October 7, 2014

Diesel emissions crackdown on the way?

‘Dirty’ diesels are new pollution target

A global crackdown on diesel engine emissions seems only a matter of time as concerns about air quality and health increase, leaving fleet operators to scratch their heads over the most suitable choice of future powertrains.

Earlier this year, the World Health Organisation (WHO) doubled its estimate of the number of people who die as a result of air pollution each year, based on increased knowledge about the health effects of pollutants such as nitrous oxides or NOx and particulates.

Inevitably, that means the finger being pointed at diesel-engined cars, which are responsible for three times the NOx emissions of their petrol-engined counterparts.

Diesel domination

Yet, for the last decade or more, diesel-powered vehicles have dominated the UK fleet scene. Successive Governments have targeted the reduction of carbon dioxide emissions through company car taxation, which has meant that diesel cars, producing less CO2 as they do, have become more popular than their petrol-engined equivalents – even though they have carried a 3% ‘dirty’ surcharge in the company car tax scales.

New car registrations by fuel type - 2000 to 2013. Source: SMMT

New car registrations by fuel type – 2000 to 2013. Source: SMMT

That surcharge is now set to be removed from April 2016 under forthcoming tax legislation, leaving fleet managers to ponder exactly what the message is that the Government is trying to convey.

The issue regarding diesel versus petrol, especially since the arrival of more fuel-and tax-efficient, lean burn turbo-charged petrol engines, has now become a much more widely debated, and less clear-cut, one.

And the switching point for which diesel is recommended from a whole life costs point of view has steadily increased over the years.

Five years ago, a diesel car was recommended for drivers who did around 15,000 miles a year, but now that has typically gone out to around the 25,000 mile mark.

This is largely because of the front end premium that fleet buyers face with diesel engined vehicles, allied to the higher prices paid at the pump. All these factors combine to start making the proposition for petrol just a little more compelling.

New Euro 6 rules

At the same time, new stricter Euro 6 regulations governing vehicle emissions are coming into force and are mandatory from next January.

Meeting these new Euro emissions standards is relatively straightforward for petrol engines. For diesel cars though, it is much more challenging.

The previous Euro 5 regulations targeted exhaust particulates, with many new diesel cars being fitted with diesel particulate filters (DPF) to meet the new standards – although their operation has not been without its problems.

This time, the stricter Euro 6 regulations are targeting ‘NOx’ because they are a significant greenhouse gas and air pollutant, linked to urban fatalities.

diesel emissions

As a result, a Euro 6 diesel car must emit 50% less NOx than its Euro 5 equivalent. Diesel engines naturally produce higher levels of nitrous oxides than petrol cars, so while Euro 5 was a daunting target for diesel engines to meet, Euro 6 is even more challenging.

To meet them, car manufacturers are having to invest in yet more new diesel engine filtration technology to clean up exhaust emissions. But ‘NOx filter’ solutions are costly. Diesel cars are already more expensive than comparable petrol models and this will only add to the price premium.

Many current generation diesel cars also require the addition of AdBlue fluid to a separate reservoir to help reduce emissions of nitrogen oxide. This will typically last 12,000 miles before requiring a top-up. However, if it runs dry, the vehicle will go into ‘limp home’ mode and, as most current service intervals differ from this mileage interval, inconvenience and other issues could ensue.

Euro 6 emissions compliance is already becoming a selling point as the new regulations come into force, and many manufacturers have moved early to ensure their new models meet the new standards ahead of time.

What to consider next

Fleet decision makers have a number of issues they need to consider in the light of the new thinking on diesel emissions.

  • Fleet buyers should only consider new vehicles that comply with the new Euro 6 rules. This will become mandatory from the start of 2015 anyway, but new models should be selected on their ability to meet the new regulations.
  • Fleets could consider the latest petrol alternatives which, due to manufacturer developments, can now offer comparable fuel economy and CO2 emissions’ performance.
  • For larger fleets and logistics companies that need to operate in town and city centres, consideration also needs to be given to investment in hybrid or electric vehicles (EVs) as emissions standards in city centres, such as in the London Charging Zone, become more exacting.
  • While a move to EVs has been facilitated by recent improvements in recharging infrastructure, this is still an expensive option, and not one all fleet operators may be able to economically consider.

Fleet operators could also consider a more sophisticated approach to journey planning, such as the use of on-board telematics, to reduce emissions. Telematics systems can provide real-time information to the driver about fuel consumption and features, such as a steep hill or a heavily congested area, and help cut fuel use and associated emissions.

The focus on air quality will inevitably lead to new challenges and diesel-engined vehicles are likely to be increasingly targeted. Many businesses will need to make adjustments to account for this – some more radical and far-reaching than others.

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