Repurposing Western Australian Gas Network for Hydrogen Transportation - A Case Study of Telfer Gas Pipeline

Abstract Blending hydrogen with natural gas (H2-NG) in pipelines is one of the pragmatic solutions to lower carbon emissions from natural gas usage. This strategy entails incorporating a defined percentage of H2 into established NG networks. This work evaluates the potential of H2-NG blending in the Telfer Gas Pipeline (TGP) – a part of the Western Australia transmission network. The effect of increasing H2 fraction on pressure profile, corrosion, and erosion along TGP was addressed. The pipeline model was developed and validated using PIPESIM-Net software. The tested gas mixtures were calibrated with comparable studies, while the pipeline model was validated with the real operating conditions of TGP. Then, a thorough sensitivity analysis was performed, investigating the impact of varying H2 concentrations. The molar fraction of H2 in the gas mixture increased from 0% to 80%, with a 10% step. The inclusion of H2 substantially increased the pressure profile at both the TGP's mainline and delivery nodes (sinks). This rise in pressure resulted from notable reductions in both density and viscosity as the H2 fraction increased, contributing to decreased hydrostatic and frictional pressure losses along the pipeline, respectively. Thermodynamically, the compressibility factor reached unity when the gas composition contained 80% H2. The heightened pressure in the pipeline caused increased corrosion rates, although the erosional velocity ratio exhibited a slight decrease with higher H2 content. This analysis offers critical insights into the impact of H2 concentration on the system, providing a comprehensive assessment of potential risks and opportunities of H2-NG blending in transmission networks.