The government will install quick-charging pantographs for e-minibuses at the new public transport interchange in Kwun Tong Town Centre, offering quick “top-up” charges and enabling electric minibuses to have much smaller, lighter batteries than an overnight charging model requires.
The Environmental Protection Department (EPD) says “overnight charging” doesn’t suit Hong Kong’s minibus business, and is seeking proposals for a paid-for “OppCharge” pantograph system in the new bus interchange. Hong Kong’s minibuses, it says, are characterised by frequent round-trips, heavy air conditioning and hilly terrains, all factors which suit frequent “opportunity” charging and lighter batteries.
OppCharge is a fast EV charging interface already popular in Europe. The system consists of a pantograph which drops down onto metal rails on the bus roof, and a wi-fi-based communication protocol to ensure the rails and pantograph are aligned. Charging is completely automatic under the system – and, just like consumer standards such as USB-C or the three-pin plug, the protocol is independent of any one manufacturer.
EPD estimates that five minutes under a 300kW charging station could give a minibus a 31.5km boost, even under “worst-case” summer conditions.
Under such conditions, the number 10M bus, which travels around 380 km a day on 22 round-trips of 17.3 km between Well On Garden to Tung Yan Street, would need around 11 six-minute top-ups a day if fitted with a 60kWh battery.
The 23B, which plies a 6.4km route from Tung Yan Street to Cha Ko Ling, could manage with just six four-minute top-ups per day with a 40kWh battery; while the 23M serving Lam Tin Station would need just four four-minute top-ups a day with the smaller battery. The EPD recommends smaller batteries for the lower-distance routes. Instead of charging heavy batteries overnight, minibuses would end their shift with a 15-minute charge, leaving them fully charged and ready for the next morning.
Although no electric minibuses are yet commercially available in Hong Kong, the government plans a 40-vehicle 12-month pilot scheme for such vehicles in 2023, and, with its Kwun Tong initiative, is laying the foundation work for charging infrastructure right now. “We aim to test the e-Public Light Buses and charging facilities provided from different suppliers so as to test their operations under local environment and compare their performances,” says the government.
The pantograph trial will run for 45 months, and will see at most three 300kW quick-chargers with two 150kW back-up plug-in chargers. The government hopes to install the system as soon as possible once a supplier is chosen.
EPD says the move is necessary to reduce roadside air pollution. “Commercial vehicles are a major source of roadside air pollution in Hong Kong, accounting for about 95% of the total vehicular emission of nitrogen oxides and respirable suspended particulates,” it says. “Electric vehicles have no tailpipe emissions. Replacing conventional commercial vehicles with electric vehicles can help improve roadside air quality,” says a spokesman.
Paul Bromley, managing director of Phoenix Business Consulting, welcomed the news. “This is an excellent first step in reducing roadside emissions for Hong Kong and we look forward to an even bigger roll-out of fast charging facilities to also include franchised buses, which would potentially offer an even bigger win for clean, zero-emissions Hong Kong public transit,” he says.