Is diesel running on empty?

Posted on: 19 April 2018

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You’d be forgiven for thinking that diesel is the worst thing ever, with the amount of negative press it has been given in recent months. What was promised as a wonder-fuel, cleaner and more efficient than petrol, has been marred by scandalous developments involving ‘cheat devices’ and better measuring tools exposing it as comparatively more polluting than petrol.

With all the confusion, drivers turning their back on diesel are ‘partly to blame’ for the first rise in carbon dioxide (CO2) emissions in 18 years (when records began)1. With alternative fuel sources gaining lots of positive industry noise, are we seeing the slow death of diesel?

Not so clean diesel

To define ‘cleanliness’ of emissions produced, we must delve to the chemical level. Petrol engines generally produce a higher amount of CO2. Diesel engines produce comparatively less, and were therefore thought to be cleaner for the environment. However, diesel engines produce much higher levels of nitrous oxide (NOx), which is more harmful to air quality and health.

It is debateable as to what is causing the renewed rise in CO2. Some blame consumers shunning diesel and buying more petrol vehicles. Others suggest the rise is explained by more SUVs and cross-over vehicles being sold, which are inherently more thirsty and polluting1.

How we got here

Advances in engine technology helped develop a market for diesel cars in the 1990s, especially in Europe. Diesel cars are cheaper to run than petrol over the long term and, as the world began to grow concerned with rising carbon emissions, governments started encouraging consumers to switch. In 2001, Chancellor Gordon Brown even cut fuel duty on diesels in a deliberate attempt to encourage people to switch2.

The positive image of diesel began to smudge a decade after Mr Brown’s pledge. In-depth studies carried out by the European Environment Agency found the NOx from diesel cars was responsible for 71,000 premature deaths in one year2. This was followed in 2012 by the World Health Organization declaring diesel fumes as carcinogenic, a cause of lung cancer in the same category as mustard gas and asbestos2.

The emissions scandal of 2015 has had far-reaching implications. Diesel models were found to display a different result for their output when under test conditions than on the road. What was particularly damaging was the revelation that companies had deliberately fitted vehicles with devices to fool the test. The fallout from this event has irreparably damaged the reputation of the fuel source.

Consumers are conflicted. The need to travel, to be able to commute, competes with a desire to reduce our impact on the environment. Diesel vehicles offered the conflicted consumer relief – and wasn’t a high-reaching alternative technology with lofty ambitions.

How it looks now

Diesel has an image problem. The emissions scandal and government rhetoric has led to the reputation of diesel being further tarnished. At the same time, manufacturers are attempting to reassure that new diesels are absolutely fine, emissions wise.

A brand new diesel car is ‘broadly on par’ with its petrol counterpart, according to The Society of Motor Manufacturers3. Thanks to tighter regulation following the scandal, new diesels generally are as clean, but the element of doubt has been sowed into the majority of drivers. The number of new diesel cars registered in February 2018 in the UK was 28,317, 23.5% less than a year ago4.

The government has been under increasing pressure to do more about urban air quality and reduce emissions to hit the ambitious targets set out within the Paris Climate agreement. By imposing new tax laws on diesel cars, which come into force this year, they hope to start weaning drivers from the internal combustion engine and onto an alternative.

Let’s not forget the drivers who bought into diesel. Understandably, they’re angry that they were encouraged to go for diesel, only to be faced with clean air zones, pollution charges and other new restrictions. They feel punished.

The wider view

Against this backdrop of changing attitudes, many things have started happening which could further drive the final nail in diesel’s coffin.

At a city level, Paris, Madrid, Athens and Mexico City have agreed to outlaw diesel vehicles by 20252. Berlin has already banned the oldest and most polluting diesel cars from its from its centre and Munich will enact a form of diesel ban this year. London has, so far, resisted a complete ban, but mayor Sadiq Khan is replacing London’s diesel buses and wants to instigate a £10 ‘toxicity’ charge on high-polluting cars in the city.

A recent ruling in Germany is being hailed as a landmark case regarding banning diesel vehicles. It was argued to be necessary because 70 German cities exceeded safe NOx levels in 20175. As the world becomes more and more concerned with environmental impact, a growing number of countries intend to turn their back on diesel.

Countries banning fossil fuel vehicles
Country Ban announced Ban commences Scope
Norway 2016 2025 Gasoline or diesel
Germany 2017 2030 Gasoline or diesel
Britain 2017 2040 Gasoline or diesel
India 2017 2030 Gasoline or diesel
Holland 2017 2030 All vehicles emission free
France 2017 2040 Gasoline or diesel
Ireland 2018 2030 Gasoline or diesel
China 2018 Undetermined Gasoline or diesel

These local and nationwide changes have spurred the automotive industry into action. A number of manufacturers have announced their intention to limit or completely stop producing diesel vehicles in the future. These include Fiat Chrysler (by 2022), Porsche (already dropped) and Toyota (who said they would ‘probably not launch’ another model with a diesel engine).6 We could be seeing the beginning of major manufacturers losing faith in the engine and fuel due to overwhelming public and government condemnation.


Electric cars are still a niche market, but it is growing. With a general shift away from diesel and encouragement, both from the government and society, to reduce our individual impact on the environment, cleaner cars and electric alternatives are increasingly being thrust into the spotlight. It seems diesel woes are fuelling alternative growth. In February 2018, 7.2% more electric vehicles were sold in the UK as consumers are now being encouraged to go greener4.

Hurdles facing the uptake of electric cars are mainly their price, the lack of a comprehensive charging infrastructure and of their individual ranges. Manufacturers are aware of these concerns and are rapidly developing technology to fix it. Battery prices are tumbling, which should translate to cheaper models. The battery technology is also improving year on year, a battery breakthrough is expected imminently, which could dramatically reduce the weight, improve capacity and improve range.

Where does this leave diesel?

It seems there is no way back for the fuel. The introduction of better particulate filters feels like the industry putting a plaster on the problem until a suitable solution emerges. Consumer confidence has never been lower, countries and manufacturers are also turning their back on it. So much so that very recently, the UK is being urged to phase out petrol and diesel cars well before their 2040 deadline.