Sinautec Automobile Technologies says tomorrow it will showcase on American University’s campus in Washington, DC., a small bus that the company claims is “America’s first ultracapacitor electric vehicle.”
The eleven-seat minibus, powered only by ultracapacitors, can be recharged by a mobile recharging unit that combines large photovoltaic array and a vertical wind turbine. Sinatec says the bus can be recharged in as little as 5-10 minutes.
Following the demonstration, company and school officials are hosting a panel discussion that includes Joel Schindall, a nanotube ultracapacitor specialist at MIT; Terrance Sankar, a vertical wind turbine specialist at AU; Scott Sklar, president of Sinautec partner Stella Group; Dan Ye, Sinautec CEO. The panel will be moderated by Paul Wapner who researches and teaches global environmental politics at AU.
Sinautec successfully developed a series of ultracapacitor municipal buses that have been in commercial use in the greater Shanghai area since 2006.
The idea of using ultracaps in electric buses may be a little counterintuitive at first, since they can only store a fraction of the energy a lithium battery can. Indeed, the buses couldn’t go far. But according to the Sinautec concept, the ultracap bus would only need to get to the next bus stop, which would have to be relatively close. The key to the Sinautec system is that each bus stop would have an overhead recharging unit that the bus would quickly latch onto. The bus wouldn’t necessarily need a full recharge at each stop. It would need just enough to get it to the next stop/recharging station where it could be boosted again.
Current versions of the bus have a range of 3.5-5.5 miles per full charge, depending on whether the vehicles air conditioner is in use.
The other part of this concept is that each recharging station would generate energy from a renewable source, such as solar or wind power, or both.
Sinautec CEO claims in a Technology Review story that his buses have several advantages over alternatives. He says his buses regenerative brakes means they use 40 percent less electricity compared to an electric trolley bus. When it comes to a comparison with diesels, Ye says Sinautec buses incur one-tenth the energy cost of a diesel bus and can achieve lifetime fuel savings of $200,000.
“The ultracapacitor bus is also cheaper than lithium-ion battery buses,” says Ye. “We used the Olympics (lithium-ion) bus as a model and found ours about 40 percent less expensive with a far superior reliability rating.” Ye adds that the environmental benefits are compelling. “Even if you use the dirtiest coal plant on the planet, it generates a third of the carbon dioxide of diesel when used to charge an ultracapacitor.”
Sinautec is working on improving the ultracaps. The ones currently in use have an energy density of 6 watt-hours per kilogram. The next generation will have capacitors that boost the density up to 10 watt hours per kilogram. It appears that additional jumps in energy density are possible, which would reduce the need for as many of the combo recharging stations–bus stops.