NEDC, WLTP And Real Range. Which One?
The acronyms used for data related to fuel consumption or range, I fear are just as confusing as those used for EVs. The reality is that fuel economy or range data for all engine types, whether petrol, diesel or electric, are at best, just a guide with a varied degree of inaccuracy!
The least accurate is the New European Driving Cycle (NEDC) introduced in the 1980s. It has become increasing inaccurate and outdated.
More accurate than the NEDC, is the more recently introduced, Worldwide Harmonised Light Vehicle Test Procedures (WLTP). Potentially, the most accurate range estimates are from 3rd parties, such as What Car?.
Bottom-line, no source is truly accurate, as the variables for assessing range are so varied. As you drive your EV, you will gain the most accurate understanding of range achieved, given your specific driving profile and conditions.
Given the emission scandal around internal combustion engines (ICE), in particular diesel, one would have expected automotive manufacturers to have improved data transparency and accuracy.
Though the ‘world of EV’ is a ‘new chapter’ for the automotive industry, the early paragraphs scripted do not give me confidence that automotive manufactures have truly learned enough from the emission scandal. There is much room for improvement in disclosing more realistic and accurate data!
In general, there still seems to be much difference between manufacturer quoted range and ‘real life’ achieved range. Range anxiety, the Achilles heel for the electric car industry has been further amplified due to such range discrepancies.
Last month, I wrote about ways to maximise range in electric cars. It is a preoccupation of every aspiring or current owner of an EV. The good news is that the recent BEV model introductions have seen an increase in battery capacity and quoted range.
In some case, like the Tesla Model 3 and the Jaguar I-PACE, the manufacturer quoted ranges are above 200 miles. However, as more data is collected in real driving conditions, will it become clearer if the disclosed ranges are robust.
The introduction of the WLTP testing procedures, is a step in the right direction. However, it does have limitations. Driving conditions vary vastly between countries, driving styles, behaviours, weather etc. At best WLTP offers more accurate guidance compared to NEDC, but still has room for improvement.
WLTP basics 101:
- Introduced to improve data for consumers on emissions and fuel consumption (internal combustion engines i.e. petrol and diesel) and range (electric cars)
- The previous standard, the New European Driving Cycle (NEDC) is based on laboratory tests i.e. not a good reflection of realistic driving conditions
- WLTP uses real-driving data, such that results reflect more accurately everyday driving conditions. The standard has been developed by the United Nations Party on Vehicle Regulations. Though, it is envisioned to be a global standard, Europe is the first region to formally adopt the testing standard.
WLTP testing conditions include:
- More realistic driving behaviour
- Assessment of driving situations to include urban, suburban, main road and motorway
- Longer distances
- More realistic acceleration and braking driving profile
- Higher average and maximum speeds
- More realistic ambient temperatures
Some differences between NEDC and WLTP:
- Test cycle: (NEDC: single test cycle/ WLTP: dynamic test cycle)
- Cycle distance: (NEDC: 11 km/ WLTP: 23.25 km)
- Average speed: (NEDC: 34 km per hour/ WLTP: 46.5 km per hour)
- Maximum speed: (NEDC: 120 km per hour/ WLTP: 131 km per hour)
Currently both NEDC and WLTP are being used. However, NEDC is being phased out since September 2017. Other factors that influence range include:
- Ambient temperature
- Battery state of charge and condition
- Driving style
- Vehicle payload
- Vehicle electronics
- Heating and climate settings
As an example, let’s look at the difference between NEDC, WLTP and real range estimates for the Renault Zoe (R110).
- Battery Capacity: 41.00 kWh
- NEDC Range: 186 miles
- WLTP Range: 179 miles (at 50 miles per hour)
- What Car? Real Range: 146 miles
The NEDC range is nearly 30% more than the What Car? Estimate. The WLTP range, though more conservative, is still more than 20% compared to the What Car? estimate.
In the case of the ubiquitous Nissan Leaf, the difference between NEDC/ WLTP compared to What Car? is over 30%.
- Battery Capacity: 40.00 kWh
- NEDC Range: 168 miles
- WLTP Range: 168 miles
- What Car? Real Range: 128 miles
Hyundai Kona Electric:
As for the Hyundai Kona Electric SUV, the NEDC range is around 14% higher than the What Car? estimate.
- Battery Capacity: 39.00 kWh
- NEDC Range: 180 miles
- WLTP Range: N/A
- What Car? Real Range: 158 miles
The issue of ‘real range’ is less amplified for shorter journeys. However, for longer distances, I would suggest being conservative with your range assumptions when planning the trip. Calculate your range with a 30% lower adjustment to manufacturer quoted range to be on the safer side!