Decarbonisation Technology - February 2024 Issue

in hydrogen fuel stations in its larger cities, the picture globally is different, as the hydrogen refuelling infrastructure is underdeveloped. For marine transport, hydrogen derivatives including ammonia and methanol are being developed (Maersk Mc-Kinney Moller, 2023). Sustainable aviation fuels are also reliant on the use of renewable hydrogen, both for the hydrogenation of biogenic residues and used cooking oils for the production of bio-jet or synthetic aviation fuels. Diesel generators are often overlooked. Diesel generators provide a means for power generation in remote, off-grid locations or an important back-up in the event of disruptions to the network supply. H2i Technology has developed a hydrogen injection system that can help decarbonise industries reliant on diesel generators, including the oil and gas and mining sectors (Hydrogen Central, 2023). Hydrogen offers a means to decarbonise a range of industries such as chemicals, iron, steel, aluminium, and glass where direct electrification is not deemed feasible. Furthermore, trials are underway in several countries to evaluate the substitution of natural gas for hydrogen in domestic cooking and heating (DNV, 2020). Challenges developing the hydrogen economy  Water demand Electrolysis requires a consistent supply of pure water combined with a supply of electricity from renewable sources. India is one of the most water-stressed countries in the world, so water resource management is a national concern. Given that 9-10 litres of ultrapure water are required for each kilogram of hydrogen produced, a water supply is the biggest challenge for green hydrogen projects in India (Harrison, 2024) (Hydrogen Council, 2021). In arid areas, such as the Middle East, there is a concentration of electrolyser projects in coastal locations with a seawater desalination plant included as part of the overall project (Harrison, 2024). Other challenges in developing the hydrogen

a major part of the US strategic petroleum reserves (US DOE, 2023). In Texas, Linde has operated the world’s first commercial high- purity hydrogen cavern for more than a decade (Linde, 2023). More recently, in Utah, Mitsubishi Power Americas and Magnum Development are preparing a salt cavern to give a storage capacity of 300 GWh, initially starting with a mix of 30% green hydrogen with 70% natural gas in 2025, then moving in increments to 100% hydrogen by 2045 (Bellini, 2022). The delivery of hydrogen requires different modes of transport, depending on a range of parameters. Pipelines are most suited for regional, short-range transport. Safety should be ‘designed-in’ whether using pipelines created specifically for hydrogen or adapting existing  Hydrogen as a means of transporting renewable energy natural gas infrastructure (Kimpton, 2023). Avoiding leakage from pipelines and hydrogen embrittlement of steel pipelines and components are important design considerations (Honeywell/ UOP, 2023). Given that green hydrogen production may be focused in sunnier locations, it may require transport over longer distances than blue hydrogen produced in closer proximity to industrial centres. Hydrogen is not the ideal medium to carry energy over long distances. In Andalusia, Spain, Cepsa is developing a hydrogen hub to meet local demand and a hydrogen corridor to supply renewable hydrogen to Northern Europe in the form of ammonia. In Northern Europe, the ammonia will be used for fertiliser production or converted back to hydrogen for industrial use (Cepsa, 2023). In different circumstances, a liquid organic hydrogen carrier (LOHC) may prove optimal (Lecarpentier, et al., 2022). Compared with direct electrification, the green hydrogen supply chain is energy inefficient. Approximately 30-35% of the energy used to produce hydrogen is utilised during the electrolysis process, while hydrogen liquefaction or conversion to an energy carrier and back again to hydrogen requires another 13-25% (Ouziel, et al., 2021). Energy is also consumed to transport the hydrogen (Ouziel, et al., 2021). However, such energy losses should be put into context. Although PowerX, a Japanese company, has

economy are generic, irrespective of the technology for hydrogen production.

 Storage for large volumes of hydrogen Salt caverns are proven locations for storing different forms of energy such as crude oil and natural gas; for example, they are used to store