Hydrogen is commonly heralded as a local weather hero as a result of when it’s used as a gas in issues like buses or metal manufacturing, there are not any direct carbon emissions (or associated warming) to fret about. Because the world tries to chop down on our use of fossil fuels, there could possibly be loads of new demand for this carbon-free vitality supply.
However how hydrogen is made may decide simply how useful it’s for the local weather. That’s the place the rainbow is available in. (I’ve added an at-a-glance desk beneath so you may untangle all these colours.)
Final week, the European Fee launched guidelines that outline what “renewable” hydrogen is: in different phrases, what it means for hydrogen to be inexperienced. There was additionally a captivating story in Science final week about naturally occurring, or gold, hydrogen.
So let’s dive into the hydrogen rainbow and discover the place this gas of the long run would possibly come from.
What do we want hydrogen for?
We already use numerous hydrogen right this moment: international demand was 94 million metric tons (Mt) in 2021. Most of that was used for oil refining, in addition to manufacturing of ammonia (for fertilizer) and methanol (for chemical manufacturing).
That’s more likely to change sooner or later, as a result of it’s additionally a superb alternative for fossil fuels in transportation, heavy business, and different sectors. If nations preserve their local weather pledges, hydrogen demand may attain 130 Mt by 2030, and a few quarter of that might be for brand spanking new makes use of.
The issue is, making hydrogen right this moment overwhelmingly requires fossil fuels, normally pure gasoline. In so-called “grey” hydrogen manufacturing, pure gasoline reacts with water, producing hydrogen gasoline and giving off carbon emissions.
It doesn’t should be that approach, although. For one factor, we may attempt to seize the carbon emissions from fossil-powered hydrogen manufacturing (this technique yields so-called blue hydrogen). It is a fairly controversial strategy, as a result of carbon seize is dear and doesn’t at all times work effectively.
