Improved methodology

methodology.md

@@ -78,10 +78,6 @@ Details are available in the source code, [src/emissions.rs](./src/emissions.rs)
 
 ### M-6: Consumption of private jet
 
-This was performed by a human, and consisted in going through different aircraft
-manufacturers' websites and identifying the aircrafts that were advertised as used
-for private flying.
-
 This was performed by a human, and consisted:
 * access websites of companies that sell private jets
 * extract the consumption in gallons per hour (GPH) of each private jet model
@@ -93,21 +89,27 @@ This was performed automatically by the program and consisted in performing the
 following calculation:
 
 ```
-leg emissions [kg CO2] = 
+leg emissions [kg CO2e] = 
   consumption [gallon/h]
   x liters / gallons [L/gallon]
   x liters to kg of jet fuel [L/kg]
   x emissions per kg [kg CO2 / kg jet fuel]
+  x Radiative Forcing index [kg CO2e / kg CO2]
+  x Life-cycle emissions [kg CO2e / kg CO2]
   x leg time [h]
+  x occupancy [1/person]
 ```
 
 Where:
 
-* `consumption [gallon/h]` is obtained via the methodology `M-6` in this document.
-* `liters / gallons [L/gallon] = 3.78541 [L/gallon]`, as specified in [NIST's guide to SI](https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication811e2008.pdf)
-* `liters to kg of jet fuel A-1 [kg/L] = 0.8 [kg/L]`, as [recommended by ICAO](https://data.icao.int/newDataPlus/content/docs/glossary.pdf)
-* `emissions per kg = 3.16 [kg CO2 / kg jet fuel]`, as used on [ICAO Carbon Emissions Calculator Methodology, v12 from Sep. 2023](https://applications.icao.int/icec/Methodology%20ICAO%20Carbon%20Calculator_v12-2023.pdf) 
+* `consumption` is obtained via the methodology `M-6` in this document.
+* `liters / gallons = 3.78541 [L/gallon]`, as specified in [NIST's guide to SI](https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication811e2008.pdf)
+* `liters to kg of jet fuel A-1 = 0.8 [kg/L]`, as [recommended by ICAO](https://data.icao.int/newDataPlus/content/docs/glossary.pdf)
+* `emissions per kg = 3.16 [kg CO2 / kg jet fuel]`, as used on [ICAO Carbon Emissions Calculator Methodology, v12 from Sep. 2023](https://applications.icao.int/icec/Methodology%20ICAO%20Carbon%20Calculator_v12-2023.pdf)
+* `Radiative Forcing index = 3 [kg CO2e / kg CO2]`, as concluded by [The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018](https://www.sciencedirect.com/science/article/pii/S1352231020305689), from 2021.
+* `Life-cycle emissions = 1.68 [kg CO2e / kg CO2]`, [Life Cycle Greenhouse Gas Emissions from Alternative Jet Fuels v1.2](https://web.mit.edu/aeroastro/partner/reports/proj28/partner-proj28-2010-001.pdf) from 2010-06, accessed 2024-01-28.
 * `leg time [h]` is obtained by computing the time difference between the last and first position of the leg, identified via the methodology `M-4` in this document.
+* `occupancy = 0.23 [1/person] = 1/4.3 [1/person]` obtained from [Average number of passengers per flight who flew private worldwide from 2016 to 2019](https://www.statista.com/statistics/1171518/private-jet-per-flight/), where there were 4.3 passagers per flight in 2019, accessed 2024-01-28.
 
 ### M-8: Identify aircraft owner in Denmark
 

src/private_emissions.rs

@@ -1,11 +1,21 @@
 static LITER_PER_GALON: f64 = 3.78541;
 static KG_PER_LITER: f64 = 0.8;
 static EMISSIONS_PER_KG: f64 = 3.16;
+static RADIATIVE_INDEX: f64 = 3.0;
+static LIFE_CYCLE_FACTOR: f64 = 1.68;
+static OCCUPANCY_FACTOR: f64 = 0.23;
 
-/// Returns the total CO2 emissions in kg of an aircraft with a given
+/// Returns the total CO2 emissions in kg of a private jet with a given
 /// consumption (in GPH) of Jet-A fuel flying for a given amount of time,
 /// as specified in [methodology `M-7`](../methodology.md).
 pub fn leg_co2_kg(consumption: f64, duration: time::Duration) -> f64 {
     let hours = duration.as_seconds_f64() / 60.0 / 60.0;
-    consumption * hours * LITER_PER_GALON * KG_PER_LITER * EMISSIONS_PER_KG
+    consumption
+        * hours
+        * LITER_PER_GALON
+        * KG_PER_LITER
+        * EMISSIONS_PER_KG
+        * RADIATIVE_INDEX
+        * LIFE_CYCLE_FACTOR
+        * OCCUPANCY_FACTOR
 }