Diesel, petrol and power

Until comparatively recently, buying a diesel car was seen as good for the environment.  Choosing diesel was encouraged by government through tax policies and promoted by car makers because it gave a relatively easy route to achieving the carbon reduction targets set by the EU. 

However, diesel engines produce far more toxic pollution such as NOx and soot, known as particulate matter, generating urban health problems.  Euro emission standards intended to limit this pollution have not worked; flaws in the regulations have been exploited by car makers and pollution levels remain high in many areas.  It is a serious problem; for every person killed on the roads of the UK (and the EU), there are several early deaths resulting from diesel pollution and UK drivers will soon face penalties for using diesel cars in urban areas.

These sanctions will not just apply to old bangers that should be replaced anyway; by 2020 drivers in central London will have to pay a pollution charge for any diesel car more than six years old and this may be expanded to cover a far larger area.  Other conurbations will soon follow suit. Nevertheless, if we had not put diesel engines in cars for the past couple of decades, we would be a long way off the UK and EU carbon reduction targets. Climate change is still the greatest long term threat to our wellbeing. For long motorway journeys the most environmental choice will still be a diesel for at least the next few years.

For urban transport, a petrol car is better, and a petrol hybrid, preferably a plug in version with increased electric only range, better still. The range of fully electric cars is increasing all the time and in the longer term, electric cars are seen as the solution.  The cars themselves generate no global warming carbon dioxide or poisonous NOx or soot and the EU and UK strategy is to have Zero Emission Vehicles only in major urban centres by 2030 and to phase out conventionally fuelled cars altogether in cities by 2050.

Unfortunately, this presents another problem. Electricity generation has remained broadly constant in the UK for decades. Renewable energy has risen dramatically but highly polluting generation is declining and overall supply has stayed about the same. 

Roughly 30% of our national energy consumption is used by road transport in all forms. Some 60% of that is used by cars To electrify just half of the car fleet we therefore need to produce 10% more electricity and do it by 2030, just over a decade away and it is not clear what plans are in place to achieve this. 

On top of this, another long term plan to reduce carbon emissions is to convert domestic gas and oil heating to electricity which will require another 20% increase in generation capacity. Hydrogen could be another clean transport fuel but making it involves large amounts of electricity.

Efficiency gains and evening out demand throughout the day may help, but coal fired power stations are closing, nuclear plants are ageing and replacements face endless delays.  Our ability to meet even the present demand for electricity seems fraught with uncertainty.  The normal result of energy shortage is a very significant increase in price.  The oil crises of the 20th century should not be replaced by electricity crises in the 21st century. 

With the introduction of diesel cars, drivers benefited from lower running costs, but had to shoulder higher initial costs and new, expensive problems such as engine replacement following accidental mis-fuelling. Now diesel owners face penalties because they followed official advice. 

Motorists need assurance that the very substantial price they pay for a car will not be devalued by changing policies and that they will have whatever fuel powers them, in sufficient quantities and at a fair and reasonable price.

Tim Shallcross, IAM RoadSmart’s head of technical policy and advice