In order to distinguish the low-carbon and clean process of hydrogen production, hydrogen produced by different hydrogen production technologies is divided into three categories: gray hydrogen, blue hydrogen and green hydrogen.

1. Grey hydrogen refers to hydrogen produced by coal, natural gas, chemical factories and other carbon-based energy sources. Due to carbon dioxide emissions in the preparation process, low carbon is not achieved, so this hydrogen is defined as grey hydrogen.

”Green hydrogen“

2. Blue hydrogen adopts "carbon-free" technology in the preparation process of grey hydrogen to achieve zero carbon emissions, which requires the capture, utilization and storage of carbon dioxide related technical support. The realization of blue hydrogen requires technological breakthroughs and development.

3. At the same time, electricity is obtained through solar energy, hydropower, wind energy and other renewable energy and nuclear power generation. The carbon free and green hydrogen can be realized. This kind of hydrogen is called green hydrogen, and the realization of green hydrogen is mainly subject to the development of renewable energy power generation technology and water electrolytic cell technology.