Audi CO2 Program: Sustainable Aluminum for Audi e-tron GT Wheels
source: Audi AG
20-inch wheels for the Audi e-tron GT2 made of CO2-reduced aluminum
Innovative aluminum smelting technology releases oxygen instead of CO2
Marco Philippi, Head of Procurement Strategy: “This lets us increase our sustainability performance in the supply chain and ensure that our models arrive at the customers with a smaller carbon footprint”
AUDI AG is systematically continuing its CO2 program in the supply chain and, as a result, already reducing the CO2 emissions of the parts used in Audi models in the production phase. As part of a pilot project, the company is procuring 20-inch wheels for the Audi e-tron GT2 that are made from low-CO2 emission aluminum supplied by Alcoa to RONAL GROUP, the wheel’s manufacturer.
Alcoa is supplying aluminum for Audi’s pilot project from a self developed, innovative smelting process that emits oxygen instead of carbon dioxide. The joint venture ELYSIS is now further developing this process. The ELYSIS smelting technology, which is currently being ramped up to a commerical scale with research in the USA and Canada, causes no direct CO2 emissions when compared to the traditional process used to make aluminum. The joint venture company uses a so-called inert anode that replaces the carbon anodes that are traditionally used during electrolysis, which is the process used to make primary aluminum. An inert anode is insoluble in the electrolyte under the conditions obtained in electrolysis.
For the manufacture of the Audi wheels, Alcoa is supplying the RONAL GROUP with a blend of metal from the ELYSIS process and Alcoa’s own low-carbon aluminum. The 20-inch aluminum alloy wheels from RONAL GROUP are used as an optional equipment variant for the model and produced using flow-forming technology for weight optimization. The special propeller-shaped design of the rim improves the aerodynamic properties while driving. The mounted blades are just two to three millimeters thick, largely cover the wheels and thus help to ensure high aerodynamic efficiency.
As a gran turismo, the Audi e-tron GT2 was designed specifically for sportiness and efficiency, and it attains a drag coefficient of 0.24. This excellent value makes a significant contribution to the electric range of up to 488 or 472 kilometers (according to the the WLTP). The Audi e-tron GT2 is the first Audi electric car to be built in the Böllinger Höfe at the Neckarsulm site in Germany. The site has been supplied with renewable energy since 2020. Since the start of series production of the e-tron GT2, a biogas-operated combined heat and power plant has been supplying the heat required for production in the Böllinger Höfe. Audi uses carbon credits from certified climate protection projects to offset CO2emissions that currently cannot be avoided using renewable sources of energy.
The RONAL GROUP produces the rims at its location in Landau, using 100-percent eco-electricity, and compensates the heat consumption with biogas certificates.
Audi, Alcoa and RONAL GROUP are members of the Aluminium Stewardship Initiative (ASI). At the beginning of the year, AUDI AG was the first car manufacturer to receive the “Chain of Custody” certificate from the ASI, which certifies that the company works with aluminum in a sustainable way, taking business-ethics-related, ecological, and social aspects into account.
In 2018, Audi initiated the “CO2 program in the supply chain” with the aim of successively decarbonizing its supply chain. The program helps to already reduce CO2 emissions in the upstream manufacturing processes for each produced vehicle. “Aluminum is the focus of our CO2 program because producing this material requires a high energy input. The aluminum has already caused major CO2 emissions in upstream processes before it even arrives at Audi. We are therefore actively searching for innovative processes that help reduce CO2 emissions as early as possible in the creation process. The process created by ELYSIS is promising because it already takes effect in the raw material processing phase,” says Marco Philippi, Head of Procurement Strategy. “These kinds of innovations allow us to increase our sustainability performance in the supply chain and ensure that our models arrive at the customers with a smaller carbon footprint”.