Each electric car has a technical sheet containing essential information such as range, consumption and polluting emissions. To calculate these data, manufacturers previously used the NEDC (New European Driving Cycle) protocol. Since September 2018, the WLTP cycle (Worldwide Light Vehicles Test Procedures) has now been operational. With a global reach, it aims to provide motorists with information that is as close as possible to reality.
What does this protocol consist of? Is it reliable? Explanations in this article.
NEDC and WLTP: what are the differences?
Before being put on the market, new cars are subject to mandatory tests. These make it possible to measure accurately:
— autonomy;
— electricity or fuel consumption;
— CO2 emissions.
To obtain figures that are consistent with each other, the certification tests are carried out under similar conditions for all cars. For years, these were governed by the NEDC standard.
However, it should be noted that this standard was designed in the early 1970s, at a time when traffic conditions and vehicle characteristics were very different.
This was compromising for motorists because the ranges and consumption announced were not reliable. Thus, the NEDC standard was abandoned in favor of the new WLTP cycle (in French, globally harmonized test procedure for light vehicles). A stricter, longer and realistic protocol is then imposed on manufacturers.
Did you know that?
The WLTP certification cycle should gradually become mandatory for all cars, regardless of the region of the world. Since January 1, 2019, in Europe, manufacturers have been required to display data obtained by the WLTP cycle. In addition, countries such as South Korea and India should also implement it very soon. On the other hand, the United States and Russia are considering how to implement it.
Electric cars: how are WLTP tests carried out?
Each certification test is carried out in a laboratory. During the procedure, the car is placed on roller benches and follows a course that is supposed to replicate maximally real driving conditions.
The test route for electric cars is carried out under the following conditions:
— duration of the cycle: 30 minutes;
— distance travelled: 23.25 km;
— average speed: 46.5 km with a peak of 131 km/h;
— temperature ranging from 14°C to 23°C;
— taking into account additional equipment. For some electric models, the options can in fact influence the consumption of the vehicle.
Two circuits are covered: the first (52% of the tests) concerns urban routes. The second (48% of the tests) consists of extra-urban trips with motorways and national and departmental roads. The average of these two courses corresponds to the” mixed cycle ”, which is indicated on the vehicle technical data sheets by the manufacturers.
For comparison, the NEDC protocol took place over a distance of 11 km for 20 minutes. The average speed was 34 km/h and optional equipment was not taken into account. As a result: a vehicle like the Hyundai KONA Electric saw its range increase from 546 km in NEDC... to 484 km with the WLTP standard.
Good to know
The WLTP procedure is complemented by another protocol: the RDE (Real Driving Emissions). Carried out on an open road in a random manner, it makes it possible to take into account external parameters that may be encountered by motorists, and which are not reproducible in the laboratory.
Should we believe the autonomy promised in the WLTP cycle?
The WLTP cycle is more in line with reality than its predecessor NEDC. According to Auto Plus magazine, the difference between WLTP consumption and the real consumption of a combustion vehicle is estimated at 1 L/100 km, compared to 3 or even 4 L/100 km with the NEDC cycle. However, the certification tests take place on a course without reliefs and at reduced speed. Depending on the driving mode and traffic conditions, it is sometimes possible to exceed the announced autonomy in the city. Conversely, for a trip at full speed on a highway, it is estimated that the real autonomy corresponds to approximately 50-60% of the announced autonomy. For example, for a Peugeot e-208 promising 340 km in the WLTP cycle, the actual range will vary between 136 and 180 km on the highway.
While WLTP data is more realistic, it should be taken with perspective. No standardized cycle of any kind is capable of reflecting precisely the autonomy and consumption of a vehicle. Indeed, many factors influence the consumption of an electric car, such as the driving mode (smooth or sporty), the type of road (flat or hilly) or even the weather.
Also to read: Autonomy of an electric car: understand everything
Sources: Clean car, AutoPlus, Renault
