Electric Car Myth Buster — Efficiency

March 10th, 2018 by Steve Hanley

This article is part of our “CleanTechnica Answer Box” collection. In this collection of articles, we respond to dozens of common anti-cleantech myths. Please read the other Myth Buster articles in this series on well to wheel emissions and the electrical grid.

The merchants of doubt paid for by the Koch brothers and the fossil fuel industry are out in full force, incorrectly publishing article after article about how electric cars are just as bad for the environment as gas and diesel ones, or possibly even worse than cars powered by gasoline or diesel engines.

We recently heard from CleanTechnica reader Martin Hemdricks, who told us about a scurrilous indictment of electric cars that recently showed up in his email inbox. It charged that electric cars put all their carbon emissions into the atmosphere before they drive a single mile. It went on to say an electric car needs to drive 15 miles or more 365 days a year for 10 years before making any positive contribution to the environment. Not true.

These sorts of bizarre statements are routine. One way you can tell they are all coming from the same source is they all make the same absurd claims — electric cars are only for wealthy people, electric cars waste taxpayer dollars on giveaways to the rich, electric cars create just as many fine particulates as a modern diesel car because of brake and tire wear.

One of the other common assertions we hear all the time from the anti-EV crowd is that electric cars are no more efficient than cars powered by internal combustion engines. Let’s take a closer look at that claim. According to the US Department of Energy’s Office of Energy Efficiency and Renewable Energy, “EVs convert about 59%–62% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert about 17%–21% of the energy stored in gasoline to power at the wheels.”

An electric motor typically is between 85% and 90% efficient. That means it converts that percentage of the electricity provided to it into useful work. The difference between the efficiency of the motor and the overall efficiency of an electric car is accounted for losses attributed to charging and discharging the battery and, for some charging (for some cars), converting AC to DC current and back again.

In a recent post for Quora, Brian Feldman, a robotics expert and entrepreneur, offered this explanation: “Consider the Tesla Model S, which has an available 85 kWh battery and a 265 mile range. Consider a similar gas-powered car, which gets 35 mpg. Gasoline contains about 33 kWh of energy per gallon. The Tesla uses 320 Wh/mile of energy (85 kWh/265 miles). The gas powered car uses 940 Wh/mile of energy (33 kWh/35 miles). Once the energy is on board (not counting the efficiency of the power generation, oil refining, or charging), the Tesla is using only about a third as much energy as the comparable gasoline-powered car.”

Electric car opponents like to point out that the source of the electricity has to be considered when determining overall efficiency, and of course they are right. Figures lie and liars figure, as we all know. And it is true that charging and EV with electricity made from burning coal is not as environmentally friendly as powering it with electricity made from wind turbines or solar panels. But that argument sets up a false premise — that we shouldn’t drive electric cars because they could use electricity from coal-powered generating plants.

The real point, however, is that electric car drivers tend to be more environmentally aware than drivers of Super Stupid Duty pickup trucks powered by enormous diesel engines. They are also more likely to demand their local utility company incorporate more renewable energy in their energy mix. The result is that electric cars are pushing the transition to a more sustainable energy grid forward.

And notice that fossil fuel advocates never include the emissions associated with exploring for oil and gas, getting it out of the ground, transporting it to refineries, converting it into gasoline or diesel fuel, transporting it to local distributors, and then trucking it to neighborhood gas stations. It’s easy to criticize the other guys when you ignore your own liabilities.

Lastly, EV bashers warn that charging an electric car will cause your electric bill to skyrocket. Well, yeah. Using more electricity will cost you more money than using less electricity. D’uh. But here’s the thing. In terms of how far you can drive on electricity versus on gasoline, electricity wins hands down. Here’s how the Sierra Club explains it:

“While you’ll spend more on electricity, the savings on gas will more than cover it. If you drive a pure battery electric vehicle 15,000 miles a year at current electricity rates (assuming $.12 per kilowatt hour though rates vary throughout the country), you’ll pay about $500 per year for the electricity to charge your battery, but you’ll save about $1900 in gas (assuming $3.54 per gallon, a 28 miles per gallon vehicle, and 15,000 miles driven). So $1900 minus $500 equals $1400 in savings — a 74% reduction in fueling costs. Some utilities are offering EV owners lower off-peak/nighttime rates. The more we successfully advocate for these off-peak incentives, the lower your electricity payments will go.”

Of course, everyone has to put in their own numbers for gas price, electricity price, previous-vehicle efficiency, electric-car efficiency, miles driven, etc.

The disinformation war being waged by enemies of electric vehicles is going on all around the world as fossil fuel companies fight to keep profits coming in the door, even as evidence mounts that their products and business practices are causing global warming and making people sick. They will stop at nothing to keep their revenue stream intact, even if it means poisoning you and your family. Are those really the kind of people you trust to give you accurate information?

For more information, visit the CleanTechnica Answer Box to get answers to various cleantech myths, or visit this electric car resource page to get all your questions about electric cars answered. You may also want to check out: “30 Reasons Your Next Car Should Be Electric.”











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