Electric Cars: Green, But No Magic Solution

Hey Mr. Green,

The cover story in Sierra asks, “Can we really get off oil in 20 years?” As long as Mr. Green claims “EVs can be responsible for releasing almost as much CO2 as a 40-mpg car” the answer will be “of course not.” The Nissan Leaf, not unlike EV conversions driven for years, has a 99 miles-per-gallon-equivalent EPA rating. Further, the same amount of gasoline used to power a combustion vehicle, if burned in a conventional power plant, can put six electric vehicles (EVs) on the road.

--Bob, Grants Pass, Oregon

Don’t get me wrong. EVs are greener than conventional cars, but beware of naive enthusiasm about the environmental blessings of EVs. An EV is only as clean as the source of its electric power, and even if it runs on 100 percent clean energy, the EV can do little to ease a host of environmental problems caused by an ever-increasing number of cars, regardless of their power supply.

The way this “equivalent” mpg rating gets presented is itself an example of the overly rosy view of EVs. The mpg rating you cite is misleading, if not downright deceptive, because it is correct only if the EV derives all its electricity from sources that don’t use fossil fuel to create electric power. Yes, the Nissan Leaf does travel 99 miles on the equivalent of the energy in a gallon of gasoline, or about 115,000 British thermal units, or 33.7 kilowatt hours of electric power. But these numbers do not reflect the large amount of additional energy required if fossil fuel is burned to generate that electrical power. This “hidden” energy isn’t reflected in the 99-mpg number.

The reason is that when its electricity is generated by fossil fuel, the EV is, in effect, being powered by fossil fuel, not by some morally superior electricity from a virginal source. When fossil fuels generate the EV’s electricity, there is a loss of energy, because fossil-fuel-powered dynamos are typically 35 or 40 percent efficient. This means that the electrical energy an EV uses from the fossil-fuel-powered plant equals only 35 or 40 percent of the fuel energy burned in the plant. Therefore it could actually take as much as 10,000 Btus to create your kilowatt hour of electricity (3414 Btus), meaning that in reality your Leaf needs the equivalent of around 335,000 Btus for its electricity, or the energy contained not in one gallon of gas, but in 2.9 gallons. So in real fossil-fuel-energy equivalents, the Leaf gets around 35 miles per gallon. This makes it obvious that burning the gasoline used by one conventional car in a power plant couldn’t possibly power six EVs, unless they were micro-vehicles with passengers of considerably less heft than our current population.

Still, EVs beat conventional cars because 1) it’s easier to control pollution from a few thousand power plants than from 250 million vehicles 2) EVs don’t require motor oil, or ooze out other toxic fluids, and 3) EVs can be powered by clean sources of energy, though it will be years before such energy is widely available.

Like all environmentalists, I’d love to see the world “get off oil” and other fossil fuels because of the immense damage caused by extracting them (e.g., mountaintop mining, oil spills), not to mention the homicidal depravity and insane waste of fighting wars to secure petroleum. But let’s not make a fetish of EV technology, as has been our habit in bowing down before technological miracles” that turned out to have some dicey unintended consequences.

Many of same old problems caused by our irrational dependence on automobile transportation would persist even if all cars were EVs rolling over the asphalt and concrete on “clean” energy. We're driving 105 million more vehicles on 200,000 more miles of roads than 35 years ago, on a paved area that already exceeds 60,000 square miles, 7,500 of which are dedicated just to parking, according to the federal government and the Environmental Policy Institute). Nor are EVs likely to diminish the immense personal grief and public-health problems caused by highway fatalities and injuries. Moreover, even clean energy doesn’t come without an environmental price to pay in building power lines and siting windmills and solar installations on the land. For all these reasons, if EVs  end up encouraging more driving by giving a green dispensation to cars, they could turn out to be a dubious blessing.

 

Comments

[hebintn]

It is so obvious to me... I love the concept of EVs, BUT.... EVs run on electrons, which are mostly generated by burning coal, which is obtained by bombing mountains in Appalachia leaving behind an environmental disaster that dwarfs all the oil spills. Don't be infantile enough to think all the EVs will run on the windmill on your roof... Ain't gonna happen. EV proponents seem to ignore the fact that we do not have enough clean electrons to keep the lights on much less run a fleet of electron guzzlers. Please, until we can furnish all the needed electrons from clean sources and close down all the coal fired plants and close all the coal mines, lets cool the fervor for EVs to a simmer.

[nissan east providence]

Among the other Electric cars, my choice is the dramatic Leaf. Nissan Leaf continues its production time to time and providing better vehicles to the market.
This really can be said one tragic Nissan popularity.

[Sherry Boschert]

Oh, Mr. Green. You've compared apples to oranges. And you've mixed up your arguments so that readers can't see the forest for the trees.

First of all, we all agree we need to get U.S. drivers out of cars and into public transportation. Cars bad. Fewer cars good. No one is arguing with you about that, and that wasn't the question. But environmentalists have known this for at least 50 years. How're we doing on that? So, could you just agree that we need to clean up the cars being driven a.s.a.p. while we also work to provide alternatives to cars?

Secondly, you rant about the efficiency of EVs if energy losses at power plants are included, but you don't do the same well-to-wheels comparison for gasoline-dependent cars. A 30-mpg hybrid isn't a 30-mpg car if you factor in the energy losses involved in refining oil into gasoline and transporting it to the pump and then into the car. If you compare apples to apples, driving on electricity is far, far more efficient than any cars driving on gasoline. And there are plenty of government studies that say so.

In response to hebintn: No, most U.S. electrons do not come from coal. It's less than 50% and declining, as it should. But even on today's approximately 45%-coal grid, driving on electricity is cleaner than driving on gasoline. See Question #2 on my FAQ page for an overview of nearly 50 studies on well-to-wheels emissions of vehicles (many of which include efficiency comparisons):
http://www.sherryboschert.com/FAQ.html#green

I'm about to update that summary (and my website overall), and I can tell you that results of more recent studies don't change the overall conclusions -- plug-in cars are cleaner than gasoline cars.

So there's no need to wait until our electrical grid is completely free of coal to start to reap the benefits of EVs. In fact, if we do wait for that, there will be no hope of slowing global warming. We can't reach the greenhouse gas reduction targets fast enough if we don't rapidly clean up cars, regardless of what else we do.

I'm not "fetishing" EVs, as Mr. Green dismissively suggests. I'm just looking at all the alternatives realistically. Electrification is the only path that offers us a chance to get off of gasoline quickly enough. (And no, it's not a silver bullet -- we need other strategies too -- but let's not pretend that they can have the same impact as EVs as quickly as EVs.) Given that every new car stays on the road for 14-17 years on average (depending on which study you look at), we need to rapidly ramp up the % of plug-in cars in the U.S. and rapidly decrease the % of gas cars sold.

[Marlene Henley]

Either way has its negative effects. But in deeper view (although it is not good but it is the truth) if there are no negative effects then the process is not balanced. It's like the Yin-yang; we just have to accept that there is nothing perfect in this world. And if we use solar panels to our auto body for a greener repair ride, then ask yourselves: how are panels made and what are they made of? If we really want to protect and save our planet, we have to give up "Technology" not just in Plano or in New York or any major cities but all over the world.

[ferragamo shoes]

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[Kevyn Hagemann]

They are indeed a great machine to lessen the damaging pollution other engines excrete to the air. But the makers should focus on the needs of the market. They must also produce more running machines that exceed more than what the people are used to having at hand. It is heart breaking to see our planet like this, but the only way to keep it safe, is to make it healthy again.

[Solar Panels]

I think the best way to use clean energy is through the installation of solar panels in your home. Not only is this guaranteed to last up to 20 years, but these devices are almost totally recyclable as well so these are value for money investments indeed!

[EVsRoll]

You are correct that the EV is only as clean as its power source. However, any generalizations regarding electric car charging and pollutants need to be site specific. Conditions can vary greatly from region to region, and utility to utility. Check your local utility for pollution levels before passing by an EV. You might also try an eBike....15 cents per day!

Details here: http://www.evsroll.com/Electric_Car_Pollution.html

EVsRock!