Tran Chi Trung, director of the centre, said the city has 2,575 operating public buses, most of which have been operating for more than 10 years.
Under a project to replace the old buses between 2014 and 2017, the city asked the centre to seek investors for 1,680 new buses.
The centre has replaced only 839 buses, or 50% of the target, of which 256 are CNG-fueled buses, accounting for 12% of the new buses, while the other buses use diesel fuel.
Trung said the centre should buy more than 800 new CNG buses by the year-end under a new city regulation that requires all new buses use CNG beginning this year.
He said the target is difficult to achieve as the cost of buying CNG buses is 33% higher than diesel-fueled buses.
In addition, the supply and price of CNG is now heavily dependent on PV Gas South Company.
Construction of CNG stations is costly as they require more space, he said, adding that the Petrol Group is researching this problem to propose solutions.
CNG buses, however, bring economic and environmental benefits, including savings of 23% of energy compared to buses using diesel.
Total emissions from CNG buses in HCM City have fallen by nearly 14,000 tonnes per year compared to buses that use diesel.
Truong Trung Kien, head of the Urban Department under HCM City’s Council, has asked the centre to continue to conduct research on the use of CNG buses in the future.
While waiting for assistance from the city government, the centre needs to encourage residents to use public buses and limit the use of private vehicles to reduce traffic congestion, he said.
CNG is methane stored at a high pressure. It is used in place of petrol, diesel fuel and propane, and emits less environmentally unhealthy gases than the other three.
CNG buses operate on Route 33, which connects university campuses in Thu Duc district and An Sương Terminal in the outlying district of Hoc Mon.