Environment and Climate

Global WLTP roll-out for more realistic results in fuel consumption

Questions and answers regarding the new international test procedure: Lawmakers require standardized test procedures to measure how much fuel a car consumes and whether it complies with the emissions limits. The new “Worldwide harmonized Light-duty vehicles Test Procedure” (WLTP) will apply to the type approval of new passenger cars across the EU since September 1, 2017. It will succeed the NEDC (New European Driving Cycle), which has been in force since 1992. It comprises both a new driving profile on test benches as well as more precise and up-to-date conditions for the entire test and is therefore intended to result in more realistic consumption data. What are the implications of this change? Seven questions, seven answers.

How will fleet emission limits be calculated in the future?

Since the more realistic WLTP test cycle was implemented starting in the fall of 2017, nominal CO2 emissions will increase – experts assume by around 20 percent. However, since the EU has already defined fleet targets based on the NEDC up to and including 2020, and the world's already most stringent CO2 fleet limit values will not be made even more stringent, the European Union will be prescribing a new conversion procedure.

In 2016, the average emissions of all newly registered vehicles in Europe continued to decline. The most recent figure was 118 grams CO2 per kilometer. In 2005, this figure was still at a level of 181 grams per kilometer, which corresponds to a saving of around 35 percent within a mere eleven years – despite a growing market share of so-called “sports utility vehicles” (SUVs), which, due to their greater mass and larger cross-sectional area, have less favorable physical prerequisites. However, the figures also show: achieving the ambitious EU targets will require further substantial efforts.

Up to now, CO2 emissions and the derived fuel consumption of individual passenger car models have been determined in the “New European Driving Cycle” (NEDC). The fleet limit value of 95 grams CO2 per kilometer, which the European Union has set for the automotive industry for 2020, also refers to this cycle. Fleet limit value does not mean that the emissions of individual vehicles are restricted but that the total fleet of each manufacturer is weighted against its registration figures. How high the individual emissions target of a manufacturer will turn out to be also depends on the weight of the vehicles sold by the manufacturer. The limit value increases when a manufacturer sells a particularly high amount of large and heavy vehicles.

Since the more realistic WLTP test cycle was implemented starting in the fall of 2017, nominal CO2 emissions will increase on paper. Experts assume an increase by around 20 percent on average. Since an exact average value will not be available before all vehicles are certified according to the WLTP procedure, the European Commission has decided not to adjust the CO2 limit value for new passenger car models until the end of 2020, but to convert the emission values determined in the WLTP on a case by case basis as if they were NEDC values. This will be done using software developed by the EU’s “Joint Research Center” (JRC). However, since these NEDC values are based on the more stringent framework conditions of the WLTP test procedure, they will be slightly higher than those according to the original test sequence. It is therefore important for anyone comparing CO2 emission values in the future to consider whether the vehicle has been certified according to the existing NEDC requirements or already according to the WLTP.

Which fleet consumption values will actually be achieved beyond a transitional recalculation in the coming decade depends less on a new test procedure, but to a great extent on two factors: firstly on how quickly partially or fully electrified vehicles can establish themselves on the market, and secondly on the feasibility of producing and using liquid or gaseous fuels from regenerative solar and wind energy. Taking these factors into account is a prerequisite for future realistic emissions legislation.

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