The country's electricity consumption in the summer months is expected to reach 35,889 megawatts (MW) at peak hours, up 4.6% from the same season last year.
Sarawut Kaewtathip, deputy permanent energy secretary, said the projection of power demand is estimated from Meteorological Department projections of the weather this summer reaching 42-43C.
A change in temperature of 1C will have a corresponding power consumption change of 400MW, according to the ministry.
Last year, peak power demand for the year was on April 24 at 2pm, reaching 34,317MW, up 0.6% from the same period in 2017.
"Demand during the peak will not affect the country's total power generation as reserves of 56,034MW remain 20% higher than the demand projection," Mr Sarawut said.
Many companies have installed power generation systems at their properties over the last three years, such as solar rooftops, biogas and natural gas. Power generation has increased in part thanks to that capacity, he said.
In 2018, firms' power generation reached 8,600MW, 15% of the total power generation and an increase of 300% from the year before.
Mr Sarawut said although natural gas supply from Myanmar's Yadana block imported via gas pipeline is being interrupted until next Wednesday, the ministry has confirmed the country's power grid will not be disturbed.
The Yadana gas block supplies 300 million standard cubic feet per day, representing less than 10% of the total gas supply for power generation.
Wuttikorn Stithit, executive vice-president for natural gas of PTT Plc, said the drop in gas supply will not affect power demand, which is expected to stay at normal levels during Songkran.
If there is an emergency during the interruption, liquefied natural gas at PTT's facility in Map Ta Phut, Rayong could be used for the power generation, said Mr Wuttikorn.
Wattanapong Kurovat, secretary-general of the Energy Policy and Planning Office, said the outlook of 56,034MW for total power generation sees state utilities making up 28%, independent power producers 27% and small power producers 16%. Power generation imported from neighbouring countries and very small power producers comprise 7% each.
Power consumption by sector consists of 40% for industry, 22% business and 20% households.