Why are there different standards for calculating therange of an electric car?
If there are a multitude of standards for defining the range of electric vehicles, it's above all to take into account geographical and usage disparities.
The concern is that standards are created to compare cars fairly, but they vary with the times and regions of the world. In fact, it's difficult to establish a universal global standard, given that road traffic road traffic and its various specificities around the globe are very different from one another. For example, American standards take into account the higher speed limits and more frequent highway stretches in the USA, while the WLTP standard takes into account a wider variety of driving situations, including city traffic.
Worldwide standards for estimating the range of an electric vehicle
Rigorous standards have been put in place around the world to ensure accurate and comparable measurements of electric vehicle range, providing consumers with a reliable basis for their purchasing decisions.
But what about it?
The WLTP cycle: the European standard
The WLTPor Worldwide harmonized Light vehicles Test Procedures, is a worldwide harmonized test for light vehicles. Although it claims to be "global" in scope, it has mainly been adopted in Europe. This homologation procedure evaluates a vehicle's fuel consumption, pollutant emissions and the range of electric vehicles. The WLTP cycle includes urban, extra-urban and mixed traffic.
Implemented since September 2017, it became mandatory mandatory for all new vehicles in September 2018replacing the 50-year-old NEDC standard, last updated in 1996.
From now on, the latter is compulsory for all new registrations from 1ᵉʳ September 2018.. Gradually, it will become the homologation standard for all vehicles marketed, everywhere in the world.
💡Did you know? The WLTP cycle is used for both electric and internal combustion vehicles to assess their fuel consumption, CO₂ emissions and pollutant discharges.
The WLTP cycle is presented as much more more realistic than the NEDC cyclecycle, thanks in particular to :
- new methods for calculating energy consumption
- and estimated CO₂ emissions more representative of everyday usage conditions.
The WLTP method takes into account the different options offered by certain vehicle models, which can influence the weight and performance of electric vehicles.
Fixed on rollers for 30 minutesthe vehicle covers a 23 km route simulating real-life driving conditions:
| WLTP certification cycle | |
|---|---|
|
Vehicle downtime
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Frequent stops 12.5% of the time
|
|
Temperature change
|
Temperature variations from 14°C to 23°C
|
|
Average speed
|
Average speed 46.5 km/h
|
|
Maximum speed
|
Reaching a maximum of 131.1 km/h
|
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Driving phases
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4 pre-calculated gearshift phases (low, medium, high and ultra-high)
|
|
Mixed cycle on the road
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A mix of urban (52%) and non-urban (48%) driving
|
💡Good to know : In addition to the WLTP standard, the RDE test (Real Driving Emissions) test has been made compulsory. This test takes into account various situations likely to occur during your journeys: weather, terrain, vehicle load, driving style and type of roads travelled.
In short, the WLTP cycle is precise, but it reflects a "standard" journeyi.e. :
- flat road,
- moderate speed,
- mild weather conditions.
This explains why theWLTP range is rarely identical to the actual range.. According to estimates, this cycle is on average 23% too optimistic compared to reality. Unless you only drive in town, adopting the best eco-driving practices.
To consult : Eco-driving: definition and how to practice it?
The NEDC cycle: the old standard dethroned by WLTP
The NEDC (New European Driving Cycle) was used in Europe from 1973 à 2017. Created at a time when vehicles and traffic conditions were very different, it is now obsolete replaced by the WLTP.
Gradually, the gap between the NEDC cycle and new vehicles widened, to the point where some of the data provided had to be almost doubled to obtain a more realistic value. doubled to obtain a more realistic value..
To take this measurement, the vehicle had to have already covered more than 3,000 km and be in running order, i.e. with full tanks and a driver weighing 75 kilos.
Fixed on rollers for 20 minutesthe vehicle covers a distance of 11 km simulating real-life driving conditions:
| NEDC homologation cycle | |
|---|---|
|
Vehicle downtime
|
Frequent stops 25% of the time
|
|
Vehicle weight
|
Special equipment and air conditioning not included
|
|
Average speed
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Average speed 34 km/h
|
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Maximum speed
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Reaching a maximum of 120 km/h
|
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Mixed cycle on the road
|
2 gearshift phases: 13 minutes for urban driving and 7 minutes for rural driving
|
As you know, the slightest slightest acceleration and long periods at steady speed are do not correspond to today's driving conditions. To illustrate this point, some electric vehicles accelerate from 0 to 50 km/h in 26 seconds, while an electric city car can do it in 4 seconds.
As a result, the impacts of the switch from NEDC to WLTP are notable. According to a Jato study published in August 2018, consumption consumption and emissions values increase by an average of 9.6 g/km CO₂ with the transition from NEDC to WLTP.. But that's not all: it can even be as much as 18,3 % for luxury cars.
Naturally, these figures are still lower than the actual emissions estimated outside homologation cycles, which are often approximately 40% higher on average.
The CLTC cycle: the Made in China cycle
The CLTC (China Light Duty Vehicle Test Cycle) is the homologation standard used in China, and is intended to replace the NEDC cycle.
Each phase is specifically designed to reflect real-life driving conditions in ChinaEach phase is specifically designed to reflect real-life driving conditions in China, in order to obtain results that are more representative of vehicle fuel consumption and emissions in a variety of situations.
Thus, through this new site, sought to establish a new test standard integrating :
- local roads,
- traffic conditions,
- and driving habits in China.
The CLTC cycle consists of 3 phases :
- slow driving (7 trips),
- average driving (consisting of 3 trips),
- and fast driving (consisting of just one trip).
In all, the process takes 30 minutes, with an average speed of 28.96 km/h and a top speed of 114 km/h.
Please note The CLTC standard is generally more optimistic than the WLTP cycle (range 15-25% greater).
The U.S. EPA standard
In the United States, theEPA (Environmental Protection Agency) standard is renowned for its stringent testing. It distinguishes between urban and highway driving, often providing more accurate estimates.
In fact, the EPA standard is often considered stricter than the NEDC cyclecycle, with average vehicle fuel consumption around 20% higher. Compared with the WLTP, EPA estimates are on average 11% lower.
The EPA test comprises 2 main cycles : urban (lasting 31 minutes) and highway (13 minutes) with a maximum speed of 100 km/h. Each cycle reproduces specific conditions, such as :
- city traffic jams,
- and long freeway journeys.
But that's not all: the tests include cold and hot starts, as well as various climatic conditions to represent realistic scenarios.
Which standard is closest to reality?
WLTP is currently the standard most representative of driving conditions in Europe.
Indeed, the WLTP standard is frequently criticized for its unrealistic test conditions. WLTP proposes a more dynamic and diversified test cycle, taking into account speed variations, frequent stops and different driving conditions. This approach provides an estimate that is closer to real-life conditions in Europe.
However, for even greater rigor, the U.S. EPA U.S. EPA standard is usually cited as the most reliable. The EPA standard uses separate urban and highway driving cycles, with simulated hot and cold stops and various climatic conditions. EPA results tend to be more conservative, offering a more accurate more accurate and often more realistic view of electric vehicle range.
Conclusion
In conclusion, understanding the different standards used to assess the range of electric vehicles is essential for consumers wishing to choose the vehicle that best suits their needs.
As SkodaThe fuel consumption and range data provided by automakers and observed in the standard cycle differ from those obtained in practice".
We have explored standards such as WLTP, NEDC, CLTC and EPA, each offering its own advantages and limitations. While the WLTP is closer to real-life driving conditionsother standards such as theEPA standards are also important to consider for a complete assessment.
Choosing an electric vehicle means taking a gamble on eco-driving and practicality. But with range still perceived by some as a hindrance, it's important to base your decision on reliable information.
For a more accurate estimate of the autonomy you'll need on a daily basis, take a look at our following articles:
Electric car battery autonomy: where do we stand?
Top 10 electric cars with the best range in 2024
By taking into account your driving habits and adopting a few eco-gestures, you can take full advantage of your electric car's potential!
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