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E-car miscalculated: The Ifo study on the CO2 balance

Electric cars hardly play a role in Germany so far. And if one believes the latest Ifo Institute study, then this should remain best in the future, because diesel cars protect the climate better than e-mobile. A Mercedes C220 with diesel engine therefore has a better CO2 balance in Germany than a Tesla Model 3, one of the most popular electric cars currently.

According to the calculations, the Mercedes has a CO2 emissions of 141 grams per kilometer. According to the study, the Tesla with long-range dual engine is 1

55 to 180 grams – depending on where and how the battery was made.

There is now plenty of criticism of the publication: According to "WirtschaftsWoche" she contradicts "in a blatant manner as well as all serious, international studies of recent months." Mobility expert Don Dahlmann explains that the study is counting on wrong numbers. The Federal Environment Agency points to an extensive earlier study, according to the e-cars perform better than diesel cars.

Much coal power

In their calculations for the Ifo study Hans Werner Sinn and his colleagues have the German power mix for charging of the e-car and the emissions in the production of the battery in the life cycle assessment. Other emissions from car production have not been considered.

The calculations are generally plausible – but the results are only valid under certain conditions chosen by the authors.

The Ifo experts assume, for example, that an electric car in Germany is loaded with plenty of coal electricity. 35 percent, to be exact. In addition, the authors assume that the power-intensive production of the battery also uses a lot of coal electricity. Result is then allegedly so lousy CO2 balance of the Tesla.

We took a closer look at the calculation and showed that the output of an electric car is usually lower than indicated in the study. Under ideal conditions, it is not 155 grams of CO2 per kilometer, as claimed, but only 31 grams.

The actual CO2 emissions of an electric car depend on several factors. We have studied five important variables of the Ifo study and found that once you use more optimistic and realistic values ​​than the Sinn team, the diesel has little chance against the e-car.

Variable 1: The performance of the Motors

In the comparison of the Ifo Institute, a very powerful E-sports car, a Tesla Model 3, compete against a much weaker motorized Mercedes sedan. The C-Class comes to 194 hp of the Tesla to at least 351.

For a better comparison, we calculated the CO2 data for the most powerful C-Class with diesel engine – the Model 300 d 4Matic 254 HP . This emits 176 grams per kilometer instead of 141. In fact, the CO2 balance for the two diesel cars is still significantly worse. Their consumption was determined in the study according to the outdated test cycle NEDC, which leads to unrealistically low values, especially in cars with internal combustion engines.

Variable 2: The capacity of the battery

According to a Swedish study from the year 2017 arise in the production of lithium-ion batteries for electric cars between 145 and 195 kg CO2 per kilowatt-hour battery capacity. In the large Tesla battery with 75 kWh, according to 11 to 15 tons of CO2 are stored . Spreading these over a running time of 150,000 kilometers, you get to 73 to 98 grams of CO2 per kilometer alone by the battery. For this, the CO2 that is in the charging current has to be added. The result is the above-mentioned values ​​of 155 to 180 grams per kilometer.

But here again in favor of the diesel is expected: First, there are doubts about the Swedish study – more on that later. And moreover, an electric car should rather not be equipped with a battery as big as the Tesla because it makes the car unnecessarily heavy. More useful are smaller batteries of 40 kWh as the Nissan Leaf or the Renault Zoe. Even Tesla offers models with smaller batteries. Correspondingly lower is the CO2 emissions per kilometer, which must be added to the battery.

Variable 3: The production location of the battery

The production of lithium-ion batteries is very energy-intensive. How much CO2 is produced depends on how the electricity is produced on site. Tesla makes its own batteries in the US and also uses solar power. In the federal state of Nevada, where the factory is located, the green electricity share is higher than in almost all other US states. Tesla has the declared goal of using only renewable energy. However, accurate data on the life cycle assessment of battery production do not exist so far.

In a current mix as in Sweden (almost exclusively green electricity), the CO2 quantity is ] about half the size of countries such as the USA . According to the Swedish study, CO2 emissions from battery production in China are about 30 percent higher than in the US due to the current high number of coal-fired plants.

However, the calculations of CO2 emissions in battery production are a snapshot. In the medium term, green electricity will and should also grow significantly in China, significantly improving the carbon footprint of battery production. The authors of the Ifo study completely ignore this potential. They are almost from the worst case.

Variable 4: The electricity mix during charging

The charging current assumptions are similarly problematic. The authors work with the current electricity mix in Germany which still has a high share of coal power – about one third. But this share should and must sink significantly in the medium term, so that almost the entire electricity in Germany is emission-free. This will then lead to a significantly better carbon footprint for electric cars.

In addition, electric cars in this country can be fueled with 100 percent green electricity . For example, Deutsche Bahn uses only green electricity for its long-distance trains.

A look into neighboring countries such as Norway shows where the journey should take us. While electricity from a German socket currently holds 550 grams of CO2 per kilowatt-hour, in Norway it is only 60 grams. The CO2 balance of a Tesla is correspondingly better when it is loaded in these countries – see diagram.

Variable 5: The mileage of the battery

The authors of the Ifo study use a mileage of 150,000 kilometers for the car battery and do not expect any later use of the battery – for example, as stationary electricity storage in a house. However, one may assume a longer mileage – Tesla gives for its large battery, for example, a guarantee up to 192,000 kilometers . And many batteries get a second life after their time in cars.

The diagram above shows the effect of a longer mileage on the Tesla Model 3. It was calculated with German power mix and 200,000 and 250,000 kilometers.


The study estimates the electric car badly – mainly because it is based solely on the status quo in Germany and a relatively CO2-intensive production of batteries. But both should and will change – and thus significantly improve the carbon footprint of electric cars.

In addition, e-car owners today can refuel their cars in Germany with green electricity – and do so, boosting demand for clean electricity. In addition, can be expected with a longer duration than 150,000 kilometers. Under ideal conditions, a Tesla Model 3 with a large 75 kWh battery comes down to CO2 emissions of only 31 grams per kilometer – instead of the calculated 155 grams.

How high the proportion of electric cars in In spite of everything, it is difficult to predict at the moment. Perhaps there will be a coexistence of different low-CO2 and CO2-free propulsion technologies. Such as the fuel cell or biogas. Electric cars should play an important role in any case, even if the authors of the Ifo study do not quite believe in it.

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