Emission-testing results show that diesel cars can emit more carbon dioxide and are more expensive than their petrol counterparts, according to a new study released on 8 May by the organisation that lifted the lid on the Dieselgate scandal.
Research by the International Council on Clean Transport (ICCT) has concluded that medium-sized diesel cars produce more CO2 under both laboratory and real-world testing conditions, despite common perception that they are the cleaner option.
Tests involved two versions of the same Volkswagen Golf and were undertaken using both the New European Driving Cycle (NEC) method and its successor, the Worldwide harmonised Light vehicles Test Procedure (WLTP). The VW Golf was chosen as the test vehicle “with a focus on comparability from the consumer’s point of view” and because of its popularity in the C-size or medium-sized segment of cars.
Diesel emissions were 124 g/km under the NEDC and 139 g/km of CO2 under the WLTP, which is considered to be a far more accurate method. Meanwhile, the petrol car only emitted 109 g/km and 126 g/km, respectively. On-road tests and driver feedback also confirmed the same trend, according to the study’s authors.
The ICCT experts concluded that the lack of CO2 emission advantage offered by buying a diesel car should kickstart a debate about how the fuel is taxed.
“EU Member States should re-assess preferential tax rates for diesel fuel and should join countries such as France, the United Kingdom and Switzerland, where diesel subsidies have already been or currently are being phased out,” the report reads. Indeed, in Germany, excise duties on diesel are around 30% lower than petrol’s, which costs the Bunderepublik around €7bnin lost revenue every year.
The ICCT also mentioned that “despite the extensive technology package deployed on the VW gasoline engine to achieve low CO2 emissions, the Golf TSI [petrol car] comes at a significantly lower price than the Golf TDI [diesel car]”. There is a price gap of around €3,200 between the 2018 petrol and diesel models, which increases to €3,600 for the 2019 version thanks to new air pollution filters and the added cost of building diesel engines.
It is possible that the study’s findings could feed into an ongoing debate about energy taxation, which recently flared up again as the EU officially registered a petition in favour of levying taxes on jet fuel.
On 7 April, German sportscar maker Porsche, a subsidiary of Volkswagen AG, acknowledged that it would pay a €535m fine for selling diesels that emitted more harmful pollutants than legally permitted. A Stuttgart court confirmed that the fine was based on “negligence in quality control” and that Porsche had abstained from mounting a legal challenge.
The maker of the popular 911 sportscar said in its own statement that the negligence in question had been identified “several levels below the board” and that the large fine had already been accounted for in the company’s Q1 results.
Dieselgate has so far cost VW an estimated €30bn.
No other cases against carmakers over Dieselgate are currently open, although legal action against individuals is still pending, including against former VW CEO Martin Winterkorn.