Skip to content

Fact check: Does a Toyota Corolla emit less than a Tesla?

ABC News, 7 March 2018
The claim
Since the summer break, tensions have been simmering within the Coalition over electric vehicles. Although Environment Minister Josh Frydenberg has thrown his support behind electric cars, some on the government benches are yet to be convinced. In a debate with UNSW’s Gail Broadbent, who specialises in electric vehicle research, on ABC’s RN Drive, Craig Kelly, a Government backbencher who sits on the House of Representatives Standing Committee on the Environment and Energy, challenged the notion that electric cars should attract a taxpayer-funded subsidy to encourage their proliferation.

Mr Kelly argued it was unfair that someone driving a vehicle in the outer suburbs of big cities or regional areas should be subsidising people driving electric cars in the inner city.

He also questioned the environmental benefits of subsidies, referring to the Federal Government’s Green Vehicle Guide, which is run by the Department of Infrastructure, Regional Development and Cities.

He said:
“Look at the [Green Vehicle Guide] website. A Tesla has a (sic) carbon dioxide emissions when charged the average of the Australian grid — that’s higher in Victoria, that’s higher in Sydney — of close to 200 grams per kilometre travelled. A Toyota Corolla on the same government website shows only 171 grams of CO2. So, the Toyota Corolla is significantly less than the Tesla and that doesn’t include the manufacturing emissions.”

Does a Toyota Corolla emit significantly less carbon dioxide than a Tesla? RMIT ABC Fact Check investigates.

The verdict
Mr Kelly is cherrypicking.

The data on the Green Vehicle Guide website shows only the more powerful Tesla models emitted “close to 200 grams” of carbon dioxide per kilometre. Most emitted less, some considerably less.

Mr Kelly referred to “a Tesla” and “a Corolla”. However, the website lists 27 different models of Tesla, with emissions varying depending on the model.

At the time Mr Kelly made his claim (the website has since been updated), emissions for the various Tesla models ranged from 174 to 212 grams of carbon dioxide per kilometre.

For petrol Corolla models, emissions ranged from 171 to 191 grams of carbon dioxide per kilometre.

Eleven models of Tesla had higher emissions than the most polluting Corolla (191 grams of CO2 per kilometre), compared with 16 that were less polluting.

All 27 models of Tesla listed at the time of the claim had higher emissions than the least polluting petrol Corolla (171 grams of CO2 per kilometre).

However, according to experts, the data for the emissions intensity of the energy grid was out of date at the time the claim was made.

The website has been updated since Mr Kelly made his claim with data reflecting the 2015-16 electricity mix between coal, gas and renewables.

This resulted in a significant improvement in the reported environmental performance of the Tesla compared with petrol Corollas, such that five models of Tesla had higher emissions than the most polluting Corolla (191 grams of CO2 per kilometre), compared with 22 that were less polluting.

After the update, 17 models of Tesla had higher emissions than the least polluting petrol Corolla (171 grams of CO2 per kilometre), while 10 had lower emissions than even the most environmentally friendly petrol Corolla.

Mr Kelly does have a point — not all Tesla models are cleaner than Corollas.

However, it is a stretch to suggest — even using out-of-date 2013-14 data for the emissions intensity of the electricity grid — that Corollas have “significantly” lower emissions than Teslas.

And experts said it was misleading to compare high-performance cars with mid-performance ones.

They pointed out that a fairer comparison for a Corolla was a small electric car such as a Renault Zoe, which according to the latest data on the website emits between 121 and 136 grams of carbon dioxide per kilometre — less than any of the five petrol Corollas.

Context to the claim
Mr Kelly has been leading a group of Coalition MPs to argue against subsidies for the industry, warning that providing taxpayer-funded support could increase emissions.

In January he told The Australian: “We need to be very careful that any subsidies or concessions we give to electric cars in Australia will not increase CO2 emissions rather than decrease them. The risk here is you’ll have the rich person in Balmain buying a Tesla, subsidised by a bloke in Penrith who’s driving a Corolla.”

“And the Tesla will have more carbon emissions than the Corolla.”

How green is my car?
The Green Vehicle Guide is designed among other things to help consumers understand how much carbon dioxide a car generates over its lifetime on a per-kilometre basis and allows users to compare vehicles across a number of measures to assess environmental performance.

To get the data, cars are driven on a set of rollers inside a test laboratory and follow a set of acceleration and deceleration patterns over a set period of time dictated by the European Test Cycle.

The tailpipe emissions are captured and analysed, and the fuel consumption is precisely measured.

For electric or hybrid vehicles, the consumption of electricity by the vehicle from the battery is recorded during the same test cycle.

These numbers are then broken up into a range of categories, including the “fuel life cycle CO2” of a vehicle, which is expressed in terms of grams of carbon dioxide per kilometre driven.

This is the measure Mr Kelly used in making his claim, as he made clear during his interview.

Up until recently some of the information on the Green Vehicle Guide website was out of date, using the 2013-14 mix of coal, gas and renewables in electricity generation.

The department told Fact Check the website had been updated with the most recent figures, after the interview with Mr Kelly took place.

In 2013-14, Australia’s energy grid produced an average of 0.94 kilograms of carbon dioxide per kilowatt hour. The latest figures show this has fallen to 0.91 kilograms per kilowatt hour.

Experts contacted by Fact Check said even updated numbers on the website should be treated with caution, given that lab-testing using a dynamometer method does not always reflect on road use, which often results in higher carbon intensity numbers for all vehicles.

UWA Professor and Director of the Renewable Energy Vehicle Project Thomas Bräunl told Fact Check: “It is not just since the Volkswagen scandal that we know these things are not correct. These numbers are a rough guide but you know all the cars have emissions that are higher and all have fuel consumption which is higher.”

However, in opinion piece published by Fairfax, Australia’s Chief Scientist Alan Finkel used the Green Vehicle Guide to compare emissions of electric cars and petrol cars.

Life cycle emissions
The website’s life cycle emissions calculations include an assessment of the carbon dioxide generated by driving.

For conventional internal combustion vehicles, this is produced by burning fossil fuels to power the vehicle.

For electric vehicles, emissions are embodied in the electricity drawn from the grid (or potentially from other sources such as rooftop solar) to charge the vehicle.

This electricity is produced in a variety of ways, including through coal-fired power, renewables, or a mix.

Victoria, which relies heavily on brown coal for its electricity, has the most carbon-intensive power. Tasmania, which relies on hydroelectric power, has the least.

The calculation also includes the emissions created by the extraction, refining and transport of fuel from refineries to a petrol station.

These figures are then divided to calculate average emissions per kilometre driven.

Some life cycle measures also include emissions from the manufacturing process. However, this is not included in the Green Vehicle Guide’s calculations “because objective, numerical values for these different factors do not exist at an individual model level and are never likely to, given the complexity, uncertainty and high costs associated with life cycle analysis”.

Because Mr Kelly did not identify a specific model of Tesla or Corolla, Fact Check compared 27 Teslas listed on the site with five petrol-only Corollas.

The following graph shows that at the time Mr Kelly made his claim, the data on the website suggested the small petrol Corolla outperformed the small Tesla models.

Medium Tesla models had comparable emissions per kilometre, while the largest Teslas listed on the website had higher life cycle emissions than petrol Corollas.

Although Mr Kelly appeared to be referring exclusively to petrol Corollas, Toyota does produce a hybrid version of the vehicle, which, according to the website, produces 97 grams of carbon dioxide per kilometre — significantly less than all models of Tesla.

Former government official and Director at Green Energy Markets Tristan Edis led the team who created the Green Vehicle Guide.

“Craig Kelly is using emissions that are not reflective of the life cycle of a Tesla, in fact they’re already out of date,” he said.

Solely relying on the government’s Green Vehicle Guide in January, it would have been impossible for Mr Kelly to get an accurate comparison between the vehicles, he said.

“A Tesla Model S has very slightly lower CO2 than a Corolla Sedan under the (January) Green Vehicle Guide which uses out-of-date 2015 emissions factors,” Mr Edis said.

“If we then revert to the latest July 2017 emission factors put out by the Department of Environment then the Tesla inches further ahead.”

Fact Check compared all 27 models of Tesla listed on the website to the five petrol Corollas listed.

Applying the 2013-14 electricity grid emissions data used by the website at the time Mr Kelly made his claim shows 11 models of Tesla had higher emissions than the most polluting Corolla (191 grams of CO2 per kilometre), compared to 16 that were less polluting.

All 27 models of Tesla listed at the time of the claim had higher emissions than the least polluting petrol Corolla (171 grams of CO2 per kilometre).