The colour terminology of hydrogen, whether grey, blue, or green, denotes which production methods were used to create the clean-burning, low-carbon fuel. The resulting fuel associated with each method is the same, but each production method has pros and cons. In short, blue hydrogen leverages carbon capture and storage technologies (CCS) to limit the carbon intensity of hydrogen production from natural gas. Green hydrogen is produced through the electrolysis of water using renewable energy.
Over 95% of hydrogen fuel is produced through the steam methane reforming (SMR) of natural gas.1 This is a carbon-intensive process which requires the application of CCS technologies to limit CO2 emissions. When CCS technologies are applied, the carbon intensity of hydrogen production can be mitigated immensely and the product is called blue hydrogen. The Shell Blue Hydrogen Process is a proven solution that can help energy producers convert natural gas into clean-burning blue hydrogen more affordably.
Green hydrogen does not require CCS technologies, as this form of hydrogen fuel is produced by separating hydrogen from H2O using renewable energy like wind and solar. Unfortunately, green hydrogen will need to become more cost-competitive with its blue hydrogen alternative in order to grow its adoption in the industry. The efficiency of this process limits the short-term viability for producers, but in the long run, green hydrogen is expected to be an important hydrogen production method. A Shell-led consortium is at the feasibility stage of the NortH2 wind-to-hydrogen project in the North Sea, and a Shell–Eneco consortium secured the right to build the 759-MW Hollandse Kust Noord project at a subsidy-free Dutch offshore wind auction in July 2020; this project will include a green hydrogen technology demonstration.
