Recycling Transmission Lines With Aluminum Separators
Australian transmission operator Transgrid has deployed a new system from Germany-based Zeck to recycle aluminum from transmission line conductors.
Transgrid, the operator of a large high-voltage electricity transmission network in the Australian Capital Territory and New South Wales, recently started running a new machine that recycles aluminum from old transmission conductors on-site.
Pieces of aluminum are funneled through a conveyor belt into recycling bags at a Transgrid site in western Sydney. Image used courtesy of Transgrid
The company teamed up with German manufacturing firm Zeck to trial a new aluminum/steel separator, dubbed “ZAS,” to recycle transmission conductors in western Sydney. In its first two weeks of operation, Transgrid ran about 40 kilometers (24.8 miles) of conductors through the machine, churning about 2.2 pounds of aluminum per meter.
The ZAS machine receives conductors under tension and separates the outer aluminum layer from the steel core. The aluminum is then sliced into 1.2- to 2.8-inch pieces, funneled into bags through a conveyor belt, and sent for smelting into new products. At the other end of the system, the undamaged steel core is wound onto a cable drum for recycling.
Video used courtesy of Transgrid
According to Transgrid, initial studies from Zeck show that recycling aluminum can triple the company’s returns compared to existing processes and save up to 90% of emissions through sending conductors overseas to be processed—generating millions of dollars in extra revenue from scrap metal. Given the size of Transgrid’s network, this scale of recycling would be significant: The company has more than 8,000 miles of transmission lines and 110 substations, serving over 3 million customers.
Zeck’s ZAS aluminum/steel separator machine. Images used courtesy of Zeck
Unlocking Cost-saving Opportunities
ZAS’s rope spins at a maximum speed of about 4 miles per hour and is efficient with a low energy supply of 17 kilowatts. ZAS can be used while stringing the old aluminum conductor steel-reinforced cable on-site or at a collection point such as a recycling service. It can be used on everything from optical ground wire cables to high-temperature Aluminum Conductor Composite Core (ACCC) conductors.
Without the new recycling system, Transgrid’s conductors would be wound up onto cable drums, shipped to offshore facilities, and then transferred back to Australia. Recycling the conductor unseparated usually receives a maximum of about $1 per 2.2 pounds after the extra cost of recycling offshore. But by bringing recycling on-site, the Transgrid’s return amounts to about three times that of its existing systems, generating $2–3 million in extra revenue over the next few years.
Video used courtesy of Transgrid
The system will also contribute to Transgrid’s goal to reach 100% renewable electricity for its offices and depots by 2025 and zero fleet emissions by the end of the decade. According to the company’s 2022 sustainability report, some of that effort involves reducing the amount of waste being diverted from landfills through reusing redundant timber poles and crushed porcelain insulators and, as demonstrated in its ZAS trial, recycling aluminum from aging transmission line conductors.