The European Commission has
published its Joint Research Centre assessment of the impact that the new WLTP
test cycle will have on European car fleet CO2 emissions. Some really
interesting summary findings of what the shift from NEDC will mean for
- The fleet-wide, sales weighted average ratio
between WLTP and NEDC officially reported CO2 emissions for conventional
passenger cars for year 2015 fleet composition was estimated to be 1.21.
- The WLTP/NEDC ratio decreases as the NEDC CO2
value increases. This ratio becomes around 1 at values of approximately
250 gCO2/km in NEDC.
- A slightly higher ratio between WLTP and NEDC
is observed for gasoline vehicles as compared to diesel ones, while there
is a decreasing trend in the ratio with increasing mass, capacity, or
power of the vehicle.
- Results for Light-Commercial Vehicles are
expected to follow the same trend as passenger cars. However the WLTP to
NEDC ratios resulting from the calculations seem overall higher than those
derived for passenger cars (especially for diesel vehicles, which however
represent the vast majority of the fleet of light-commercial vehicles)
- Battery electric vehicles, fuel cell vehicles
and hybrid vehicles show slightly higher WLTP/NEDC ratios than ICEVs and
for BEVs and FCVs the dependency of the ratio from the size of the vehicle
is less pronounced and opposite in sign, with bigger vehicles experiencing
slightly higher ratios).
- Different considerations hold for plug-in
hybrid vehicles instead. Due to the difference in the two procedures (NEDC
& WLTP) for calculating the final CO2 emissions, after several
analyses it resulted that the WLTP to NEDC ratio will quickly decrease as
the size of the vehicle batteries will increase. Given the uncertainty in
the market evolution, in the present report it was considered appropriate
to assume that in the coming years the WLTP CO2 emissions for plug-in hybrid
vehicles will be very close to the NEDC ones.