## 2 Materials and Methods
### Estimation Method
#### 2.4.3 GHG Emissions from Incineration of Waste  
The method in IPCC as well as the _Guidelines for accounting of greenhouse gas emissions from municipal solid wastes incineration enterprise_ according to the Beijing local standard DB11/T 1416-2017 were used for the calculation of GHG emissions from incineration of waste [53]. The GHG emissions from incineration of MSW include the direct CO\({}_{2}\) emissions from fossil carbon in the incineration process and the CO\({}_{2}\) emissions caused by the net purchased electricity and heat consumption of enterprises. The first part includes the direct emission of CO\({}_{2}\) from incineration of fossil carbon of MSW and the direct emission of CO\({}_{2}\) from fossil fuel combustion added for auxiliary combustion. It is worth noting that the CO\({}_{2}\) emissions caused by the burning of bio carbon in MSW were not included in the calculation. Grate furnaces are mainly used in incineration plants in Beijing, which do not need combustion improvement in normal operation, but a small amount of fossil fuel is added during ignition, and thus the direct emission of CO\({}_{2}\) from fossil fuel combustion added for auxiliary combustion was not considered in this paper. The second part includes the CO\({}_{2}\) emissions from the purchased electricity and heat consumption of the incineration plant minus the CO\({}_{2}\) emissions from on-grid electricity generation by incineration and from external heating. In this paper, it was assumed that the on-grid electricity generated by the incineration plant was the net electricity after self-deduction. So the calculation of the GHG emissions from incineration of waste was shown as Equation (16). \(E_{i}\) and \(E_{e}\) were calculated by Equations (17) and (18) [61]:  
\[E_{I}=E_{i}-E_{e} \tag{16}\]  
\[E_{i}=MSW_{i}\star\sum(f_{i}\star dm_{i}\star CF_{i}\star FCF_{i,t}\star OF_{w}) \star\frac{44}{12} \tag{17}\]  
\[E_{e}=AD_{e}\star EF_{e} \tag{18}\]  
The on-grid electricity of electricity generation from incineration of MSW, \(AD_{e}\) is related to the amount of MSW incineration (\(MSW\)), the heating value of MSW (\(HV_{MSW}\)), the thermal efficiency of incineration plant (\(\xi\)), and the auxiliary electricity ratio (\(\zeta\)). The calculation was conducted with Equation (19) [62]. In this paper, \(\xi\) was assumed to be 20%, and \(\zeta\) was assumed to be 20%. The meaning and value of related parameters in the model are shown in Table 8.  
\[AD_{e}=MSW_{i}\star HV_{MSW}\star\xi/3600\star(1-\zeta) \tag{19}\]  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Notation** & **Description** & **Typical Values** \\ \hline \(DOC\) & Fraction of degradable organic carbon & — \\ \(DOC_{i}\) & Degradable organic carbon for waste fraction \(i\) & shown in Table 1 \\ \(f_{i}\) & Waste composition & shown in Table 4 \\ \(DDOC\) & Mass of decomposable DOC & — \\ \(MSW_{l}\) & Mass of waste landfilled & shown in Table 3 \\ \(DOC_{f}\) & Fraction of DOC that can decompose & 0.5 \\ \(MCF\) & CH\({}_{4}\) correction factor for aerobic decomposition & 1 \\  & correction factor for aerobic decomposition & \\  & Fraction of CH\({}_{4}\) in generated landfill gas & \\ \(F\) & 4 & 0.5 \\  & in generated landfill gas & \\ \(R_{l}\) & CH\({}_{4}\) recovered rate & 0 \\ \(OX\) & Oxidation factor & 0 \\ \(CH_{4}^{L}\) & Mass of CH\({}_{4}\) emissions in landfill & — \\ \(E_{CH_{4}}^{L}\) & Carbon dioxide equivalent of CH\({}_{4}\) emissions & — \\ \hline \hline \end{tabular}
\end{table}
Table 7: Relevant parameters of GHG emissions calculation model for MSW landfill.