Greenly study casts doubt on Tesla's claim of 20 million tons of CO2 savings. Here are all the details.
A new study casts doubt on Tesla's claim to have saved 20 million tons of CO2 by 2023. Calculations show that the figure could be up to 49% lower.
Tesla has long touted its electric cars as a key solution to greening traffic. The company claims that by 2023 its cars will have prevented 20 million tons of CO2 from reaching the atmosphere.
But according to Greenly, an independent actor in CO2 calculations, there are flaws in Tesla's methodology. The study estimates that the real savings could be as low as 10.2 million tons.
The figures in Greenly's report are based on a repetition of Tesla's own methodology, but with alternative data for fuel cars and electricity production.
Greenly believes that Tesla is overestimating the emissions that would have occurred with fuel-powered cars. At the same time, Tesla may have underestimated the emissions that come from the electricity that powers its own cars.
Tesla compares electric cars to fuel cars by assuming that each car drives 320,000 kilometers over 17 years.
Fuel cars are estimated to emit 333 grams of CO2 per kilometer, while electric cars have a lower figure, based on the country's electricity mix.
Greenly argues that Tesla's assessment of fuel cars is too high, while the emissions from the power grid are underestimated.
Is Tesla exaggerating the emissions of fuel-powered cars?
For the US, Tesla uses a factor of 445 grams of CO2 per kilometer, derived from consumer data. However, this is significantly higher than the official figures from the US environmental authorities.
In Europe, Tesla estimates the emission factor at 459 grams, while British authorities only estimate it at 415 grams.
Because the method is so dependent on assumptions about fuel vehicles, small changes can make big differences. For example, adjusting the fuel factor number from 333 to 400 grams increases the calculated savings to 14.4 million tons.
This suggests that Tesla has chosen a method that provides the highest possible savings figure.
Underestimation of the electricity grid's emissions
Greenly also criticizes Tesla's use of low emission factors for electricity. In the US, Tesla uses a value of 116 grams of CO2 per kilometer, but Greenly estimates the figure to be 78% higher. Here too, Tesla may have optimized the calculations to achieve a more impressive figure.
Tesla states that part of the charging is done via solar energy, but does not explain exactly how they have calculated the effect of the solar current.
In their calculation, Greenly has assumed that all Tesla cars are charged via the power grid, which gives a more conservative result.
Consequences for the electric car industry
Tesla is not alone in marketing electric cars as climate-friendly, but the case raises questions about how the industry calculates CO2 savings.
Greenly argues that independent analysis is necessary to ensure transparency. Without verifiable data, confidence in the climate impact of electric cars could be at risk.
At the same time, the case may have political consequences. If electric car manufacturers consistently overestimate their climate benefit, this could lead to stricter regulations.
In the US, opponents of electric car subsidies have already used similar arguments to cast doubt on climate policy. If doubts arise about the actual climate impact of electric cars, it could weaken support for the sector.
Greenly is now calling on Tesla and other manufacturers to publish their methods in detail. According to Greenly, this allows for transparent calculations that can be verified by independent experts.
If the automotive industry does not ensure more transparency, it could have serious consequences for public trust in electric cars.
