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Frequently Asked Questions

Do electric vehicles produce more CO2 than petrol or diesel vehicles?

No, they do not.

However, this hasn't always been the case, and in some rare circumstances, EV emissions may be similar to a conventional vehicle. It's also a very complex comparison to make, with many different published studies which have sometimes presented opposing findings, so there are a few things to consider.

How is the electricity generated?

Electric Vehicles are only as clean as the grid which serves them. In areas with coal-intensive electricity generation, the benefits of EVs are smaller, and they can have similar lifetime emissions to the most efficient conventional vehicles.

Thankfully, as countries reduce their emissions to meet their climate targets, grid electricity supply all around the world is getting cleaner as more and more renewable energy supplies come online. An electric vehicle someone bought five years ago produces less CO² now than when it was first purchased. In the UK in 2019, Carbon Brief found that the lifetime emissions per kilometre of driving a Nissan Leaf EV were about three times lower than for the average conventional car, even before accounting for the falling carbon intensity of electricity generation during the car's lifetime.

In a petrol or diesel vehicle, there is no opportunity for the emissions to get cleaner over time. What's worse is that by their very design, petrol and diesel cars actively deliver emissions to the places where people are the most, directly affecting air quality and public health.

Carbon Brief - Lifecycle emissions Nissan Leaf 2019

Carbon Brief's chart compares lifecycle emissions of a conventional vehicle to those of a 2019 Nissan Leaf. Chart by Carbon Brief.

What about manufacturing?

The manufacturing of the batteries for electric vehicles incurs a significant amount of the overall carbon footprint. Many of the associated supply chains are yet to be decarbonised, and critical ingredients such as Lithium, Nickel and Cobalt use extractive industries which are still high-carbon, and the CO² footprint can vary between extraction methods. Overall footprint from manufacturing will vary between different manufacturers based on their choices of supply chains alone.

Lithium carbon intensity

Within the specific area of Lithium extraction, CO² footprint varies hugely between mines and extraction techniques. Image from Vivas Kumar at Benchmark Minerals, data from The CO2 Impact of the 2020s Battery Supply Chain by Alex Grant, David Deak and Robert Pell.

Using low-carbon electricity also hugely affects manufacturing, most likely a constant with all types of vehicle manufacturing, but some EV manufacturers have an advantage over others. Tesla operates some of its battery manufacturing in Nevada, where it plans to eventually run its manufacturing 100% renewably via many renewable energy systems, including solar. Efforts by manufacturers such as these can have a significant impact on lifecycle vehicle emissions for EVs.

Manufacturers can make huge gains in carbon footprints by improving the longevity of the batteries in their vehicles. It is one of the reasons that EV leader, Tesla, is working towards a million-mile battery, and they are due to announce this later in 2020. A million-mile battery would exceed the average EU vehicles lifespan of 130,000 miles by over seven times.

Data for the complete manufacturing process of Electric Vehicles has been hard to come by, and it is one of the reasons which has led to such differences in report data for lifecycle emissions. For example, the IVL 2017 Study which concluded that battery manufacturing emissions are likely between 150 and 200 kg CO2-equivalent per kWh of battery capacity was updated in late 2019 with a substantial revision. Researchers now estimate that "battery manufacturing emissions are actually between 61 and 106 kg CO2-equivalent per kWh, with an upper bound of 146 kg".

Carbon Brief - Differences in studies of battery lifecycle emissions

Carbon Brief's comparison shows the differences in studies of battery lifecycle emissions, both how they vary and how they've changed over time. Chart by Carbon Brief.

Beware of misinformation or outdated reports

Energy generation and electric vehicle technology are rapidly changing and improving all the time. Additionally, the comparison between electric and petrol or diesel engines is complex, and there are vested interests from fossil fuel companies to see electric vehicles fail. It's relatively easy to claim that electric cars are worse for climate change. All you need to do to present the case that electric cars produce a lot of CO² is to use outdated EV battery production data with high carbon, fossil fuel electricity generation. Then compare it to manufacture-quoted lab data for fuel efficiency of small size petrol or diesel vehicles (yes, the same data that got VW in a multi-billion dollar lawsuit) and you're probably nearly there.

Brighton Council managed to fall into this trap recently. In the agenda for the Council's ETS Committee meeting on October 8th 2019, alongside plans to install EV chargers, a note was made referencing a report by Ricardo on lifetime CO2 emissions of electric vehicles (available here):

7.4 A report by the Ricardo consultancy estimated that production of an average petrol car will involve emissions amounting to the equivalent of 5.6 tonnes of CO2, while for an average electric car the figure is 8.8 tonnes. Of that, nearly half is incurred in producing the battery. Despite this, the same report estimated that a typical medium sized family car will create around 24 tonnes of CO2 during its life cycle, while an electric vehicle will produce around 18 tonnes over its life

This report is over nine years old, only published back in June 2011. So much has changed in the EV and energy generation industries since then. As an illustration of how out of date one aspect of it is - it bases its grid carbon intensity calculations on 2010 DECC data of 500g CO2/kWh. In the UK, this figure is already less than half that now, as the UK's energy mix is considerably cleaner than in 2010. February's was 176g CO2/kWh, May 2020's average was 142g CO2/kWh. The report even states that "Decarbonising both electricity supply, through renewables; and the production of batteries will, therefore, be essential for electric vehicles to deliver ultra‐low carbon lifetime emissions.". That is something that has been taking place since 2011 and is still taking place now.

Reports must be up to date in order to be relevant in this fast-changing area of technology and climate action.

Article last updated on August 18th 2020.