As the global demand for cleaner energy accelerates, hydrogen is seen as a crucial player in reducing emissions across heavy industries, transportation, and power generation. A recent study from Morocco dives into the supply chains of grey and blue hydrogen—both derived from natural gas but with distinct environmental footprints. By comparing the two, researchers reveal insights into the energy efficiency and greenhouse gas (GHG) emissions associated with each, offering critical pathways for optimising hydrogen production with sustainability in mind.
How Grey is Different to Blue Hydrogen
Grey hydrogen is produced through steam methane reforming (SMR), a method that releases substantial CO₂ directly into the atmosphere. Blue hydrogen, on the other hand, also uses SMR but incorporates carbon capture and storage (CCS), preventing much of the carbon from being emitted. Although blue hydrogen is greener, both supply chains come with energy losses and carbon emissions that vary depending on stages like production, storage, and transport.
Key Findings: Trade-offs Between Efficiency and Emissions
In terms of energy efficiency, grey hydrogen achieves slightly higher efficiency (38%) than blue hydrogen, which drops to around 36.9% with 90% CCS. However, blue hydrogen significantly cuts emissions—by up to 10% compared to grey—demonstrating a clear environmental advantage for applications where lowering emissions takes precedence over slight energy losses.
Transportation and storage emerge as notable contributors to emissions. For instance, transporting liquefied hydrogen via truck results in higher emissions than pipeline transport. By optimising transport and selecting compressed over liquefied options, the study’s Dijkstra algorithm pinpoints the shortest, most energy-efficient pathways in the supply chain, balancing emissions with energy needs.
Practical Implications for a Greener Supply Chain
This study’s insights could inform policy and infrastructure investment in the hydrogen economy, making a compelling case for transitioning to blue hydrogen while refining grey hydrogen pathways. With targeted improvements, such as adopting more compressed hydrogen transportation and advancing CCS technologies, the supply chain for hydrogen could become more sustainable, marking a step forward in global decarbonisation efforts.
Source
Supply Chain of Grey-Blue Hydrogen from Natural Gas: A Study on Energy Efficiency and Emissions of Processes, Clean Energy and Sustainability, 2024-10
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