Carbon emission computations
For hotels
This section describes how CO2 emission factors are computed for hotels (see Accommodation for the full hotel list).
CO2 emission for hotels mainly comes from electricity and water consumption. It is possible to estimate such quantities, for one night, according to their comfort rating, defined by the number of stars and their ecological type:
for conventional hotels,
for ecological hotels, i.e., which have the La Clef Verte / The Green Key or the European Ecolabel international environment label for tourist accommodation
for Accor's group conventional hotels with Planet 21 ecological certification, with a 10% CO2 emission reduction aim to 2015 (-5.5% obtained in 2010, which is used for our computations).
Of course, the more comfortable the hotel, the more CO2 it emits. Electricity and water consumption for conventional hotels and ecological hotels come from a study made by ADEME, EU Ecolabel and AFNOR. Knowing each hotel's electricity and water consumption in one night, e.g., 74.8 kWh of electricity and 335 l of water for -hotels, CO2 emission is computed using some conversion factors: 0.09 kg/kWh for electricity and 3.67e-5 kg/l for water [ADEME 2010]. All results can be found in the table below.
| Comfort rating | Electricity consumption (kWh/night) |
Water consumption (l/night) |
CO2 emission (kg/night) |
CO2 emission factor (% increase) |
|
74.8 | 335 | 6.85 | 1 (base) |
|
77.8 | 424 | 7.16 | 1.04 (+4%) |
|
83.5 | 454 | 7.68 | 1.12 (+12%) |
|
96.4 | 594 | 8.89 | 1.30 (+30%) |
|
33.4 | 201 | 3.08 | 0.45 (-55%) |
|
33.7 | 210 | 3.11 | 0.45 (-55%) |
|
34.2 | 283 | 3.18 | 0.46 (-54%) |
|
58.6 | 310 | 5.39 | 0.79 (21%) |
|
70.7 | 317 | 6.47 | 0.945 (-5.5%) |
|
73.5 | 401 | 6.77 | 0.98 (-2%) |
|
78.9 | 429 | 7.26 | 1.06 (+6%) |
|
91.1 | 562 | 8.40 | 1.23 (+23%) |
When hotels are not explicitely known, we user a mean CO2 emission value, which is equal to 6,5 kg/night [ECORISMO 2012].
For transport
This part provides the emissions factors for transport of participants from home to Lille, i.e., CO2 equivalent greenhouse gases (GHG) mass per distance unit and passenger [ADEME 2010].
- Train emits on average 22 g CO2 equivalent of GHG for each km and passenger in France (TGV high-speed train). It is 44 g in Europe, as an average. Difference comes from the coal, gas, nuclear and renewable resource mix in order to produce electicity. Uncertainty on this value is 20%.
- Plane emits on average 260 g CO2 equivalent of GHG for each km and passenger for short distances (< 1500 km). This is 12 times more than train in France (x6 in Europe). This value is 268 g for longer distances. These values are averages over second-, first- and business-class. Uncertainty on these values is 50%.
- Car emits on average 217 g CO2 equivalent of GHG for each km and passenger. This value is dedicated to extra-urban journeys. It is an average on petrol and diesel vehicules with various power, in France. This is 10 times more than train in France (x5 in Europe). Uncertainty on this value is 20%.
- Bus, e.g., shuttle from the airport, emits on average 40 g CO2 equivalent of GHG for each km and passenger. For inter-city journeys. This is 2 times more than train in France, and is equivalent than train in Europe. Uncertainty on this value is 12%.
For Local mitigation
Local mitigation project is to plant 30 trees and 1285 bushes, as 3 hedgerow groves whose total length is 528.5 m. It could capture from 141 tons of CO2 in 20 years to 243 tons of CO2 in 40 years, as carbon stored in trunks and grounds [Agroforesterie2009]. This would completely mitigate our local emissions (152 tons of CO2 equivalent). Please find below computation details. One hedgerow grove is able to capture about 1 kg of Carbon per hedgerow grove meter and per year [Agroforesterie2009]. The whole hedgerow grove may then capture 1.94 t CO2/year. Over 20 years, which is a typical lifetime, the whole hedgerow groves may capture 38.8 tons of CO2. Trees are willows. We treat them as poplar in order to estimate that each tree may capture 170 kg CO2/year [Agroforesterie2009]. These 30 trees may then capture 5.1 tons of CO2/year, i.e., from 102, 153 or 204 tons of CO2 in 20, 30 or 40 years, respectively. These willows, if maintained, may last longer. Total is 141 tons of CO2 in 20 years, up to 243 tons of CO2 in 40 years (hedgerow grove is not counted over 20 years).
References
[ADEME 2010] Bilan Carbone - V6.1 Emission factors guide, ADEME, June 2010.[ECORISMO 2012] Gilles CIBERT, Hubert VENDEVILLE, Agnès LECOMPTE. Etiquetage environnemental
des hôtels : expérience nantaise. Forum ECORISMO Nantes-2012, 18-19 January 2012, Nantes.
[Agroforesterie2009] X. Hamon, C. Dupraz, F. Liagre, L'agroforesterie, outil de séquestration du Carbone en agriculture, AGROOF, INRA Montpellier, 12/2009.