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

摘要

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.