Electric Vehicles: As Clean As The Grid Powering Them

How Green Is My Plug-In, illustration by Holly Lindem

How Green Is My Plug-In, illustration by Holly Lindem

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Electric vehicles are zero emissions, right?

That's a rhetorical question. As I'm sure most of you are aware, that statement is only correct up to a point. Most electric vehicle manufacturers, such as Nissan with their 2011 Leaf, are keen to point out that their vehicles produce zero tailpipe emissions, meaning only the cars themselves are zero emissions. But how clean is the electricity you're putting into the car?

EV detractors usually begin with a tired statement along the lines of, "But EVs do produce emissions, where do you think you're getting the power from? Hmm? HMM?".

First 2011 Chevrolet Volt built on production tooling at Detroit Hamtramck plant, March 31, 2010

First 2011 Chevrolet Volt built on production tooling at Detroit Hamtramck plant, March 31, 2010

Enlarge Photo

If you live in California, your electricity is coming from many sources - the California Energy Commission provides figures for natural gas (45 percent), nuclear power (14.4 percent), hydropower (11 percent) and coal. A further 10.6 percent of California's power comes from renewable sources such as geothermal plants and wind farms.

Some states are obviously cleaner than others, but in many you don't get such a choice. Hydropower is pretty much ruled out in much of the Midwest, for example. Many states rely on either coal or nuclear, with coal being significantly less favorable as far as emissions are concerned.

Even if you do run your EV solely using coal power though, the emissions savings are significant over the average internal combustion car.

A popular term for the chain of  production for electricity or gasoline is known as the "well to wheels" study. The well to wheels chain for gasoline doesn't make for great reading...

You need to:

  • Search for oil
  • Set up a rig
  • Drill for the oil
  • Store it
  • Transport it across the sea
  • Refine it
  • Transport it to a filling station
  • Store it again
  • Pump it into your car

According to the Natural Resources Defense Council, this process results in the typical gas-powered car putting out 465 grams of carbon dioxide per mile. But an electric car powered using the Californian grid produces a well to wheels figure nearer 142 grams per mile.

Elsewhere, with natural gas and coal more prevalent, the figure is nearer 214 grams per mile - still under half the amount of a gasoline car.

Dirtier coal and natural gas plants are getting cleaner all the time too, which brings us onto another advantage of EVs: "their" emissions will decrease throughout their lives, as the sources powering them become cleaner. As more energy is harnessed from renewable sources or nuclear power, well to wheels emissions will tumble.

EV owners take more of an active interest in where their power is coming from, too. Many have taken steps to reduce their home energy usage by fitting wind turbines or solar panels, and if you live in an area suited to either of these power sources, you might even find they produce enough power to make your EV completely zero-emissions. If you make enough electricity, you might even find you're able to sell it back to the grid.

This is the situation Steve Casner of Sunnyvale finds himself in - as an owner of a 2009 Tesla Roadster and an electric Toyota RAV4 EV (originally sold between 1997 and 2003, though there may be a new one in the pipeline), Casner uses solar panels to power his home. Although his cars are charged at night, the amount he generates during the day is enough to sell any excess to the grid.

"I can't make gasoline at my house, but I can make electricity," reasons Casner.

Interested in finding out more? British actor and television presenter Robert Llewellyn has a great summary of the benefits of EVs in the pilot episode for his show, Fully Charged.

FOR MORE INFORMATION: Green Car ReportsIEEE Spectrum

[San Francisco Chronicle]

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Comments (11)
  1. Fantastic article, Antony. It is the poster child news article for just why we need all-electric cars in our lives. And it just provokes in me thought as to how I can produce my own electric power through solar panels and such. I am all for it-the Detroit wheels thing just never seemed quite right, too self-important and too much stinky oil and ghastly to be real and it to last. Once again, this one is a keeper and one to spread all around to the uninformed. Keep up the good work!

  2. I'm tired of people pointing out power plant emissions when we're talking EVs. I always like to point out gas stations to them, like the power all gas stations are using all the time plus their little in station mini marts and the pump is electric powered. And my home, I'm using power constantly on little things, charging a car or two or even 4 won't make much difference. I heard Elon Musk say once that charging a Tesla is equal to running a refrigerator. People don't have any problem powering one or more refrigerators for years at a time so they need to stop worrying. After all the computer you may be using right now, is producing
    emissions through a power plant right now.

  3. People should stop replying to this old saw. The people that bring it the most are mainly fossil-fuel shills anyhow. Yes most powerplants (esp american ones) are "dirty" by any definition. But how that fails to make the status-quo better somehow totally escapes me. Fossil-fuel production is incredibly filthy and damageing at every SINGLE step, from intital exploration right thro to thowing it out the tailpipe. And the damage done by ICE's only builds up over time. Once an EV "burns" its fuel, there is no further damage done, besides whatever emissions the power-plant happens to produce. But of course, the shills that make this so-called argument never seem to be bothered by the emissions plants produce to run their TV's, fridges and electric-can openers. so really why does powering EV's via the same network seem to cause all the shills such a problem? Gee I wonder..

  4. California "exports" a good part of its emissions via EVs to neighboring states and other countries - that "hydro power"? It's from OREGON, killing our salmon.
    Those batteries - take a look at how screwed up China's air, land, and water is in mining and making them.
    No poop in your own birdnest, which is all that matters, right? Chirp chirp birdbrains.

  5. Bundy,Al Bundy....where did I hear that name......let's stop all progress,all research in EV tech and allow Al to get a cold Bud ,watch ESPN and put a hand down his trousers......who needs a future anyway....:(

  6. Solar power is nice but how much energy and oil did it take to get to this point? I'd love to have the panels myself but it's not zero emissions either. In the long run though (like 20 years at least) this alternative energy should pay for itself and also produce positive impact on the environment.

  7. @ Alfons Bundy - Humans have an impact on the envioronment in everything they do. Regardless of where the electricity is coming from (which is produced to power far more things than just EVs), it's a source of power we already generate so it makes a lot of sense to use it to power cars, rather than digging for oil which is an *additional* process that uses a great deal of energy in itself, and then also produces pollution when it's used.
    Unless you somehow live your life without electricity, it's hard to pick holes in how we produce it without being totally hypocritical.

  8. Are the equivalent emission numbers calculated using current power generation statistics? If so, then the true emission numbers for EVs needs to be redone based on a power grid that can support an increase in power demand. The current power grid is already strained, as evidenced by rolling blackouts during the summer months and heat waves. If we add a significant amount of EV power demand on existing infrastructure, it will most likely collapse.
    As we start putting more and more EVs on the road, there is going to be greater and greater demand placed on the power grid. More power plants will need to be built (they already do since we are struggling to meet demand as it is). The only way emissions won't go up is if the new power plant itself is zero emissions. Are EVs a better option than traditionally fueled vehicles? Yes, but in the long run. However, we need to bring more clean energy to the power grid first before EVs will make a significant impact on reducing greenhouse gasses.

  9. Electric vehicles are a good idea, but using photovoltaic cells to power them is not. It produces far more pollution to make them then they will ever save, even compared to gasoline. Do something that actually works like building nuke plants.

  10. Hmmm...Try walking or bicycles every now and then. Public transportation if available.Try going without a car for a day. Then a week. If you have to rely on a car for such basic things as groceries, going to work, or other daily activities, then you have made some bad decions. Most decions about where you live in relation to where you work or shop do not take into account "environmental impact".

  11. Wow, an article that finally addresses the lie about zero emissions regarding electric cars. What about the carbon footprint of the battery production? That's part of the fuel system.
    And people that love to say how clean solar is, what about all the toxic, filthy chemicals used to create the solar panels?

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