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Is diesel really cleaner than electric?

Yes, and for the most part, no. It all depends on how you look at it, but perhaps also on the commercial interests that are at stake. When I say clean or dirty, I of course mean the emission of fine particles (from tyres and from the exhaust) and NOx from the exhaust. CO2 is neither clean nor dirty and I won’t go into that right now. Back in 2014 TNO and CE Delft had already demonstrated that an electric car emits less CO2 than a gasoline or diesel car taking the current electricity mix and manufacturing process into account.

The recently promised CO2 emission reduction targets for new passenger cars for 2025 and 2030 have been released, however, they do not oblige car manufacturers to move away from internal combustion engines. These new standards require car manufacturers to reduce the CO2 emissions of all new cars by 15% by 2025 and 37.5% by 2030 (respectively 15% and 31% for vans), compared to 2021. According to Transport & Environment (T&E), the regulation will encourage car manufacturers to promote the sale of 15% zero and low-emission vehicles in the EU (i.e. including plug-ins) by 2025, and by up to 35% before 2030.

Increase in sales in Germany

The diesel car will be allowed to stay with us for a while longer. The number of diesel cars sold in Germany has risen since the beginning of 2019 once more. In the July/August 2019 issue of Automotive Engineering, there is even talk of developing the combustion engine up until 2050, but this is mainly due to the market in less accessible areas. It is a different story in Europe. The diesel is also making a slight recovery here according to IHS Markit. In 2025, it is estimated that 25% of European car production will still be made up of diesels. Most of these will have to be sold in the EU.

I wonder whether this will all work out, as the diesel has come under pressure due to the high costs involved in exhaust gas after-treatment systems and the steadily declining running costs for electric cars. In this respect, the ‘dieselgate‘ effect on consumers is still alive and kicking. However, we have a tendency to forget things rather quickly. Who else is remembers the T&E cycle beating report back in 1998? At the time, according to research by T&E, car manufacturers scandalously used modern equipment in order to adapt the car to the test. The (corrupted) computer was even able to recognize when the car was in a certain test cycle so that the combustion engine could be switched to a different mode. The result was that the NOx emissions were increased by a factor of three when driving in real time on the motorway! Mind you, this was 17 years before the modern-day dieselgate!

Significant reduction in fine particles

Yet there is some good news. Competition that the combustion engine gets from its electric counterparts ensures that the accursed diesel in particular is making rapid advamces. A test by Emissions Analytics in conjunction with Auto Motor & Sport (15 August 2019) shows that it is actually Volkswagen who is the cleanest with its model Tiguan 2.0 TDI 4Motion. In polluted air (50,000 PN/cm3), significantly less fine particles are measured in the exhaust than are drawn in. With clean air (10,000 PN/cm3), the amount of fine particles is slightly higher than the amount of air that is drawn in.

You could joke that the very latest diesel engines should drive around in polluted areas to purify the air, like in Amsterdam for instance. Needless to say, that’ s meant in a slightly cynical way. A diesel does emit NOx and other toxic substances as well. The electric car is the future, but because the diesel will be with us for a little longer, it’s better to make it as clean as possible. And if that is due in part to the advent and promotion of the electric car, then that’ s a double bonus.

Over deze column:

In a weekly column, alternately written by Eveline van Zeeland, Jan Wouters, Katleen Gabriels, Mary Fiers, Lucien Engelen, Peter de Kock, Tessie Hartjes and Auke Hoekstra, Innovation Origins tries to find out what the future will look like. These columnists, occasionally supplemented with guest bloggers, are all working in their own way on solutions for the problems of our time. So tomorrow will be good. Here are all the previous columns.