With many of the worlds automotive giants including the likes of General Motors, Ford , Toyota and Honda introducing new ranges of electric vehicles (EVs) to their fleets, one would be forgiven in thinking the future of motoring lies with these battery powered electric cars. Further incentives to buy into this evolution of the automotive industry are given by the UK government who offer to cover 25% of the cost of an EV up to a maximum of £5,000. At the time when this grant scheme was introduced, the then Transport Secretary Phillip Hammond lauded 2011 as ‘the year the electric car took off’ [1]. Similar actions are being mirrored in other major countries such as the US where new EVs are subject to federal tax credits as well as additional incentives from states such as California, in China where subsidiaries are paid to manufactures of these vehicles, and in Japan where incentives are also offered by considerably lowering the cost of EVs to the public.
These past few years have also seen considerable increases in the levels of technology associated with EVs, notably with the lithium ion batteries used to power them. Nissan boast that their new Leaf has an improved range of 124 miles and with a charge time as low as 4 hours with the ‘S charge package’ [2]. Given that REVA’s original G-Wiz which introduced the concept of plug in motoring in 2001 could manage just 50 miles with a full charge time of up to 8 hours [3], it is clearly evident that things are improving. These figures however, may not be easy to accept for the average petrol or diesel fuelled car driver of today.
Valid arguments have been put forward against the EV stating that when the full life cycle for production to end of life of an EV is compared to that of an ordinary petrol fuelled car, an EV will offer little in the way of environmental benefits. A study put forward by The Norwegian University of Science and Technology in the Journal of Industrial Ecology highlights that the production of an EV has approximately twice the environmental impact than that of an ordinary car [4, 5]. Therefore in order to regain some of its green credentials it must run largely on electricity from clean sources. When taking into account the source of electricity, the current mix of renewable and non renewable sources in Europe do offer a 10 to 24% decrease in the carbon footprint of the vehicle according to the study. However, for nations such as China, still predominantly fuelled by conventional fossil fuels, it is thought that EVs may not actually offer any environmental impacts at all, in fact it may even be the case that they result in a larger carbon footprint that an ordinary car. Many who argue the case against the EV claim the answer to the future of motoring lies with the hydrogen fuel cell powered cars. The production, transport and storage of hydrogen however all pose considerable barriers to make it a greener way to power our cars. For example, in order to use hydrogen for this purpose it must be 99.999% pure [6]. The production required needs considerable energy input to the extent that in some cases it is thought to take more energy to produce than it eventually provides. Other arguments against also include the fact that hydrogen has a propensity to leak through most materials owing to the fact it is the smallest molecule in existence. Therefore a whole new infrastructure for transport and storage would be required before any hydrogen fuel cell powered cars could be used on a global scale.
What becomes apparent amongst the all the governmental schemes, industry advertisements and even social pressures is that one form of technology seems to be being left behind and forgotten by many in the automotive industry largely in favour of plug in electric vehicles and to a lesser extent hydrogen cars. This technology being liquid nitrogen.
The basic concept behind the use of liquid nitrogen to fuel a car is that the pressure created when liquid nitrogen is converted to its gaseous form can be used to drive a piston or turbine engine and thus run a car.
Advantages of liquid nitrogen over its automotive fuel counterparts are numerous. They include the fact that production of the cars would be likely be cheaper and less harmful to the environment without the need to produce numerous lithium ion batteries, therefore not producing the same emissions during production. The materials used in construction would also not need to handle the same high temperatures a battery powered car experiences, therefore allowing for the use of cheaper materials. [6] Some figures give the cost of a liquid nitrogen car with comparable range to a Nissan Leaf at little over half the cost of the EV [6]. Moreover, much of the infrastructure and the technology required to get fuel from production plants into cars already exists because liquid nitrogen is already widely used as an industrial coolant. Granted the infrastructure would need a vast overhaul, but at least the same issues associated with the use of hydrogen transportation and storage do not arise.
Seemingly on of the most important issues after cost for the everyday motorist is refuelling time. Trying to comprehend even the most optimistic targets given by EV manufactures such as Nissan for charging time seem hard when we are used to the two or three minutes in takes to refuel an ordinary petrol or diesel car. Happily liquid nitrogen cars would require the same fast process we have all become accustomed to.
Despite all the arguments for and against EVs, hydrogen cars and liquid nitrogen cars, it appears that for the time being car manufactures are choosing to invest in the electric vehicle. Let us just hope all the money and effort which has been ploughed into the technology associated with EVs is worthwhile and history doesn’t show battery powered vehicles to be somewhat of a dead end.
[1] http://www.guardian.co.uk/environment/2011/oct/21/electric-car-uk-sales-sputter
[2] http://www.nissanusa.com/electric-cars/leaf/
[3] http://www.thegreencarwebsite.co.uk/blog/index.php/g-wiz-ac-electric-cars/
[4] http://www.bbc.co.uk/news/business-19830232
[5] http://www.ntnu.edu/news/2012-news/shocking-electric-car-news
[6] http://www.economist.com/blogs/babbage/2012/10/nitrogen-cycle
