The cost of electricity will rise about 14% to a minimum 5.37 baht per unit between January and April next year on rising fuel costs, the Electricity Regulatory Commission (ERC) warned on Monday.
Secretary-general Khomgrich Tantravanich said the ERC had three options - and the increment to 5.37 baht would cost consumers the least.
The two other choices were 5.70 baht and 6.03 baht per kilowatt-hour (unit).
The Electricity Generating Authority of Thailand is subsidising the power charge. At the 5.37-baht rate, Egat would have 122.25 billion baht in losses by the end of April.
The 5.70 baht and 6.03 baht rates would leave Egat with a deficit of 101.88 billion baht and 81.50 billion baht respectively.
Without a fee rise next year, the state enterprise would face a deficit of 170 billion baht, Mr Khomgrich said.
The present rate is 4.72 baht per unit, already an all-time high. The smallest increment, to 5.37 baht, would be a rise of 13.77%.
The ERC based the new electricity fee mainly on the cost of natural gas, imported coal and diesel.
It expected the price of natural gas to rise by 17% to 564 baht per million British thermal units (BTU) from the current 482 baht per million BTUs. Natural gas is used for about 60% of electricity generation in Thailand.
The ERC also predicted the price of imported coal, used for 6.5% of power generation, to soar 27% to 5,165 baht per tonne, and diesel, accounting for 6.3% of generation, to increase 14% to 31.94 baht per litre.
The ERC will accept public opinion on the planned electricity fee via its website until Dec 1.
