Climate ratings on emissions from plug-in hybrid vehicles (PHEVs) will become much more realistic after the European Union agreed to assess its CO emissionstwo real, reducing the utility factor. As of 2025the EU will significantly reduce this coefficient that represents the proportion of electric driving that regulators use to calculate CO emissionstwo of the PHEVs. As of 2027the utility factors will fully correspond to the real world driving.
Plug-in hybrid models are becoming more common in the manufacturers’ catalogue. It is a technology halfway between a combustion car and an electric one that has the advantages (and disadvantages) of offering the best and the worst of both worlds. However, in the WLTP homologation cycle, with just 50 or 60 kilometers of autonomy, cars with 300 horsepower and weights of more than 1,700 kilograms obtain a consumption of around 1.2 or 1.3 liters per 100 kilometers. Even the large five-meter-long SUVs remain at 2 liters and all this because the homologation cycle is very permissive with them.
The Transport & Environment (T&E) organization has been warning for years to highlight the true impact of plug-in hybrid vehicles, which it considers “false“. In his opinion, the new system “will end the emissions scandal that misleads consumers and allows automakers to significantly weaken their CO emissions targetstwo”.
“For years, emissions from plug-in hybrids were based on unrealistic driving conditions,” explains Anna Krajinska, T&E engineer. The new rules reflect the reality that PHEVs pollute far more than manufacturers claim. Governments that still incentivize the purchase of these fake electric vehicles must now stop their harmful subsidies.”
The most recent data shows that, on average, privately owned PHEVs emit three more times COtwo than what their homologation indicates and, therefore, they use three times more fuel than what is officially registered. In the case of company car fleets, the situation is even more unfavourable. Plug-in hybrids emit five times more than their official rankings. The car manufacturers have focused their arguments on indicating that it is the drivers who do not recharge the batteries on a regular basis. Although this may be one of the causes, the truth is that plug-in hybrids generally have small batteries, highly dependent on combustion engines for energy and without fast charging capacity.
The engineering solutions to reduce CO2 emissions from plug-in hybrids go through installing higher capacity batteries to extend the electric range and have smaller combustion engines that reduce fuel consumption. Estimates suggest that the size of the battery that should be installed would be around 30 or 40 kWh which is too close to what is put in some 100% electric vehicles of small size and urban character.
Current emissions ratings allow most PHEVs to count as “low emission” vehicles under EU rules. The law gives manufacturers of a bonus for every zero- or low-emission vehicle they sell, prompting automakers to make more plug-in hybrids as a way to lower their fleet average emissions target.
The WLTP protocol establishes consumption based on the amount of COtwo issued and in the case of PHEVs the cycle repeats several times. The first test is carried out with a full battery and continues to be repeated until it is empty. Finally, a new cycle is performed with the battery at zero. The COtwo It is calculated as the proportion of the electric range recorded in the test over the total range. The homologation is the result of the consumption of the first 100 kilometers of the car. The following, until recharging, will be in hybrid mode or even in battery recharging mode, which will increase consumption. In them the battery will be recharged enough for the electric motor to help somewhat in decelerations. But it will be a much higher consumption than approved. All the advantage they may have over a non-hybridized car is lost.
In addition, the protocol records the “Utility factor (UF)”, which represents the proportion of electrical conduction. In an electric car it is 100% and in a combustion car it is 0%. CO emissionstwo they are calculated according to the ratio between the electric autonomy and the total autonomy. The reality is that this factor gives an idea of the consumption of a plug-in hybrid combining its use as a combustion car and as an electric car.
The EU has decided to review this concept in 2024 depending on the data collected by the fuel consumption meters located on board these cars and which are sent automatically. Your analysis will provide a more complete assessment of the proportion of kilometers traveled in electric mode. With the real data on the table, it will be possible to modify the utility factors between 2025 and 2027 so that they correspond to the real behavior of drivers.
The European Union began to receive these real data on the consumption of cars registered since last April 1. This information, which is transmitted completely anonymously so that the owner of the vehicle is not known, but the make and model is, and can be analyzed later to find out the consumption and, therefore, the emissions in a real way. The data that is sent also includes the operating mode of the vehicle in the case of a hybrid or a plug-in hybrid.
“We welcome the end of the myth that plug-in hybrids are low emission vehicles. If manufacturers want to avoid EU fines, they will have to sell genuinely green cars that help reduce our oil consumption,” Krajinska said.