Local traders and fleet operators of compressed natural gas are calling for the Energy Ministry to control the retail price of the fuel to make it 50% cheaper than diesel.
The request is based on their fear that many commercial buses and trucks are shifting to biodiesel, for which the ministry is subsidising prices.
The operators established the Natural Gas for Vehicle Business Association in order to increase their negotiating power with the ministry.
The association includes well-known companies such as Sakol Energy Plc, Scan Inter Plc, Wind Energy Co, Saraburi Truck Sales Co, Kiatthana Transport Plc, Cho Thavee Plc and Siamraj Plc.
Compressed natural gas, also known as NGV (natural gas for vehicles), used to be capped at 8.50 baht per kilogramme during 2007-14 because the ministry aimed to support motorists suffering from global crude prices rising to US$90-130 per barrel. NGV was positioned as the alternative fuel.
As the sole NGV seller, PTT Plc was ordered to subsidise NGV prices.
The ministry then decided to float NGV prices in 2014 as oil prices declined.
PTT has an accumulated loss from the NGV price subsidy of roughly 100 billion baht over the past 12 years.
NGV now costs 15.88 baht per kg while the diesel price tag is 25.79 baht per litre. Two biodiesel types, B10 and B20, have been subsidised to the tune of three baht and five baht per litre.
Sakchai Leesavan, president of the new association, said NGV traders and fleet operators want the ministry to promote NGV again by keeping the retail price lower than for diesel or biodiesel.
"We are suffering from the market price because the government is ignoring support for NGV, while this gas is a good solution to the air quality problem and the smog crisis," Mr Sakchai said.
He said aggressive support of biodiesel is not the best solution to tackle poor air quality.
Moreover, the association is calling for an import tax exemption for truck chassis and NGV-related equipment, contending that natural gas releases less emissions.
Jakkraphong Sumethchotimetha, the association's vice-president, said NGV consumption dropped from 9,000 tonnes per day to 7,600 tonnes in 2017.
"The transport sector is now consuming roughly 5,500 tonnes daily," he said. "NGV stations also dropped from 500 in 2013 to 462 stations in 2017. Now there are 440 NGV stations nationwide."