Electric bus

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An electric bus is a bus powered by electricity.

There are two main electric bus categories:

  • Non-autonomous electric buses:
    • The trolleybus is a type of electric bus powered by two overhead electric wires, with electricity being drawn from one wire and returned via the other wire, using two roof-mounted trolley poles.
    • The gapbus is a bus without rails or surface power lines, and it can share the road lane with other vehicles as well. Power is supplied over a gap of 12 cm from a power line embedded in the ground.
  • The onboard stored-electricity bus (autonomous electric buses):

For information on buses using a combination of internal combustion engines and electric propulsion, see Hybrid electric buses and Dual-mode buses.Template:-

Contents

Capabus

Main article: Capabus

The best ultracapacitors can only store about 5 percent of the energy that lithium-ion batteries hold, limiting them to a couple of miles per charge. This makes them ineffective as an energy storage medium for passenger vehicles. But what ultracapacitors lack in range they make up in their ability to rapidly charge and discharge. So in vehicles that have to stop frequently and predictably as part of normal operation, energy storage based exclusively on ultracapacitors begins to make sense.<ref name="technologyreview.com">Template:Cite web</ref>

China is experimenting with a new form of electric bus, known as Capabus, which runs without continuous overhead lines by using power stored in large onboard electric double-layer capacitors, which are quickly recharged whenever the vehicle stops at any bus stop (under so-called electric umbrellas), and fully charged in the terminus.

A few prototypes were being tested in Shanghai in early 2005. In 2006, two commercial bus routes began to use electric double-layer capacitor buses; one of them is route 11 in Shanghai.<ref>[1] (in Chinese, archived page)</ref> In 2009, Sinautec Automobile Technologies,<ref>Template:Cite web</ref> based in Arlington, VA, and its Chinese partner, Shanghai Aowei Technology Development Company<ref>Template:Cite web</ref> are testing with 17 forty-one seat Ultracap Buses serving the Greater Shanghai area since 2006 without any major technical problems.<ref name="treehugger.com">Template:Cite web</ref> Buses in the Shanghai pilot are made by Germantown, TN-based Foton America Bus Co.<ref>Template:Cite web</ref> Another 60 buses will be delivered early next year with ultracapacitors that supply 10 watt-hours per kilogram.

Foton America Bus Co is in talks with New York City, Chicago, and some towns in Florida about trialing the buses.

The buses have very predictable routes and need to stop regularly, every Template:Convert, allowing opportunities for quick recharging. The trick is to turn some bus stops along the route into charging stations. At these stations, a collector on the top of the bus rises a few feet and touches an overhead charging line. Within a couple of minutes, the ultracapacitor banks stored under the bus seats are fully charged. The buses can also capture energy from braking, and the company says that recharging stations can be equipped with solar panels. A third generation of the product, which will give Template:Convert of range per charge or better. <ref name="technologyreview.com"/>

Sinautec estimates that one of its buses has one-tenth the energy cost of a diesel bus and can achieve lifetime fuel savings of $200,000. Also, the buses use 40 percent less electricity compared to an electric trolley bus, mainly because they are lighter and have the regenerative braking benefits. The ultracapacitors are made of activated carbon, and have an energy density of six watt-hours per kilogram (for comparison, a high-performance lithium-ion battery can achieve 200 watt-hours per kilogram), but the ultracapacitor bus is also cheaper than lithium-ion battery buses, about 40 percent less expensive, with a far superior reliability rating.<ref name="technologyreview.com"/><ref name="treehugger.com"/>

There is also a plug-in hybrid version, which also uses ultracaps.

Future developments

Sinautec is in discussions with MIT's Schindall about developing ultracapacitors of higher energy density using vertically aligned carbon nanotube structures that give the devices more surface area for holding a charge. So far, they are able to get twice the energy density of an existing ultracapacitor, but they are trying to get about five times. This would create an ultracapacitor with one-quarter of the energy density of a lithium-ion battery.<ref>Template:Cite web</ref>

Future developments includes the use of inductive charging under the street, to avoid overhead wiring. A pad under each bus stop and at each stop light along the way would be used.

Solar-charged

Main article: Solar-charged vehicle

Tindo is an experimental battery electric bus being tested in Adelaide, Australia. The word "Tindo" comes from the aboriginal word for sun. The bus will get its electricity from a photovoltaic system on Adelaide's central bus station. Rides are free as part of Adelaide's public transport system.<ref>Template:Cite web</ref>

Zinc

There is a Template:Convert pure electric bus being developed, using a pre-commercial battery technology. Electric Fuel Corporation is developing and demonstrating a Template:Convert electric bus powered by a zinc air cell,<ref>http://www.electric-fuel.com</ref> along with an ultracapacitor. The zinc-air energy device, often described as a battery, converts zinc to zinc oxide in a process that provides energy to the bus. The bus is not recharged; instead, the zinc oxide cartridges are swapped out for new zinc ones. This bus has shown a range of over Template:Convert in testing and has been demonstrated in Las Vegas, Nevada. However, this technology is in the development phase, and several major hurdles must be overcome before it can be adopted for transit fleet use, including available refueling infrastructure or use in bus stations.<ref>http://www.fta.dot.gov/documents/Electric_Drive_Bus_Analysis.pdf</ref>

Onboard solar panels

Main article: Solar vehicle

Air conditioning

Solar panels and supercapacitors are used in some electric buses to power the specific air conditioning circuit.

Makers and models

There are currently more than 25 manufacturers of trolleybuses. See Trolleybus makers.

Makers of other types of all-electric buses (mostly battery buses):

Transit use

For information on where trolleybuses are in use, see Trolleybus and list of trolleybus systems.

Transit authorities that use battery buses or other types of all-electric buses, other than trolleybuses:

Canada

Québec

China

Europe

There is an European Union directive that mandates the purchase of electric buses for public services.

Spain

United States

This section requires expansion

Federal Transit Administration Clean Air Program <ref>Template:Cite web Template:Dead link</ref>

California

There is a Californian mandate (Zero Emission Bus, in short, ZBus) that 15% of new buses after 2011 be electric.<ref>Template:Cite web</ref> The ZBus Regulation is part of the Fleet Rule for Transit Agencies, which is also referred to as the Public Transit Agencies Regulation.

See also

External links


In other languages

es:Autobús eléctrico hr:Električni autobus ja:電気バス

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