*2.3. Calculations Criteria*

For emissions due to air travel, the calculation methodology and factors given by the UN agency International Civil Aviation Organization (ICAO) have been used [37]. In substance, this methodology applies the best publicly available industry data for aircraft types, route specific data, passenger load factors and cargo carried. The CO2 emissions per passenger was assessed taking into a total of 565,000 km per year of business and field trips flights, by means of these four basic steps:

1. Estimation of the aircraft fuel burn.


It is interesting to note that for flights over 3000 km, the CO2 emissions per passenger in the premium cabin are twice as high as the corresponding emissions per passenger in the economy cabin, as seen in other studies [38].

As regards car, bus and train travel, calculation was based on these criteria:

• 2018 Guidelines Defra Conversion Factors [39].

*By car*: average diesel car 0.178 kg CO2 person/km, one seat occupied; average petrol car 0.184 kgCO2 person/km, one seat occupied. *By bus:* regular diesel bus, 0.023 kg CO2 person/km.

• For train and metro, a Renfe/SNCF methodology based on the Ecopassenger calculator was considered [40]:

*By train/Metro:* 0.025 kg CO2 person/km (regular Spanish electric mix).

It should be noted that by using the railroad electric mix with green certificates instead of the regular Spanish electric mix, GHG emission drops by half [41].

For daily employees' commutes, the values shown in Table 2, obtained from an internal survey, express the number of kilometers traveled by employees to work per year. Results are presented in rounded numbers.

**Table 2.** Employee travel to work (Scenario 1).


In Table 3, business and field trips values are shown. It describes annual travel for educational and business reasons of students, lecturers and managers, by road, air and railway modes of transport:


**Table 3.** Business and field trips (Scenario 1).

<sup>1</sup> Average occupation 3 passengers per car.

Table 4 summarizes the main emission sources, including trips and employees commuting, organized in the corresponding three scopes.


**Table 4.** Main emission sources inventory (Scenario 1).

<sup>1</sup> Invoices supplier company. <sup>2</sup> High density polyethylene. <sup>3</sup> Calculated results.

## **3. Results**

The results of the calculations obtained are presented in Table 5. The total gives a figure of about 255,548 kgCO2-e.

Electrical energy consumption, producing 72,471 kg CO2-e (Scope 2), stands out as the main source of emissions. The 31,548 kg produced by Diesel C stationary combustion for heating (Scope 1) represents the second most significant emission. The WTT transmission and distribution losses (18,802 kg CO2-e) also represents an important source (Scope 3). This source is not manageable as it depends on the electrical system. For purchased products, from 34,645 kg CO2-e of materials, 10,075 kg are related to paper consumption (included photocopying) and 11,388 kg to textiles used for fashion practices. As regards commuting, road private combustion modes correspond to 28,290 kg CO2-e, significantly higher compared to urban bus (2564 kg CO2-e) and rail transport (14,626 kg CO2-e). Concerning business and field trips, flights represent a significant part of GHG emissions: 21% of Scenario 3 and 12% of total ESNE emissions were international flights (28,992 kg

CO2-e), representing the main part of the total of 29,855 kg CO2-e. Private car road transport (6382 kg CO2-e) is also significant compared to buses (991 kg CO2-e), even more taking in account the km·person relation. AVE transportation means the less affecting mode (1153 kg CO2-e).


**Table 5.** ESNE carbon footprint 2018/19 (Scenario 1).

<sup>1</sup> WTT (Well to tank): additional emissions (related to electricity).
