Lifecycle Emissions From Gas and Coal Do Not Support a Coal-to-Gas Shift

Abstract

The greenhouse gas methane (the main component of natural gas) contributed 0.5°C to the gross increase in global average temperature since pre-industrial times, compared to 0.8°C from carbon dioxide and a reduction of 0.5°C from the cooling effect of sulfur dioxide (IPCC 2021). Nevertheless, lifecycle greenhouse gas emissions from fossil fuels were not a factor in Germany's decision to phase out coal-fired power generation. Germany has even given natural gas a bridging role in its hydrogen strategy. This review of the literature highlights that the top-down approach is preferable to the bottom-up approach from a methodological point of view because it comes closer to the actual methane emission rates. Our own calculations of emissions from electricity generation are based on the efficiency of simple-cycle gas turbines, as could be used in the German government's power plant strategy, rather than on historical averages, which also reflect the significantly higher efficiency of combined-cycle gas power plants. Finally, the net lifecycle greenhouse gas emissions of liquefied natural gas (LNG) from the USA or Qatar are compared with those of coal, taking sulphur dioxide emissions into account. When used in a simple-cycle gas turbine, they are higher than those of coal. In part-load operation, the results shift further in favor of coal.

Note: Downloadable document is in German.

Keywords: Lifecycle greenhouse gas emissions LNG Vorkette Emissionen

JEL Classification: Q4, Q54