The Volvo 7900 Electric is a low-floor, single-deck, battery-electric city bus built by Volvo Buses for the European market. Part of the Volvo 7900 family of buses, the Volvo 7900 Electric offered as an integral product (i.e. completely-built-up) and assembled in Wroclaw, Poland.
2 units of the Volvo 7900 Electric bus have been brought into Singapore as part of an Autonomous Bus development project headed by the Energy Research Institute @ NTU (ERI@N), in partnership with various other agencies. Read more about autonomous bus development here. Testing is expected to begin in early 2019, but no passenger trials have been announced. The first unit arrived in Singapore in late October 2018.
European bus operators are primary customers of the Volvo 7900 Electric with units operating in Sweden, the Netherlands, United Kingdom, Luxembourg and Poland.
The Volvo 7900 range of buses was produced by Volvo Buses since 2011, when it was initially offered with a diesel or CNG engine in both rigid and articulated bus variants. The Euro VI engine range was offered starting from 2013, along with the diesel-hybrid variant known as the Volvo 7900 Hybrid.
Two newer propulsion systems have been developed for the Volvo 7900. The Volvo 7900 Electric Hybrid, launched in September 2014, is an improved diesel-hybrid bus designed to run mainly in electric mode. The Volvo 7900 Electric was unveiled in October 2015, and is a fully-electric bus solely powered by batteries and electric motors. Both versions are complemented with Volvo’s Opportunity Charging System, a rapid charging station at the end stations of a bus route that quickly tops up a vehicle’s battery via an overhead charging system.
By building on its strong Volvo 7900 product line, the Volvo 7900 Electric rides on Volvo’s strong branding and is leading the company’s push for electric city buses. It is touted to have a 80% lower energy consumption compared to a corresponding diesel bus.
Volvo touts the 7900 Electric bus as being silent and comfortable. Contributing little noise and zero tailpipe emissions, the bus is ideal for urban environments and compliant with existing low-emission and low-noise zones within European cities. The Opportunity Charging System is also touted as superior to overnight charging, allowing Volvo to use a smaller and lighter battery pack, which improves bus capacity. The Volvo 7900 Electric is available with a choice of 150, 200 and 250 kWh batteries.
During normal operations, energy stored within the onboard batteries is released to power the electric motors and onboard systems. The electric motors drive the rear wheels via a simple two-speed automated transmission, and also acts as a generator to recover mechanical energy back into electrical energy in a process known as regenerative braking.
The Volvo 7900 Electric offers a fully-automatic fast charging sequence in just six minutes via a roof-mounted conductive charging system, paired with the OppCharge opportunity charging interface.
Supplied by Swiss-Swedish engineering group ABB, OppCharge is an open and competition-neutral interface seeking to accelerate the adoption of electric buses by being compatible with multiple bus manufacturers, hence offering operators choice and flexibility of buses without the need to modify existing charging infrastructure. These overhead pylon chargers with extendable pantographs are usually installed at the end stops of bus routes, allowing buses to quickly receive a full charge in-between trips.
Charging is fully automatic and secured by a two-way WiFi communication sequence. The driver gets a clear indication in order to stop within the specified ± 200 mm from the reference point. The charging sequence is started by activating the parking brake, and the driver can interrupt it at any time.
In addition, the Volvo 7900 Electric can also be charged via cable. Combined Charging System (CCS), which is the European standard for charging of electric vehicles from the mains grid, is more suited for high-power charging when buses are stationed at the Depot.
In Singapore, a plug-in charging station has been set up to facilitate the charging of the Volvo 7900 Electric Bus.
See Also: Autonomous Buses in Singapore
Volvo 7900 Electric:
On 11 January 2018, an agreement was signed between the Nanyang Technological University (NTU) and Volvo Buses for the development of an autonomous bus, also known as a driverless bus. To enhance Singapore’s land transport system, new forms of shared mobility in the form of autonomous vehicles are envisioned to improve the first and last mile commute.
Two Volvo 7900 Electric buses are being brought into Singapore as a testbed for development. The first bus arrived in Singapore in late October 2018. This unit is currently registered as “RD3162L“.
|Basic Technical Specifications|
|Motor / Battery||Electric Motor paired with Lithium-Ion batteries
Electric motor rated at 160 kW / 400 Nm.
|Transmission||Volvo 2-speed automated transmission|
|Bodywork||Volvo Integral Bodywork (TBC)
Assembled in Wroclaw, Poland and shipped to Singapore fully assembled
|Other Features||To Be Confirmed|
The Volvo 7900 Electric is designed around the concept of opportunity charging and is available with a choice of 150, 200 and 250 kWh batteries. In contrast, the BYD K9 previously trialled on Singapore roads had a battery capacity of 324kWh, but the batteries take up much more space on the bus, adding to the overall vehicle weight.
In its European specification, the Volvo 7900 Electric is a fully-low-floor bus with three doors. However, the buses supplied for the trial in Singapore only has a front entrance door, with an emergency exit on the offside.
The autonomous bus trial:
The project to develop the Autonomous Bus is led by the Nanyang Technological University (NTU)’s Centre of Excellence for Testing and Research of Autonomous Vehicles (CETRAN) in collaboration with Volvo Buses. CETRAN was set up by LTA and JTC in partnership with NTU and was operational in the 4th quarter of 2016.
The bus will be tested at CETRAN’S 1.8-hectare test facility within the Jurong Innovation District. Opened in August 2016, the test circuit emulates a multitude of urban scenarios, including an area with simulated rainfall. This would allow a safe environment for rigorous testing of the bus before it enters public roads.
The buses will be equipped with GPS along with a Light Detection and Ranging (LIDAR) laser system for charting, positioning and scanning the area around the vehicle. The bus will also automatically regulate their steering, gear changing and speed.
Volvo started developing autonomous technologies on its cars in 2006 and embarked on a large-scale trial of self-driving cars as part of its Drive Me project conducted in Gothenburg, Sweeden. The research cooperation into Singapore represents Volvo’s first foray into autonomous uses for buses and public transport.
While one unit will be stationed at CETRAN, the second Volvo 7900 Electric bus would be tested within an SMRT Bus Depot to finetune the autonomous technology for conventional depot operations. The objective is to ensure that autonomous buses are able to charge their batteries, drive through the depots to the vehicle wash and park – entirely autonomously.
- BYD K9
- Go-Ahead Singapore trials BYD Electric Bus
- Volvo 7900 Hybrid
- Volvo Diesel Hybrid Buses procured by LTA
External Links & References:
- Volvo Buses History – Volvo Buses [Accessed 11/01/18]
- New Volvo 7900 Electric offers greater range and flexibility – Volvo Buses
- Volvo 7900 Electric – Volvo Buses
- Busworld Kortrijk 2016 – Bus & Coach Buyer
- OppCharge website
- Autonomous Driving – Volvo Cars
- Driverless electric buses to be tested from 2019 in collaboration between NTU, Volvo – Channel NewsAsia
- Volvo and NTU to trial electric buses in Singapore – Volvo Buses
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