Could natural gas-powered trucks be an answer to China's smog problem?

The way our cars are being fueled is changing - and fast. Consumers are seriously looking at alternatives to the petrol and diesel vehicles we've gotten so used to driving.

According to the U.S. Department of Energy's Alternative Fuels Data Center, around 150,000 vehicles in the U.S. are powered by natural gas, with that figure hitting 15.2 million worldwide.

In China, which is notorious for its thick smog, the liquefied natural gas (LNG) revolution is gathering pace, with some truck drivers keen advocates because of its cost saving benefits.

"Since we started using LNG trucks, I would say the cost saving has been around 30 percent," truck driver Jia Yu Jun told CNBC's Sustainable Energy. "Say we drive about 15,000 kilometers a month – we save more than 100,000 yuan ($15,000) a year," he added.

Private energy company ENN has helped to build China's national LNG infrastructure, including refueling stations. The environmental benefit of LNG is just as important as its cost.

"In recent years, China has made considerable efforts in dealing with the climate and environment, and the transport emissions have a major impact on the environment," Wang Feng Shen, executive vice president of ENN Energy, said.

"Natural gas produces 85 percent lower emissions than diesel, especially in terms of carbon monoxide and sulfur dioxide, which are more than 90 percent lower," Shen went on to add.

Alongside LNG, other renewable energy sources for cars are being investigated. In England, the Bio-Bus is fueled with food and human waste, while solar powered vehicles – such as the Eindhoven University of Technology's Stella – are being designed by a host of bright minds.

Back in China, ENN's Wang Feng Shen sees huge potential for LNG vehicles. "At the moment there are 5.5 million heavy trucks in China, and 1.2 million buses," he said.

"Now, we only have 200,000 vehicles [using LNG] so the market share is less than 3 percent. It could increase 30 fold in the future."