Decarbonisation Technology - February 2024 Issue

The challenges of transitioning to green hydrogen Green hydrogen is a significant and promising source of renewable energy, but it faces several economic, technical, and regulatory challenges

Himmat Singh Formerly CSIR-Indian Institute of Petroleum

G reen hydrogen produced from the converted into derivatives, namely, ammonia, methanol, synthetic diesel, and jet fuels. These are promoted by governments and industries as renewable chemicals and sustainable alternative fuels for long-haul trucking, shipping, and air travel. Hydrogen is also viable as a means to store renewable energy and could even be used for cooking and heating homes. Costs are dropping significantly, with electrolyser prices down 50% and renewable energy costs falling 50-60% over the last 10 years. Further decreases are anticipated. However, economic, technical, and regulatory hurdles remain for the developing hydrogen economy. electrolysis of water using renewable energy can be used directly as a fuel or Introduction Preserving our planet is a formidable challenge for humanity, with the Intergovernmental Panel on Climate Change (IPCC) stressing the need to limit global temperature increases to 1.5°C above pre-industrial levels to avoid the most severe climate consequences (IPCC, 2022). Green hydrogen emerges as a valuable tool in this endeavour. Hydrogen serves as a clean-burning molecule and versatile energy carrier, applicable in a wide range of energy and industrial uses. Its potential and challenges stem from two primary energy characteristics: hydrogen has a high specific energy (energy content per unit of mass) but a low volumetric energy density. This means that hydrogen requires pressurisation or liquefaction to become a practical fuel (NITI Aayog, 2022), while hydrogen carriers may

prove more economical for longer-distance transport. Hydrogen promises to decarbonise sectors that have historically been challenging to decarbonise. However, it is crucial to note that a staggering 99% of hydrogen production currently relies on fossil fuels, which are associated with significant pollution. Green hydrogen, produced from the electrolysis of water using electricity from renewable energy sources, presently represents a mere 0.1% of global hydrogen production (Nelson, 2021). Nevertheless, it holds immense potential for addressing the intermittency issues of renewables. It facilitates policies and practices to advance the production and uses of hydrogen where direct electrification is problematic. Hydrogen can be used directly as fuel for heating industrial processes such as the production of iron, steel, aluminium, and glass, as a fuel in hydrogen fuel cells, or converted into derivatives such as ammonia, methanol and synthetic diesel and jet fuels. As such, there is a need to prioritise green hydrogen project deployment at scale, leveraging multi-sector opportunities to simultaneously scale supply and demand. Hydrogen production and demand Hydrogen is the universe’s lightest and most abundant element. It is highly reactive, so it is rarely found in its elemental form and must be extracted from compounds. Its role in decarbonisation depends on the environmental friendliness of the production method, leading to different classifications (NITI Aayog, 2022): • Black/brown hydrogen is produced from the gasification of coal or lignite. The process produces hydrogen but also produces high levels