The amount of cassava used in producing ethanol will nearly double to 3 million tonnes next year, driven by Commerce Ministry moves to push up the price of the crop.
At present, 38% of ethanol produced in the country is made from cassava and the rest from molasses.
The Commerce Ministry last month announced allocation of 10 billion baht to manage the cassava income guarantee plan for the next season.
"But if the new government next year chooses not to implement the income guarantee plan, ethanol producers can purchase fresh cassava root directly from farmers at a lower price [than the guaranteed price]," said energy permanent secretary Suthep Liumsirijarern.
He said this will result in lower production costs for producers and reduced ethanol prices.
Ethanol made from cassava is now priced at 39 baht a litre, four baht higher than molasses-based ethanol.
Thailand's renewable power development plan stipulates renewable energy capacity must total 13,927 megawatts or 25% of the country's overall generating capacity by 2021, up from 11% at present.
The Energy Ministry is revising its power plan, gearing it towards security since 70% of the country's electricity is generated using gas.
"Sticking with our existing plan will result in a liquefied petroleum gas crisis. The only way out is to lower our reliance on natural gas and use biofuels instead," said Mr Suthep.
Biomass, biogas, ethanol and biodiesel are all biofuels.
Mr Suthep said if there is no further natural gas exploration, it will be depleted within six or seven years.
But if more concessions are granted, Thailand will be able to use natural gas for an additional six or seven years.
But Chen Namchaisiri, a vice-chairman of the Federation of Thai Industries, warned against overreliance on alternative energy, warning that solar and wind power are unreliable and still expensive.