In the face of soaring petrol prices, Fan Chunsheng spent 5,600 yuan (US$690.5) last month converting his 1.3-litre-engine Xiali taxi into a bi-fuel vehicle that can be powered in turn by both petrol and natural gas.

By doing so, Fan will make a saving of around 50 percent on his fuel costs, or 1,000 yuan (US$123.3) every month.

"It is economical," said Fan, 42, a taxi driver of six years in Yinchuan, capital of northwest China's Ningxia Hui Autonomous Region.

"I used to spend an average 2,000 yuan (US$246.6) on petrol. After the petrol price rose last week, it would work out too expensive."

Fan, who works on the 10-hour day shift, feels that driving with the new fuel has almost no difference to using petrol only.

"It is 15 percent slower than petrol but I don't think that is such a big deal," he said, adding that natural gas is environmentally friendly.

A car with a natural gas-powered internal-combustion engine emits 87 percent less nitrogen oxide, 70 percent less carbon monoxide and 25 less carbon dioxide than a car with an engine that uses petrol, according to research by the Honda Motor Co.

Since the end of last year, its many advantages have triggered a citywide campaign among taxi drivers to adopt to natural gas as the major fuel for their cars.

So far, about one-fifth of more than 5,000 taxis in Yinchuan have been running on bi-fuel.

The cost is the major incentive for taxi drivers to convert their engines, said Tian Xinping, deputy director of the Yinchuan Communications Bureau.

Tian predicts more pre-converted natural gas cars will be added to taxi fleets following the recent 6 percent rise in the cost of petrol and diesel oil a significantly larger jump than any of the other four increases this year.

The fee for converting a car scared away many taxi drivers who only earn about 2,000 yuan (US$246.6) every month in the competitive taxi business. Fan did the maths before making the decision: the new fuel saves him 1,000 yuan a month. After installing the new tank, the cost of the conversion could be recouped within six months of using the new fuel.

"In the long term, the natural gas costs less," Fan explained.

Thinking of the future, Fan and other taxi drivers who now drive bi-fuel cars have rallied for more natural gas filling stations.

"The city only has three natural gas stations at present," Fan complained. "It is not convenient."

"When you have to fill the gas tank twice a day, you realize that the present number of gas stations is far from enough."

"Besides, the natural gas tank installed in the car has a limited capacity, which doesn't allow for long distance driving. That is why we need a plan B - the petrol tank," the driver continued.

Despite some teething problems, natural gas has become increasingly popular among taxi drivers in cities and is favored by some city governments.

The city government of Shenyang, capital of northeast China's Liaoning Province, has started cooperating with an operator of natural gas stations in offering conversions free of charge for taxis in the city.

This is part of the city's project aiming to make all public transportation vehicles including buses and taxies adopt natural gas.

To rule out concerns of a shortage of natural gas stations, 12 stations will be built in Shenyang. All 12 will be operational by November.

(China Daily July 29, 2005)