Comparative analysis of hydrogen vs. methane pipeline transport systems with integrated methane pyrolysis for low-carbon hydrogen supply

Establishing a climate-neutral energy system is among the most urgent challenges facing humanity, with the natural gas network forming a critical component of energy and commodity infrastructure. The hydrogen economy, based on climate-neutral hydrogen, which serves as both energy source and raw-material for numerous sectors, offers a promising pathway for significant reduction in CO2 emissions. However, the lack of an extensive hydrogen infrastructure underscores the need for transitional solutions. Given this infrastructure gap and the urgency to establish a reliable and less emission-intensive commodity network, methane pyrolysis (MP) emerges as a promising technology for supporting the transition to a climate-neutral energy system. Within this context, this study evaluates the intricacies of long-distance pipeline transport of hydrogen (H2) and methane (CH4), focusing on the placement of MP units. The primary goal is to provide “turquoise hydrogen”, produced from natural gas via MP, along with solid carbon, from distant locations to industrial consumers. Two configurations are assessed: Configuration I represents a centralized supply concept, transporting molecular hydrogen, while Configuration II delivers methane to consumers for on-site hydrogen production. The reference system covers a transport distance of 500 km, extending to 4000 km, with recompression stations every 125 km. The transport capacity of the hydrogen pipeline is set at 13 GW, with the methane mass flow set to match the equivalent hydrogen output chemically bound in methane. A parameter study examines power requirements and global warming impact (GWI) over various transport distances. For distances between 2000 and 4000 km, Configuration II requires less power (Δ = 229.4–443.0 MW) and results in GWI savings of 0.25 to 0.37 kgCO2-eq.kgH2−1, owing primarily to the lower specific energy consumption for methane transport compared to hydrogen. The study concludes that the electricity mix of the exporting and importing regions significantly affects the GWI of hydrogen supply, with the MP unit contributing a substantial part (6.92 kgCO2-eq.kgH2−1) to the total GWI. The approach of Configuration I is favorable for regions with a low-GWI electricity supply, while Configuration II is better suited for regions where the electricity mixes of both the exporting and importing regions are similar.