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How do we calculate the Ecoscore?

The ecoscore is calculated based on the most important pollutants emitted by the vehicle during the driving phase (exhaust emissions) and emissions from the production and distribution phase of the fuel (fuel cycle emissions). This is called a well-to-wheel approach.

Remark: the detailed sheet for an individual vehicle in the search section only contains tank-to-wheel emissions, i.e. the emissions of the fuel cycle. For most cars, these TTW emissions are more important in the total WTW emissions than the WTT emissions, although some exceptions exist (e.g. full-electric vehicles).

The emissions are divided into three categories: emissions with impacts on global warming, emissions with impacts on air quality (divided into impacts on human health and impacts on ecosystems) and noise emissions.

  • The following greenhouse gases are taken into account for the calculation:
    • Carbon dioxide (CO2)
    • Methane (CH4)
    • Nitrous oxide (N2O)

The relative weight of the various greenhouse gases is determined by their global warming potential (GWP), by which all greenhouse gases are expressed in CO2 equivalents. The GWP conversion factor is computed according to the IPCC (Intergovernmental Panel on Climate Change) of the UN.

  • Concerning air quality emissions, the calculation takes the following pollutants into account:
    • Carbon monoxide (CO)
    • Hydrocarbons (HC)
    • Nitric oxides (NOx)
    • Particulate matter (PM)
    • Sulfur dioxide (SO2)

We use the external cost methodology for the weighing of the air quality emissions. This methodology attaches a monetary value (in EUR/g) to the various emission categories, based on the impact that the emissions have and the damages they cause to human health and the environment. These monetary values ​​were calculated in extensive research projects, with inputs from environmental and health experts and economists. Moreover, the methodology provides different values ​​for pollutants emitted in an urban or a non-urban environment. For evaluating the fuel cycle emissions, the non-urban external cost figures are used. Regarding exhaust emissions, an urban/non-urban average is used for the calculation of the environmental score. The values ​​used are taken from the ExternE project, a project funded by the European Commission and a scientific reference in the field of external costs.

  • Regarding noise emissions, the following parameter is taken into account:
    • Engine noise (dB(A))

For all types of vehicles, the impact over the three categories is then compared to the impact caused by a reference vehicle. The reference for passenger vehicle is defined as a vehicle that meets the Euro 4 emission standard with CO2 emissions of 120 g / km. The weighing of the three impact categories into one indicator for the environmental friendliness of the vehicle is based on the weights that you find in the following figure.

 

 

Formula for the calculation of the Ecoscore of passenger cars en light-duty vehicles (specific formulas for PHEV can be found here):

Ecoscore  = 100*exp[-0.00357*(A * CO2 + B * HC + C*NOx + D*CO + E*PM + F*FC + G*dB(A) + H)]

Ecoscore 'Greenhouse gases' = 100*exp[-0.00357*2*(A * CO2 + f1 * FC + h1)]

Ecoscore 'Air quality' = 100*exp[-0.00357*2.5*(B * HC + C * NOx + D * CO + E * PM + f2 * FC)]

Of which the following parameters are mentioned on the certificate of conformity 

CO2

CO2 emission (combined) (g/km)

HC

for petrol, LPG and CNG vehiclesHC emission (g/km)
for diesel vehiclesthe difference between the HC+NOand the NOx emissions (g/km)

NOx

for petrol, CNG and LPG: NOx emission (g/km)

for diesel vehicles(for more info, click here)

  • for vehicles complying with standard Euro 0 till Euro 5, this is 0.63 g/km . 
  • for vehicles complying with Euro 6, this is 0.50 g/km

CO

CO emission (g/km)

PM

the particulate emissions (g/km)

FC

for petrol, diesel and LPG vehiclesthe average fuel consumption (combined cycle), expressed in l/100km


for CNGthe average fuel consumption (combined cycle), expressed in kg/100km


for EV:  the average electricity consumption (combined cycle), expressed in kWh/100km

dB(A)

the noise level (driving), expressed in dB(A)

and with the coefficients A, B, C, D, E, F, f1, f2, G and the constants H, h1, h2 corresponding to the values in the table below, each time subdivided per fuel type and Euro standard. For Euro 6 cars and vans, the formulas are elaborated here.

 

 

Cte

 

 

CO2

HC

Nox

CO

PM

FC

dB(A)

 

 

H

h1

h2

A

B

C

D

E

F

f1

f2

G

petrol

Euro 0

-12,63

0,71

-13,33

0,36

23,17

101,88

0,011

1407,75

7,01

1,12

5,89

0,333

Euro 1

-10,26

3,07

Euro 2

-11,77

1,57

Euro 3

-12,63

0,71

Euro 4

-12,63

0,71

Euro 5

-12,63

0,71

Euro 6

-12,63

0,71

diesel

Euro 0

-10,34

2,99

-13,33

0,36

23,17

101,88

0,011

1407,75

5,19

0,94

4,25

0,333

Euro 1

-13,03

0,3

Euro 2

-12,71

0,62

Euro 3

-12,39

0,95

Euro 4

-12,39

0,95

Euro 5

-12,39

0,95

Euro 6

-12,39

0,95

LPG

Euro 0

-11,55

1,78

-13,33

0,36

23,17

101,88

0,011

1407,75

2,91

0,59

2,32

0,333

Euro 1

-11,55

1,78

Euro 2

-11,87

1,46

Euro 3

-12,63

0,71

Euro 4

-12,63

0,71

Euro 5

-12,63

0,71

Euro 6

-12,63

0,71

CNG

Euro 0

-10,68

2,65

-13,33

0,36

23,17

101,88

0,011

1407,75

3,67

1,64

2,03

0,333

Euro 1

-10,68

2,65

Euro 2

-11

2,33

Euro 3

-11,76

1,58

Euro 4

-11,76

1,58

Euro 5

-11,76

1,58

Euro 6

-11,76

1,58

electric

 

-13,33

 

-13,33

 

 

 

 

 

2,17

1,01

1,16

0,333

last database update: 12/05/2022 - next database update planned for: 15/07/2022
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