Automotive Climate Change Question 11

From RankaBrand
Jump to: navigation, search

<< back to Automotive section
Previous: Automotive Climate Change Question 10
Next: Automotive Climate Change Question 12


“Does the brand sell a car that has a CO2 emission of 100 grams per kilometer (g/km) or lower?”

Dutch version: “Verkoopt het merk een auto met een uitstoot van 100 gram per kilometer (g/km) of minder?”

German version: Verkauft das Unternehmen ein Auto, das einen CO2-Ausstoß von 100 Gramm pro Kilometer (g/km) oder weniger hat?


With reference to any CO2 reduction target, it is imperative that cars with a low CO2 emission are necessary to compensate for cars with high CO2 emissions. Progress can be made with innovations and continuously higher performances of new models.

A car with a CO2 emission of 100 g/km or lower is proven possible. Many brands have at least one car below the 100 g/km threshold [1]. The question therefore aims to measure good practice within the automotive industry.

Please note that when car brands have already launched a plug-in hybrid, electric, or fuel cell car on the market, it is important that the energy efficiency data is also provided by the brand, e.g. in terms of kWh/km, even this is not common practice in the automotive sector yet. Here we quote Transport & Environment: "electric cars should be rewarded for their energy efficiency, not for moving emissions from exhaust pipes to powerstation chimneys." Based on the EU average carbon emissions per kWh of electricity generated, it is possible to estimate the carbon emissions per km driven in a (semi-) electric car.

Comparable CO2 emissions levels for Plugin and Electric vehicles

For plugin-electric and electric vehicles, the comparable carbon emissions level per km can be estimated as follows:
1. Find out the energy consumption in kWh or Wh per km (check if tested according to NEDC).
- For plugin-electric vehicles, emissions from electricity use is additional to carbon emission from fuel consumption. E.g. Opel reports for the plugin Ampera (p.27) that carbon emissions from fuel consumption are 27 g/km and electricity use 169 Wh/km.
- For some electric cars, the energy consumption might be directly reported by brands, e.g. for the Mitsubishi i-MiEV, which gives 135 Wh/km. Alternatively, the energy consumption can be estimated from the action radius with the battery capacity. For example, for the Nissan Leaf the action radius is 175 km, the battery capacity is 24 kWh. This results in 137 Wh/km.
2. Calculate the comparable carbon emissions level per km, based on a well-to-wheel EU average value of 443 g CO2/kWh (source p.7) for energy production corrected by the Tank-to-Wheel factor of 0.83; which gives 368 g CO2/kWh.
- For the example of the plugin Ampera the comparable CO2 emissions level per km can be estimated at: 27 + 169*0,368 = 89 g CO2/km.
- For the example of i-MiEV, the comparable emissions level is 135*0,368 = 50 g CO2/km.

Why we use the correction factor
The factor of 0.83 is applied for the reason of comparability. The issue is that CO2-efficiency for fuel-powered vehicles is reported on the basis of Tank-to-Wheel (=CO2 emissions from fuel consumption) where Well-to-Tank emissions (fuel production) are not included. For electric vehicles however, the estimated CO2 efficiency is always based on the principle of Well-to-Wheel (CO2 for the generation and distribution of electric energy, while emissions at driving are 0). With the correction factor of 0.83 we get what we call the comparable carbon emissions level per km. This number is virtual, but comparable to the common reporting standard based on Tank-to-Wheel as used for fuel powered vehicles. Tank-to-wheel is the common reporting base we need to adhere to until Well-to-Wheel becomes the new standard.

The Well-to-Tank energy (and consequently CO2-) efficiency for fuel (from the primary energy source to the fuel tank) is namely around 83% (p.5). This means that the production, refining and distribution of a liter of fuel delivered to the vehicle and fuel tank consume the equivalent of a fifth liter of fuel. In other words, when 'Well-to-Wheel' values are multiplied by factor 0.83 we obtain the commonly used Tank-to-Wheel value in g CO2/km.

Answering guidelines

Rank Yes:

- <<Brand>> sells the <<diesel/petrol>> <<model(s)>> with a reported CO2 emission level of <<value below 100>> g/km.
- <<Brand>> sells <<model(s)>> which is a <<plugin hybrid / fuel cell / electric car>> <<model(s)>> with an estimated comparable CO2 emission level of <<value below 100>>> g/km, based on European average CO2 emissions from electricity production, and corrected to better compare to tank-to-wheel values of fuel powered vehicles.

Rank ?:

- <<Brand>> does not report on the fuel efficiencies of its vehicles. - <<Brand>> does not sell a (hybrid) petrol or diesel car with a CO2 emission of <<value below 100>> g/km. <<Brand>> sells an <<plugin hybrid / fuel cell / electric car>> <<model(s)>>but does not provide the efficiency rates of these models.

Rank No:

- The brand catalog has no car with a CO2 emission of 100 g/km or lower, nor a plugin hybrid, fuel cell or electric car with comparable efficiency performances.