Indoor buses: Volvo ElectriCity shows the possibilities
If you want to demonstrate how quiet and clean modern public transport can be, what better place than a library? Users casually browsing the shelves for the latest novels and bestsellers and then the doors open and in glides an electric bus to a bus stop within the library.
This is not a work of fiction however, it’s what was happening in Gothenburg last week where Volvo and its partners in the city demonstrated that electric buses can not only help to tackle climate change, they can also transform urban transport and city planning.
Imagine a bus service that is fully integrated into a city’s facilities, including running inside shopping centres, sports venues, railway stations and airport terminals. The electric bus makes this a real possibility.
The indoor bus stop in Gothenburg was part of the launch of the ElectriCity project, led by Volvo, which co-incided with the city’s hosting of the finale of the gruelling nine-month Volvo Ocean Race. A temporary library in the race village was created, complete with an indoor bus stop used by the new batch of three full-electric and seven electric Volvo 7900 hybrids dedicated to the new Line 55 bus route.
Indoor bus demonstration as part of ElectriCity launch programme.
The 8km route runs from Chalmers to Lindholmen where there is a permanent indoor bus stop which includes a cafe and a DHL facility for passengers to use as a collection hub for online shopping orders.
The route has a PVR of seven, so there is plenty of capacity built in to cope with any teething issues with the full-electric buses. Both types of vehicle use the charging stations at either end. The Lindholmen charging unit is housed at the indoor stop, while at Chalmers the batteries are re-charged alongside a concept bus stop that is evaluating a related project on creating ‘silent’ public spaces.
“Quiet, emission-free electric buses create new possibilities for public transport,” says Håkan Agnevall, president, Volvo Buses. “With noise and air pollution out of the equation, the vehicles can get closer to where people are – even indoors. To show how this can work, we’ve constructed a temporary bus stop in the form of a library.”
Charging station and ‘silent’ bus stop at Chalmers.
Jessica Sandström, senior vice president City Mobility at Volvo Buses adds: “Indoor bus stops mean that you can take the bus to where the passenger is, rather than take the passenger to the bus”.
The ElectriCity project involves a total of 14 partners, led by Volvo which has alone invested around €20million in developing the buses and in contributing a third towards the costs of operating the vehicles. The partners have committed to creating an open technology solution for the charging infrastructure to demonstrate to cities that the charging systems can be used by other manufacturer’s electric buses in the future.
The electric version of the 7900 is still a concept bus and has been built to 10.7m length with a central driving position and double-width passenger doors in the middle. The front axle has been moved forward to accommodate more passengers with a capacity of 86, compared to 95 in the electric hybrid 7900 which is almost 1.5m longer. The 3.3m-high concept bus has a front overhang of 1.2m and a 7m wheelbase. It is fitted with 20 seats plus nine tip-ups which can be locked in a closed position by the driver at busy periods to accommodate more standees.
Volvo intends to develop serial production of full-electric buses in 2017.
As part of the ElectriCity project, an analysis has been undertaken by KPMG on behalf of Volvo of the ‘true total cost of ownership’, which includes evaluating the full benefits in terms of noise reduction, emission-free operation and the value of passengers’ travel time. The latter point refers to the claim of reducing overall travel time with reduced dwell time at bus stops due to the use of the double-width door which enables faster boarding and alighting, according to Volvo.
Niklas Gustafsson, Volvo Group chief sustainability officer, asserts that the traditional total cost of ownership is around €23,000 more for a full electric bus, compared to a diesel bus, but when the other factors are taken into account, the true total cost of ownership is minus €27,000.
Double-width doors designed to reduce dwell time at stops.
Extending the concept of electric buses across a city like Gothenburg could deliver additional benefits, according to the KPMG study for Volvo, amounting to a total annual saving of €11million, including €3million in reduced healthcare costs, one million hours saved by passengers and a reduction of 33,000tonnes of CO2. The savings in terms of carbon are of course likely to be more significant in Sweden, where electricity production includes significant wind power and hydropower rather than the predominant fossil-fuelled power stations that are found elsewhere.
A key element of the ElectriCity project in Gothenburg has been to establish open systems in terms of the charging infrastructure. Volvo recognises that cities may be reluctant to accept proprietary charging units which only work with specific marques, so it has insisted that its key partners in this area, Siemens and ABB, consult with other manufacturers to develop solutions that can be used by many different types of vehicle.
The charging system operates automatically once the bus is positioned in the correct place with the charging interface lowering to connect with conductor rails on the roof of the bus. The first generation of charging units had a pantograph on the bus, but Volvo and Siemens have refined the approach and all moving parts are now on the charging pylon which minimises vehicle maintenance and weight.
The same charging interface is used for the full-electric and electric hybrid buses although since the latter have only a single battery, they receive a maximum charging power of 150kW, compared to 300kW for the full-electric buses.
Volvo’s technicians estimate that the current generation of batteries in the full electric buses have a useful life of around six years, after which time they would need to be replaced with the original units refurbished for re-use if possible. Since concerns about battery life and performance among operators remains a potential constraint, Volvo has decided to offer the electric buses on a pence per kilometre basis so that the manufacturer absorbs the full technical risk of the batteries.
The electric 7900 buses have four 19kW batteries.
The full-electric 7900 has four water-cooled, lithium-ion 600v 19kW batteries, each weighing 350kg, which can be re-charged in around six minutes at the charging stations. Although the electric buses are designed to be charged at either end of the route, they have an estimated 20km range which means there is enough capacity to miss one charge if required. The electric hybrids, which include telematics to enable full remote monitoring, operate on electric power on parts of the route controlled by a geo-fencing system.
A slow overnight charge is also used to ensure that the battery cells remain well balanced, and for the Line 55 buses this is carried out at a new technical centre which has been established in Gothenburg by Volvo which also monitors and maintains the fleet on behalf of the route’s operator Keolis. The maintenance facility includes specially-constructed platforms to work on the buses at roof level for maintenance of the batteries and other roof-mounted components. A single maintenance switch is removed when any work is being carried out on the batteries which completely isolates the 600v system.
Inside the vehicles, passengers benefit from phone chargers and wi-fi which is also provided in the Line 55 bus stops with seamless connectivity between bus stop and bus. The bus stops also include passenger infotainment screens and charging points.
While leather seats have become synonymous with quality urban buses in recent years, Volvo has opted for a different seating material, a jacquard weave from pure wool. The choice of material is important in reinforcing the vehicle’s environmental credentials, according to Volvo.
“We’ve gone for sustainable quality all the way,” says Ingrid Karlsson, who is responsible for the design of the electric bus’ surface materials and textiles.
“Wool is a durable and authentic natural material that is attractive to look at and comfortable to sit on. It warms when the weather is cold, and it cools when it’s hot. What’s more, it is practical and repels both moisture and dirt. It is eminently suitable in a bus designed for sustainable transport.”
Natural seating material, jacquard wool.
The ElectriCity project is also being used as a test-bed for a range of other technologies, as well as being subject to research projects to assess the impact of electric buses on the city environment and on passenger behaviour and choices.
Lindholmen Science Park research team is to assess a new system of automatic passenger counting on the Line 55 buses. Its approach recognises that the roll-out of APC systems has been hindered to date because of the costs of new, dedicated systems. Therefore it is aiming to use images from existing CCTV cameras installed on a vehicle with a program that can recognise and separate individuals, as an alternative method of developing accurate passenger counting systems.
And MariAnne Karlsson, Chalmers University of Technology professor, is leading research into aspects of the operation and impact of Line 55. She points to the challenges of operating buses indoors, particularly given Sweden’s external climate. “A cold, wet bus that drives into a heated space is a challenge from a climate and energy perspective,” says Karlsson. “Chalmers will investigate how a comfortable indoor climate can be maintained and how energy use can be kept to a minimum.”
Among the research areas for Karlsson are whether the new indoor bus stops change people’s perception of public transport if they can become places for meeting, socialising and learning, as well as somewhere to wait for a bus. She acknowledges that in Sweden public transport is already firmly associated with a more sustainable way of travelling: “But how important is it that public transport buses are electric? Will it influence travellers’ choice of transport mode or route?”
The control centre can monitor the fleet across Gothenburg and links to maintenance scheduling.
Gothenburg’s Line 55 provides Volvo with an effective proving ground for its electric hybrid and full-electric buses, and the city is likely to be hosting visiting operators and officials from around the world wanting to understand how the technology can be used in their own cities. In the UK, Volvo has an initial target list of 30 cities which it is trying to engage with as part of the City Mobility project. Edinburgh is due to be the first UK city to have a large-scale electric hybrid bus operation with plans for 24 Volvo 7900s on Lothian Buses’ route 30 in Edinburgh.