People talk about "plug-in" electric cars that could replace our current gasoline burning ones with clean, non-polluting ones.
Moving a car from place to place requires energy. In our current cars, we put that energy into the car in the form of gasoline.
A typical small car gas tank holds 40 L. Gasoline has about 35 MJ/L, which means that tank contains 1400 MJ of energy. Gasoline weighs 0.718 kg/L, so that tank of gas weighs about 29 kg. That's 1400 MJ of energy, in 29 kg.
There is a fair amount of talk about battery life: how we can manage to store enough energy in a battery to make a car with a driving range comparable to a gasoline powered one. In other words, how can you make a battery that can store the 1400 MJ of energy and weigh close to 29 kg.
But nobody seems to talk about power. A typical (possibly slow) gas pump moves about 10 L/minute (i.e. 4 minutes to fill your 40 L tank).
10 L gasoline / minute = 350 MJ energy / minute = 6 MJ energy / second = 6000 kW = 6 MW
The gasoline pump delivers 6 MW of power. If you had an electric car that stored enough energy to be comparable to a gasoline car, and you wanted to charge the battery as fast as you can fill up a car with gasoline, you would have to charge it with 6 MW of power. A typical electrical substation seems (my research is a bit bad) to produce around 500 to 1000 kW of power, so you would need the power of an entire electrical substation to charge your car.
