# Real emissions of electric cars

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this post was originally written in 2017 and is just a copy from a backed up database

Elon Musk did a great job selling the idea that electric cars are the indisputable future. However, in the time of alternative realities, it is always wise to verify some of the facts that are given for granted. It is true that an electric car does not emit gases while in circulation, but the generation of electricity needed for moving as well as the fabrication of the batteries must be taken into account.

There are two numbers that can be calculated for any product: the emissions generated during the use and the emissions generated since the start of the fabrication process. During use, I've found a magical number quoted in several sources, a diesel car would emit around 120g CO2/km[1]. For an electric car, the consumption is around 0.2kWh/km, while in Europe the emissions for generating electricity are around 300gCO2/kWh. With this values, it can be calculated that an electric car emits roughly 60gCO2/km. This is a rough estimate showing that electric cars, with existing technologies in Europe, generates half the emissions of CO2 than what a diesel car would have.

However this is not a complete picture. Apparently, the fabrication of batteries has a mayor impact in the quantity of emitted gases. Using as an example the Tesla cars, which use NCA batteries, the emissions generated for their manufacturing are around 116kgCO2/kWh. With a battery 100kWh and assuming a lifetime of 200000 km, we should add 58gCO2/km to our previous result. This yields almost the same emissions per kilometer than a diesel car.

The numbers that I am presenting are nothing but approximations to first order and are based on sources that I didn't verify myself, but that look trustworthy. There are many details missing, like the emissions derived from extraction and refining of fuel, but the message I wanted to convey is the importance of understanding what is behind what they are trying to sell us. Whatever we manufacture is going to have a negative impact on environment; it is crucial to have to proper tools to discern. It is a market plagued with interests and it is not easy to find organizations that are impartial when presenting results.

[1] A non-small detail is that these are equivalent grams of CO2.

Some complementary readings: 1. Transport and Environment: This report 2. Ecometrica: Some acronyms explained. 3. Battery University: To understand more acronyms about batteries 4. Wikipedia about Tesla S 5. IVL (Swedish Environmental Research Institute): This report