Less is more
How the weight of a car relates to sustainable mobility
The heavier an object is, the more difficult it is to move it. This is simple physics. And our cars are getting bigger and heavier. The average weight increased by 20 percent to around 1.5 tons between 2000 and 2022, according to calculations by the French consultancy Inovev. The main reason for this is the growing demand for SUVs and electric cars. But additional modern equipment like larger on-board computers, extensive entertainment electronics, and safety components such as airbags and sensors also have their own weight.
The heavier a vehicle is, the more power the engine has to use to move it. And that means it needs more fuel and emits more CO2. This amounts on average to around two percent more consumption per 100 kilograms of additional weight. And this is the case regardless of whether you are driving a petrol, diesel, electric, or hybrid car.
Heavy in weight, in consumption and in production
But more fuel is consumed not only while driving the vehicle, but also beforehand. That’s because more mass also means more energy consumption and higher greenhouse gas emissions during vehicle production. The European New Car Assessment Program (Euro NCAP) has analyzed the additional masses. The result: for every 100 kilograms of additional weight, vehicle production generates an additional 500 to 650 kilograms of greenhouse gas emissions and 1.9 to 2.4 MWh of energy consumption.
The reverse is also true: anything that makes a vehicle lighter leads to lower fuel consumption and emissions, making it more sustainable. Nobody wants to sacrifice safety and comfort, so it’s worthwhile to check the materials and components used for optimization possibilities.
Our innovations help cars “lose weight”
In recent years, new, weight-saving solutions have been developed for surfaces, tires, and sound systems, for example. One especially impressive innovation comes from Neunkirchen: spring steel from Saarstahl is now rolled there at temperatures between 750 and 900 degrees. This gives it a microstructure that cannot be achieved through heat treatment or other processes. It ensures stronger recrystallization, which means it has a much finer structure. As a result, this thermomechanically rolled spring steel can cut the weight of the end product – the vehicle spring – by 20 percent. Added technical detail: now double mechanically rolled
Steel can also make car production more sustainable in other ways. One example is by using bainitic steels, which don’t require any special heat treatment after forging and instead are simply air-cooled in a controlled process. This saves energy and carbon emissions during production. The bainitic steel developed by Saarstahl can now be found in steering knuckles, in common rails, and as a rolling bearing material. Pure innovation meets pure sustainability.