Going beyond electrolysis for hydrogen production, there has been a notable surge in industrial interest in biogas reforming over the past decade
Photo: iStock Despite increasing global political support, green hydrogen constitutes less than 1 per cent of the world’s hydrogen production and usage, according to the September release of the Global Hydrogen Review 2023 by the International Energy Agency (IEA).
To align with the organisation’s Net Zero Emissions (NZE) Scenario, green hydrogen capacity must grow more than 100 times by 2030.
On January 4, 2023, the Indian Union Cabinet approved the National Green Hydrogen Mission (NGHM) with a budget of ₹19,744 crore. The mission’s objective is to position India as a global centre for the production, utilisation and export of green hydrogen. It aspires to achieve a highly ambitious goal of developing a green hydrogen production capacity of five million tonnes per annum by 2030.
The increasing interest in hydrogen stems from its superior calorific value (119.93 megajoules / kg) compared to gasoline (44.5 megajoules / kg). Additionally, burning hydrogen results in fewer harmful emissions into the atmosphere. Hydrogen, existing as a diatomic molecule (H2), is odourless, tasteless and colourless under standard conditions of temperature (25°C) and pressure (1 atm).
In the natural environment, hydrogen is not readily available in its pure form as it forms compounds with other elements like oxygen and carbon. It exists within various compounds, including water, biomass and hydrocarbons. Different pathways have been developed to extract hydrogen from these compounds, and these methods are categorised into conventional and renewable technologies based on the raw materials used.
In conventional technologies, fossil fuels serve as reactants for hydrogen production. Techniques such as hydrocarbon pyrolysis, steam methane reforming, auto-thermal methane reforming, dry methane reforming and partial oxidation are employed. These conventional methods satisfy over 95 per cent of the industry’s hydrogen requirements and are primarily utilised in refineries and fertiliser production.
The demand for hydrogen remains concentrated in industrial and refining sectors, with less than 0.1 per cent originating from new applications in heavy industry, transport or power generation, highlighted IEA’s Global Hydrogen Review 2023.
Adopting low-emission hydrogen in existing applications is progressing slowly, constituting only 0.7 per cent of total hydrogen demand. This indicates that in 2022, hydrogen production and utilisation were associated with over 900 million metric tonnes of carbon dioxide emissions, originating from fossil fuel sources without any carbon capture, utilisation or storage.
The second classification employs renewable sources such as solar, wind and biomass for hydrogen generation. Within this framework, hydrogen can be produced either through electrolysis or biomass-based processes, involving thermochemical or biological methods.
While there is substantial research interest in electrolysis for hydrogen production, there has been a notable surge in industrial interest in biogas reforming over the past decade. This process transforms two major greenhouse gases in biogas (CH4 and CO2) into environmentally friendly chemicals, namely syngas or bio-hydrogen.
The study on green hydrogen conducted by the Fuel Cells and Hydrogen Joint Undertaking in Europe identified approximately 10 options for generating hydrogen from renewable resources. Among these options, biogas utilisation was the least expensive and most promising.
This is primarily because biogas, with methane as its main constituent, is the raw material for hydrogen production. Given the similarity in composition between biogas and natural gas, the systemic steam reforming process does not require significant modifications.
The primary distinction between methane and biogas steam reforming lies in including carbon dioxide in the composition of the latter gas. This characteristic renders the unit particularly susceptible to carbon formation under operational conditions, leading to its deposition on both the support and the catalyst.
To avert carbon deposition in the latter scenario, the system can be supplied with an excess of steam, which can subsequently be recovered at the outlet through condensation.
Hydrogen meeting specific sustainability criteria is referred to as “green” hydrogen, yet a universally accepted definition is lacking, and there is no international standard for green hydrogen.
Various approaches have been employed to define green hydrogen and establish guarantees of origin. These approaches differ in whether green hydrogen is derived from renewable energy, the parameters of the carbon accounting system, emission thresholds designating hydrogen as green and the inclusion of specific feedstocks and production technologies in the framework.
Decisions on these aspects are often influenced by existing national and international standards, as well as the legal framework governing the green hydrogen supply chain.
In August 2023, the Union Ministry of New & Renewable Energy, Government of India, provided a definition for green hydrogen, specifying it as having a well-to-gate emission (encompassing water treatment, electrolysis, gas purification, drying and compression of hydrogen) not exceeding 2 kg CO2 equivalent per kg H2.
In contrast, grey hydrogen, on average, emits 10 kg of CO2 per kg of H2 produced. This definition covers both electrolysis-based and biomass-based hydrogen production methods. The notification also designates the Bureau of Energy Efficiency (BEE), under the Union Ministry of Power, as the nodal authority responsible for accrediting agencies for monitoring, verifying and certifying green hydrogen production projects.
Governments worldwide have introduced numerous hydrogen initiatives to support early adopters, but in many instances, these programs either remain unimplemented or the allocated funds are not yet accessible.
Urgent action is required to implement these initiatives and allocate funding, facilitating a scale-up that aligns with their decarbonisation goals. Governments should strive to streamline licensing and permitting procedures, enhancing efficiency.
Additionally, they must take more decisive measures to stimulate the creation of demand for green hydrogen, especially in existing applications like chemicals or refining, which are well-suited for rapid demand expansion.
Clear definitions are essential for hydrogen offtake mechanisms, procurement prices and the percentage blending in gas grids to enable the preparation of compressed biogas projects near refineries, fostering the adoption of appropriate infrastructure and product diversity to meet refinery demands.
Prioritising the establishment of worldwide hydrogen standards is important for creating high-quality fuel for export. Initially, the recently formed Global Biofuel Alliance, led by India, could be crucial in formulating global standards for hydrogen derived from biomass.
Furthermore, to encourage innovation, research proposals focused on compressed biogas to hydrogen should be prioritised under mission-mode projects in the research and development roadmap for the green hydrogen ecosystem in India.
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