New study: Plug-in hybrids jeopardize climate targets

According to a new analysis conducted by the Ifeu Institute, in collaboration with the Öko-Institut and the European umbrella organization Transport & Environment on behalf of the Federal Ministry for the Environment, the increased use of plug-in hybrid models puts climate goals at risk. The boom in electric cars in Germany is currently mainly taking place among large plug-in hybrid vehicles, the authors state. More than three-quarters of these are registered as company cars. Since they generally use the internal combustion engine predominantly in daily operation, they emit significantly more CO2 than previously assumed in calculations of German greenhouse gas emissions for 2030.

"Our calculations show that, given market forecasts, we must expect up to 4.3 million tons of additional CO2 emissions in 2030 for the transportation sector due to plug-in hybrids if the electric driving shares remain as low as they are today," warns Ruth Blanck, Senior Researcher at the Öko-Institut.

Based on current estimates, the CO2 target in the transportation sector of 95 million tons of CO2 for the year 2030 will be exceeded by about 30 million tons of CO2. In previous scenarios for the development of CO2 emissions in the transportation sector, these higher emissions are usually not included, as the calculations are based on type approval emissions, the authors clarify. However, actual emissions - especially from heavy plug-in electric vehicles - are often several times higher than these values. The already challenging achievement of the 2030 climate protection target will thus become even more difficult, the institutes warn.

Lack of incentives for charging - one-third of PHEVs are SUVs

The researchers see the main reason for the low share of electric driving in the lack of economic incentives for electric charging and (especially in the case of company cars) often high daily mileage. Additionally, there are sometimes no charging options available at home or at the workplace. Moreover, plug-in hybrids often have above-average energy consumption due to their design, engine, and weight. Furthermore, about one-third of newly registered plug-in hybrids are SUVs or off-road vehicles.

Battery and electric motor insufficient for company cars

In many cases, the battery of such heavy vehicles is not sufficient for the daily kilometers. At high speeds or during strong acceleration, the internal combustion engine turns on even when the battery is still full. The electric motor usually only accounts for about one-third of the maximum engine power and cannot provide sufficient drive power on its own.

Only with green electricity and defensive driving plausible

If the vehicles were fueled with low-CO2 electricity, driven defensively, and predominantly used in electric driving mode, CO2 emissions could be significantly reduced. For a medium-sized plug-in hybrid in 2030, real CO2 emissions are about 130 g per kilometer, while the target fleet average is approximately 60 g/km.

"Under current conditions, the further market ramp-up of plug-in hybrid vehicles jeopardizes Germany's 2030 climate targets in the transportation sector. From an environmental policy perspective, the support from purchase premiums and tax advantages needs to be urgently reviewed," concludes study director Julius Jöhrens from ifeu.

Daily charging crucial for CO2 balance

Especially for private plug-in hybrids, the study authors believe that charging discipline pays off for the CO2 balance. Only if all private plug-in hybrids are charged daily will these vehicles save about as much CO2 as assumed in the emissions calculations for 2030, the forecast predicts. However, for company cars, the situation looks bleak: Even under very optimistic assumptions for charging discipline in 2030, real CO2 emissions would remain about twice as high as in standard test procedures. Here, significantly higher electric ranges would be required to improve the situation, the institutes demand.

"Benefits for plug-in hybrids should be tied to strict criteria for electric range, electric performance, and proof of regular charging options," explains Julius Jöhrens.

Moreover, Jöhrens believes that electric driving should be made financially attractive for users. Without changes in support, there is a risk of having a large number of plug-in hybrid vehicles with very limited real electric range in the stock for many years, which could only achieve limited electric driving shares despite disciplined charging, Jöhrens warns in conclusion.