By Kim Tae-gyu
Hybrid diesel- or clean diesel-powered buses are being seen as alternatives to compressed natural gas (CNG)-powered ones after the explosion of one of the latter on Monday in northeastern Seoul.
Industry watchers say that clean diesel buses are the most viable models as they are widely available at relatively competitive prices while having low tailpipe emissions unlike their predecessors.
Some even contend that Asia’s fourth-largest economy is required to phase in the next-generation buses with the hybrid diesel engines while skipping over the clean diesel models.
“Over the past decade, CNG buses have been favored thanks to their eco-friendliness in comparison to traditional diesel engines. Excluding the sole outstanding advantage, however, they lag behind in fuel efficiency and economy,” a Seoul analyst said.
“With the advent of clean technologies, diesel engines continue to overcome their shortcomings. And the explosion on the CNG bus has triggered talks on the necessity to replace them with clean diesel models.”
A CNG bus exploded Monday at a crossroads near the Haengdang-dong Subway Station, injuring 17 passengers. A female had her feet severed due to the accident, and the tragedy caught the country by surprise.
This prompted citizens to express concerns over the CNG buses which number over 7,000 in Seoul alone due to the brisk introduction of the eco-friendly vehicles at the start of the new millennium.
An investigation by the Ministry of Knowledge Economy (MKE) amply demonstrated that such worries are by no means groundless.
Early this year, the ministry commissioned safety checks on a total of 4,300 CNG buses across the country to learn that 4.7 percent of them have defects in their gas tanks, which is believed to have been the cause of the Haengdang-dong explosion.
About two thirds of the faulty gas tanks were found to have a critical leakage of gas. Yet, the bus involved in the latest accident was excluded from the check-up.
Those who put more stress on environmental performance claim that hybrid diesel models or electric vehicles are much better.
“The government has pursued the use of CNG buses and the result is that around half of all buses are CNG-based ones here. It appears to be adverse to diesel buses and that’s the problem,” professor Kim Pil-soo at Daelim College said.
“With the technological advances, clean diesel vehicles are as eco-friendly as CNG buses. Accordingly, we need to diversify our models by ceasing the CNG-only policy. In the long run, hybrid diesel or electric automobiles can also be the answer.”
Kim warned that citizens would be forced to commute on landmines — the CNG buses that contain high-pressured gas tanks below passengers’ feet. “Something should be done immediately but the hitch is that the Seoul administration seemingly does not know what to do.”