-See also Charging, Part I, Part II, and Part III
I bumped into someone who threw out that electric vehicles ‘just mean emissions somewhere else.’ Allow me to say “YOU ******* ********.”
The lie that EVs simply shift around pollution is a bumper-sticker talking point, or “truthiness”- it’s true because it sounds true, right? And I really want to believe it. So it’s true. Really. Really!
Now, how about some evidence, in the form of engineering data, test results, and decades of industry experience, verifiable by multiple outside reviewers? How about three?
1. Electric drivetrains are vastly more efficient than internal combustion. An electric vehicle will put over 70%, possibly 80% of its electricity to the wheels, to actually move forward. Diesel-cycle engines and transmissions are around 20% or so. Gasoline? Ha, 17% if you’re lucky, possibly as low as 14%. Electric motors alone are over 90% efficient, and in particular, their wide powerbands mean direct drive and little to no first-order transmission losses. By contrast, a piston engine wastes a majority of the fuel’s possible energy content as heat losses, out the tailpipe or through the engine compartment. And no, the heater only captures a small fraction, even if that actually counted. And no, your manual transmission is still quite lossy; being better than an automatic isn’t saying much.
This is important, because as the last link in the chain, every loss in the vehicle increases demand and loss further up the chain. Electric transmission lines are also about 80% efficient, but motor fuels are delivered via ships, pipelines, heavy trucks, and station pumps. Yes, pipelines consume energy; the drag along a significant pipeline soon becomes huge. So we’ll call this one part a wash, percentage-wise. But, since electric drive demands less energy to begin with, the loss due to lines and transformers is overall less than the fuel losses.
Then, further up the chain, large, stationary power plants are much more efficient than small, mobile devices. In particular, vehicle engines must meet weight, producibility, reliability/maintenance, and powerband demands that are reduced or often nonexistent in power plants. One of the benefits of a hybrid is that the piston engine can stay in a narrower rpm range more often, like a power plant. A coal-fired plant, by contrast, can achieve 55-75% efficiency from its fuel energy, depending on how modern it is.
2. And that’s even assuming your electricity comes 100% from coal– not a good bet. Nationwide, only half of our electricity starts from coal; a quarter is nuclear, and has no smokestack. After that comes either natural gas or hydroelectric dams, both much cleaner than small, cheap, seldom-serviced piston engines.
Regionally, it gets even better. The Pacific Northwest into California has much hydropower, plus nuclear and wind. They, along with New England, New York, and some of the Great Lakes states will also draw Canadian hydropower when needed. (Quebec/Ontario and British Columbia are absolutely lousy with dams.) Southern California to Texas has, as you’d expect, the most solar installations; Texas is a leading state for wind power. Of course, Tennessee is the namesake of the TVA, a major hydro producer.
Even in the worst, high-coal areas, a grid-charged vehicle is still better than the average car. You’d have to drive a gasoline car with better than 33 miles per gallon overall efficiency to beat an all-electric- do you? The average consumer vehicle in 2011-2012 actually gets about 25 mpg overall.
State of Charge: EV Emissions and Savings
3. And this is all assuming today’s power plants, not tomorrow’s energy sources. Grid emissions are actually improving overall, even while nuclear is pretty much holding steady.
The largest increase in electrical generation is new wind turbines; wind is easily growing faster than any other source. Both natural gas and solar have had major price breakthroughs in recent years, and are expanding; solar is expected to continue falling in price for years. (In particular, solar panels operate close to the end users and reduce transmission losses.) Large dams have not gained recently in the U.S., but are still being developed in Canada, to send us even more surplus. Meanwhile, developers are seeking small-hydropower installations, including adding turbines to the thousands of inconspicuous dams that aren’t generating right now. Coal is then shrinking as a percentage of the overall portfolio.
And before you say ‘the Sun doesn’t shine at night’ or ‘the wind doesn’t blow all the time,’ you’ve just pointed out that the Sun often shines when the wind isn’t blowing, and vice versa. Meanwhile, hydropower, geothermal, and tidal help cover both. Then add regionwide grid interconnections (with the regions being larger than storm fronts and weather systems), and highly-flexible natural-gas peakers.
Even old-fashioned coal ain’t so old fashioned. As I mentioned above, a new coal plant is cleaner and more efficient than one from just a human generation ago. Coal ain’t free, and plant operators want to wring out more watts per lump. Mainly by tall, high-efficiency plumbing, but also by finding a few percent here, a percent there via computer analysis and optimization. It’s also easier to add modern, efficient scrubbers to one plant, than to a million tailpipes, particularly when the plant is already being watched round-the-clock by on-site professionals. A significant drive in the industry is simply closing those old power plants, and letting new ones fill in.
But hey, why not add 4. Solar charging sites? Like Kentucky, or Texas, Atlanta, or San Diego? Or even cloudier places like New York or Maine? Because it sounds fake, right? I really don’t want to believe it. So it’s fake. Really. Really!