Currently, most hydrogen is made from natural gas or even coal. This is cheap but it produces lots of greenhouse gases. However, if you capture those greenhouse gases and bury them in the ground, you are allowed to call it “blue hydrogen”. Again, they say the technology to capture and store greenhouse gases is unproven and will be expensive. One is reminded the conversion of hydrogen to energy produces water vapour, which is a major greenhouse gas.

Source: The Guardian January 11, 2022 09:40 UTC