Debunking the “Electric Cars Aren’t Green” Myth

‘Electric cars aren’t green’ is a great bit of counter-intuitive headline bait, but it’s bad maths. This is how the argument goes, again and again:

Electric cars have higher manufacturing emissions than normal cars. Electric cars also use electricity that has its own footprint. And put together these two factors are a ‘dirty little secret‘ that negate any climate benefit of electric cars!

No. Let’s clear this thing up once and for all.

It’s all about the juice

One of the most irritating things about articles discussing electric car emissions is the way it’s always very black and white. In one corner you have the ‘zero emissions’ brigade and in the other the ‘worse than combustion engine’ crew.

But as ever, real life comes in shades of grey.

The reality is that even after you account for the bigger manufacturing footprint of an electric car it is all about the fuel mix of the power you use, the ‘juice’ if you will.

Using coal powered electricity electric cars do nothing to cut emissions, using natural gas electricity they’re like a top hybrid and using low carbon power they result in less than half the total emissions of the best combustion vehicle, manufacturing included.

Mapping electric car emissions

The following map compares the carbon footprint of electric driving using average grid electricity in 40 or so countries. The actual carbon intensity of electricity you use may differ from the national average for a number of reasons, but it’s a great starting point.

The results are shown in terms of grams of equivalent carbon dioxide per vehicle kilometer (g CO2e/km). Each estimate includes emissions from vehicle manufacturing, power station combustion, upstream fuel production and grid losses.

The specs are based on a full electric vehicle, similar to a Nissan Leaf, using the 2009 average fuel mix in each country. For each country vehicle manufacturing emissions are assumed to be 70g CO2e/km, based on a number of studies detailed in the report.

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Of the 40 countries covered in this map emissions vary from 70g CO2e/km in hydro loving Paraguay, up to a 370g CO2e/km in heavy coal using India. The US average is 202g CO2e/km, in China it’s 258g and in Canada 115g.

In Paraguay virtually all the emissions are from vehicle manufacturing, as the power is incredibly low carbon. Whereas in India the breakdown is 70g for vehicle manufacturing, 200g from power plants, 30g for fuel production and a whopping 70g for grid losses.

The colors in the legend split the countries into five different groups based on carbon intensity. As you can see, even after vehicle manufacturing is included the carbon intensity of driving an electric car varies 5 fold based on the juice.

For a bit of reference, the average American gasoline vehicle is up at about 300g CO2e/km, while a new hybrid might manage 180g CO2e/km after you include vehicle manufacturing, fuel combustion and fuel production.

Compared to combustion vehicles

Because grams per kilometer is such a funny metric it is nice to convert these results to something more familiar. Working backwards from the data we can estimate what type of conventional vehicle (if any) would produce similar emissions.

For want of a better phrase lets call this the ‘Emissions equivalent petrol car’.

Click image to expand.

Now the figures are much easier to get a grip on.

In coal heavy India, China, Australia and South Africa electric cars using grid power are just like typical gasoline vehicles, in the 25-30 MPGUS range. In the UK, Germany, Japan and Italy they are as good as the best petrol hybrids, in the 45-50 MPGUS range. But in low carbon supply places like France, Brazil, Switzerland and Norway they are in a different league, averaging well beyond 100 MPGUS for equivalent emissions.

It is important to remember that the electricity you get might not match your national average for any number of reasons. The night time intensity might vary, you might have solar panels or live in a country like the US, where the grid is actually a bunch of separate grids. For example in Colorado a grid powered electric car is equivalent to about 30 MPGUS, whereas in California it’s up around 70 MPGUS.

For all the comparisons in this map the vehicle manufacturing of a gasoline car is just 40g CO2e/km compared to 70g CO2e/km for the electric vehicle. This is because we have accounted for both a greater manufacturing footprint and lower lifetime mileage in an electric car.

If you are interested in the detail check out the full report. It includes a breakdown of all figures, sensitivities to manufacturing, vehicle performance and comparisons to diesel vehicles.

Electric cars are as green as their juice

Critics of electric cars love to talk about manufacturing emissions and putting horses before carts. But they never seem to offer any better solutions. If they were waxing lyrical about urban densification, electrified public transport and the joys of bicycles their critiques would ring true, but that’s not what you hear.

Electric cars are relatively new at a commercial scale and are dealing with issues of cost, range and charging speed. Each of which will be helped by improving batteries. Despite this they offer enormous hope for reducing carbon emissions, improving local air quality and limiting noise pollution.

Electric cars are far from perfect, and there are plenty of valid ways to critique them. But let’s not pretend that a gasoline vehicle can compete with an electric car in terms of carbon emissions. It’s just not a contest.

Give an electric car the right juice and it crushes combustion engines.

Author’s note: in case you are wondering, I don’t own an electric car. We have an efficient Skoda diesel which is mostly used at weekends with 4 people in it. My preferred mode of transport is my old dutch bike, which in terms of gCO2e/km trashes all comers (foodprint included).

in a report of a similar vein, Green Electricity and Transportation (GET) Smart: Policy solutions to increase energy independence at http://www.policymattersohio.org/electric-vehicles-may2013, I note trends and examples in the electric power sector demonstrating the role electric vehicles can play in transitioning the cars we drive from their dependency on imported and polluting fossil fuels towards cars relying on electricity generated from homegrown, clean energy sources.

For example, the city municipal electric utility of Oberlin, Ohio is on track to procure more than 90% of their energy from renewable sources by 2015, nearly all of which comes from local sources. That means EVs plugging in to the Oberlin grid will run on green local power, and energy dollars spent will stay in the community.

The article including CO2 emissions from mine or well to power plant or to gas station is the correct approach to evaluate plug-ins, such as the Chevy-Volt vesus higher-mileage vehicles.

The below article illustrates this approach using the US grid. It shows higher mileage vehicles, say 50 MPG and up, will not only REDUCE annual fuel bills from what they would have been, but also reduce CO2 emissions at a much lower cost/metric ton than plug-ins.

The primary reason is the cost of lithium-ion batteries and the addition of the hybrid drive which together add about 10000 to 12000 dollars to the cost of the Chevy-Volt.

Even with increased production, there is not much room for improvement of lithium-ion batteries to significantly reduce their costs, according to the American Physical Society, whereas much can be done, at much lower cost, to improve the mileage of standard gasoline vehicles and with NON-plug-in hybrids, as Toyota has shown.

After the initial plug-in rah-rah wore off in Europe, it decided to emphasize higher-mileage vehicles and NON-plug-in hybrids, which can be produced by the millions by existing plants, instead of plug-ins.

Cheers Willem, I’ll have a read of those. I didn’t look at plug-in hybrids because there are so many assumptions that you have to make.

If we get away from the geographic issues of energy mix I would agree in general that the expense of electric cars is the strongest argument against them. I’ve seen them characterized on a few marginal abatement cost curves over the years and they are indeed way off to the right.

The counter argument is that if we are honest about what carbon dioxide concentration stabilzation requires, then there is virtually no room for tailpipe emissions at all. Which is all quite depressing really.

I know what the vehicles are, its just language we are talking about. I’m in the UK, and the terminology I’m used to is BEV (Leaf), EREV (Volt), plug-in hybrid (plug-in Prius) and hybrid (prius). In most of europe traction is limited because diesels dominate and have been used to hit EU fleet rules by manufacturers.

Europe has great experience with small diesel engines. It would be a natural for Europe to have millions of non-plug-in diesel hybrids made in existing factories; they would be very efficient, i.e., 60 mpg or greater.

In the US, the EPA uses a metric called EPA mileage equivalent which states 85 to 110 MPG equiv. for plug-in hybrids, such as the Chevy-Volt.

The metric is totally unrealistic and deceptive, as in pure hybrid mode, after the battery range has been used up, the Chevy-Volt has an EPA Combined rating of 37 MPG, which compares with the Prius EPA Combined rating of 50 MPG.

Yeah, I’m not a great fan that metric because my interest is emissions. I have a little Skoda diesel myself, not a hybrid but on longer run it gets close to 60 MPG (US). That said diesel has higher emissions per gallon as well as particulate and BC issues. My preference remains my bike. Thanks for the feedback, I enjoyed you post too.

Lindsay

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Zach Sears

June 19, 2013 18:49

Why does the solution have to involve continuing a car culture? When you write “But they never seem to offer any better solutions” you seem to assume that solutions have to involve continuing a car culture or advocate for bieks and public transit. While I do advocate for both of those, I think this is untrue in that the solution to our societies environmental problems is to use less energy not just add a battery. Batteries as you pointed out use lots of energy to produce them, and in some cases more energy than they ever store and release. Then you have mining processes which involve diesel trucks and toxicity issues.

On top of that there’s the issue of net energy in our society. If we add transportation to our grid via plugged in vehicles even with massive solar and wind investment (which is currently not happening in the US which has the most cars) we’re not going to be able to handle the demand on the grid without continuing coal and other fossil fuel electricity production. If we make the switch to electric cars we’re going to have to produce at least 64% more energy just to power electric cars and we also have to replace millions of cars with EV’s which take even more energy to build than standard vehicles. Replacing the 254.4 million cars in the US with EV’s would produce insane amounts of Co2 by itself. At 30k pounds per EV thats 7.632e+12 pounds of Co2 entering our atmoshpere. Electric cars over their life powered totally by green energy produce less emissions than a gas powered car, but this isn’t the debate. The question is if they’re green, and they’re obviously not. See a blog post I recently wrote for more depth on this. http://zachsears.blogspot.com/2013/05/electric-cars-green-or-sustainable.html

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Jeff Crunk

June 28, 2013 01:36

“Why does the solution have to involve continuing a car culture?”

I would say because of path dependency. The Wiki has a concise definition: Path dependence explains how the set of decisions one faces for any given circumstance is limited by the decisions one has made in the past, even though past circumstances may no longer be relevant.

The automobile society was made. It can hypoethically be heavily modified. But it can’t happen overnight. Unfortunately, climate scientists are telling us that close to overnight is about the timeframe to decarbonize the economy. So given that sobering constraint, an electrified car culture is not a total pipe dream relative to an imagined re-engineering of American life as you suggest. The climate crisis, rate and scale. Rate and scale again. And, theory of social change.