It's been a while now that electric cars are gladly presented as the ideal solution to two inconvenients generally quoted first when discussing transportation issues :

no noise,

no apparent pollution.

Alas, things are not that simple :

the absence of noise is essentially valid at low speed,

the noise generated by vehicles on wheels mainly comes from rolling (friction of the wheels on the road, and friction of the air on the car itself) as soon as they go over 50 to 60 km/h (30 to 40 mph), the noise coming from the engine becoming then secondary,

using cars at low speed only means using them in urban trafic, precisely where cars - electric or not - generate other problems, such as congestion, and the necessity to devote an important surface to streets and parking lots, etc, that won't be solved with electric cars,

The absence of pollution of the electric car is actually a simple shift of the problem, that goers from the car to "elsewhere" :

electricity can never be produced in a totally clean way, so that electric cars pollute just as much as the power plant that produced the electricity.

In particular, if the electricity is mostly produced out of coal, oil or gas, which is the case almost anywhere in Europe except in France, Sweeden and Switzerland (cf. chart below), then the CO2 emissions per km, once taken into account the electricity generation, are the same or superior to what they are with a gas engine. If the electricity generation is done with gas, the emissions are even, but gas is far less abundant than coal).

Breakdown of the electricity production for various european countries in 2001. Data from Ministère de l'Industrie, Observatoire de l'énergie. The OECD Europe average (bar at the top) is 30% coal, 5% oil, 16% gas, 30% nuclear, 17% hydro, and 3% other (including other renewables, such as geothermal, solar, and wind power). Hence a rough 50% of the electricity generated in Europe is produced out of fossil fuels. The world average is closer to 66%.

 

And at last converting to electricity all the cars in the world would suppose :

that we build several hundred million batteries (and 3 billion if we want one car per adult able to drive in the world), when these objects sometimes contain materials for which I don't know the abundance. Is such a spreading compatible with the known resources ?

that we build a couple of extra power plants ! Let's do a little calculation for France. The present consumption for transportation in France is 54 million tonnes oil equivalent (1 tonne oil equivalent = 11.600 kWh), that is, converted on the final energy basis, 600 TWh (1 TWh = 1 billion kWh). But an electric engine is three times more efficient than a petrol engine, so that to propel our 30 million cars (in France) we just need 200 TWh of electricity, the possible losses in batteries not taken into account. Let's take a bracket of 200 to 250 TWh, which would equal half the present electricity generation in France, to convert 30 million cars to electricity.

If this electricity is produced with a fossil fuel, as the efficiency of power plants is 50% at best, and that cogeneration poses the problem of simultaneous use of heat and electricity (having cogeneration everywhere would suppose that we get electricity only in winter or when industries consume a lot of steam !), we would in fact need 400 to 500 TWh of primary energy,

"All electric" would mean, in rough figures, an increase of 50% to 75% of the power plants in France. We can do it, but it's not nothing !

In conclusion, thinking that we ought to massively convert urban trafic to electric cars to solve the problem of local pollution - which is not far from what is seriously considered in California, for example - is :

a remedy worse than the disease if the country where it happens produces massively its electricity with coal (typically most US states). Of course,we avoid the urban pollution - a process which is quite reversible on the short term - but with the price of increasing their contribution to greenhouse effect, a process irreversible for much more than a man's life.

forgetting that the additionnal electricity production required is far from being ridiculous compared to the present installed power,

forgetting that congestion, that uniquely comes from a great number of individual transportation means, would not disappear with electric cars. This statement is also partly valid for noise.

The electric car is therefore an idea as good as the context in which it takes place : converting all cars to electricity, if in the same time the car number must be divided by 2, used 4 times less, composed of small vehicles, and fed with electricity coming from pretty "clean" means of production (solar or nuclear) is definitely a solution to consider.

But to advocate the massive conversion to electricity of all existing cars (or worse : all cars to come if we prolongate the trends), each car driving as much as today (or worse, more if we prolongate the trends) would be a "solution" that only moves the problem and puts it elsewhere, but does not solve it.

This reflexion is not valid for hybrid cars, that own both an electric engine and a thermal engine, and are more efficicent than "classical" cars (because they get back the kinetic energy when braking to convert it into electricity, and use the electric motor at low regimes, when the thermal engine has a very low efficiency), because these cars do not require additionnal power plants. But this technological innovation does not eradicate all inconvenients of trafic : some gasoline is still required, even if it less than for the equivalent conventional car, (and oil is not renewable, still), and with a continuing city spreading we will get an increasing fleet of vehicles, and thus an increasing congestion.