# Impact of Disruption on Ship Emissions in Port: Case of Pandemic in Long Beach
## 3 Model and Methodology
### Ship Emission Estimation Model
#### 3.3.2 Engine Power Calculation and Estimation  
The first term in the formula is each ship's engine power. It is crucial to account for the engine's power and operational condition during determining ship emissions. The type of engine utilised by boats in varied operational circumstances varies. Consequently, the emissions will also alter. The database provides access to the engine power of specific ships. However, not all vessels are searchable. To get an accurate estimate of the ship's ME information, we integrated the estimation equations of [PERSON] [38] and [PERSON] et al. [39]. The ship's ME power can be estimated by design speed and ship size, whose definitions are given by:  
\[MEP_{T}=\left[7\times 10^{-7}\times\left(-617.39+9.158\times DWT^{0.6}\right)^{ 2}+0.1737\times\left(-617.39+9.158\times DWT^{0.6}\right)+321.58\right]\times V \tag{4}\]  
\[MEP_{T}=\left[7\times 10^{-7}\times\left(-617.39+9.158\times DWT^{0.6}\right)^{ 2}+0.1737\times\left(-617.39+9.158\times DWT^{0.6}\right)+321.58\right]\times V \tag{5}\]  
\[MEP_{C}=\left(7\times 10^{-7}\times\left(-5412.3+1003.1\times TEU^{0.3} \right)^{2}+0.1737\times\left(-5412.3+1003.1\times TEU^{0.3}\right)+321.58 \right)\times V \tag{6}\]  
\[MEP_{\text{\emph{cargo}}}=7.52\times 10^{-5}\times\left(L\times B\right)^{2}+0.59 \left(L\times B\right)-41.48 \tag{7}\]  
\[MEP_{T}=3.32\times 10^{-4}\times\left(L\times B\right)^{2}+0.27\left(L\times B \right)+57.20 \tag{8}\]where \(MEP_{T}\) denotes the ME total power of a tanker (kW); \(MEP_{C}\) represents the ME total power of a container (kW); \(MEP_{B}\) indicates the ME total power of a bulk carrier (kW); and \(V\) represents ship design speed (m/s). \(MEP_{cargo}\) represents the main engine power of a cargo ship (kW); \(DWT\) is deadweight tonnage, indicating the capacity of a tanker, bulk carrier, cargo ship, etc; \(TEU\) is twenty-foot equivalent unit, indicating the capacity of a container ship; L indicates the length of a ship (m); B indicates the breadth of a ship (m).  
Furthermore, for lacking information on ship size or design speed, the average engine power of all ships of the same ship type within the POLB range is used as the ship's engine power. If the ship has no information on its kind, its engine power is determined by the mean power of all vessels in the POLB with the same length and breadth. The size and type of small vessels, such as fishing boats and tugboats, are generally similar. Hence, we apply the IMO statistical averages to the lacking engine data for these vessels [40]. The IMO average install power and design speed can also be used to calculate emissions for ships without these data.  
Based on the characteristics of AE power, it may be anticipated that there is a precise ratio of ME to AE for various ship types [41]. Table 2 displays numerous ship classes' AE power to ME power ratios. The average AE power ratio for ships of unknown ship type was also determined. Based on the study by [PERSON] et al. [42], this paper estimated boiler emissions to account for 1.25% of overall emissions when calculating boiler emissions.