Turning over a new Leaf

The Scientific Alliance

Nissan has announced that the first mass-produced all-electric car in Europe is to be built at its Sunderland factory in the UK (the third production site, after Japan and the USA). It is to be called the Leaf, a suitably green name, but possibly an unfortunate one in the event of problems. The company had previously decided to produce lithium ion batteries to power the vehicle at a nearby plant. The UK government is promising incentives for consumers who buy all-electric cars, and there are various plans – most of them currently rather vague and aspirational – to install charging points to cater for the expected demand. So, does this (and similar initiatives in other countries) finally bring electric cars into the mainstream?

Are we really likely to see a major shift in the market away from conventional petrol and diesel engines? Despite what enthusiasts may say, a cold-blooded look at the facts would suggest not.

Cost is clearly an important factor. Nissan claim that they can build the new car for essentially the same price as a conventional one, but have not yet announced how the batteries will be paid for. These will form a significant proportion of the overall vehicle cost, and may well need to be replaced during the lifetime of the car.

One option is to lease them to the car owner, rather than sell them as part of the overall package (although in the USA, customers can choose to buy or lease the car including batteries). Whatever the model, the overall capital cost to the buyer will inevitably be higher, which is why the UK government is offering a subsidy of up to £5,000 to encourage uptake. Current cost is not in itself necessarily a big obstacle.

As with any new product, there will always be early adopters eager to get the latest technology, and this demand should be sufficient to sell the proposed 50,000 cars due to roll off the production line annually, starting in 2013 (presumably for sale across the whole of Europe). Battery technology will undoubtedly continue to develop, and it is likely that those available for cars will become both lighter and more powerful over the next few years. Probably the cost will also fall. Running costs at present are low, until governments find a way to extract more revenue from owners. The Leaf will have a 24kWh battery, powering an 80kW motor, driving the front wheels.

Cruising range is claimed as over 160km. But here we come to one of the major limitations of this and competitive cars. The Leaf may be a 4-door hatchback with room for five passengers, but how far can it take them? The limited range will effectively confine the electric car in its current incarnation to urban use. And, in towns, cars do rather little cruising. Unlike petrol or diesel engines, electric cars use no idling power while stationary.

And they make use of regenerative braking, whereby the kinetic energy of the moving car is used partly to recharge the battery (or is stored in a capacitor) rather than simply being lost as heat. But acceleration takes considerably more energy than cruising and, in stop/start urban driving, the actual range of the car is likely to be significantly less than the cruising range.

Add to this the extra drain of carrying more passengers or luggage or driving up hills, and realistic driving distances are reduced still further. But the battery does not just power the engine. For large parts of the year, commuting motorists will need to use their headlights. So add in two 55W bulbs plus sidelights and dashboard lights. Conventional cars recycle some of the waste heat from the engine to heat the car, an option which is not available for the Leaf or its ilk.

The simple but most energy-intensive option is to use a resistance heater, but alternatives such as heat pumps seem to be the favoured route. Whatever the option, there is still an extra demand for energy. A significant reduction in practical range is something motorists could live with if recharging after each journey was a practical option. There has been general talk of putting in charging points in the street; indeed a few have already appeared in central London.

But for battery-powered cars to be a realistic option, there must be a high degree of certainty that there would be somewhere convenient to plug it in between journeys. If those journeys are short enough, then recharging at home overnight would be sufficient. But that would be difficult for the large numbers of city-dwellers who do not live in houses with garages or off-road parking. If you have to park in the street, or have an apartment a with a separate parking space, plugging the car into an indoor socket is not feasible.

So, there would be significant new infrastructure needed to keep these cars running. If there really is a move away from the internal combustion engine, then at least battery power has big advantages over the once-fashionable ‘hydrogen economy’, which would require enormous investment in a completely new (and unproven) fuel distribution system. At least we have an established and efficient electricity distribution network, and extending that would be quite manageable, albeit at a cost.

There is also legitimate debate about the environmental credentials of battery power. Ignoring for now the carbon intensity of battery production and the cost of recycling these at the end of their life, there are inefficiencies built into the energy distribution process. In simple terms, it is more efficient to burn fossil fuel in a petrol or diesel engine than to burn an equivalent amount to generate electricity (with some energy wasted), distribute it to charging points (with losses en route), charge and discharge batteries (at less than 100% efficiency) and then drive an (imperfect) electric motor to overcome the same rolling resistance and air resistance as in any car.

This only makes sense if the electricity is generated from renewable or low-carbon sources; otherwise, the carbon footprint of the car is arguably higher than the conventional one it replaces. Conversion from the internal combustion engine to batteries will need additional generating capacity, and the new power stations, given the state of current technology, should be nuclear or biomass-fired rather than wind or solar.

The big question is how popular the electric car will be with motorists. Nissan’s chief executive last year said that electric cars would account for 10% of the market in ten years. That sounds a lot but, even if 20% of Europeans were to buy a new car each year, electric cars would only increase their market penetration by 2% annually. Nevertheless, that is still a big number.

There are about half a billion people in the EU, and roughly one car for each two people; say 250 million. 2% of that is 5 million. If we are to get anywhere close to that figure, electric cars will have achieved a good level of acceptance from consumers. But it seems very unlikely that this level of sales will be reached until battery technology has advanced so that cars like the Leaf can be used for much longer journeys that short commutes. If not, they will never fully replace petrol and diesel power. Governments have a tightrope to walk: it is right to provide incentives for the development of new technologies, but not if there is little prospect of that technology being economically competitive in the medium term. If the bulk of consumers are not interested, or if a better understanding of climate change and energy policy suggests that transport fuel is not a sensible target for intervention, then politicians should have the courage to change their minds.

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