Biocatalysis Approach for Affordable and Sustainable Green Hydrogen Production

Abstract

Green Hydrogen is widely acknowledged as one of the important pillars for decarbonisation of hard-to-abate sectors and to transition the global economy to Net Zero. The current priority in the energy sector is to rapidly establish and scale a green Hydrogen based energy value chain that meets three core objectives: affordability, sustainability and security of supply, also referred to as ‘Energy Trinity’. Green hydrogen is produced from electrolysis of fresh water through technologies such as alkaline electrolyser, PEM (proton exchange membrane), and SOEC (solid oxide electrolyser). The production of green hydrogen from water is an energy intensive process, due to the high thermodynamic stability of water molecules. The cost of producing green hydrogen at scale is large proportional to the cost of renewable electricity. This requires green hydrogen production basins to be located close to regions/ geographies with access to surplus and low-cost renewable electricity, such as Australia, Middle East, Norway, Scotland and Chile. The current cost of green hydrogen in the UK has a 5-10 times cost premium as compared to fossil fuels. The primary inputs from green hydrogen production through electrolysis technologies are renewable electricity and freshwater. There has been an increasing concern globally on the availability and preservation of water resources. There are publications from water companies in the UK citing that the supply of constant fresh water supply for industrial applications such as green hydrogen production cannot be guaranteed under rapidly changing scenarios of climate change. There is a potential to set up large scale desalination plants to meet the fresh water for hydrogen production, however the large quantities of discharge water with high brine concentration might pose environmental hazards to marine habitat. This calls for alternate technologies to be developed which addresses the freshwater dependence for green hydrogen production and the significant green premium on cost structure. The paper describes a novel biocatalysis approach for production of green Hydrogen from wastewater, without requiring electricity input.