Neutral technology

Many technologies claim to be able to make a significant difference to the carbon footprint of supply chains - and yet it seems that nothing is quite as it seems. This section looks at some of the technologies which may be able to replace traditional "brown" technologies across the supply chain. A good example is the debate over fuel choice - is diesel better than petrol at reducing the carbon footprint ?

Diesel vs. Petrol

On the one hand it is well known that diesel engines have lower fuel consumption and therefore emit less CO2 per km than a gasoline car with similar specifications. On the other hand diesel engines emit more air pollutants like nitrogen oxides and soot (black carbon). Their main impacts are the formation of ozone (O3) – which is a strong greenhouse gas – through photochemical reactions caused by NOx and black carbon which has a warming impact on surface temperatures due to absorption of sunlight. So – from a climate change perspective – do the higher pollutant emissions from diesel engines outweigh the reduction in CO2 emissions due to a better fuel economy?

Recent research shows that the answer is ‘No’. This is because CO2 has a much longer atmospheric residence time of hundreds of years compared to a few months (ozone) or a few days (black carbon) and therefore imposes a much longer warming effect on the planet. Moreover, many modern diesel cars are equipped with particulate filters that effectively reduce the black carbon emissions to gasoline engine levels. There are also technologies that reduce the NOx emissions down to gasoline levels and they will penetrate into the market within the next decade (latest by 2014 with the introduction of the EURO6 standard) and diesel engines will be on one level with petrol engines but with lower CO2 emissions. A very attractive alternative are hybrid cars because they achieve a similar or even higher fuel economy than diesel cars but with the low air pollutant emissions of today’s petrol engines.

The Neutral Group therefore concludes that modern diesel cars with particulate filters are a viable option to reduce the climate impact of corporate company cars. Apart from diesel, hybrid cars also offer great advantages over conventional petrol cars.

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