Blending low-carbon hydrogen with natural gas: Impact on energy and life cycle emissions in natural gas pipelines.

Hydrogen (H 2) is considered an alternative energy carrier to reduce greenhouse gas (GHG) emissions related to power and heat generation. A quantitative analysis was conducted to estimate the energy intensity and GHG emissions associated with the transportation of NG/H 2 mixture in high-pressure transmission pipeline, considering blending ratios up to 100% of low-carbon H 2. The life cycle emissions were obtained by including upstream supply chain emissions, compression and transportation emissions, and end use combustion emissions of the NG/H 2 blend. This study accounts for global warming potential of fugitive methane and H 2 emissions associated with pipeline transportation of the blend in the life cycle analysis. A significant reduction in the overall life cycle GHG emissions can be achieved when delivering the same volume throughput but at a reduced energy flow to end users. However, to maintain the nominal energy throughput of the pipeline regardless of the H 2 mole fraction, a maximum reduction of about 6% is obtained as the H 2 mole fraction in the blend will be practically limited to approximately 30% H 2 when the pipeline operates at capacity. • NG/H 2 mixtures in a high-capacity NG transmission line was modeled with Aspen Plus. • Emissions decreased by 96% with 100% H 2 when delivering the same volume flow rate. • Delivering the same energy flow rate can limit emissions reduction to less than 6%. [ABSTRACT FROM AUTHOR]