We devote a great deal of our attention to the propulsion methods of cars and trucks, but there’s a potentially more environmentally significant aspect to focus on. You may know that steel is used extensively in automobile production. While the material is essential, it has a high embedded carbon footprint. This is why some carmakers are beginning to invest in “green steel.” Here’s what you need to know.
Emissions associated with steel
When the economy is strong, as many as 17 million vehicles are sold in the US every year. By association, that’s a lot of steel – around one ton per car, to be exact. Forty percent of this amount can be found in the chassis, body panels, doors and trunk closure of the vehicle. In internal combustion engine cars, the drivetrain accounts for around 23% of total steel. Electric vehicles (EVs) do use as much steel thanks to their lack of a cast-iron engine block and other components. But some carmakers remain concerned about the impact of traditional steelmaking processes, and for good reason.
Each year, steel production accounts for more than seven percent of the world’s greenhouse gas emissions, which is slightly greater than the combined emissions of all the cars in the world. Manufacturing virgin steel is an energy-intensive process that relies on super-hot furnaces as well as a coal derivative called coke that separates oxygen molecules from iron ore. The trouble stems from the carbon dioxide emitted as a byproduct of this chemical reaction.
Recycled steel, meanwhile, is used extensively but doesn’t always meet the rigorous weight and strength standards required in the automotive sector.
Automakers experimenting with potential solutions
It will take a lot of research and development to decarbonize the steel industry in a way that’s viable for large-scale manufacturing. Some automakers are hoping to get the ball rolling by showing interest in green steel.
Right now, all eyes are on a new Swedish plant that’s in the process of commercializing a steelmaking process that replaces fossil fuels with hydrogen. Nordic steelmaker SSAB, state utility Vattenfall and mining company LKAB joined forces to form HYBRIT, or Hydrogen Breakthrough Ironmaking Technology. The plant uses electricity from renewable sources to produce hydrogen gas via electrolysis. The gas will reduce iron ore into what’s known as “sponge iron,” which will be further refined in an electric arc furnace after being mixed with scrap metal.
Recognizing that steel is one of the largest sources of embedded carbon in car manufacturing, Volvo signed a statement of intent with HYBRIT in July 2021. The carmaker believes green steel is key in fulfilling its mission of becoming carbon neutral by 2040.
In August, the first batch of green steel was delivered to Volvo for testing and use in prototype applications. A couple of months later, the company unveiled a massive autonomous electric haul truck for the mining industry built almost entirely from fossil-free steel.
Mercedes-Benz was the latest automaker to partner with HYBRIT, a move it hopes will help achieve a carbon-neutral product lineup by 2039. Soon after, Faurecia, a leading supplier of parts for vehicle interiors, announced it would equip its seat structures with HYBRIT green steel as well.
The car of the future will truly be carbon neutral
To understand a vehicle’s true carbon footprint, it needs to be considered in its entirety. Now that electric drivetrains are mainstream, steel decarbonization is a logical next step in the pursuit of a truly fossil-free car.
The HYBRIT program provides an intriguing solution to a challenging undertaking. While a lot of electricity is required for electrolysis and powering the electric arc furnace, the facility itself has the potential to store hydrogen and schedule its operations so as to not exacerbate peak grid loads while further increasing demand for clean energy provided by utilities.
If the idea scales up efficiently and the final product is suitable for use in car manufacturing, green steel could be a game-changer for global emissions reduction in the auto industry.