Cars consume much more fuel than stated

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Fuel gauge (symbolic image): Economical only on paper

Photo: iStockphoto / Getty Images

There is an increasing gap between official consumption data from car manufacturers and the reality on the road. The research organization International Council on Clean Transportation (ICCT) came to this conclusion in a study published on Wednesday. Accordingly, cars with combustion engines registered in Germany in 2022 burned 14 percent more gasoline or diesel per kilometer driven than stated - and accordingly also emitted 14 percent more climate-damaging CO₂. In 2018, the difference between official and actual consumption was noticeably smaller at 8 percent.

This means that the effect of the global test procedure WLTP that was introduced at the time for more realistic measurements is already canceled out. According to the previously used New European Driving Cycle (NEDC), the gap had been growing for years and was recently around a third. WLTP was intended to enforce more honest and reliable information - but apparently not with lasting success.

The European Union's requirements for manufacturers to reduce the CO₂ emissions of their new car fleet "do not apply in the real world," criticized ICCT senior scientist Jan Dornoff. "This undermines the EU's efforts to reduce transport-related CO₂ emissions and means that consumers have to pay more for fuel than expected."

Big gap between Opel and Hyundai

In addition to the official consumption data collected by the European Environment Agency, the analysis is based on fuel logs recorded by drivers during everyday driving via the spritmonitor.de portal. Adjusted for extreme cases with high or low consumption and cars with low mileage under 1,500 kilometers, data from more than 160,000 vehicles were received. The number of entries compensates for differences in individual driving style, which have a major influence on consumption and emissions.

The brands with particularly high values ​​include Opel, Hyundai, Ford and Seat. At Mercedes-Benz, VW, BMW and Audi, the real consumption was closer to that stated. In the old NEDC test cycle, the trend was the other way around: Audi in particular consumed more than the official fuel consumption, while Opel and Hyundai had the smallest gap.

The EU Commission has now established its own method to prevent fraud: Since 2021, manufacturers have had to install measuring devices in new cars that automatically inform the authorities about the real consumption. However, data from this on-board monitoring is not publicly available and, according to the ICCT, can only be meaningfully analyzed with a delay of several years. The EU published the first interim results in March 2023 and found an even larger discrepancy between official and real data than the ICCT at 22 percent.

The organization called for quick countermeasures. The actual consumption data recorded on board must soon be reflected in the manufacturers' fleet targets and not just from 2030, as the EU is planning. In addition, real energy consumption should also be recorded for electric cars in order to prevent waste of electricity as well as oil. Recently, however, there has not even been a semblance of progress: in 2023, the officially reported CO₂ emissions of the German new car fleet had increased instead of decreasing.

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