Home editor's blog on evs & phevs Are electric cars really zero emission vehicles?

Are electric cars really zero emission vehicles?

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Nissan advertises its all-electric LEAF as zero emission in multiple places on the vehicle.

editors-blog-entry3Here’s a simple question with a complicated answer: Is an electric car a zero emission vehicle?

The answer is, yes – and here’s where things get complicated, even convoluted -- and no.

Yes, an electric car is a zero emissions vehicle inasmuch as it has no tailpipe and the car itself doesn’t emit any pollutants directly into the air.

But, no, an electric car is not truly a zero emission vehicle because the electricity which fills its battery pack has to be generated somehow and this is often by burning coal.

Poll: Zero emission

Which term do you prefer?
 

Of course, if the electricity that “juices” an EV’s battery is produced directly by 100 percent renewable energy forms such as wind, solar and hydroelectric power, an electric car might in fact be accurately called a zero emission vehicle.

Then again, maybe not.

Solar, wind & air pollution
Renewable energy forms such as solar, wind and hydro do technically contribute to air pollution. Air pollution is produced when the raw materials needed to build renewable energy producing devices are harvested, when renewable energy devices such as solar modules are produced, and when they are transported to the place where they’re installed.

Once these renewable energy producing devices have achieved what’s called “energy payback” – the time it takes for them to produce as much energy as it took to produce them – they are clearly creating air-pollution free electricity. And, if you plug an electric car into an electricity stream produced 100 percent by renewable energy electricity producing devices that have achieved energy payback, you will, in fact, be driving 100 percent, air pollution free.

Of course, the scenario under which an electric car owner might end up driving around in an EV whose batteries have been charged 100 percent by renewable energy producing devices that have achieved energy payback is rarely likely to occur.

plug-in-top-10-wash-dam

A high percentage of hydro power means the Northwest could be the best place in the U.S. for getting close to true zero emission driving.

Pacific Northwest & hydro power
In the U.S., those who live in the Pacific Northwest, where a large percentage of electricity is generated by hydro power and who also have home solar, residential wind, residential geothermal electricity, or all three of these, are among those most likely to achieve true 100 percent air pollution free electric driving.

Those who have home solar but who live in places like, for instance, Colorado – where we happen to live – are less likely than folks with solar in “hydro” land to achieve that “pure”, zero emissions driving experience. This is especially true if the electric car gets plugged in at night, when there is no sun, and the EV owner is using solar offset electricity generated during the day to “power” the vehicle.

In this case, most likely the EV will be “fueled” with a mixture of coal and natural gas generated electricity and, perhaps if you’re lucky, via a smattering of wind generated electricity as well.

solar-lease-green-panel

Even with home solar, it's tough to achieve 100% emissions free EV driving.

Clouds, solar & zero emissions
True, if you plug that same EV in during times when a home solar system is producing enough electricity to meet the EV’s full electric draw plus the rest of the household electricity use at that moment in time, you are indeed back to true zero emissions driving.

However, just one puff cloud that reduces your solar output enough to force your household to temporarily draw some electricity from the general electric grid – and, poof, just like the appearance of the cloud itself, your claim to true 100 percent zero emissions driving evaporates.

If 100 percent zero emissions driving is rare, why call it zero emissions in the first place?

That’s a good question and, frankly, it’s one I don’t have a great answer for, other than to point to the fact that, yes, an individual EV does not itself emit any pollutants directly into the air.

imiev-plus-solar1

EVs are only as green as the energy used to create the electricity they run on -- and even solar-charged EVs are unlikely to be 100% air pollution free.

Greenwashing?
To me, zero emissions feels like an attempt at greenwashing, or an attempt to make people forget the often dirty energy sources used to generate the electricity EVs run on, if sometimes only partially.

It’s difficult to believe such greenwashing works – especially given the volume of fervent anti-EV rhetoric out there that so often attacks the term “zero emission”.

In fact, I believe “zero emission” backfires. In its attempt to obscure the original fuel source question, the term ends up drawing extra attention to the fact that the electricity powering an EV’s batteries is generated by some energy forms, or, more specifically, via some electricity grid mix.

Again, for most people, this mix is likely a mixture of coal, natural gas and nuclear with perhaps a smattering of renewable energy -- though, as I’ve taken pains to point out in the past, grid mix varies widely based on where you live in the U.S. (EV critics tend to ignore regional and local grid mix variability).

plugging-in-to-coal2

While it's true that an EV's tailpipe often extends to a coal plant, a gasoline car's tailpipe also extends to the coal plant thanks to the fact that large amounts of electricity are needed in order to refine oil into gasoline.

Gas cars have long tailpipe too
It is important to point out that gasoline cars are also connected to the coal smokestack via the electricity intensive oil refining process – a fact 99% of EV critics ignore.

However, the fact that gasoline cars also run partially on coal doesn’t erase the fact that virtually every EV out there will be running on electricity generated at least some of the time via coal and/or natural gas.

This includes our own future “solar-charged” EV because we will sometimes be plugging in when our 5.59 kW home solar system isn’t producing enough electricity, meaning at night, when it’s cloudy, when snow covers our panels, etc.

On the other hand, the whole thing can be pushed to a level of absurdity: For instance, if an EV can’t be called zero emission because it’s got a “long tailpipe”, does this mean we need to be talking about “long tailpipes” for refrigerators? computers? clothes dryers? desk lamps?

Zero tailpipe emissions
In the end, I personally don’t feel comfortable with the term zero emission. It just doesn’t seem 100 percent accurate, even, I have to concede, when we’re talking about a “solar-charged” EV, or at least about a solar-charged car that’s part of in an on-the-grid, solar offset situation -- an EV connected to a 100 percent, off-grid solar system is another story.

Where does this leave us then?

With an amended term: Zero tailpipe emissions.

Zero tailpipe emissions accurately captures the fact that an individual EV has no tailpipe and emits no pollutants directly into the air where it is being driven. And, no matter how you look at things, zero tailpipe emissions is a huge advantage – just ask the millions of people sitting in a traffic jam somewhere in the world right now breathing in the fumes from the hundreds, even thousands, of vehicles which surround them.

What do you think: Is “zero emission” vehicle accurate, or do you prefer “zero tailpipe emissions” -- or maybe there’s a better term than either of these?

[We’re also interested in which term different people in the auto industry, plug-in movement, etc. are using – Zero Emission(s), or Zero Tailpipe Emissions, etc. Check back soon for our second installment in this series: Zero Emissions or Zero Tailpipe Emissions – who’s using what?]

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Should Nissan be using the term zero tailpipe emission instead of zero emission on the LEAF?


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