TOKYO -- Nissan Motor has begun reusing aluminum scraps in its popular Rogue SUV to reduce the environmental impact of producing the metal as governments and investors have become increasingly focused on emissions from automakers besides those that come out of the exhaust pipe.
Aluminum has become an increasingly prominent metal in auto bodies because of its light weight. However, producing the metal emits massive amounts of carbon dioxide, a greenhouse gas that scientists say contributes to climate change.
Nissan has installed equipment at its plants in Fukuoka Prefecture and the U.S. state of Tennessee that collects aluminum scraps from the production of vehicles, shreds them into small pieces and then gathers just those suitable for recycling.
The fragments are processed into aluminum sheet by Japanese aluminum giant UACJ and Novelis of the U.S., and Nissan uses these to make hoods and doors.
This closed-loop recycling helps reduce the carbon footprint by lowering the amount of new aluminum used.
The recycled aluminum was first adopted in the new Rogue sport utility vehicle, known in Japan as the X-Trail, that launched last autumn. The compact crossover SUV is one of Nissan's most popular models, with roughly 380,000 units produced worldwide in fiscal 2019, accounting for 8% of the total. Plans call for using recycled aluminum in other models in the future.
Aluminum sheet for car bodies needs to be high quality. Nissan has been using aluminum sheet in some models, but the scraps were reused to make other parts. Partnering with a major producer of rolled aluminum with advanced technologies was essential to using recycled aluminum in a mass-produced vehicle.
Toyota Motor is also using newly developed recycled aluminum materials for some parts of the body of its Mirai fuel cell vehicle that was fully remodeled in December.
Automakers are increasingly using aluminum to reduce vehicle weight. Use of the metal surged 50% over the past two decades to 172 kg per auto in 2019, according to the Japan Aluminum Association. Assuming a vehicle weighs a ton, 17% would be aluminum.
Aluminum processing has a big carbon footprint because of the large amount of electricity used to extract the base metal from bauxite and to refine it. Compared with processing 100 kg of plain steel, producing 100 kg of aluminum produces quadruple the carbon dioxide and is four times as expensive.
To reduce both the carbon output and the costs, incorporating technology for recycling aluminum is imperative.
Audi, the German auto brand under Volkswagen, implemented a program to recycle aluminum offcuts at press plants into new aluminum sheets. This process reduced carbon dioxide emissions by about 40% in 2018.
Major automakers now face pressure to cut carbon emissions in all parts of the production process. Life cycle assessments determine the environmental impact of the whole process.
Discussions in Europe started last year about requiring automakers to implement life cycle assessments. The idea of taking carbon emissions into account when choosing components and raw materials emerged in that context.
Volkswagen is having suppliers of its ID.3 electric vehicles sign zero-carbon contracts. Germany's Daimler urges suppliers of its luxury brand Mercedes-Benz to achieve carbon neutrality by 2039. To date, 75% of the roughly 2,000 suppliers have agreed to institute carbon neutral manufacturing in the future.
Starting July 2024, the European Union will require producers of electric-vehicle batteries and other components to report emissions volumes over life cycles, including production. The common market will later set emission caps, expected to be enforceable by sales bans.
The Japanese business community is following a similar trend. Chemical maker Teijin will start disclosing carbon dioxide emissions from production of automaking material to disposal.
Nissan is also reducing the carbon footprint in the coating process as well. For the new Ariya EV crossover, the automaker has developed water-based paints that can be applied at lower temperatures. This ensures that the parts can be painted together, which streamlines the process and reduces carbon emissions. The ventilation system that retrieves leftover airborne paint has also been upgraded. Overall, these improvements are expected to cut carbon output by 25%.