Exhaust emissions

Since the early twentieth century, the automotive industry has powered the development of the world’s economies. It has enabled people and goods to travel progressively faster, more safely and more economically.
But the motive power behind that development, the internal combustion engine, is now regarded as a significant factor in the pollution of our atmosphere – to the detriment of the health of the world and its inhabitants. The engine produces emissions which, in a concentrated form, contribute to global warming and which are injurious to the human respiratory and cardiovascular systems.

Exhaust emissions from internal combustion engines

The exhaust emissions which represent the greatest threat are carbon dioxide, carbon monoxide, nitrous oxides, unburnt hydrocarbons and particulate matter. Carbon dioxide is the most important of the greenhouse gases which are causing global warming and climate change

The magnitude of the threat is emphasised by the fact that in the European Union, road transport is responsible for some 20% of all CO2 emissions, with passenger cars contributing about 12%. In Britain, 19% of the nation’s CO2 emissions come from road vehicles. On a global scale, the burning of transportation fuels account for 14% of annual greenhouse gas emissions. This is the third largest source (after power stations and industrial processes). If we take carbon dioxide emissions in isolation, transportation fuels represent almost 20% of the total (again, after power stations and industrial processes).

European Union regulation

In the EU there has been legislation to reduce exhaust emissions from petrol and diesel vehicles sold in the member states. The regulated pollutants are carbon monoxide, unburnt hydrocarbons, nitrous oxides (all invisible gases) and particulate matter which is visible in the smoke emitted from diesel engine exhaust and older petrol engines.

The emission standards are defined in a series of EU Directives which legislate for the progressive introduction of increasingly stringent regulations. The passenger car stages are Euro 1, which came into force in 1993, through to Euro 5 (2009) and Euro 6 (2014). There is similar legislation for commercial vehicles.

The dramatic impact of this legislation is illustrated by the fact that today, it would take 50 new cars to produce the same emissions per kilometre as a single vehicle made in 1970.

But the same improvements are very far from the case with regard to CO2 emissions.

CO2 emissions from cars

At the 1997 Kyoto Conference on climate change most developed countries agreed to legally binding targets to reduce greenhouse gas emissions but there was no such legally binding agreement to reduce CO2 emissions from cars. Instead, in 1998, the EU and the industry associations representing the major car manufacturers agreed a set of voluntary targets which, from the start, were unlikely to be achieved. The aim was to reduce the average carbon dioxide emissions of new cars to 140g/km by 2008/9 – a reduction of 25%. By 2006, with this target obviously out of reach, the EU decided to legislate.

Following intense lobbying by the major car manufacturers, a compromise agreement was finally adopted in December 2008. The key elements of this are:
•    A gradual reduction in CO2 emissions from new vehicles to 120g/km for 65% of new cars in 2012. This will comprise a target of 130g/km to be reached by improvements in vehicle technology plus a 10g/km target to be achieved by complementary measures - better tyres, for example and the use of biofuels.
•    The 120g/km target will apply to 75% of new cars by 2013, 80% in 2014 and 100% in 2015.
•    Each manufacturer will be given a target based on the type of vehicles it sells. The heavier cars produced in Germany, for example, will have a higher g/km target.

The major car manufacturers are already voicing their concerns about this agreement and the resulting EU regulation which will impose binding targets on them to limit CO2 emissions on the vehicles they currently produce. Achieving those levels and the required introduction dates will require very significant investment which will result in higher prices for conventionally powered vehicles. The pricing gaps between conventional vehicles and hybrids/electrics will narrow, making hybrids/electrics more attractive to car buyers.

One a wider scale, the EU’s policy is to achieve a 20% reduction in greenhouse gases by 2020. However it found little resonance at the December 2009 UN climate change conference in Copenhagen. Because the193 nations represented at the conference failed to agree on any substantive targets, the EU will now pursue a new deal on global warming through the Group of 20, rather than the UN. The EU is determined that it will be the driving force of the global climate change debate. The G-20 is an international body that meets to discuss economic issues. Its members - 19 countries with some of the world's biggest industrial and emerging economies, plus the European Union - represent about 90% of the world's gross national product, 80% of world trade and two-thirds of the global population.

CO2 awareness to encourage new propulsion methods

On the consumer side, awareness of global warming and climate change will continue to rise and carbon dioxide emissions will play an increasingly significant role in car purchase decisions. An important factor is the desire to be seen as socially responsible and to be ‘doing one’s bit’ for the environment. The success of hybrid cars, at their relatively high prices, is indicative of this consumer attitude.
As electric vehicles come on stream, quite apart from any financial considerations, they will benefit from consumers’ wishes to be associated with cars which do not emit pollutants.

Global warming will therefore encourage the development of alternative forms of vehicle propulsion which are cleaner than today’s conventionally powered cars. Hybrids and electrically powered vehicles can be expected to account for a significant share of new car registrations as early as 2015.

And forty years from now?

The global car population is currently some 650 million units. Carlos Ghosn, chief executive of the Renault / Nissan alliance, has forecast that it will reach 2.9 billion by 2050 and at least two billion of that will be in countries where the car market is currently almost non-existent. He is convinced that people will not give up the privilege of having an individual motorised means of transport.

If Ghosn is right, it is inconceivable that those vehicles will be powered as they are today. Car manufacturers’ adherence to global emission standards and the price, and scarcity, of oil will drive the market to zero emission cars. And that means, from today’s perspective, fuel cell technology that will allow cars to run on hydrogen produced from a clean source.