CHENNAI: The trial study of government buses running on Compressed Natural Gas (CNG), which is 12% to 13% cheaper than diesel, has yielded encouraging results, reducing average fuel expenses by Rs 4 to Rs 4.5 per km. Additionally, the CNG buses achieved a mileage of 6 to 6.98 km per litre compared to 5.2 to 5.96 km for diesel buses. The average price of CNG is Rs 75 to Rs 79 per litre, depending on the supplier, while high-speed diesel is Rs 91.5 per litre.
Conducted by Pallavan Transport Consultancy Services, a technical arm of transport department, the study revealed that six buses (two each from Madurai, Salem, and Kumbakonam corporations of TNSTC) run on CNG fuel for more than 50 days are not only cost-effective but also offers better mileage compared to diesel. Moreover, it also showed that the cost of around Rs 6 lakh to convert a bus to CNG can be recovered in a month.
Official sources noted that the savings in operational expenses could amount to several crores of rupees with a large-scale migration to CNG. A study on five more CNG buses operated by Coimbatore, Tirunelveli, and Villupuram corporations is under way.
K Phanindra Reddy, secretary of the state transport department, told TNIE that the study assessed cost savings from increased mileage, reduced fuel expenses, and the performance of the companies involved in the conversion of buses. “The expenses of Rs 5.5 lakh to Rs 6 lakh per bus incurred for converting a diesel bus to CNG can be recovered within a month. The CNG buses performed better during daytime operations. However, minor leaks were reported at night. With these encouraging results, staff will receive more training on the usage and maintenance of CNG buses.”
An MTC bus converted to run on a CNG engine caught fire on July 2. An inquiry by a committee from MTC and the private company involved in the conversion revealed a leak in the CNG engine had triggered the accident.
Reddy said the study also evaluated the performance of the companies converting diesel buses to CNG. “When the government decides to expand the use of CNG vehicles for public transport, companies that convert the best-performing buses will be given preference,” Reddy said.
According to the trial study, a mofussil bus from Madurai consumed 437 litres of CNG, whereas the diesel bus required 519 litres of diesel for covering 2,697 km. The CNG bus recorded a mileage of 6.17 km per litre compared to 5.2 km for the diesel bus. The Madurai transport corporation spent Rs 47,361 on diesel, while the cost of CNG was Rs 34,755, saving a total of Rs 12,606 and registering per km savings of Rs 4.67.
Similarly, two buses from the Kumbakonam corporation saved Rs 17,913 and Rs 19,024, operating for 4,523 km and 4,260 km respectively. The average savings per km were Rs 3.96 and Rs 4.47.
As per official data, the eight transport corporations run 78.7 lakh km per day, with TNSTC Salem buses alone covering 9.15 lakh km daily. The remaining divisions cover 7.8 lakh to 9.9 lakh km per day.
The state has nearly 10 companies that supply CNG including IOCL, IRM Energy, Torrent Gas, Adani Total Gas and others.