Just how environmentally friendly are electric vehicles?


August 31, 2010

Just how environmentally friendly are electric vehicles like the Tesla Roadster?

Just how environmentally friendly are electric vehicles like the Tesla Roadster?

Because they produce no exhaust gases in operation electric vehicles (EVs) are seen as the eco-friendly alternative to conventional gas-fueled cars. While zero-local emissions is clearly a big plus, other factors contributing to the overall environmental impact of EVs are often overlooked – namely the manufacture, usage and disposal of the batteries used to store the electrical energy and the sources of power used to charge them. Now, for the first time, a team of scientists from the Swiss Federal Laboratories for Materials Testing and Research (or EMPA) have made a detailed life cycle assessment or ecobalance of the type of lithium-ion batteries most frequently used in EVs, to see if they really are as environmentally friendly as their manufacturers would have us believe.

Fuel source is the key

The investigation shows that, if the power used to charge the battery is not derived from purely hydroelectric sources, then it is primarily the operation of the EV that has an environmental impact, exactly as is the case with conventionally fueled vehicles. In other words, the size of the environmental footprint depends on which sources of power are used to “fuel” the EV. Contrary to initial expectations that the manufacture of the batteries could negate the advantages of electric drive vehicles, the Li-ion battery itself was actually found to have a limited effect.

The team calculated the ecological footprints of electric cars fitted with Li-ion batteries, taking into account factors such as those associated with the production of individual parts, the operation of the vehicle during its lifetime, all the way through to the scrapping of the vehicles and the disposal of the remains. The electric vehicles evaluated were equivalent in size and performance to a VW Golf, and the power used to charge the batteries was assumed to be derived from sources representing an average European electricity mix – that is, a mixture of atomic, coal-fired and hydroelectric power stations.

For comparison the team used a new petrol-engined car, meeting the Euro 5 emission regulations. It consumes on average 5.2 liters (1.37 U.S. gallons) per 100km (62 miles) when put through the new European Driving Cycle (NEDC), a value significantly lower than the European average. In this respect, therefore, the conventional vehicle belongs to the best of its class on the market.


The study shows that the electric car’s Li-ion battery drive is in fact only a moderate environmental burden. At most only 15 per cent of the total burden can be ascribed to the battery (including its manufacture, maintenance and disposal). Half of this figure, that is about 7.5 per cent of the total environmental burden, occurs during the refining and manufacture of the battery’s raw materials, copper and aluminum. The production of the lithium, in the other hand, is responsible for only 2.3 per cent of the total.

“Lithium-ion rechargeable batteries are not as bad as previously assumed,” according to Dominic Notter, coauthor of the study which has just been published in the scientific journal Environmental Science & Technology.

The outlook is not as rosy when one looks at the operation of an electric vehicle over an expected lifetime of 150,000 kilometers (93,205 miles). The greatest ecological impact is caused by the regular recharging of the battery, that is, the “fuel” of the e-car. Topping-up with electricity sourced from a mixture of atomic, coal-fired and hydroelectric power stations, as is usual in Europe, results in three times as much pollution as from the Li-ion battery alone. If the electricity is generated exclusively by coal-fired power stations, the ecobalance worsens by another 13 per cent. If, on the other hand, the power is purely hydroelectric, then this figure improves by no less than 40 per cent.

The EMPA team concluded that a petrol-engined car must consume between three and four liters per 100km (or about 70mpg) in order to be as environmentally friendly as the electric car studied, powered with Li-ion batteries and charged with a typical European electricity mix.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

The fundamental problem that isn\'t being addressed is using ~3000 pounds of steel to transport ~300 pounds of human. Meanwhile, my electric bicycle kit comes in tomorrow... expected fuel efficiency equivalent? ~960 mpg. Not to mention the ancillary benefits of cleaner air, increased physical fitness/health, and money saved from licensing/registration/fuel.


I\'m not sure why they do not mention other renewable sources such as wind and solar, only specifying \"hydroelectric sources\". Maybe that\'s all they have to work with in Europe? (I doubt it.) It seems odd that they wouldn\'t mention wind and solar as equal alternatives.


It is an interesting study but there are some things wrong or exaggerated.

Does the average European really toss away their car after 93,000 miles? My current car has over 140,000 and therefore will be recycled at half the rate they are calculating. (by the time I get rid of it).

Also, in the time they are calculating, the EU is scheduled to increase renewable sources by about 25% of now. This will change the the math year to year. That does not appear to be the case in the study.

The big picture is also missing here. When we run out of fossil fuels, or run low enough that the cost sky rockets, it won\'t matter how efficient a standard fuel powered car is. There will be nothing to put in the tank.

Raum Bances

This whole article treats the source of the electricity to charge the car as static. Like it will never change. This is foolish. Once we have a significant amount of cars that are electric, governmental policy can cause what power sources we have to change over time to renewable forms. Renewable sources continue to gain ground on efficiency and cost. At some point in the next decade or so we may be able to make the choice to stop burning coal. I am no tree hugger, but telling the oil companies and coal companies to stick it is a worthy goal. Dennis

I\'d like to look at the way they did this as EV\'s only use 33-12% of the energy/mile of an ICE, depending on electric source.

Plus I\'d bet they didn\'t include gasoline\'s full cost to pump, refine which is at best 60% eff plus the cost of importing, protecting the oil. Plus by the time any real numbers of EV\'s are online, power will have far less coal and more RE. Now add the fact that most EV\'s will be charged off peak when the energy is going to waste from nukes, some RE and running EV\'s is far better than running ICE\'s on oil.

Add that one can make one\'s own fuel for EV\'s by solar, wind or biomass/CHP units, and eff increases, impacts drops far more.


It is interesting that the battery has little impact on the environment. The typical European mix for electricity does not seem to take into account the rapidly increasing use of PV, wind, geothermal and tidal. Since coal plants are becoming a smaller percentage and renewable is rapidly increasing in the percentage mix it would seem to indicate that the future electricity will become cleaner. I can easily predict that fossil fuels will only increase there ability to pollute. Gulf of Mexico Spill is of course the latest stain on the fossil fuel tapestry.


There was a group a few years ago that determined all the costs for building, operating and disposing of a hybrid vehicle, compared to a conventional vehicle. The environmental burden of the hybrids such as a Prius exceeded that of a Hummer H3. Here is a summary of that report here: Or find all the reports here: Look at the Dust to Dust report. The main reason a Hummer is less burdensome to the environment is that the engineering is simple and several decades old. It\'s a hunk of steel with plastic thrown inside. Over time the engineering cost for hybrids will be diluted by millions of vehicles. Another downfall for the hybrid is the expected lifetime of just 100,000 miles.


This is all well and good, until demand for electricity to charge all the new electric cars surpasses supply, and new fossil fueled power plants are built to makeup the short fall.


Hybrids are made to be a temporary solution to ease the transition from gas to no-gas. Going cold-turkey from oil is not a good idea when we realize how entrenched oil is in our modern lives; look around, it has an effect on everything; just because we don't notice it doesn't mean the connections are not there. The biggest tentacle is the TAX added to every gallon of gas. You know that the government doesn't like to give up a tax until it has a replacement in place. LOL


Hopefully they also took into account that car engines are horribly inefficient when compared to using the exact same fuel at a power plant. By having the electric cars pull the power from the grid we can at least shift the fuel consumption to the more efficient means of electrical production.

Colter Cederlof

\"Another downfall for the hybrid is the expected lifetime of just 100,000 miles\" LOL. Where did this information come from... Anyway, if you plan to power your EV with PV panels and thereby offset the cost of gas at 2.90 /gal the solar panels pay for themselves in almost 1/4th the time that they normally would considering gov incentives of course. Want to see the numbers, see for yourself here: Or you can remain at the mercy of the utility company as the demand for electricity goes through the roof along with rates. Your choice.

Jeremy Dory

Many people like to qute the dust-to-dust article, without ever reading it. I read it. The numbers are arbitrary and unsubstantiated. The results are not peer reviewed. In short, it\'s a crock.

Yet there are a few that think they are actually pointing to a valid and scientifically researched paper when they reference it. The numbers are all made by assumption, and not by actually investigating actual car companies who have actual data. Just more FUD to help big oil and car companies extend the legacy of gasoline.


From my research, electric cars use anywhere between 11 kw-h/100km (the EV1) & 18kw-h/100km (the Tesla Roadster) of electricity. If all that electricity comes from coal, then the car will generate-on average-150.96kg = 14.4kg of CO2/100km traveled. Meanwhile, the conventional car they mention above (which is actually very above average-by Australian & US standards-in terms of fuel efficiency) would generate 5.22.32 = 12.1kg of CO2/100km traveled. So already the very best ICE vehicle is only modestly better than an average Electric vehicle even if all its electricity comes from coal. Of course, I wonder if they accounted for the fact that, in peak time travel, many ICE vehicles consume as much as 20% more petrol than their official fuel efficiency figures claim (which are for highway travel only)? If you factor that in, then the ICE vehicle they use as a comparison generates 14.5kg of CO2/100km traveled. Throw in regenerative braking for the electric vehicle, & the CO2 emissions fall even further for peak travel. If all of the power for the vehicle comes from natural gas, though, then the EV leaves the ICE vehicle in the dust-with emissions of only 7.2kg CO2/100km traveled. Lastly, of course, there are other factors beyond CO2 to consider when we ask about the environmental friendliness of a vehicle. ICE vehicles are also major point sources of Carbon Monoxide, Benzene, Particulate Emissions & NO2-all of which are bad for our environment & human health. Dreamer-Reedemer is right, though, in pointing out that the key issue is why we still insist on using such a massive object to transport a single person!


jmatus, in many cases an electric vehicle consumes less electricity in a week of peak-hour travel than the average household uses in a single day. So even if you have 3 million of these vehicles on the road, they\'ll be using about 1/5th of the electricity used by 3 million average sized houses. As someone pointed out above, countries with large amounts of coal power already have a serious issue with over-supply in off-peak times (between 10pm & 6am roughly). If you charge these cars during these time periods, then you\'d no new energy capacity at all. Many electric vehicles can also be plugged into homes to feed any left-over electricity back into the grid.


Thanks for the above inputs. They crystalise the facts for me and make the need for and viability of EV\'s very clear to me. I note also that if people become owners of large capacity power storage (in the car) that the overall investment in power generation capacity would decrease because the peak power requirement could be met by battery power.


Yes, I like what Goatman is saying, can we plug our cars into our service panels to \"time-shift\" our usage? Utilities like Southern California Edison offer an attractive electricity rate called Time Of Use for Electric Vehicles (TOU-EV) This gives the owners a much much cheaper rate at night between 12-6 am. So charge your car for cheap, then use it for your homes power during the day with an inverter- of course if you aren\'t planning to go anywhere. This will offset usage during the day, thereby increasing the grid stability by decreasing peak demand good for the utility, good for consumer who saves money on their electric bills with the delta in rate from night to peak day.

Fabian Rousset

Does anyone know just how much electricity was produced from renewable energy sources from 2009 to present? i don\'t know the specific amount but i doubt that there are enough electricity to power EVs yet. That is why i think the scientists didn\'t put solar or thermal,etc to account. there are not enough pv panles or wind turbins just yet. But i think we are getting there.

bio-power jeff

Yeah, the problem they (and everybody else) are overlooking is that the batteries break after a few years. First they become less efficient and then they have to be replaced. That not only costs money, it also nearly doubles their environmental impact (assuming you only have to replace them once). I hope that future battery technology will improve not only their efficiendy, but also the manufacturing cost and ther lifetime.


@pizzaeater The \"dust to dust\" so-called study is flawed in many ways. There are many critics online explaining why.


I believe the big problem with increasing uptake of EVs is quick charging or replacing the drained battery with a charged one. Petrol/diesel has the huge advantage of transmitting, say, 400miles range in 150 seconds via the filling pump & hose. Even if the technology allowed such a rapid charge for Li-Ion there would need to be monster cables dangling from every home, garage and workplace car park - clearly impractical and very resource-hungry in copper consumption. Replaceable battery packs make much more sense, but again the average commuter would need or want one at home and one at work thus potentially tripling battery requirements. Having packs at \'filling stations\' would help but the electricity infrastructure would need radical modification to allow every forecourt to \'pump as much electricity per second as it now does with petrol/diesel. Even LPG users get impatient at waiting for the slower tank fill - roughly 5 minutes for 200 miles. So we need portable energy with high filling rates. Hmmm. Petrol would be a good idea....

Chris Knowles

A couple of points on EV Energy:

First EVs do offer the choice of charging from alternative energy sources if you wish. This is not an option with the ICE.

Then, as dreamer.redeemer mentions, EVs make much better use of the energy you put in them.

Most EVs carry around the energy equivalent of around 1 gallon of gasoline. They have to burn gas, there is no choice, these vehicles will pollute a lot, and not just Co2 by the way.

Check a few out here:

Regarding e-bikes, they must be the most efficient transport machines on the planet. My e-bike will go at least 30 miles on 1/2 kW of electric energy, more if I pedal too. Since 1kW of electricity from the grid is about 2 pounds of Co2, you can see that the carbon from the e-bike ain\'t much.

This is especially interesting when you compare it to a 20mpg car that puts out 20 pounds Co2 from 1 gallon of gas, 36kWh electric equivalent.


Well...yet again, a \"study\" that doesn\'t study everything! Think about WHERE the lithium is mined and WHERE the lithium is converted into a usable product like a battery. How do they get the raw ore from the mine to the factory? Here\'s a hint for you...the factory is NOT in the same location as the mine! The raw ore is shipped to china or korea and from there it\'s manufactured into a battery...notice I said \"shipped\"? The \"shipping\" is done with tankers that use petroleum sludge as fuel...highly toxic and nasty stuff...this is the stuff that can no longer be refined out of the fractional distillation of the oil. They say that a single one way voyage of just a single tanker across the pacific creates more pollution than 50 million vehicles. So add THIS into your environmental analysis of electric vehicles! Remember, the average hybrid uses materials that are shipped by tanker several average gasoline vehicle is only shipped once...unless you purchase it and use it in the country of manufacture!


I know it is still a long way off, but the more solar panels each home has could help reach a stage where smart home owners actually power their cars from their solar panels. If we get to the stage where we have more efficient panels then home owners could be better off feeding excess power to their car and not back into the power grid where greedy politicians are likely to tax them.


Electric cars were infact first developed even before the fuel consuming engines were made, since the 1800\'s...So we have the technology, but we are in dire need of efficient technology that will enable easy recharging of the electric batteries..The electric auto makers have to sort this issue at hand for affordable electric battery recharging.

Facebook User

This article illustrates the importance of increasing renewable energy production. Electric cars will be truly viable when we improve our solar power production, especially if we encourage fueling during daylight hours.

Christopher O

only way to make this work is use local energy i.e solar pannels and wind energy to power the electric vehicles. for the vehicles to be produced localy. will never happen but thats where we should be focusing on. and from the sound of things an electric bike is much more efficient then a car so maybe they should make a bike that is big enought to carry items like a car but not as big

Joseph Rudwick

For a school project I’m seeing how people feel about using electric/environmentally friendly cars. I could use some help with getting enough responses. You can help me by going to and answering a few quick questions. It will only take a minute and is completely anonymous. Thanks!

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