There are hydrogen production pathways with better than green hydrogen economic and environmental costs

While the present hydrogen (H-2) is mostly grey, from steam reforming of methane (CH4) with direct carbon dioxide (CO2) emission, different pathways have been proposed to produce H-2 more environmentally friendly. Blue H-2, adopting carbon capture and storage (CCS), has no direct CO2 emission, but the additional cost to capture and store the CO2. Thus, green H-2, from the electrolysis of the water (H2O) molecule, is becoming the preferential pathway for future H-2 production. Two additional pathways are proposed for reduced economic and environmental costs, both free of direct CO2 emissions, based on the use of concentrated solar energy (CSE). White H-2 is produced from the catalytic solar thermochemical splitting of the H2O molecule. Aquamarine H-2 is produced from solar thermochemical CH4 pyrolysis with a carbon catalyst. Here we provide an estimation of costs by 2030 of white and aquamarine H-2 lower than the cost of not only green H-2 but also grey H-2 disregarding the CO2 emission. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

While most current hydrogen is produced from steam reforming of methane with CO2 emission, more environmentally friendly pathways like green H-2 from water electrolysis are becoming preferred for future hydrogen production. Two additional pathways based on concentrated solar energy are proposed to reduce economic and environmental costs.