People, Environment

Diesel Harms More Than Petrol

Diesel Harms More Than PetrolDiesel Harms More Than Petrol

Diesel engines could be a bigger cause of climate change than petrol engines, according to a new study which has warned that the fuel’s environmental benefits could have been overstated.

The results of the study, conducted by Eckard Helmers at Trier University with Michel Cames of the University of Luxembourg, were presented to the European Parliament last week by environmental action group Green Budget Europe. These showed Europe’s diesel-dominated fleet was emitting significantly more carbon dioxide, on average, than petrol and hybrid-heavy markets.

Despite the steep decline in Europe’s new car CO2 emissions over the last 20 years, Japan has recorded a lower average since 2006, and the gap is growing. In 2013, new cars in Japan (where hybrids have a 22% market share and diesels 1.8%) emitted an average of 108g/km CO2, compared to 128g/km in the European Union, where diesel has a 53% share and 1.4% were petrol hybrids.

Although the results were not adjusted to reflect differences between the Japanese and European test cycles, Helmers said that the difference could be even higher.

Meanwhile, the gap between petrol and diesel models in Europe was 1.6g/km in 2013, which Helmers noted was largely due to vehicle size.

The study also pointed out that black carbon emissions, another greenhouse gas, are higher for diesel vehicles and aren’t considered with the CO2 output.

Based on the results, Green Budget Europe is recommending that policymakers end preferential treatment for diesel engines, including weaker nitrogen oxide emissions limits and lower tax, to encourage development of hybrid and electric models.