Forty all-electric taxis, believed to be the first to go into service in China, were officially launched Monday in southern Guangdong Province's Shenzhen City.

Shenzhen was the first city to have officially put electric taxis in operation in China, said Hu Jianping, president of Shenzhen Bus Group (SBG) at the launch ceremony.

"The E6 cars' ET (environment technology) batteries give off zero emissions and cause no harm to the environment," said Wang Chuanfu, chief executive of BYD, manufacturer of the electric taxis.

The five-passenger E6, with a maximum speed of 140 km/h, consumed 21.5 KWH of power per 100 km and could run about 300 km on one charge, a record for a vehicle of its kind, Wang said.

The electric taxis are being operated by Pengcheng Electric Taxi Co., Ltd, a joint venture of BYD and SBG.

They were priced a little over 40,000 U.S. dollars each, Wang said.

BYD plans to have 100 E6 taxis on Shenzhen's roads by the end of June. The company expects to start selling E6 cars to the United States through its headquarters in Los Angeles later this year, he said.

Wang said BYD would try to roll out E6 in the European market in February 2011, but gave no details.

The electric taxis were an important measure to build a low-carbon urban transport system and Shenzhen planned to have more such taxis on its roads, said Vice Mayor Zhang Siping.

If all-electric taxis could be promoted across China, it would greatly improve the air quality in cities, said Huang Yonghe, an expert at the China Automobile Technology and Research Center.