The fines are state measures aimed at reducing electricity prices, according to a source at the Energy Ministry who requested anonymity, reports the Bangkok Post.
PTT announced late last year that it charged a gas supplier B4.3bn for failing to deliver a certain amount of gas as required by contract, known as a shortfall of gas, to the company. PTT was required to hand over the money to authorities to help them reduce the power tariff, which is used to calculate power bills.
The government has the authority to decide how to allocate the fines, as PTT is state-owned.
The ERC was instructed by Energy Minister Pirapan Salirathavibhaga to inspect whether there were more fines for gas shortfalls as part of efforts to ease electricity bills.
The regulator found shortfalls worth B4.7bn between 2013 and 2020, said the source. A panel working on the shortfalls is scheduled to meet on Monday to discuss payment details.
Mr Pirapan wants PTT to give the B4.7bn to the government to help reduce electricity prices, the source said.
According to the ERC, B4.7bn could reduce the power tariff by B0.078 per kilowatt-hour (unit).
If PTT disagrees with the report on shortfalls or the amount of fines, it can appeal the findings.
PTT sent the B4.3bn in fines to the government in January, helping it control power prices from January to April when the power tariff was B4.18 a unit.
The ERC maintained the power tariff at the same rate for May to August and will determine the rate for the last four months of this year at a later date.
PTT and the regulator are jointly studying a plan to import more liquefied natural gas (LNG), a key fuel for power generation, under long-term contracts to avoid price fluctuations in the spot market. LNG prices in the spot market recently fell by US$0.2 per million British thermal units (BTU) to $9.6 per million BTU.
Prices are declining, following the shutdown of gas-fired power plants in Taiwan during an earthquake and high LNG reserves in Asia and Europe, said Veerapat Kiatfuengfoo, director-general of the Energy Policy and Planning Office.