Page 22 - Commercial Vehicle Engineer - December 2019

ELECTRIC BUSES IN CHINA
With close to 6,000 buses in its eet, most of which are now battery- powered, Ma’s claim that SBG is “the largest new-energy bus operator in the world” seems justi able.
He has details of the eet composition at his ngertips. Single-deckers at
10.5 metres in overall length are the workhorses of the SBG eet. There are 3,990 of them, supported by about 70 double-deckers at present, though Ma expects that number to grow substantially in the near future.
SBG also operates small numbers of midibuses at 7.0 and 7.5 metres in length, together with about 1,000 8.5-metre midibuses. The three bus manufacturers supplying SBG at present are BYD, Nanjing Jiniong and Wuzhoulong. There are around 4,500 BYD buses in the SBG eet, together with most of the 4,700 electric taxis operated by the company.
“We were the rst operator anywhere to start using electric taxis, in 2010,”
says Ma. “We set up a joint venture company with BYD.” The city’s local government decreed that all 22,000 taxis operating there had to be electric by the end of last year.
“We started the whole electri cation process back in 2008, with 10 hybrid (diesel/electric) buses. In 2011 we started running our rst all-electric buses, 100 of them. Then within the space of two years, between 2015 and 2017, we moved to full electri cation.”
Doubling down on double-deckers: there are only 70 in the huge Shenzhen Bus Group eet at present, but that number is set to grow substantially.
New type of charging
As UK eet operators are now discovering, provision of charging points proved to
be “one of the biggest challenges” in the whole process. “We’ve had to introduce a new type of charging technology, called net-type quick charging,” says Ma. This means several cables running from a single charging pylon to enable several buses to be charged at once, though naturally charging time per vehicle increases commensurately.
Ma’s gures on electricity costs make it easy to see why he is keen to ensure that most bus charging takes place overnight rather than during the day.
Shenzhen’s electricity is generated mainly by nuclear power stations, but there is a huge difference between peak (daytime) and off-peak charges. The cost per unit
of electricity can be as low as 0.237 yuan (CNY) – or £0.026 – at night, reckons Ma. But during the day the cost rises as high as 1.2 CNY per unit.
“Buses typically return to depots to
be charged between 11pm and 6am,” says Ma. “Our charging pylons have several cables each. One bus at a pylon can be recharged in two hours but
with three or four buses being recharged at the same time it can take about
seven hours.”
22 DECEMBER 2019 > COMMERCIAL VEHICLE ENGINEER