Decarbonizing Heavy-Duty Transportation in Saudi Arabia: A Life Cycle Assessment of Renewable Methanol

As Saudi Arabia pursues its 2060 net-zero greenhouse gas (GHG) emissions target, the decarbonization of its heavy-duty transportation sector remains a pressing challenge due to its high energy demands and diesel reliance. This thesis presents a comprehensive Well-to-Wheel (WTW) Life Cycle Assessment (LCA) of methanol as an alternative fuel for heavy-duty trucks operating in Saudi Arabia. Five fuel pathways are evaluated: conventional diesel, grey methanol (via steam methane reforming), blue methanol (via CO₂ hydrogenation with blue hydrogen), imported green methanol (from Iceland), and locally produced green methanol (via CO₂ hydrogenation using green hydrogen). Using GREET, the study quantifies emissions (CO₂, CH₄, N₂O, NOₓ), energy consumption, and midpoint and endpoint environmental impacts. The results show that grey methanol exhibits the highest environmental burden among the methanol pathways and even exceeds diesel in GWP-100 due to unabated fossil-based hydrogen production. Blue methanol achieves moderate reductions (~1.4 kg CO₂-eq/mi) relative to grey methanol (~2.0 kg CO₂-eq/mi) by incorporating carbon capture and waste CO₂ utilization. Green methanol pathways demonstrate the greatest environmental benefits: imported green methanol reduces GWP-100 by 66% and locally produced green methanol by 57%, relative to diesel. These gains also extend to endpoint categories such as human health and ecosystem damage. A revised multi-phase policy framework is proposed: beginning with imported green methanol to stimulate demand and retrofit methanol-compatible vehicles, followed by expansion of blue methanol under a decarbonizing grid, and culminating in large-scale domestic production of green methanol as renewable hydrogen infrastructure matures. The analysis highlights methanol’s compatibility with current infrastructure and its viability as a scalable solution for Saudi Arabia’s transport decarbonization strategy. Although capital infrastructure emissions are excluded, the study provides robust insights into fuel-cycle impacts. Future work should incorporate techno-economic analysis and transient operational testing to refine the findings and support broader deployment decisions.