You don’t have to be a mechanical engineer or a chemist to know that a vehicle is only as green as the fuel that powers it. Accordingly, a common critique of electric vehicles is that they’ll do little to mitigate the climate problem if they draw electricity that’s generated from carbon-intensive sources. Since coal — the dirtiest source out there — accounts for nearly half our power generation, it seems unlikely that putting new electric cars on the road would do much in the short term to reduce carbon-dioxide emissions.
Or would it?
In interview with the Wall Street Journal (sub. req), Tesla Motors CEO Elon Musk points out the fallacy of the logic underpinning the above paragraph:
Even if you draw electricity from coal, or natural gas or even directly from oil, because stationary power plants are so much more efficient than small gasoline engines in cars, an electric car actually ends up getting more range for a given amount of, say, coal or oil that’s burned than an a gasoline car gets. In other words, the CO2 per mile is actually less for an electric car even if it’s coming from a high CO2 source like coal.
This is the first time I’ve heard this reasoning mentioned in the mainstream press. As far as I can tell, coal power plants have efficiency rates between 28 percent and 45 percent. Gasoline engines, meanwhile, fare much worse:
Only about 15 percent of the energy from the fuel you put in your tank gets used to move your car down the road or run useful accessories, such as air conditioning.
Hmm.
One point that Musk doesn’t address is the efficiency losses that occur during electricity transmission and distribution. I’m not an electrical engineer, so I’ll defer to anyone out there who’s reading to either corroborate or dismiss Musk’s assertion.
Regardless of where we are now, Musk agrees that we’ll need to find newer, more sustainable sources of energy moving forward. (This is perhaps not that surprising, given his role as a chairman of SolarCity.)
Long term, we have to find sustainable power generation and sustainable transportation. And even if electric cars weren’t there, we’d still need to get sustainable power generation.
The interview is definitely worth a watch. Beyond Tesla, topics covered include: SpaceX, which Musk forecasts could have a person on Mars within ten years; and Robert Downey Jr.’s character Tony Stark in “Iron Man.” (RDJ apparently visited Musk while working on the role.)








