Comparison of global warming potential between conventionally produced and CO2-based natural gas used in transport versus chemical production

Abstract

In the future, the capacities of renewable SNG (synthetic natural gas) will expand significantly. Pilot plants are underway to use surplus renewable power, mainly from wind, for electrolysis and the production of hydrogen, which is methanated and fed into the existing gas pipeline grid. Pilot projects aim at the energetic use of SNG for households and transport in particular for gas fueled cars. Another option could be the use of SNG as feedstock in chemical industry.The early stage of development raises the question of whether SNG should be better used for mobility or the production of chemicals. This study compares the global warming potential (GWP) of the production of fossil natural gas (NG) and carbon-dioxide (CO2)-based SNG and its use for car transport versus chemical use in the form of synthesis gas. Since the potential of wind energy for SNG production is mainly located in northern Germany, the consequences by a growing distance between production in the North and transport to the South of Germany are also examined.The results indicate that CO2-based SNG produced with wind power would lead to lower GWP when substituting NG for both uses in either transport or chemical production. Differences of the savings potential occur in short-distance pipeline transport. The critical factor is the energy required for compression along the process chain.