Energy authorities are planning to make gasohol E20 the primary oil fuel at petrol stations in place of gasohol E10, also known as gasohol 91, which will be gradually phased out.
Gasohol E20 is a mix of gasoline and 20% ethanol, while gasohol E10 is blended with 10% ethanol.
Gasohol E10 is known by motorists as gasohol 91 or 95, which refer to their octane ratings.
The latest move is aimed at supporting domestic production of ethanol, which is made from sugar and cassava.
Pornchai Jirakulpisan, the Oil Fuel Fund Office's director of the policy and strategy unit, said authorities are seeking ways to encourage motorists to shift from gasohol E10 to gasohol E20.
One tactic is to make the retail price of gasohol E20 cheaper than gasohol E10 by three baht a litre, imposing a levy on the latter through the Oil Fuel Fund. Money collected from gasohol E10 users will be used to support the fund, he said.
The retail price of gasohol E20 is currently lower than gasohol 95 by 1.11 baht per litre.
Authorities plan to start increasing the price difference between gasohol E20 and gasohol E10 in December or January next year, gradually raising the price gap to three baht per litre within the next couple of years.
Gasohol 91 will be phased out, leaving petrol stations with only gasohol 95 for sale to motorists as an alternative fuel, said Mr Pornchai.
He said many registered cars on the road, especially those manufactured after 2008, are compatible with gasohol E20.
Authorities will also consider whether they should phase out unpopular gasohol E85, which is composed of 85% ethanol. Mr Pornchai said discussion on the issue has yet to begin.
Domestic consumption of gasoline and gasohol as of July stood at 29.8 million litres a day. Up to 15.6 million litres of gasohol 95 were consumed a day, while 7 million litres of gasohol 91 were sold daily.
Daily consumption of gasohol E20 was 5.63 million litres, while sales of gasohol E85 tallied 970,000 litres.
If authorities achieve their goal to make gasohol E20 the primary fuel, demand for ethanol is expected to increase to 6-7 million litres per day, up from 4.5 million litres at present, said Sureeyot Khowsurat, president of the Tapioca Ethanol Association and managing director of Ubon Bio Ethanol Co.
