# Port-Related Shipping Gas Emissions--A Systematic Review of Research
## 3 Discussion and Results
### Analysis of the Most Commonly Applied Methodologies and Datasets--Third Layer
#### 3.3.1 ENTEC and NAEI Research  
The primary objective of the ENTEC 10 research established by the Department for Environment, Food and Rural Affairs (Defra) was to develop a detailed ship emissions dataset that could be used to inform United Kingdom (UK) policies targeting shipping emissions [31]. Although this inventory was based on information about ship movements from 2007, it is a continuation of the ENTEC 02, ENTEC 05 and ENTEC 07 studies. The approach is consistent with the methodology for quantifying ship emissions in the EEA 09 and relies on information that largely dictates the emissions from a vessel: installed engine power, type of fuel consumed, vessel speed and distance travelled (or time spent travelling at sea), time spent in port and installed emission-abatement technology [31]. Although the methodology follows the EEA 09 guidelines, equations, types of vessels and EFs are different, so this research was analysed separately. Activity data on vessel movement and port entries was provided by the Lloyd's Marine Intelligence Unit (L MIU) which used AIS data for movements that were not recorded in the port arrivals statics. In addition, the aforementioned information was compared with the Department for Transport's (DfT) data in order to corroborate them. Static data that largely dictate emission volumes, such as vessel characteristics (type and service speeds) and main engine (ME) and auxiliary engine (AE) characteristics (type, speed and fuel type) were gathered from the L MIU database. Although this study has a UK focus, the generic values of key elements for quantifying  
Figure 3: Citation quantity overview of methodologies and datasets originated from the papers and studies that explored ship emissions estimation.  
emissions can be applied in different research areas since L MIU compiles one of the largest datasets containing vessel information. Although this research treats of three different movement activities, the equation for at-sea activity is separated from the equation for port emissions that is related to hoteling and manoeuvring activities. Equation (5), presented below, is applicable for determining port emissions [31].  
\[\text{E}=\text{T}\times\text{[(ME}\times\text{LF}_{\text{ME}}\text{))}\times \text{EF}+\text{(AE}\times\text{LF}_{\text{AE}}\text{))}\times\text{EF} \tag{5}\]  
where:  
E: Emissions per vessel--in grams (g);  
T: Average time spent at berth/manoeuvring per calling--in hours (h);  
ME: Installed main engine power--in kilowatts (kW);  
LFME: Average load factor of main engine at berth/manoeuvring--as a percentage of ME power (%);  
AE: Installed auxiliary engine power--in kilowatts (kW);  
LFAE: Average load factor of main engine at berth/manoeuvring--as a percentage of ME power (%);  
EF: Emission factors assigned to each vessel for at berth/manoeuvring depending on each fuel type and engine speed--in grams per kilowatt hour (g/kWh).  
ENTEC 10 was the last research provided by Entec ltd. that explored shipping emissions for Defra, relevant to the UK waters [31]. That is why it should be emphasised that in the latest UK National Atmospheric Emissions Inventory (NAEI) conducted for Defra, EEA methodology was followed with differences in applied data [78; 79].