When hydrogen will assist local weather change—and when it received’t.

Hydrogen is usually 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 may very well be loads of new demand for this carbon-free power supply.

However how hydrogen is made might 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 under so you’ll be able to 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 may come from. 

What do we want hydrogen for?

We already use loads of hydrogen right now: world 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 substitute for fossil fuels in transportation, heavy trade, and different sectors. If international locations maintain their local weather pledges, hydrogen demand might attain 130 Mt by 2030, and a few quarter of that may be for brand new makes use of. 

The issue is, making hydrogen right now overwhelmingly requires fossil fuels, often pure fuel. In so-called “grey” hydrogen manufacturing, pure fuel reacts with water, producing hydrogen fuel and giving off carbon emissions. 

It doesn’t should be that approach, although. For one factor, we might attempt to seize the carbon emissions from fossil-powered hydrogen manufacturing (this methodology yields so-called blue hydrogen). This can be a fairly controversial method, as a result of carbon seize is dear and doesn’t all the time work effectively.