Sinautec's forty-one seat Ultracap Buses have been serving the Greater Shanghai area since 2006. The bus is powered entirely by electricity, which is stored in ultracapacitors and batteries onboard. When the bus stops at passenger stops, the overhead charger quickly recharges the ultracapacitor onboard to allow the bus to go to its next destination. The Ultracap Bus has a top speed of 35 miles per hour and has a maximum range of 3.5 miles between charges. The bus is ideal for on-campus shuttles and municipal bus lines with short in-between-stop intervals.
When solar panels are placed on top of charging stations and surrounding building, Sinautec's Ultracapacitor Bus can be powered completely by the sun. The bus draws electric power from the charging station solar panels in sunny days, and from the electric grid in cloudy conditions. Ultracap Bus uses less than 20% the fuel cost of a conventional bus. Compared to a diesel engine bus, an Ultracap Bus can achieve a lifetime fuel saving of up to $200,000. The vehicle is noise free and generates no tailpipe pollution. Compare to a diesel bus, a Ultracap Bus can prevent over 100 tons of carbon-dioxide from entering the atmosphere each year.
1. Can people be electrocuted under the charging station?
The charging stations charges with 600 volt, 200 amp current. The charging station is protected by three layers of insulation. Unless someone climbed on top of the thirty feet charging station and holds both charging rails, the chance of electrocution is zero. The charging station is designed so that people will not be able to climb on top.
2. What happens when the bus run out of electricity midway?
The ultracapacitor bus does not run out of electricity. As the ultracapacitor bank approaches its limit, the ultracapacitor will encounter diminishing performances. However, there will be enough electricity for the vehicle to travel to the nearest bus stop. The bus driver will be able to see on screen the amount of electricity in the ultracapacitor bank. We design the bus route so that there is an optimal number of charging stations for the driver to charge, and that the chance of an electric shortage is minimal. Finally, we have an emergency charging vehicle for ultracapacitor bus for a fall-safe scenario when the bus did run low on electricity. The ultracapacitor buses have been running in Shanghai since 2006, and there was only one instance where the bus required this emergency charging station. The situation occurred when a new driver was negligent in charging the bus, and drove the vehicle as if it were a diesel bus.
3. How often does the ultracapacitor bus have to be charged?
The ultracapacitor bus charges every other stop in the summer, when air conditioning is running on maximum. The vehicle charges on average once every five to six stops for the rest of the year. The ultracapacitor bank does not charge on a linear curve, meaning that the ultracapacitor charges faster at 30% capacity than it does at 98% capacity. It takes 10 minutes to charge the vehicle to 100% full capacity, but typical charging times at bus stops is under 30 seconds. Thirty seconds of charging would allow the ultracapacitors to travel over a mile. The average distance between stops in Shanghai is three thousand feet. We have a mathematical algorithm that will place the minimum number of charging stations on a route, while guarantee that the bus driver will have plenty of opportunities to charge the vehicle.
4. How often does the ultracapacitors need to be replaced?
Depending on operating mileage, we recommend the ultracapacitor banks should be replaced every four to six years. The Shanghai ultracapacitor buses, in use since the summer of 2006, are still operating with the same original ultracapacitor modules. The ultracapacitor’s modules optimal working temperature is -40 to +105 degrees Fahrenheit, and is regulated by a forced air cooling system. The ultracapacitors are not affected by high humidity or high salt content.
The transit buses in the United States have an average life of twelve years, meaning that an ultracapacitor bus would require one to two replacements within its lifetime depending on its operation mileage. An average diesel buses requires one engine replacement within its lifetime. The replacement costs of the ultracapacitor modules is comparable to the cost of replacing a similar capacity engine engine. The maintenance costs of the ultracapacitor buses are comparable or lower that of a similar sized diesel bus.
5. Why not just use battery buses instead of the ultracapacitor buses?
A battery bus would only require one charging station at the terminal stop, and therefore would not require the high infrastructural cost of the ultracapacitor bus. However, several bottlenecks prevent the commercialization of battery buses: First, a lead acid battery bus can only operate 40 miles a day, and requires eight hours of charging. This restricts the vehicle to be used in very limited settings, such as in theme parks. Lithium-ion battery powered buses would have range over 100 miles. However, lithium-ion battery buses consistently have overheating issues that has never been completely resolved. The overheating issue could result in fire or explosions that are dangerous to passengers. This problem is especially acute under high voltage quick charging.
Finally, lead-acid battery buses require eight hours, while lithium-ion battery buses require three hours of high voltage charging. This would be feasible for a small number of buses. But for a fleet of buses, the charging infrastructure would be very expensive. Utility companies would also have to build expensive on-demand electric facilities to accomodate the simultaneous charging of a large fleet of battery electric buses.