Blending blue hydrogen with natural gas for direct consumption: Examining the effect of hydrogen concentration on transportation and well-to-combustion greenhouse gas emissions

Jurisdictions are looking into mixing hydrogen into the natural gas (NG) system to reduce greenhouse gas (GHG) emissions. Earlier studies have focused on well-to-wheel analysis of H-2 fuel cell vehicles, using high-level estimates for transportation-based emissions. There is limited research on transportation emissions of hythane, a blend of H-2 and NG used for combustion. An in-depth analysis of the pipeline transportation system was performed for hythane and includes sensitivity and uncertainty analyses. When hythane with 15% H-2 is used, transportation GHG emissions (gCO2eq/GJ) increase by 8%, combustion GHG emis-sions (gCO2eq/GJ) decrease by 5%, and pipeline energy capacity (GJ/hr) decreases by 11% for 50-100 million m(3)/d pipelines. Well-to-combustion (WTC) emissions increase by 2.0% without CCS, stay the same with a 41% CCS rate, decrease by 2.8% for the 100% CCS scenario, and decrease by 3.6% in the optimal CO2-free scenario. While hythane contains 15% H-2 by volume only 5% of the gas' energy comes from H-2, limiting its GHG benefit. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study focuses on the feasibility of mixing hydrogen into the natural gas system to reduce greenhouse gas emissions, with research limited to the transportation emissions of hythane showing a decrease in combustion emissions but an increase in transportation GHG emissions.