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Emissions concept

General information:

  • Emission types considered: CO2, methane (CH4), and nitrous oxide (N2O), based on data from Germany's National Inventory Report.
  • Global warming potentials (GWP) over a 100-year time horizon, relative to CO2, are adopted from the IPCC Fifth Assessment Report (AR5): CH4: 28, N2O: 265.
  • Energy sources are categorized as fossil, synthetic, or biogenic, with the assumption that only carbon-capture-based synthetic imports are considered.
  • No positive balancing is applied to electricity imports, constrained by country-specific limitations.
  • Negative offsets are applied to imported biogenic and synthetically produced energy sources that carry CO2.
  • Negative offsets also account for the growth of biogenic resources within Germany and for processes involving carbon capture (CC) or direct air carbon capture (DACC).
  • Sector-specific emission targets are not defined, due to sector coupling and the multiple potential conversions of energy sources before final consumption.
  • Exogenous demand and carbon-carrying by-products are allowed, with limited CO2 sinks; the system boundary is set at the product demand level.
  • Emissions are differentiated globally (CO2): a foreign key links to the global table of emission factors per energy source.

  • Sector- and process-specific emission factors are used for CH4 and N2O, as they are more dependent on specific process conditions (e.g., firing temperature for N2O, material moisture for CH4).

  • Negative emissions are implemented within the model structure, as demonstrated by the following visualized emission concept.

emission_concept

Summarized, this means:

  • Fossil: CO2 emissions from combustion
  • Biogen: CO2 emissions from combustion & negative emissions from production/source processes of biogenic energy sources.
  • Synthetic: CO2 emissions from combustion & model-endogenous negative emissions for import and production with carbon captured CO2.