Techno-economic analysis of hydrogen transport via repurposed natural gas pipelines: Flow dynamics and infrastructure tradeoffs

Hydrogen's potential as an energy-efficient fuel is well recognized; however, its transport through existing natural gas pipelines poses significant technical and economic challenges. This study evaluates the feasibility of hydrogen transport through existing natural gas pipelines by analyzing pipeline flow dynamics, pressure drop, energy balance, and cost implications. Results show that hydrogen's lower density and higher velocity cause pressure losses up to 3.5 times greater than methane, requiring increased inlet pressures and additional compression to maintain comparable volumetric energy output (∼35.8 MJ/m 3 for methane). Pressure drops along a 300-mile pipeline can exceed 120 psi for hydrogen at high flow rates, compared to 40 psi for methane, highlighting the need for infrastructure upgrades. A comparative analysis of three scenarios—repurposing existing pipelines, achieving methane-equivalent energy output through compression, and constructing new hydrogen-specific pipelines—reveals that matching methane's volumetric energy delivery increases operational costs by ∼35 % due to higher compression demands. While repurposing offers short-term cost benefits, it necessitates extensive modifications to address hydrogen embrittlement and efficiency losses. Conversely, dedicated hydrogen pipelines, despite higher capital investment, provide a more cost-effective long-term solution. These findings underscore the importance of optimized compression strategies, hydrogen-compatible materials, and supportive policies to develop scalable, safe, and economically viable hydrogen infrastructure. • Analyzes hydrogen flow and pressure drop in repurposed methane pipelines. • Quantifies pressure needs for hydrogen to match methane energy delivery. • Compares retrofit, energy-parity upgrade, and new pipeline scenarios. • Finds retrofitting cuts CAPEX by up to 75 % but needs key safety upgrades. • New pipelines cost more but offer safer, long-term hydrogen transport.