The first large electric car charging station in east China's Shandong Province, capable of charging 45 cars at a time, is being built in Linyi City, as part of a program to promote the development of new-energy vehicles.

The project, costing 23 million yuan (3.37 million U.S. dollars), would be completed by May, said Li Guohua, deputy director of the sales department of Shandong Electric Power Corporation, which is developing the station.

Shandong is one of China's biggest auto producing provinces and has been developing electric cars since 2004. The province has more than 30 electric car producers, and is aiming at an annual production capacity of300,000 vehicles by 2015.

"How we charge the electric cars is the key to the industry's success. Whether the green cars can enter China's mainstream market depends on a nationwide charging network that we are building," said Li.

China was the world's largest electric car producer and market, said Li. "Many other cities, including Shanghai, Shenzhen and Wuhan, have built electric car charging stations."

Developing and popularizing the zero-emission cars was one of the best ways to curb China's growing fuel demand and to reduce air pollution, said Yang Yusheng, an academician of the Chinese Academy of Engineering.

But the biggest challenge was the charging problem, Yang said.

"Building an electric charging network is the key to popularizing electric cars in China," said Yang.

According to China's State Grid Corporation, 75 electric vehicle charging stations are planned in 27 cities across China by the end of the year.

China overtook the United States as the world's largest car market in 2009. New auto sales rose 46.15 percent year on year to 13.64 million units in 2009 in China, according to the China Association of Automobile Manufacturers.