1.A.3.e i - Other Transport: Pipeline Transport

Under category 1.A.3.e i - Pipeline Compressors emissions from compressors in pipeline transport of natural gas are reported.

In past years, statistical fuel consumption data from the National Energy Balances for Germany was used (AGEB, 2021)¹⁾. But a comparison with data from German ETS (available as of 2005) exposed several inconsistencies within these statistics.

Therefore, as the fuel consumption of a compressor station depends strongly on the amount of transferred natural gas, a conversion factor was derived reflecting the relation between the fuel consumption of all compressor stations and the primary energy consumption of natural gas within Germany. Using this conversion factor, the insufficient statistical data could be replaced by much more solid estimates for the years 1990 to 2004 whereas for 2005+ the abovementioned ETS data is used.

Table 1: Consumption of natural gas in compressor stations, in [tJ]

The emission factors for pipeline comporessors have been taken from the research project “Determination and evaluation of emission factors for combustion systems in Germany for the years 1995, 2000 and 2010” (DFIU, 2002)²⁾. A detailed description of the procedure is presented in Chapter: 1.A.1.a - Public Electricity And Heat Production. In 2018 and 2019 emission factors were revised by using emission data from large combustion plants (UBA, 2019)³⁾.

Compressor stations, in Germany mostly gasturbines, are responsible for maintaining a constant pressure in the pipline. Basically they work discontinuously which causes relatively high specific emissions. In order to reflect this point the German law allows exemptions for installations with a low level of utilization.

Table 2: EF used for 2022 emission estimates, in kg/TJ

The following diagram gives an overview of the fuel consumption in NFR 1.A.3.e

Since 1990 natural gas consumption has shown an increasing overall trend. Annual fluctuations are due to the varying primary energy consumption. The maximum fuel consumption occured in 2006, the year with the so far highest German total primary energy consumption of natural gas. Thereafter, natural gas consumption decreases considerably.

For the purpose of improving the data quality National Energy Balances for the years 2003 to 2021 have gone under revisions through fine-tuning of the computational models, consideration of new statistics or re-allocation of activity data, along with other revision mechanisms. These updates led to re-calculations in fuel uses in different sub-categories and in their corresponding emissions.

Currently no further improvements are planned.