POSTS ON SOCIAL media have argued that electric vehicles are a “con”, as there are significant greenhouse gas emissions released during their construction. While there are ecological costs to building electric vehicles, many analyses find that they are significantly better for the environment than petrol or diesel cars.

An image which was shared more than 14,000 times on Facebook shows a photo of a heavy, earth-moving vehicle with text: “It Burns ~1000 liters of fuel in 12 hours. Moving ~250 tons of dirt to extract materials to produce ONE Tesla battery.

“And people still call it ‘zero emissions’ when they drive their eletrical car “ [sic]

Despite the post’s layout implying the three statements are neatly connected, it’s not clear these statements are linked.

For example, while it appears to imply that it takes about 12 hours for the machine pictured – the Caterpillar 994K – to displace 250 tons of dirt, this is very unlikely.

The digger is able to lift up to 42-60 tons of material at a time, so should be able to move 250 tons of dirt in about six scoops. Demonstration videos of the vehicle show this should only take a few minutes.

It is also unclear why it’s implied the amount of emissions released before the construction of a car should affect whether “zero emissions” are released when it is being driven. Fully electric vehicles have no tailpipe emissions.

However, despite this, the post raises valid questions: How much emissions are released obtaining the materials and constructing fully electric vehicles, and does driving electric cars emit any pollution?

Batteries

Electric vehicle batteries have been criticised for the environmental impact of manufacturing them, in particular the mining of materials such as lithium and cobalt.

This criticism is often spread by climate change denial groups with connections to the fossil fuel industry. 

However, there are real environmental costs to producing these batteries, including emissions, water use, contaminating the nearby environment with toxic waste and possible support for human rights abuses – though the same is frequently said of the fossil fuel industry.

Tesla, the manufacturer mentioned in the Facebook posts, uses a mix of lithium ion batteries for their vehicles. 

A 2018 estimate put the CO2 cost of Lithium-ion batteries at about 73kg of CO2 equivalents per kWh of battery, which is also within the range of estimates given by a Swedish Energy Agency study. 

The estimate was based on data from a mix of countries, including ones where manufacturing would have a higher environmental cost. Although Tesla claims to be particularly green, they continue to manufacture in countries such as China.

So, applying that estimate to a 100kWh Tesla model S car battery  – (most electric car batteries are much smaller than this) –would release the equivalent of about 7,300 kg of CO2.

This 7,300 kg of CO2 is about the same amount released by burning 3,050 litres of petrol, or about two-and-a-half year’s worth for Irish drivers, an estimate derived from 2022 figures provided by the AA.

So, if we were to account for just the battery alone, we might say: a petrol-powered car has a lower initial environmental cost than a battery-powered vehicle, but due to fuel emissions, this breaks even sometime after two years, and thereafter causes more damage to the environment.

Scientific estimates

However, the figures above are massively simplified. They don’t take into account the considerable amounts of emissions released in drilling, refining and transporting fuel such as petrol before it is put into a car.

Nor do they consider other differences in how electric cars and fuel-powered cars are built.

Nor do they take into account the carbon cost of the energy used to power electric cars taken from the electrical grid.

While fully electric vehicles do not release tailpipe emissions, that does not mean that driving them is carbon neutral. The cars still require energy; so how environmentally friendly recharging a car is depends on how clean the local electricity grid is.

Tesla claims that even when one of their cars is recharged from the grid in China, it will have significantly lower lifecycle emissions than a car using an internal combustion engine. In Europe, they claim Tesla lifetime emissions would be less than a third that of fuel-powered cars. 

However, Tesla has been criticised for not publishing enough information about their environmental impacts, and their analysis doesn’t account for “Scope 3” emissions, which could include materials bought from a supplier.

One analysis showed that in countries that generate a lot of electricity with coal, electric vehicles may have little benefit over vehicles that burn fuel.

However, estimates provided from academic and government sources found that, even when the pollution caused by electricity production used to recharge these cars is taken into account, electric vehicles massively outperform traditional vehicles. 

A MIT study of 125 vehicles, showed that while manufacturing electric vehicles tends to release a higher amount of greenhouse gases than manufacturing petrol or diesel vehicles, this is dwarfed by the emissions caused by driving over the lifetime of the vehicles. 

“Even the dirtiest batteries emit less CO2 than using no battery at all,” an overview of the sector by the MIT Climate Portal updated in October 2022 said. 

A Reuters analysis in July found a Tesla Model 3 charged using the average United States energy mix would to break even with a comparable fuel powered car after being driven about 21,725 kilometers.

Multiple other studies also back up claims that the use of electric vehicles dramatically reduces CO2 emissions compared to gas powered vehicles.

Researchers also note the environmental cost of manufacturing batteries for electric vehicles is expected to reduce and that, as a country switches to cleaner energy sources, so too do the benefits of driving an electric vehicle increase.

Ireland

So, given Ireland’s mix of energy sources, how long should it take for an electric car to become better for the environment than a car with an internal combustion engine?

A 2022 study that takes Ireland’s electricity mix into account (which is close to the EU average), finds that electric cars in Ireland emit less than a third of the CO2 that petrol cars do. Depending on where the car and battery are produced, petrol and electric cars break even at about 20,000 km, after which the electric vehicles are better for the environment.

Irish private cars travelled, on average, 16,352 km in 2019, the latest year without COVID restrictions that figures are available for. Taxis, hackneys and limousines travelled an average of almost 40,000 km that year, according to the Central Statistics Office.

This means that an electric vehicle in heavy use may become carbon neutral within the first year of being driven.

Other pollutants

However, there are emissions other than greenhouse gases that should be considered.

While fully electric vehicles don’t produce tailpipe emissions, they still produce traffic air pollution from tyre and brake wear, which some studies show make up most of the “primary particulate matter” from cars that match EU exhaust emissions standards.

Given that some electric cars – such as Tesla models – are heavy, they may emit more of these pollutants than light, petrol-powered cars.

Traffic pollution has been linked to respiratory and cardiovascular diseases, as well as allergic conditions .

An Oireachtas committee was told last year that “a correlation between traffic produced air pollution and stroke admissions” had been demonstrated in Ireland. 

“All cars, including electric propelled cars, produced particulate matter from other sources such as tyre wear and brake pads.” Dr Colm Byrne, from the Irish Doctors for the Environment and consultant geriatrician at the Mater Hospital in Dublin, told the committee.

As such, while electric vehicles are, over their average lifetimes, better for the environment than fossil fuel-powered cars, this is only true when they are driven enough to offset extra emissions released during their manufacture.

And while they do not release tailpipe emissions, they do release particulate matter from their wheels and brakes, which are believed to have significant negative health effects.

With reporting from the PA