil sources (coal or natural gas) as raw materials. Paradoxically, 95% of the hydrogen produced today in the world is used in the petroleum refining process;
- Blue hydrogen is manufactured in the same way as grey hydrogen, except that CO2 emitted during manufacturing process will be captured for reuse or storage;
- Yellow hydrogen, more specific to France, is produced by electrolysis like green hydrogen but electricity comes mainly from nuclear energy.
ADEME has also recently suggested changing the terminology. The hydrogen that used to be called “green” is now called “renewable”, the grey hydrogen becomes “fossil”, and finally, the blue and yellow hydrogen are grouped under the name “low-carbon”.
