Electricity usage hit a new daily high of 36,700 megawatts on Monday, when temperatures averaged 35-38°C across the nation, peaking at 42°C, according to energy authorities.
However, they say there is little danger of power interruptions or blackouts as usage is still at around 75% of maximum generating capacity.
Demand surpassed the previous record, set on April 27, at 8.57pm on April 29 when usage hit 36,356MW.
The hot spell has led to nine record highs being set since Feb 22 when demand was 30,989MW, which was a record at the time, according to official figures.
Electricity consumption in Thailand is usually less than 30,000MW outside the summer, they said.
Before the addition of renewable energy resources, particularly solar power, demand usually peaked in the afternoon, but this shifted to the early hours of the night a few years before the arrival of the Covid-19 pandemic, one official said.
The Energy Policy and Planning Office had expected demand would peak above 35,000MW this year due to the effects of the cyclical El Niño weather pattern, which causes oceans to heat up, increasing temperatures and bringing drought to many countries.
Though consumption records are being set seemingly every other day, Thailand’s power reserve margin is still a healthy 25.8% of total capacity of 48,000MW, so households and businesses can rely on sufficient supply, said Weerapat Kiatfuengfoo, director-general of the Energy Policy and Planning Office.
This year’s reserve margin is down from 30.9% during the hot season last year.
Mr Weerapat said energy authorities are closely monitoring fuel resources and power plants across the country to ensure adequate availability of natural gas, domestic and imported coal, oil and imported power from neighbouring countries.
The Electricity Generating Authority of Thailand (Egat) is also closely monitoring power generation and fuel resources to prevent interruptions, even though capacity currently exceeds peak demand by more than 10,000MW, said Jakgree Sirimaneewattana, assistant director for power system control and operations.
Natural gas accounts for 55% of all fuels used for power generation. Egat, PTT Plc and liquefied natural gas shippers traditionally meet every month to discuss gas supply plans.
Imported and domestic coal are also highly reliable because each coal-fired power plant is required to have stocks on hand for 60 days of operation, said Mr Jakgree.