The average energy consumption of an electric vehicle has always been measured without heating the car, which can have a significant impact on driving range – in some cases even halving the range, according to new test methodology developed by Green NCAP.
When Green NCAP was launched in 2019 as an assessment programme for vehicle emissions, its main focus was testing the quality of exhaust gasses. Over time, additional parameters were adopted to increase its scope on the sustainability of cars, including the testing of electric vehicles’ (EVs) energy consumption.
Every EV, when it is homologated for the European roads, goes through the worldwide-harmonised Light vehicles Test Procedure (WLTP) and is tested for its energy consumption during a standardised driving cycle.
The WLTP is developed as a global test cycle designed to represent common driving patterns from different regions across the world. However, as Dr Aleksandar Damyanov from Green NCAP points out, the average energy consumption of EVs can vary widely depending on different factors.
“It has become increasingly clear that comparing vehicles’ average energy consumption can be very misleading,” Damyanov explains. “Under what conditions is the vehicle using this amount of energy? How is this vehicle being driven? In what temperatures and on what roads?”
Inconsistent energy consumption results in uncertainty regarding an electric vehicle’s driving range, which is a major factor in consumers’ decision making when purchasing an EV.
E-mobility Europe, the trade association representing the European electric vehicle ecosystem, speaks of "range anxiety": “Consumers, particularly those transitioning from internal combustion engine vehicles, often experience range anxiety, which makes them hesitant to switch.”
When testing vehicles’ energy consumption, the WLTP driving cycle is performed without any form of climatisation. This is of course understandable, as it aims to be representative for many different regions across the world with widely varying climates. The problem is that heating in particular will have a major impact on an EV’s energy consumption — far bigger than what we are used to for combustion engine vehicles.
“With EVs we have seen that the main contributor to a vehicle’s energy consumption differing from what has been officially declared, is the impact of climatisation,” Damyanov says.
“It’s not wrong that the WLTP-type approval is performed without that climatisation,” he continues, “but it is the task of consumer protection organisations, and of the manufacturers themselves, to inform consumers that the real consumption figure will depend on their needs and their behaviour.”
Much more than cooling, it is the heating of an EV in cold temperatures that will have the biggest impact on energy usage.
While combustion vehicles can use waste heat from the engine to heat-up the car, EVs need the heat to be delivered by the battery. “What was once essentially ‘free heat’ from the engine, now comes at a significant cost,” Damyanov explains.
“We have identified that there is indeed a lack of knowledge when it comes to heating electric vehicles. People are not always aware, and just want to switch from a conventional to an electric car. Suddenly, they can experience a big surprise when in winter, under severe conditions, their driving range can be halved. This is where Green NCAP comes in.”
To address this lack of knowledge, Green NCAP has developed their own energy consumption tests. The aim is to hold manufacturers to account and check how the numbers are deviating from what has been declared, but more importantly, to give consumers the ability to compare a wide array of different EVs that have been tested under the same conditions.
Ultimately, the goal is to allow European consumers to be more informed, avoiding potential range anxiety. In Damyanov’s words: “When you are informed, you can at least deal with that. You can plan your trip better. You can pre-condition your vehicle.”
Green NCAP first introduced the ‘cold ambient temperature test’. It is designed to simulate a scenario where a car is parked outside during a harsh winter. The test is performed at -7 centigrade in the laboratory, with the vehicle left to ‘soak’ in these cold weather conditions for a long time before the driving cycle starts, with the heating turned on to 23 degrees Celsius.
“You can imagine it’s a cold winter day, your vehicle was left on the street overnight at minus seven – you get to your car, everything is freezing cold, and you need to start your journey,” Damyanov says.
The cold ambient test unveils a surprisingly stark difference between an average vehicle’s WLTP result and the energy it consumes during the harsh winter simulation.
For the vehicles that were included in Green NCAP’s test so far, the average type approval consumption value was 16.7 kilowatt-hour (kWh) per 100 kilometres. While the cold ambient test averaged a staggering 31 kWh per 100 kilometres for these same EVs.
“So this is an increase of 86 percent,” Damyanov points out, “there are vehicles where the driving range is halved, or even worse.”
“We also found that the heating performance of electric vehicles can be highly deviating, certain models take a very long time before the required temperature is reached, if it is reached at all.”
Of course, the cold ambient test depicts a very specific situation, and might not be as representative for everyone looking to find out how much energy their vehicle consumes in winter conditions.
“Answering the question of total driving range is difficult, because the cold ambient test results are mostly impacted by the first part of a potentially much longer trip. This is where the vehicle needs to get warm and heat up the cabin. After that, the energy demand will drop as the initial thermal inertia has been taken care of,” Damyanov explains.
With this in mind, Green NCAP is expanding its focus on EV cold weather performance in 2025 and will be introducing a new test in the next few months.
The new test will be performed in the same cold weather conditions, except this time the vehicle will not be soaked in the minus seven temperatures beforehand. Damyanov describes the situation: “What if my vehicle was not left on the street? What if I had it in my garage? I need to make the same trip, on the same cold winter day, but the difference is that I don’t need to heat up all the components and the cabin when starting my journey.”
“The combination of both tests allows us to make a much more consumer friendly estimation of the total driving range of an EV under cold conditions.”
Although Green NCAP is very much in the middle of testing, and it is too early to come out with decisive figures, Damyanov is able to reveal that on average the cold ambient test uses approximately 25 percent more energy than the new ‘warm start’ cold ambient test.
He illustrates these initial findings using the test results of an unspecified EV: “One of the vehicles we tested for example used 29 kWh per 100 kilometres in the cold start cold ambient test and 22.5 kWh in the warm start cold ambient test.”
CLEPA, the European Association of Automotive Suppliers, welcomes Green NCAP’s efforts and emphasises their value: "Cold-weather testing is pivotal for electric vehicles, as it provides consumers with accurate insights into real-world performance. At the same time, it acts as a catalyst for manufacturers, offering crucial data that drives continuous improvements."
When asked whether car manufacturers are working on improving the cost of heating EVs, E-mobility Europe is very clear: “EV manufacturers are fully aware of the impact of climatisation on battery performance and are actively developing solutions to mitigate its effects.”
Aside from the wide array of innovative heating technologies, like heat pumps and battery thermal management systems (BTMS), Damyanov highlights the importance of also taking different approaches: “Why should the entire cabin be heated if it’s just the driver occupying it? It’s much more energy efficient to deliver the heat directly to the occupant of the car through seat heating or steering wheel heating for example or through directing the warm airflow only to the people currently in the car.”
“To go one step further, some manufacturers even think of integrating heater elements in the seat belt, because this is what touches you directly,” he continues. “We are not at the end of technological development — we see that some manufacturers can indeed improve on heating efficiency, by having better ideas and better engineers.”
“As battery technology improves and infrastructure expands, concerns about range will diminish, but for now, maximising efficiency — including through better climatisation — is key to improving consumer confidence,” E-mobility Europe concludes.
The objective is clear, Green NCAP will continue to increase its focus on cold weather performance of EVs. “In our protocols for 2025 we are including the new cold ambient test which starts warm, as well as a new insulation test,” Damyanov says.
A well-insulated vehicle can of course preserve its heat much better, and will, as a result, be much more energy-efficient. “As combustion engines always delivered heat for free, this is something that has not had much attention in the past,” Damyanov explains.
The importance of these projects is nicely summarised by E-mobility Europe: “As Green NCAP assessments highlight the real-world efficiency of different EV models, manufacturers will be incentivised to develop smarter and more efficient climatisation systems, leading to broader consumer acceptance and a faster transition to electric mobility.”
Green NCAP has already started testing vehicles for their 2025 protocols and aims to make a first release of test results in the first half of the year.
Green NCAP is a green vehicle-assessment programme, hosted and supported by the European New Car Assessment Program (Euro NCAP) in cooperation with European governments. This article was produced in collaboration with EUobserver.
Green NCAP is a green vehicle-assessment programme, hosted and supported by the European New Car Assessment Program (Euro NCAP) in cooperation with European governments. This article was produced in collaboration with EUobserver.