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Debunking the "Electric Cars Aren’t Green" Myth

 

Electric cars green myth

It’s time to bust this thing wide open.

‘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.

In our recent study ‘Shades of Green: Electric Cars’ Carbon Emissions Around the Globe‘ we calculated grid powered electric car emissions in twenty countries. But we actually had data for quite a few more countries we didn’t include.

So let’s break out the data and put this thing to rest.

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.

EV emissions by countryClick image to expand

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’.

EV emissions equivalent

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.

 

Download the report here: Shades of Green 

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).

Lindsay Wilson's picture

Thank Lindsay for the Post!

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I K's picture
I K on June 7, 2013

This is a bad study becuase it uses average fuel mix whereas a new load will add to marginal fuel burn. 

So for instance add a million eletric cars to the UK grid and our 20% of nuclear mix wont power them it will be a combination of gas and coal depending on the time of year.

Worse yet any additional load will be using marginal power stations so any additional load is more dirty than the average existing load. 

 

But most importantly of all you need to compare new electric cars to the new oil cars of 10 to 30 years from now. On an energy basis a fair comparision vs oil cars twebty years from now will see no notable energy saving

Lindsay Wilson's picture
Lindsay Wilson on June 7, 2013

Thanks.  

I think the first metric is pretty hard for normal people so the MPG comparison makes it more accessible.  The Union of Concerned Scientists used something similar in their State of Charge report, but because I’ve included manufacturing emissions my figures are less flattering on electrics.  But the conclusion is the same, its all about power supply.

On population of car buyers, certainly China is a right off, but then you have parts of the US, Brazil, Germany, Japan, Russia and France where EVs can all be beneficial, particularly if you start thinking about air quality.  I think the stronger critique, which you rightly hinted at, is than in the marginal countries there are far cheaper ways to cut emissions. That is certainly why I drive an efficient diesel in the UK.

On innovation I think the much more interesting question surrounds EVs.  We know roughly what is going on with ICE innovation, and in many countries the growing carbon intensity of oil supply is cancelling out some of those efficiency gains.  The US is a good example where the carbon intensity of the grid is going one way, while the carbon intenisty of oil goes the other.  In fact for the US if I account for unconventional oil the average jumps to 43 MPG, then if we use 2012 grid intensity istead of 2009 the figure jumps to about 46 MPG.

The big question of innovation surrounds electric cars, in particular batteries.  Improving batteries could cut manufacturing emissions, improve range, reduce charging speed and bring down cost.  But failure to improve batteries is likely to keep EVs on the fringe for many more years.

Thanks for your thoughts, appreciate the feedback

 

 

I K's picture
I K on June 7, 2013

Greening your grid does noting to imrpove the emissions of EVs becuase they use marginal generation. So if the uk went feom 20% nuclear to 40% these EVs would emmit just the same amoubt becase they are an additional load which is meet by load following marginal power stations. That means coal or gas eletricity from below average efficency power stations. 

 

Whats more you should not discount efficency gains in ICEs. Auto ICEs pale in comparison to best in class iCEs used for other applications. Whereas eletric car efficency gains are far less likely and aby improvement is likwly to be minor . After all eletric motors outnumber ICEs perhaps 100 to 1 and all aspects of power in to kinetic energy are aleeady in thw 90 to 95 percent range so there is little headroom to improve

 

Also the EV is pointless. Computer cars will reduce transport energy demand some 80 to 95 percent. At those levels transport energy use will be trival its better to concentrate on heating abd electricity generation at this point

Lindsay Wilson's picture
Lindsay Wilson on June 7, 2013

I understand this marginal critic, but why choose the UK?  We just closed a quarter of coal capacity and nightime carbon intensity (car charging) tends to be lower.  Slated additions to the grid are all gas/nuclear/wind.  Plus co-ownership of solar/EVs is very high. For innovation I’m talking about the manufacturing emissions.  In this study the EV manufacturing emissions are almost double that of the ICE, if they are improved all these number change dramatically. 

Regards, Lindsay

Bob Lee's picture
Bob Lee on June 7, 2013

Interesting article. I do have two questions that I would love to have answered.

What is the ratio of recycleable goods in an EV compared to a gas/diesel vehicle?

What is the life expectancy of an EV compared to a “regular” vehicle?

I am just recalling an article a few years back that compared a Hummer to a hybrid and, in the end, the Hummer actually proved to have a smaller footprint due to its long term life and the ease of rteusing or recycling its parts.

 

Thanks,

Bob

I K's picture
I K on June 7, 2013

Almost every country in the world uses load followong coal and gas to meet marginal demand ot doesnt matter if the EV is in the Uk or egypt or Australia.

Adding a nike to the uk grod doesnt greeen an EV as its not load following.  Same gor wind or solar

That they may be charged overnight is a benefit in that the marginal coal or gas plant will be sligjtly more efficient than a day time charge but this won’t vary massively.

Also tjat the UK closed some coal plants is fairly irrelevant as we still use coal and gas to produce marginal production.  Also some people make the mistake that becuase coal plants were clpsed we qill birn less coal. This isnt certain becuase we coild jist run exosting plants at a higher capacity factor its more dependant on coal/gas prices 

CelloMom on Cars's picture
CelloMom on Cars on June 7, 2013

Thank you for simultaneously de-bunking the “Electric cars aren’t green” and the “EVs have zero emissions” myths. Because as you said, the reality is in between.

The recent price reductions on several EVs are also de-bunking the “EVs are expensive” myth – when I went through the back-of-the-envelope math I was surprised to discover that some EVs were already competitive (over 10 years, at 15,000 miles per year) even before the price reductions. (Tesla didn’t help that discussion:  Tesla ought to be compared to Porsche, not to Nissan Leaf).

But besides more green energy, we desperately need something better than the current batteries, which are too Californian: life is good between 65-75F (18-24C) but they don’t hold charge at very low temps and lose lifetime at very high temps (it’s for this reason that I drive an efficient diesel). EVs need to be able to stand up to the extreme weather that climate change will bring.

James Thurer's picture
James Thurer on June 7, 2013

I K’s point that analyses like this can be very misleading, because they do not consider the impact of marginal electricy consumption is a very good one.

More fundamentally, the question of whether or not substituting electric vehicles for ICE vehicles reduces greenhouse gas emissions misses the central policy problem of whether or not subsidizing substituting electric vehicles for ICE vehicles is an effective and cost effective mechanism for reducing greenhouse gas emissions and a wise use of resources.

I suspect that the answer is no, it is not.

Nathan Wilson's picture
Nathan Wilson on June 8, 2013

The question “are EVs a good (green) choice today?” misses the more important point, which is “are EVs a good choice for 30 years from now“.

If we want EVs to have a large market share 30 years from now, we can’t wait 27 years, and then ramp up really fast.  The world (outside of consumer electronics) does not work that way; vehicles and their infrastructure are long term investments.

Despite the claims of advocates, EVs are pretty lame today; the dirty grid that charges them is only one of the problems.  But they are a step in a reasonable direction; we should grow our EV industry slowly, but not too slowly.

——————

An interesting thing about the maps that is noteworthy: the countries with the greenest grid power use large amounts of hydro, nuclear or both.  Someday, there might be green countries with large amounts of wind and solar, but for today, hydro and nuclear are the only proven solutions!

Nathan Wilson's picture
Nathan Wilson on June 8, 2013

EV charging is one case in which I think “smart grid”-like technology will make a big difference.  It is just a minor software change to home chargers for them to wait until late at night to start charging (unless the user presses the manual over-ride or the battery is deeply depleted).

With EVs charging most at night, the EVs themselves (and some corresponding daytime load too) become baseload.  In places like California, where there is enormous resistance to building a new power plant, yes the existing (dirty fossil fuel) plants will just run more (reversing all of the gains from added solar PV).  But in places that still build new plants, (e.g. developing countries), baseload power is cheaper than load-following. In nuclear-friendly countries, this means zero-emissions; in wind-heavy countries, maybe 30% emissions reduction compared to current grid power.

Regarding the comparison to ICE cars, yes there is still some room to improve ICE efficiency.  But much of the improvements in vehicle fuel efficiency (at least in the US) will come from making cars smaller, and that improves the EVs just as much as the ICEs.

I K's picture
I K on June 8, 2013

That is a mistake. Its clear ICEs actually have a lot of headroom to improve. Current best in class ICEs get close to 55 percent efficency on constant output. Variable ICEs in cars are perhaps only 35% on average. The difference of 35 to 55 percent isnt a 20 percent improvement it is a massive 57 percent improvement.

Compare that to an eletric motor at currently 93 percent efficiency how much headroom does it have? Get it to 95 percent and you have improved efficency by just  2.1 percent. 

 

Also regarding your idea of night charging allowong more baseload is correct at only very high levels of baseload. So eg france. For all other countries there isn’t a huge improvement in marginal efficency vetween day and night most months of the year. This is largely because most power stations are actually multiple generators. Eg a 2GW gas plant is fir example actually 5 x 400MW. So if demand is J

ust 1GW they don’t run each unit half capaciry at a lower efficency they run half at full ccapacity and half at zero

 

 

 

Alsomost people imagine lots of eletroc cars will need more power stations that isn’t true most nations have well in excess of spare capacity to chaege at non peak times

 

 

Thw only way to green eletric cars is to improve marginal load following plants efficency amd that is not easy. Wven if CCGTs are improved to say 70 percent an almost impossible task it takes three four or five decades for current plabts to be phased out so the new tech becones the marginal generator. 

 

Overall eletric cars will do nothing to reduce primary energy demand anytime soon. Far more likely are hybrids with tiny vattery packs to just allow ices to work at higher constant efficency

Gary Tulie's picture
Gary Tulie on June 8, 2013

There are many complex issues in this discussion, and variables which could make a huge difference to the future relative emissions of ICE and electric vehicles. 

1. There is an arguement that there is little head room for efficiency improvements in electric vehicles

In terms of the engine, this is partly true. Good electric motors can achieve 97% efficiency, however avarage efficiency is likely to be much lower due to the high proportion of part load use where efficiency is lower. 

There are however ways to improve efficiency such as improving aerodynamics, reducing tyre rolling resistance, reducing the weight of the vehicle structure and batteries so reducing the power required to move the vehicle, and increasing the effectiveness of regenerative breaking. 

2. There is the arguement that all electric vehicles will in effect be charged by additional use of load following gas and coal fired plant. 

This may be largely true now, but does not need to be in the future with a smart grid and suitable interactions with electric vehicles. 

Nearly every vehicle spends most of the day parked somewhere, with only an hour or two per day of actual driving. This leaves around 22 hours on an average day in which to accomplish charging. In a system with large amounts of intermittant renewable energy, it should be possible to use all these batteries to level out supply and demand to some degree – absorbing excess wind or solar energy when it is being produced, or even giving power back to the grid to avoid the need to run peaking plants. 

3. One factor referred to in the article but not yet in the discussion is the effect of increasing the service life of the batteries – with much longer battery life, many batteries will begin to live longer than the vehicles they are attached to in which case, the batteries can be removed from the vehicles and reutilised as static battery storage – enabling integration of more wind and solar power. 

Schalk Cloete's picture
Schalk Cloete on June 8, 2013

You make a good point about the increasing carbon intensity of oil. However, this is also just a matter of a few percentage points one way or the other. Overall, it can be stated with reasonable certainty that the map will look pretty much the same two decades from now. We can debate whether it will be slightly greener or slightly redder, but the overall CO2 case for EV’s will probably be unchanged for all practical purposes.

Regarding EV and general cleantech innovation, I must say that the enormous dependence on battery innovation is one of the primary reasons why I am deeply sceptical about the whole green solar/wind/EV idea. Humanity has been trying to develop better batteries for ages, but, after all of this time of intense research interest we are still stuck with the lead-acid battery which was developed in 1859. Vaclav Smil tells this interesting story of how arguably the greatest inventor of all time, Thomas Edison, wasted 10 years of his life unsuccessfully trying to develop a better battery.

Batteries for electronics which can be small, relatively expensive and short-lived are one thing, but batteries for EV’s and utility scale energy storage which have to be very cheap, massively scalable, rapidly chargable/dischargable, highly recyclable and long-lived is a completely different story. Personally, I would be very (pleasantly) surprized if we ever make this work. 

I K's picture
I K on June 8, 2013

Wrong imo

For a start EVs even if large numbers represent still a small fraction of a grids output. You are looking at aroind 10GWh of storage in a country like the UK which is a fairly trivial amoint for a grid that generates closee to 1,000GWh a day. So your EVs can store about 15 minutes of grid output and this is assuming you want your finite cycle batteries to cycle more than you need them to

More importantly any idea that these will not be powered by marginal gas or coal for now is fantasy. Any idea is effectively an accounting or infrastructure limit.

For instance in framce an EV woild ne cjarged bt nuclear so does that make an EV green?  Well what if france built 10GW interconnect to nearby nations then tje EVs are effectively charged by the newer larger grid woth ots marginal coal or gas.

So were EVs green or was it an accounting trick?

Either way EVs are pointless before computer cars. Ev self drive taxis make more sense and a small fracrion can gain a large miles driven share

I K's picture
I K on June 10, 2013

Overall you have debunked the debunking the myth that eletric cars aren’t green…..

 

 

 

Also its somewhat unfair to draw the map as it has vwwb ddrawn. You look at green canada and little red India and rhink hummm thats not too bad most the world is green-ish without taking into account that ibdia has nearly a billion and a half people vs canada with a hell of a lot less. So nations shoild be scaled up or down to represent their population rather than landmass. 

 

 

Also your colors need revising.  Greeb should surely be reserved foe wlwteic caea that are cleaner than the currebt cleanest oil cara which achieve sib 100g…

Lindsay Wilson's picture
Lindsay Wilson on June 10, 2013

Just to clarify, in case you didn’t get it.  It is manufacturing emissions plus wells to wheels emissions.

For example:

50 MPG (US) = 40 g manufacturing, 108 g combustion, 22 g fuel production = 170 g CO2e/km

The electric manufacturing emissions are 70 g CO2e/km.  So very low carbon energy the electric comes in less than half that of a top hybrid.

 

 

 

I K's picture
I K on June 10, 2013

An efficent oil car gets sub 100g (and some as low as 80g) and they way 22g was chosen for the eneegy cost of the fuel os absurd. It means a 80g/km oil car is supposidly poweredby oil which is about 30% of the ebergy cost of oil

Also the manufacturing cost seems quite high 40g per km over 200.000 km equals 8,000 kg

So it veey much appears nunbers were just randomly picked 

 

Also as noted there is almist nowhere on earth that has the 

ability to provide your many electric cars with marginal 

electricity with no carbon.  Wvwn in nations with green grids an additional load is lokely to be powered by marginal coal or gas.

I K's picture
I K on June 10, 2013

.

I K's picture
I K on June 10, 2013

.

Lindsay Wilson's picture
Lindsay Wilson on June 10, 2013

Numbers all come from EIA, DEFRA and WRI.  Manufacturing emissions a compilation of studies.  

Generalisations about ‘load following coal’ for a given country are quite odd.  If places have hydro it does load following, in places with a mix of nuclear, coal and gas it tends to be gas.  With high penetration of coal they do cycle coal, but you just can’t generalise.

Published elsewhere this note has been critised for understating the benefits of EV’s due to not taking account of the load balancing capacity they provide

I K's picture
I K on June 10, 2013

Its hardly generalising to say the majority of the worlds population live in coal and gas powered grids its a plain fact

Regarding the storage potential of EVs its a myth they cant store much utility scale energy. Your looking at around 15 minutes of a grids daily output as a maximum

Lindsay Wilson's picture
Lindsay Wilson on June 10, 2013

I’d have to say I agree that batteries is probably the area where innovation has been at its most glacial.  Currently I feel it is the major thing holding back EVs.

In terms of decarbonising electricity I’m less pessimistic.  If we are talking about Smil why not look back.  In the last 20 years almost every wealthy country has decarbonised power supply to a degree, the only OECD exception I can think of is Australia.  US is down 12%, Germany down 24% and UK down 32%. Even China is down 14%, but still very high.

That said without CCS I doubt India or China can get low enough for EVs in the medium term, but then again the major driver may be air quality problems rather than CO2

 

Lindsay Wilson's picture
Lindsay Wilson on June 10, 2013

I’ve done my best to answer you queries, please don’t put words in my mouth

 

I K's picture
I K on June 10, 2013

My apologies I was perhaps overly negatuve. Energy isn’t really the saving grace of EVs its their no tailpipe emissions and their ability to somewhat link oil prices to coal and gas prices. Even if they save no energy we would be better off with EVs powered by a coal station a hundred miles away than the exhaust pipe 2 meters away. 

Lindsay Wilson's picture
Lindsay Wilson on June 12, 2013

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.

Thanks for the links, Lindsay

Lindsay Wilson's picture
Lindsay Wilson on June 12, 2013

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.  

Best, Lindsay

Lindsay Wilson's picture
Lindsay Wilson on June 12, 2013

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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