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Electric Buses: Zero Emissions in the Cities of the World
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Electric Buses: Zero Emissions in the Cities

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For zero-noise and zero-emission mobility in cities electric buses are indispensable. They are already widespread in China. Metropolises in other regions of the world are catching up, though.
Andreas Neemann, March 23, 2021
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Andreas Neemann wrote his first ZF text in 2001 about 6HP transmissions. Since then, the automotive writer has filled many publications for internal and external readers, showcasing his passion for the Group's more complex subjects.
A city bus is one of the most energy-efficient means of transport – even if it is powered by diesel. If you convert greenhouse gas emissions to passenger kilometers, diesel city buses in Germany, for example, generate a CO2 equivalent of 80 grams per passenger kilometer. By way of comparison: The German Environment Agency determined 143 grams per kilometer traveled in a passenger car with a combustion engine.

This advantage does not comfort the residents of major cities, though, with thousands of buses running in tight time schedules every day. In addition to exhaust emissions, noise is another problem. To reduce both, many cities are already using electric buses. China was the first and most consistent country to electrify its bus fleet. The southern Chinese coastal metropolis of Shenzhen with a population of 12 million citizens is a good example. Between 2009 and 2017, the city changed over to electric buses. Today, 17,000 battery-electric buses drive through Shenzhen; bus operation is 100 percent electric.

Other regions are catching up. It is primarily megacities and their initiatives that are keeping the trend toward electric buses on a stable level. In Europe, London and Moscow are the leaders with their low-emission bus fleets. While the 500 electric buses in Moscow also include trolleybuses, London relies on electrified double-deckers from different manufacturers. In addition to more than 300 purely electric buses, there are also 3,800 hybrid buses and ten fuel cell vehicles. London's mayor Sadiq Khan intends to significantly increase the share of zero-emission vehicles in the near future.
The use of electric buses is accompanied by a perfect harmonization of the timetable with the available charging infrastructure. British Prime Minister Boris Johnson has just decided upon a package worth 3 billion pounds to improve the bus infrastructure, cheapen fares and purchase 4,000 new electric buses.

Many reasons for the triumph of electric buses

Many reasons for the triumph of electric buses
Indeed, government regulations, local emission reduction initiatives and subsidies are key drivers for the triumph of electric buses. Public transport systems are not only supposed to contribute to meeting the Paris Climate Agreement targets and reducing CO2 emissions – cities also want to reduce noise and improve air quality. China has demonstrated that financial incentives by the government can be a powerful tool. Electromobility – even if it affects public transport – is primarily about achieving a critical mass from which development becomes irreversible. With the European Green Deal and the pricing of CO2 emissions, the EU has paved the way for more sustainability. The EU also sees procurement for public transport as an effective tool and therefore defines quotas: With immediate effect, according to the Clean Vehicles Directive, contracting authorities shall order at least 45 percent of vehicles with clean drives when ordering new buses, half of which shall be emission-free – i.e. purely electric. From 2025, the share of clean drives is expected to increase to 65 percent of new purchases. "Clean" also refers to buses with a plug-in hybrid drive as well as buses that are mainly powered by hydrogen, natural gas, synthetic fuels or bio-fuels.
The industry service Bloomberg New Energy Finance (BNEF) is forecasting a huge global increase in electric buses for the next two decades. Subsequently, the share of battery-electric buses in public transport will increase to almost 70 percent by 2040. The procurement of electric buses is backed by massive investments in urban charging infrastructure.

By 2025, the number of e-buses worldwide will increase by 50 percent compared to 2019

By 2025, the number of e-buses worldwide will increase by 50 percent compared to 2019

Experience with thousands of electric bus drives

Experience with thousands of electric bus drives
For ZF, electric drives for city buses are no new technological territory. The Group has been selling its AxTrax AVE electric portal axle for many years. It is particularly suitable for low-floor buses. ZF is pursuing a technology-open approach. The electric portal axle can be operated with electricity from batteries or with energy from fuel cells or overhead contact lines. Meanwhile, electric buses featuring ZF's AxTrax AVE have traveled thousands of miles a day in metropolises worldwide between London and Los Angeles.
In addition, volume production of the CeTrax electric central drive started last year, which has a maximum output of 300 kilowatts. Its advantage is that it can be easily installed in vehicles with a conventional driveline layout. "We offer bus manufacturers a complete product and service portfolio, true to our approach 'Mobilizing Commercial Vehicle Intelligence'," says Winfried Gründler. At ZF, he is responsible for E-Mobility in the Commercial Vehicle Technology Division. "Because our approach is essentially about integrating components and systems optimally so that vehicle manufacturers and transport companies can better master the many challenges they're currently facing."
"We offer bus manufacturers a complete product and service portfolio, true to our approach 'Mobilizing Commercial Vehicle Intelligence."
Winfried Gründler, Head of E-Mobility in the Commercial Vehicle Technology Division

Since the acquisition of WABCO in 2020, ZF has considerably expanded its service portfolio for buses as well: In addition to existing driveline and chassis technology, sensors and connectivity solutions, ZF now also offers brake, stability and air suspension control systems as well as compressed air management systems from a single source. This enables the Group to directly reduce CO2 emissions and further considerably increase energy recuperation, safety and operating efficiency for buses.
ZF has already equipped thousands of city buses worldwide with electric drive axles, including double-decker buses like this one in London.

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