New cars would have consumed an average of 5.79 liters of gasoline in 2016, the federal office of energy reports. In practice, however, these cars burn seven to eight liters per 100 kilometers.
- Hanspeter guggenbuehl
Swiss people like to buy big and powerful cars. But they are only as economical as they should be according to the CO2 law under laboratory conditions.
New cars would have consumed an average of 5.79 liters of gasoline in 2016, the federal office of energy reports. In practice, however, these cars burn seven to eight liters per 100 kilometers. Because the test cycles do not reflect reality in many aspects.
Since 2015, the average CO2 emission of new cars put on the road may only be 130 grams per kilometer driven; this corresponds to 5.6 liters of gasoline per 100 kilometers driven. In this way, switzerland adopted the EU’s regulations in the CO2 law in order to slow down global warming.
the 320,000 cars newly registered in switzerland in 2016 almost reached this standard on average. At least, that is what the media release sent out by the Swiss Federal Office of Energy (SFOE) at the beginning of the week shows ("consumption of new cars was 5.79 liters per 100 kilometers in 2016"). because the 5.79 liters of gasoline equivalent per 100 kilometers (determined from gasoline, diesel and a few electric cars) result in an average value of 134 grams of CO2 per kilometer.
Consumption 20 to 40 percent higher
What the SFOE’s media release fails to mention is that the 134 grams of CO2 and 5.79 liters of gasoline equivalent are average values achieved on the test bench according to the 1996 "new european driving cycle" (NEDC). But there is a wide gap between the results of these laboratory measurements and consumption on swiss roads. In practice, cars newly registered in 2016 burn 20 to 40 percent more than the law allows on the test bench, i.e. seven to eight liters, measured in gasoline units.
These seven to eight liters are an estimate, because true fuel consumption varies depending on vehicle equipment, weight and driving style. But this estimate is well documented. The following results show this:
- Every year, the touring club of switzerland (TCS) calculates the difference between test bench and real-world consumption for the cars it tests. Results: the gap between the test bench and the real world is widening sharply: in 2000, the difference was only 0.4 liters; in 2014, it was already 1.5 liters, or 25 percent. According to this, the 2014 newly registered cars consume 7.6 liters of gasoline equivalent per 100 kilometers. Per average car and year, this resulted in an additional consumption of over 200 liters of fuel.
- A study by the international council on clean transportation (ICCT) compared the difference between the test bench and the real world by brand. Result of the survey published by "kassensturz" in 2015: the difference varied between 25 and 38 percent. It was noticeable that the differences were greater for expensive brands – and tend to be bigger gas-guzzlers – such as mercedes or BMW than for brands such as toyota, peugeot or renault, which produce cheaper cars with lower fuel consumption on average.
- Christan Bach, head of department at the Swiss Federal Laboratories for Materials Science and Technology (empa), which has been involved in test bench measurements for many years, estimates that the difference between test bench and real-world consumption in 2015 was around 40 percent, and the trend is also upward. Bach also relies on several independent samples and surveys.
Fuel consumption test falsified in many cases
This raises the question of how the huge differences between legally relevant testing and climate-relevant practical consumption come about. "the manufacturers are cheating," some criticize. "no," respond empa experts, "the manufacturers are simply optimizing their vehicles for a legal test cycle that has less and less to do with reality."
Even manufacturers and importers of passenger cars now admit this. Among other things, the following laboratory conditions are far removed from any automotive practice:
- On average, the cars on the test stand drive more slowly and accelerate at a slower pace than in real traffic.
- Manufacturers test those versions of their models that bring the least weight to the test stand. These rarely sold light models can be several hundred kilos lighter than the best-selling versions, which are equipped with many extras. The rule is: one hundred kilograms more weight increases fuel consumption by 8 percent for the same engine. This is important because the average new car is getting heavier and heavier – in 2016 it already weighed 1565 kilograms and carried an average of 1.6 people. The package is thus ten times heavier than the "freight" carried.
- the average temperature in the test laboratory is 20 degrees celsius. At this optimum temperature, the heating and air conditioning systems remain switched off during the test with the blessing of the legislator, as do the on-board computer, radio and other energy-guzzling installations that are now standard equipment in most cars.
- Manufacturers optimize engine settings for the test cycle, fit cars with thin tires for lower rolling resistance, etc.
New test conditions bring slight adjustment
For years, politicians and authorities at home and abroad have been calling for an adjustment of the 21-year-old test cycle. The modified NEDC is finally to be introduced in September 2017 and will come into force in 2019. It brings the laboratory conditions somewhat closer to those in road traffic, but without reaching the level of practical operation with the air conditioning switched on or the bike and ski racks strapped on.
The gap between legal standards and practical car use will thus continue to exist. And the controversy about the right test cycle will flare up again at the latest when it comes to the introduction of the stricter CO2 limits from 2021 – as decided by the swiss energy law.