Opportunity charging will form a “key step” in the Transport for London journey to a wholly zero-emission bus fleet, the body says.
Such a clearly stated position comes as more details of existing and future use cases of the technology in the capital are revealed. An inverted pantograph unit from ABB already installed at Go-Ahead London’s Bexleyheath garage is servicing 18 BYD ADL Enviro400EV battery-electric double-deckers used on route 132, with those vehicles being connected to the unit via roof-mounted rails multiple times daily.
In 2023, that work will be followed up in a separate project involving 20 Irizar ie tram battery-electric single-deckers, also with Go-Ahead London, on route 358. In that case, a 450kW inverted pantograph unit supplied by Jema Energy will be placed at each end of the 15-mile route.
TfL says that with opportunity charging reducing the number of battery-electric buses required when compared to a scenario reliant solely on overnight charging, savings “can be reinvested into other areas of the network.” The Enviro400EVs concerned receive overnight battery replenishment in addition to their regular opportunity connection.
RFID technology is used to enable buses to communicate with the pantograph unit. Pictures circulated by TfL show that two rubber strips, within which the bus’s front wheels settle, are used to locate the vehicle correctly underneath the pantograph.
BYD and ADL announced the addition of opportunity charging capacity to the Enviro400EV in March 2021, saying at that time that the model can accept in excess of 300kW of power via an inverted pantograph. The two manufacturers pointed out that in addition to increasing range, such an approach may also be useful where depot space for floor-mounted charging units is constrained.
TfL Director of Bus Louise Cheeseman describes opportunity charging as “a key step to help us [to] get zero-emission buses running on routes all across London.” Currently 850 such vehicles are in service on TfL’s behalf, including a small number of hydrogen fuel cell-electric examples.
Adds Go-Ahead London Managing Director John Trayner: “Route 132 is the latest in a long line of pioneering zero-emission firsts for Go-Ahead London. Working innovatively with our supply chain, we have extended vehicle range by harnessing technology, in the process reducing the overall number of buses required to provide service, and delivering significant cost savings.”
On 30 August, after reaching agreement with the government over a further funding settlement, TfL announced contract awards for further route conversions to battery-electric with a combined PVR of 136. At least one more such award has been made since then.
