For the last couple weeks, I've been hearing a lot of talk surrounding Tesla and "the electric car". What I'm curious of is whether or not it is more efficient to actually power an electric car (the power produced by the power plant) over a typical gas powered car. Obviously there are a lot of variables, where you drive, how, gas mileage, etc. Which is more sustainable in terms of , electric cars or gas-powered ones?
In terms of energy for movement, the electric car is more sustainable. There are two main resons for that.
Firstly, when hydrocarbons are burnt to provide movement, local pollution is released: NOx, particulates, carbon monoxide, carbon dioxide.
And secondly, it's much easier to clean electricity, than to clean hydrocarbons. That's because the clean electricity resource is affordable and plentiful: solar, hydro and wind can together power the world many many times over.
Efficiency turns out to be a useful proxy, occasionally. But often it's misleading - it doesn't really get to the core of what we need to know. Electric engines are about four times as efficient as internal combustion engines. The efficiency of any wider system, would depend on where you draw the system boundary. And then you're adding up efficiencies that may or may not make sense. Wind, water and sunlight are free: does it make sense to include the efficiencies at which they are harvested? Efficiency is one of many things that affects the economics: but there are sufficient other factors that can more than make up for low efficiency.
There are several factors to consider:
1) How efficient is the generating station? In general, if any attempt is made to capture "waste" heat and use it for domestic heating or some industrial process, the answer is "very".
2) How efficient is the transmission system? This can vary quite a bit, both from location to location and over time. For example, a system under heavy load is less efficient than one under less of a load. As load increases, you get more heating of the cables.
3) How efficient is the charging system? Modern battery chargers are more efficient, but any time you change voltages or convert alternating current to direct current (or vice versa) you have losses.
4) How much is lost as the battery sits there? NiMh batteries are far better than lead-acid. Some of the newer technologies promise to be better still.
5) How efficient is the motor and drivetrain of the car?
6) And last, but certainly not least, how much energy went into building the car? The least impactful product is the one that has already been produced!
Of course, ultimately, the best answer is to ride mass transit, if you really must travel.