ABB and Volvo Buses are partnering to co-develop and to commercialize electric and hybrid buses with open standards-based direct current (DC) fast charging systems. The cooperation will create a city-wide standardized charging system for electric and electric hybrid buses that can charge buses quickly through an automatic roof-top connection system at bus stops or through cabled charging systems overnight.
This approach, based on internationally accepted standards (EN61851-23), enables maximum re-use of existing e-mobility technologies, thereby ensuring a rapid deployment of urban e-mobility. The first joint project will be the implementation of Volvo Electric Hybrids and ABB’s automatic e-bus chargers in the Luxembourg public transport system, where as many as 12 Volvo Electric Hybrid buses operated by Sales-Lentz will be running on existing lines by 2015.
The project is integrated into Luxembourg’s Mobility Network linking different mobility projects in the western European country to exploit synergies and develop common visions for the mobility of the future.
|Volvo hybrid bus. Click to enlarge.|
Volvo’s new Electric Hybrid bus, which reduces fuel consumption by 75% compared to conventional diesel buses, will debut at the IAA exhibition in Hannover, Germany, in September.
The fast charging solution with Volvo is quite different than the “flash charging” system ABB has been developing and has implemented in the TOSA (Trolleybus Optimisation Système Alimentation) electric bus system pilot project. (Earlier post.) That system enables onboard batteries to be charged in 15 seconds with a 400 kW boost at selected stops using a roof-mounted system (“Flash station”). The flash stations are connected to the 50 kVA electricity network and also have a 3kWh storage unit (supercap) for smoothing peaks in consumption.
Under the TOSA solution, more charging stations are needed, notes ABB, because a charge is needed every 1 to 1.5 km or every 2 to 3 bus stops. 400 kW of power is also required at intermediate bus stop to perform the 15-second flash charge. At the end of the route, the TOSA bus uses a 200 kW charge boost for 3-4 minutes while the bus is waiting.
TOSA is also a full ABB package solution: ABB equipment in the bus roof, inside the bus and at the charger stations in the bus stops.
By contrast, the Volvo solution envisions a charge needed every 7 km for hybrid electric buses and every 15 km for electric buses; i.e., it requires fewer charging stations in the stops of the bus lines.
The power requirements are also lower: 150kW for the hybrid electric bus and 300 kW for electric bus. Charging time ranges from 1 minute in the bus stops to 6 minutes at the end of the route when the bus needs to wait. The system is based on internationally certified standards.
Developing e-bust fast-charging standards. ABB and Volvo will contribute with their respective expertise in power grids and e-buses to further develop e-bus fast-charging standards, such as communications protocols for infrastructure, electrical grids and e-buses.
An electric-bus charging standard will be largely based on the recently adopted global DC fast charging standards for passenger cars, guaranteeing safety and helping stimulate investment, long-term commitment and increased adoption of clean mobility.
The partnership is focused squarely on standardization of automatic e-bus fast charging, including the communications protocol between the infrastructure charging solution and e-bus, the electrical interface and specifications for the rooftop automatic connection system (ACS).
Volvo Buses launched its first hybrid bus in 2009 and has delivered nearly 1,600 hybrids to 21 countries. Its first fully electric bus will be launched in June 2015 as part of the ElectriCity project in Gothenburg, Sweden.
ABB has delivered more than 1,500 DC fast charging systems for passenger vehicles worldwide since 2010, rolling out charging networks for automotive, utility, government and retail customers including nationwide networks in the Netherlands, Estonia and Denmark.