The southern Chinese city of Guangzhou is set to inaugurate the world’s first tram powered solely by supercapacitors, eliminating the need for unsightly overhead wires.
Supercapacitors store electrical energy at a fairly low rate – about 10 percent of conventional batteries – but their power density is normally between 10 and 100 times greater. This means charging and discharging periods are shorter, and unlike conventional batteries, their charge/discharge cycles are virtually limitless.
The tram cars will be charged as needed at stops on the line in Guangzhou, a process that will take between 10 and 30 seconds, with mobile charging cars available in the event of charging failures at stations. The trams will be able to run for up to about two-and-a-half miles between charges. Top speed will be just under 45 mph.
Each tram will be made up of four stainless-steel cars with a total length of about 120 feet and will have a capacity of 386 passengers. Each car is designed to have 10 “priority seats” and two spaces reserved for wheelchairs.
The Guangzhour Tram Co., a subsidiary of the Guangzhou Metro Corp., contracted with CSR Zhuzhou to build seven trams. So far, one vehicle has been completed and is undergoing static tests, and soon will be moved to Guangzhou for dynamic tests. Meanwhile, Siemens, the German engineering and electronics giant, is responsible for the trams’ propulsion and braking systems.
A similarly designed tram line is under development for another Chinese city, Nanjing. And as novel as these trams are, they’re not the first trams to avoid overhead electrical lines. The first such tram line was in Bordeaux, France and began running in 2003. But it doesn’t use supercapacitors. Instead it relies on an underground “third rail” that has turned out to be impractically expensive.
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Wireless tram lines have piqued the interest of commuters in cities around the world. One is Washington, D.C., where local law prohibits overhead tram wires in certain parts of town. So far, though, there’s no word on whether a tram powered by supercapacitors would be cost-effective for the U.S. capital.
Wales, too, is in search of reliable wireless public transportation. Overhead cables, which rely on a network of supporting cables, complicate the planning of tram lines and are expensive to build. They’re also an urban eyesore.
Supercapacitor trams, though, sweep these problems aside, says Stuart Cole of the University of South Wales. He notes that the infrastructure for Swansea’s bus line was originally designed to eventually accommodate a parallel tram system.
“If the Chinese are trying it out, there’s an opportunity to see if it’s reliable,” Cole says. “It sounds good in that it would appear to reduce costs significantly.”
By Andy Tully of Oilprice.com
Andy Tully is a veteran news reporter who is now the news editor for Oilprice.com