Fast charging of batteries keep buses on the road longer and lets them carry more people
As some 3,000 government leaders, industry executives and policy experts arrive in Davos for the World Economic Forum (WEF), they will be able to move about town and between conference venues in a fully electric bus.
This isn’t a conventional electric bus. The Davos bus is powered by an innovative battery-charging network ideally suited to public transportation in a municipal setting. This technology is already in use in Geneva, where the system is known as TOSA, and is being installed in Nantes, France.
TOSA, one offering within ABB’s extensive portfolio of charging and drivetrain solutions for electric buses, uses a flash-charging system that enables the e-bus to run quietly, with a maximum passenger capacity. The flash-charging station recharges the compact battery in 20 seconds or less, as passengers alight and others board.
While much of the Davos forum involves peering into the future, the buses demonstrate a sustainable mobility technology that is available today. One ABB-powered bus will drive a circuit of 3 kilometers (1.8 miles), making seven stops on a route running through the city.
The Davos bus is emblematic of Zurich-based ABB’s deep involvement and commitment to its Swiss homeland and heritage. For more than a century, ABB has been helping make Switzerland a world leader in transportation, industrial and power-management technologies. The ABB Corporate Research Center in Baden-Dättwil collaborates with leading research universities around the world, including the Federal Institutes of Technology in Zurich and Lausanne. TOSA, which was developed in Switzerland and has won international awards for innovation, is part ABB’s proud tradition as a technology leader.
A boost of power, then on its way
A TOSA bus looks in many ways similar to the various types of articulated buses used around the world. People may notice only that the electric TOSA bus is nearly silent, compared with the diesel buses prevalant in many urban areas. And of course the e-buses do not spew exhaust clouds when pulling away from the bus stop and accelerating into traffic.
The big difference, though, occurs when the TOSA bus reaches a stop equipped with a flash charging system. As soon as the bus arrives, a laser-controlled arm on the roof connects in less than a second to an overhead receptacle built into the bus shelter. The connection provides a high-power charge – using a feed of up to 600 kilowatts. The boost recharges the battery enough to let the bus continue on its way.
Bus stops with charging stations are equipped with a converter, fed by alternating current (AC) from the utility grid and delivering direct current (DC) to the e-bus. To ensure public safety, the high-voltage overhead connectors are energized only when the battery is being recharged.
TOSA buses can use much smaller, lighter-weight batteries as a result of the flash charges along the route. There is an added boost when braking energy is recaptured and stored in the batteries. With TOSA, even the full charges at an end-of-line station require only a few minutes.
Additional efficiencies are achieved through ABB’s self-learning control system and on-board technology, which manage the battery charging and energy storage.
But energy efficiency is only part of the picture. A TOSA bus line is also more economical and flexible for cities to deploy than, say, an electric trolley system or a small tramway. That’s because no web of overhead power lines needs to be installed, and no tracks embedded in the street. Those advantages allow more flexibility in routing. And they make it possible to execute impromptu detours when road repairs or a traffic accident blocks the regular route.
Tackling climate and terrain
The Davos installation is a pilot program for the duration of the World Economic Forum. But afterward, the City of Davos plans to take up formal discussions to explore installing permanent electric bus routes and expanding the TOSA charging network. With clean hydropower already supplying most of the electricity for Davos, a switch to a TOSA e-bus fleet would represent a further step toward sustainable mobility.
The project represents the first electric bus line in Davos and the first TOSA bus installation in an alpine city – Davos’s elevation is 1,550 meters (5,100 feet) – and provides an ideal demonstration of the technology’s reliability in harsh weather conditions and hilly terrain.
A broader European push
ABB is supporting the European Commission’s European Clean Bus Deployment Initiative. The program, the first of its kind, will encourage collaboration among infrastructure providers, transport operators and bus manufacturers to incorporate more alternative-energy buses into Europe’s public transportation systems. Organizers hope to improve the share of alternatively fueled buses in Europe to 30 percent by 2025, up from only about 12 percent today.
“Policy makers across the world are promoting sustainable public transit solutions to tackle emissions in and around densely populated cities,” says Thierry Lassus, head of ABB’s Sustainable Public Transportation initiative. “At ABB we have always been at the forefront of developing state-of-the-art and cost-efficient solutions that meet our customers’ needs and enable a greener future for all.”
