Why electric cars aren’t always greener

Electric cars are widely hailed as the answer to pollution on our roads. Once a niche product, over the last few years their production has expanded at breakneck speed.

In America, three years ago only two models of zero-emission vehicles (ZEVs) were available, and only in a few states. Now there are 20 different models for sale across the country.

ZEVs are plug-in electric vehicles that rely on rechargeable batteries to power the car. Part of the reason for the uptick in production is increasingly demanding environmental regulations imposed by governments. But the fact that a car runs on electricity rather than petrol or diesel doesn’t necessarily make it more environmentally friendly.

What determines whether or not an electric car is greener than the alternative?

Firstly, it depends on what kind of car it is replacing. If it eliminates an old, heavy, petrol-guzzling tank then certainly. But if it replaces a modern diesel car of a similar size and weight, then one may be simply trading emissions from the tailpipe for emissions created by the energy used to charge the car.

The green factor also varies depending on where the car is charged. If the area uses clean or renewable energy sources like hydro-electricity, nuclear or wind and solar power, then the car will be cleaner. But if the power is created using coal – still the leading source for power generation in many populous countries – then it will be little better than a regular car.

Lastly, the environmental impact varies based on the time of day that the car is charged. Using a power source during peak hours can result in proportionately lower emissions overall. This is because peak demand requires that every available energy generator, including clean as well as dirty sources, is put to use. The inclusion of clean and renewable sources to the mix reduces the overall amount of carbon dioxide emitted per kilowatt-hour of electricity generated.

Many see zero-emission vehicles as an integral part of improving environmental prospects. China wants 30% of its government vehicles to be ‘new-energy’ in two years, aiming for 5m by 2020. Europe is aiming for 10% by 2025. But unless the creation of the power itself is addressed, how green these vehicles actually are will continue to be a lottery.

25 comments

  1. what about planes, cargo ships, trucks? how do they plan to make those run
    on electricity…ZI bet those are polluting way more than cars

  2. Considering the world average was 41% coal power, I think it’s safe to say
    that an electric vehicle is greener in most cases.

  3. I beg to disagree. A gasoline engine is about 20% efficient. Even if turbos
    are used the efficiency is only 30% at best. A coal fired plant is about
    60% efficient. That’s because a stationary plant can be scaled up to
    recapture and use wasted energy (heat). About 10% is lost in transmission
    and an electric motor is about 90% for a total efficiency of 40%. So, even
    if you charge your electric vehicle using the dirtiest source energy you
    about twice as efficient as a gasoline engine! Imagine that. 

  4. Electric cars are great when all easy oil is burnt away in next 25 to 50
    years. Gasoline are cheap and easy for now oil supply. Transport Tech is a
    evolutionary phase with trade offs. Foot, Horse, Bike, Gas Car, E Car, H
    Car. No great miracles, just more r and d investment needed.

  5. The economist skips over the fact that power generation at a power plant is
    far more efficient compared to a small internal combustion engine. It also
    does not take into account the environmental impact in the production of
    the batteries used to power the car. Lithium based batteries, by far the
    best hope for electric cars, are also very damaging to the environment to
    produce. Lastly it does not consider fuel cell based cars powered by liquid
    hydrogen which are available in California today.

  6. how green hidrorogic an electric power steering pump is ?people when do
    report should investigate.

  7. It is much easier to change national energy production instead of the
    efficiency of all the cars currently on the road. Also, let’s not forget
    all of the pollution created and energy lost during the oil refinement and
    transportation.

  8. Using peak electricity is BAD. The average CO2 per kWh will be lower, but
    the only reason is that baseline power generation is polluting is because
    its underutilised. The average CO2/kWh is higher, but the marginal CO2/kWh
    is close to 0. Its like how an empty train is more polluting than a car,
    but taking the train doesn’t add any emissions because the train would go
    anyway.

    Overall using electric cars isn’t much more efficient than new petrol, but
    it has better long term environmental potential.

  9. Even if the electricity come from cole the electric car is still cleaner
    than a diesel car, this is because the combustion engine is a much more
    ineffective way to transform fossil fuel to motion than a electric
    engine…

  10. Air pollution is better far off at the factories than in the cities where
    people drive and live.

  11. Well in Norway where I saw the most Teslas in the World!
    They have 99% of the power produced in Hydro.

    So you can draw the conclusion yourselves!

  12. But isn’t the CO2 required to generate the electricity less per mile driven
    than what is produced through gasoline combustion? The goal with electric
    cars isn’t to reduce emissions to 0, it’s to reduce emissions. This video
    seems to be saying something like ‘electric cars aren’t environmentally
    perfect’, but fails to make any nuanced comparisons between the
    technologies. The question isn’t whether or not electric cars are perfect,
    it’s whether or not they’re better, but this video only really addresses
    the former.

  13. This misses the key point that electric cars generate emissions usually far
    away from densely populated areas, where tail-pipe emissions have a
    significant health impact. They may sometimes be little better in terms of
    climate change but generally they will be far better in terms of impact on
    human health.

  14. I won’t go into much detail about the relative emissions and efficiency of
    electrical power generation versus automotive internal combustion (which i
    think are unfairly represented in this video), except to make one point.

    Fossil fuel burning cars are at their cleanest and most efficient when
    they’re new, and become less so as they age and their engines wear.
    Electric cars on the other hand have an opportunity to actually become
    cleaner and more efficient over their usable life, due to the future
    availability of better energy generating technologies. The greater
    flexibility in choosing where your energy comes from, to me, is a great
    advantage that fuel burning cars just can’t provide.

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