The petrol-fuelled motor vehicle kills and maims our children, clogs ups our streets, pollutes the air we breathe and contributes to global warming.
Is the electric vehicle (EV) therefore a possible solution to reduce the environmental impact of road transport?
A number of different categories of EV currently exist. These include ‘plug-in’ EVs which like other domestic appliances require you to plug them in to recharge the battery. Some EVs are solely dependent on the battery as its main source of power. In these vehicles if you don’t use heating or air conditioning and drive sensibly you can travel up 80 -120 miles.
If you wanted more certainty in driving then ‘plug-in’ hybrids allow you to switch between electric or traditional fuel.
These tend to have smaller batteries which means you can only undertake electric travel for about 10-40 miles. Hybrid EVs tend to have a smaller battery which is charged while driving and can therefore be used only over short distances.
The Toyota Pirus is a successful example of a hybrid. Although it has been referred to as the ‘hippie car’ it has been the car of choice for a number of Hollywood celebrities. Finally, there are fuel-cell vehicles which generate their own on-board electricity by using fuels such as hydrogen and therefore do not need to be plugged-in.
Although the UK EV market is the early stages of development, the government’s Committee on Climate Change recommends we should aim to have 1.7 million EVs on the road by 2020 if progress is be made towards achieving the national target of an 80% reduction in greenhouse gas emissions by 2050.
Battery operated EVs tend to be more energy efficient when in use as 80% of the stored energy goes to driving wheels. This is compared to cars with internal combustion engines which are about 20% efficient with most of the energy lost as heat.
Although when loss from energy generation is considered, the energy efficiency of EVs is reduced. On the whole carbon emissions from driving EVs are comparable with the most efficient diesel cars and are about 30% less than the average for new fossil fuel cars.
In addition, EVs produce no tail-pipe emissions when in electric mode so poor air quality will not be experienced in congested urban areas. This is particularly important for large urban conurbations which are grappling with high levels of vehicle-related particulate matter and nitrogen oxides emissions that exceed EU limits.
In London an estimated 4,000 extra deaths occur each year due to airborne particulates costing up to £20 billion a year – twice the cost of obesity. EVs contribute less to noise pollution as they are much quieter that traditional cars – perhaps a reason why many milk floats were battery operated in the heyday of doorstep milk delivery. However, concerns have been raised with regard to pedestrian safety especially of the visually impaired.
So is the EV a greener option? Researchers at the Norwegian University of Science and Technology undertook a life cycle assessment of the EV and highlighted the ‘toxicity’ of EV manufacturing process compared to conventional vehicles (e.g. extraction of minerals for the battery).
They calculated that the ‘global warming potential’ of manufacturing is about twice as high as conventional vehicles. They argue that promotion of EVs does not make sense in regions where electricity is produced from oil, coal and lignite combustion.
We still have a long way to go before the EV is seen as desirable option by the majority. The public image of EVs needs to be improved and recharging infrastructure needs to be targeted, convenient and safe. For example, the majority of recharging taking place at home, at night, after the peak in electricity demand as well at the workplace for commuters and these need to be available. We also need to understand how to reduce environmental impact of the EV manufacturing process and improve battery recycling.
Until we are able to make a significant shift to renewable energy sources, EVs are simply a means of reducing roadside emissions rather than global emissions. Improvements in technology will inevitably improve the environmental credentials of EVs.
In the short term emission savings in transport are likely to come from better efficiency of conventional vehicles. Walking, cycling and public transport also have a role to play as well as reducing the need to travel in the first place.
© Gary Haq 2013