Optional amendment of the 13^th BImSchV

The German Federal Government declared in its current NAPCP 2023, that an optional amendment of the 13^th BImSchV will be considered for solid (other than coal), liquid and biogenic fuels in case there is non-compliance with the reduction commitment for NO_X projected. Because it is very difficult to define all solid (other than coal), liquid and biogenic fuel uses in installations falling under 13^th BImSchV in the inventory database, as there is often not only one single fuel used in those installations or complex calculations for an overall emission limit value of all installations falling under one facility (e. g. for refineries) are necessary, only for three exemplary categories of installations a hypothetical NO_X mitigation potential was quantified. This follows a conservative approach and does not anticipate any political decision. Thus, mitigation potential is only assumed for 2035 at the earliest.

• potential NO_X reduction in pulp and paper production through an optional amendment of the 13^th BImSchV:

According to the existing 13^th BImSchV (as of 2021), different maximum amounts of NO_X emissions are permitted according to the production process (sulphate and sulphite process) and the size of the plant (measured in RTI in MW) in pulp and paper production (NFR sector 2.H.1).

It is assumed for the sulfite process that all plants located in Germany are operated with an RTI of 50-300 MW. A maximum emission factor of 300 mg/Nm³ for all plants according to the 13^th BImSchV is assumed for the further calculation of the reduction potential. The NO_X emission factor for the sulfite process was taken over from the 2024 submission in the year 2010, which is 2 kg/t. The new emission factor results from the historic emission factor (2 kg/t) and the maximum emission value proposed for the optional amendment (85 mg/Nm³) divided by the calculated mean value of the currently applicable law (300 mg/Nm³). This results in an emission factor of 0.57 kg/t for 2035 onwards as shown in (5).

  (5) implied NOx emission factor (sulfite process) = (2 kg/t * 85 mg/Nm³) / 300 mg/Nm³ = 0.57 kg/t

In the field of the sulfate process (also known as kraft process) a weighted maximum average emission factor according to the limit values of the 13^th BImSchV was assumed as shown in equation (6).

  (6) implied NOx emission factor (sulfate process) = 0.36 * 250 mg/Nm³ + 0.64 * 200 mg/Nm³ = 217.78 mg/N³

The implied emission factor for the sulphate process was taken over from the 2024 submission in the year 2010. The new emission factor results from dividing the 2010 emission factor and the maximum emission value proposed for the optional amendment of the 13^th BImSchV by the calculated mean value of the currently applicable law. This results in an emission factor of 0.68 kg/t for 2035 onwards as shown in equation (7).

  (7) implied NOx emission factor (sulfate process) = (1.75 kg/t * 85 mg/Nm³) / 217.78 mg/Nm³ = 0.68 kg/t

• potential NO_X reduction in refineries through an optional amendment of the 13^th BImSchV:

An optional amendment of the 13^th BImSchV would lead to emission reductions in the area of refineries and is assigned to the WAM scenario. It causes a reduction in the emission factors in the affected time series of the NFR sector 1.A.1.b. A distinction must be made between refinery plants and the fuel input used by them. For plants using raw petrol (naphtha), light heating oil or other petroleum products, the proposed NO_X limit value is set to 85 mg/Nm³ and adopted as the maximum emission level. When using heavy fuel oil, there is a so-called bell-rule applicable for the plants, whereby individual parts of the plant are allowed to exceed the limit value of 85 mg/Nm³ if other parts of the plant fall below the limit value and the plant emission is on annual average not above the limit value.

For plants using raw petrol (naphtha), light heating oil or other petroleum products as fuel, the new maximum emission level corresponds to the limit value of 85 mg/Nm³ NO_X. Consequently, only the conversion factor of the specific flue gas volume for heavy fuel oil or light heating oil (Table 1) has to be used to convert to kg/TJ NO_X. The conversion is carried out for all source groups as shown in (9) using the example of refinery underfiring in LCP with light heating oil as fuel.

  (9) implied NOx emission factor (refinery underfiring with light heating oil) = 85 mg/Nm^3 / 3.49 = 24.4 kg/TJ

This results in NO_X emission factors of 24.4 kg/TJ for light heating oil and 25.1 kg/TJ for other petroleum products for 2025 to 2040.

For a total of twelve plants with heavy fuel oil as fuel input the bell-rule is applied. First of all, the emission limit value according to the current 13^th BImSchV and its specific RTI is assigned to each plant and the mean value is calculated across all plants (274.75 mg/Nm³). The bell-rule allows parts of plants to exceed the maximum emission level if another part of the plant emits proportionally less. The estimated percentage reduction, taking into account the bell-rule, is calculated as shown in (10) by setting the limit value of 85 mg/Nm³ NO_X in relation to the mean value of the current emission limit values.

  (10) percentage NOx emission reduction (refineries) = 1 - (85 mg/Nm^3 / 274.75 mg/Nm^3) = 0.69

A calculated reduction of approximate 69 per cent is assumed for the bell. The projected emission factors for the concerned source categories for 2025 to 2040 are now derived from the current emission factor of the source category under consideration from the 2022 submission minus the proportional reduction.

The conversion is carried out in the same way for all source groups as shown in (11) for the refinery underfiring in LCP with light heating oil as fuel.

  (11) NOx emission (refinery underfiring with light heating oil) = [400 mg/Nm^3 * (1 - 0.69)] / 3.39 = 36.5 kg/TJ

NO_X reductions in other large combustion plants through an optional amendment of the 13^th BImSchV:

Emissions from other LCPs, which emerge from the energy balances, but cannot be clearly assigned to a specific fuel use or fuel mix and also show a reduction potential by an optional amendment of the 13^th BImSchV are assigned to the NFR sector 1.A.1.c and a reduction in the NO_X emission factor was calculated.

The NO_X emission factors for all non-gaseous materials other than coal for electricity and heat generation are considered and the maximum emission amount for NO_X is assumed to be 85 mg/Nm³. According to the 13^th BImSchV, only plants with more than 1500 operating hours per year are taken into account for which the new limit value of 85 mg/Nm³ NO_X applies. Table 13 shows the estimated relative and absolute plant split of the LCP according to its annual operating time assuming an equal fuel use distribution.

Table 13: Estimated relative and absolute plant split of LCP according to annual operating hours

The emission factors will be recalculated for 2025 to 2040. First, the limit value of 85 mg/Nm³ is converted into kg/TJ using the specific conversion factor (Table 1). The new emission factor results from the sum of the reduction for the 82.2 per cent of the fuel use with an operating time of more than 1500 h/a and the unchanged value from the 2022 submission for the 17.8 per cent of the fuel use with less than 1500 h/a operating time, that is not obliged to be reduced by the optional amendment of the 13^th BImSchV.

The calculation is shown using the example of the source category of electricity generation in large industrial power plants using other liquid fuels (reference value in 2020: 42.5 kg/TJ) in (12), whereby the procedure is analogous for all other source categories.

  (12) NOx emission factor (electricity generation in large industrial power plants) = (85 mg/Nm^3 / 3.39) * 82.2 % + 42.5 kg/TJ * 17.8 % = 28.2 kg/TJ

Emission reduction in small combustion installations by tightening the emission limits of the Ecodesign Regulations (EU) 2015/1185 and (EU) 2015/1189:

Through amendment of the Commission regulation (EU) 2015/1189 with regard to ecodesign requirements for solid fuel boilers, it was assumed that requirements for placing on the market and putting into service solid biomass boilers regarding emissions of particulate matter will be set at 2,5 mg/m³ TSP from January 1^st, 2027 (measured according to VDI 2066 Sheet 1, May 2021 edition and based on 13 % reference oxygen content).

Through amendment of the Commission regulation (EU) 2015/1185 with regard to ecodesign requirements for solid fuel local space heaters, it was assumed that requirements for placing on the market and putting into service solid biomass local space heaters regarding emissions of particulate matter will be set at 20 mg/m³ TSP from January 1^st, 2029 (measured according to VDI 2066 Sheet 1, May 2021 edition and based on 13 % reference oxygen content).

Considering these assumptions as well as the potentially increased biomass use described above, a potential emission reduction of 1.4 kt PM_2.5 in 2030 compared to the WM scenario in combination with a potentially increased biomass use in the building sector due to the proposed amendment of the building energy act (described above) was quantified. The absolute emission mitigation potential in 2030 depends on the projected biomass use as well as the year, when the proposed amendment applies for new installations. Less stricter requirements regarding particle emissions in the national law will basically increase the mitigation potential of the proposed amendment of the EU ecodesign regulations.

Additional reduction in agriculture compared to the German NAPCP 2023:

For the emission projections submission 2025, in contrast to the emission projections submission 2023 as well as to the German NAPCP 2023, no further mitigation potential has been reported in the current WAM scenario regarding additional measures in the agricultural sector (NFR 3). The support measure to increase the co-fermentation of slurry in biogas production to further reduce GHG emissions of the agricultural sector has been stopped in 2024, and currently there is no other concrete measure under preparation. In addition, the support measure was not very effective due to low adoption rates in the first years until 2024. Therefore, no increase in co-digested slurry is expected above the assumptions in the WM scenario until 2030, and thus no increase of NH₃ emissions from digestates. Without an expected increase of emissions, and on the background of a buffer of roughly 11 (based on inventory submission 2024) respectively 28 kt NH₃ (based on inventory submission 2025) in the current WM scenario in the year 2030, no additional measures are necessary, and no specific WAM for NH₃ is calculated. The assumptions on co-fermentation of slurry in biogas production for the projections on greenhouse gas emissions (submission 2025) are documented in “Treibhausgas-Projektionen 2025 für Deutschland”¹⁾.

In addition, the amount of ammonia emissions from the previous year will be checked annually in the future. This should be carried out for ammonia emissions from agriculture as part of the previous year's estimate of greenhouse gas emissions in accordance with Section 5 Paragraph 1 of the Federal Climate Protection Act. The previous year's estimate is based on current statistics on important activity data for the previous year (livestock, N-mineral fertiliser sales) and must be submitted annually by March 15^th. If the ammonia emissions of the previous year's estimate are above the linear target path according to NEC Directive (EU) 2016/2284, the BMEL, in consultation with the BMUV, will develop a bundle of agricultural measures, that will assure compliance with the linear target path as soon as possible. Because of uncertainties in the emission projections a minimum gap of 10 kt is agreed. If the previous year’s estimate in the following year has again a gap of 10 kt or more, the bundle of agricultural measures enters into force immediately.