Air quality issues drive vehicle alternatives


Courtesy of Energy Institute (EI)

Vehicle exhaust systems remain a major source of air pollution in cities, despite the progress being made to reduce emissions from new models. Energy World takes a look at efficiency improvements, and the alternative fuel alternatives to petrol and diesel.

In early April, the south of Britain woke to a hazy blanket of smog. A few weeks earlier, Paris had choked and spluttered through its own shroud. Tales of the nightmare air of Beijing have gone global. The World Health Organisation estimates that in one in eight deaths worldwide, the cause is linked to, or exacerbated by, air pollution. There is no one culprit. Coal burning and construction make major contributions, as do naturally occurring conditions, like dust blown from the Sahara. Yet one factor almost all have in common is high levels of emissions from traffic, particularly the fumes from diesel vehicles.

Since 2002 the number of diesel cars in Europe has soared. The UK is no exception. By 2012 more than 50% of all the cars and trucks on the roads were diesel. The reasons are simple. Diesel engines are more energy efficient than standard petrol (gasoline) engines. Yet there are downsides. Diesel engines produce far more soot than most other forms of car engine and as a result particulate emissions, including very fine particles less than two microns across – PM2.5, – have soared. (The smaller the particle the more damage it tends to cause, as it is able to penetrate deep into the lungs).

At the same time, carbon emissions from vehicles, while declining, are one of the largest sources of greenhouse gases in Europe. In the UK, they account for around a sixth of all greenhouse gases released. As a result of these twin pressures, efforts are underway to find new methods of increasing the energy efficiency of vehicles, and indeed entirely new ways of powering them.

EU Fuel Efficiency Directive

Perhaps the most important legislative tool to control emissions from vehicles in the UK is the EU Emission Standard. These Europe-wide rules set limits for a whole range of pollutants which can be released by vehicles, with the aim of encouraging greater fuel efficiency. For carbon dioxide these limits have been set to an average of 130 g of carbon dioxide per kilometre travelled (g CO2/km) for passenger vehicles by 2015, falling to 95 g CO2/km by 2021. A whole host of other toxins released by vehicles, from nitrogen dioxide to carbon monoxide are also set to be controlled and reduced in this way, raising the potential for significantly reduced vehicle emissions in the coming years.

However, despite the general improvements many have argued that these measures do not go far enough. Some also question the reality of the emissions standards reached. The campaigning group Transport and Environment claims that many manufacturers have been inflating their energy efficiency by engaging in underhand tricks to fool the testing regimes, including running stripped down vehicles to reduce their weight, or testing at high altitude tracks to reduce fuel consumption. Nonetheless the direction of travel is clear. Engines are becoming increasingly more efficient, and manufacturers are investing significant sums in develop new ways of saving energy.

During the debates prior to the introduction of the new standards, some car manufacturers, particularly of luxury vehicles, argued that the targets were too ambitious, and would be impossible to achieve. So far this has proven not to be the case. From 2007 to 2013, the average emissions of carbon dioxide from new cars on the European market has fallen by 20%, to the point where the 2015 targets have been reached, with emissions averaging 127 g CO2/km (compare this to the US where the average passenger vehicle had emissions of 262 g CO2/km in 2011). The results have been felt on the forecourt too, with sales of fuel in the UK, including diesel, falling.

While these improvements may sound encouraging, local concerns remain, as the smog in major cities testifies. In 2014, the European Commission launched legal proceedings against the UK government for failing tomeetminimumrequirements for clean air, something the authorities have so far seemed reluctant to address. To tackle such deep seated problems will require more innovative solutions. Part of this must undoubtedly involve encouraging people to drive less, but technology will also have a crucial role to play.

According to some, such as the consultancy McKinsey, the only way manufacturers will be able to reach their 2021 targets will be through the widespread adoption of entirely new fuel and engine technologies. The government’s Committee on Climate Change has backed this up, saying that by 2050 the entire transport sector will need to be effectively decarbonised. The UK government has recognised this, at least in part. In April 2014 it was announced that an additional £500mn would be invested in a raft of new measures to support low emissions transport – see news story on page 10.

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