Nationwide peak demand reached 57,977 MW at 1.50 pm on August 13, 5.5 per cent above the 2025 peak. Daily electricity consumption also hit 1.18 billion kWh that day, up 8.1 per cent from the previous week and 6.1 per cent year on year.
Demand rose particularly sharply between 1 pm and 1.30 pm, increasing by about 2,700 MW and requiring additional hydropower, coal-fired and LNG-fired generation.
In northern Vietnam, peak demand reached 29,088 MW on August 12, while daily consumption stood at 604.3 million kWh, up 18.7 per cent and 15.2 per cent respectively from the previous week.
During the heatwave, northern electricity demand peaked between about 9:30 pm and 10.30 pm, when solar power was no longer available, adding pressure on reserve capacity.
NSMO said it adjusted daily operating plans and power generation and grid configurations to keep pace with changing demand.
Backup transformers were temporarily brought online at the start of the heatwave, while maintenance work that could affect supply security was postponed.
Coal-fired plants in the north were operated at maximum available capacity, while small hydropower plants were used flexibly to maintain reserves during periods of tight supply.
NSMO also brought LNG-fired units at Phu My 21 and Nhon Trach 4 online early to boost available capacity. Oil-fired power plants were instructed to maintain adequate fuel stocks and readiness if needed.
The operator said investment in fast-starting generation and battery energy storage systems could improve the grid's ability to respond to sharp increases in peak demand.
Despite the surge in consumption, the national power system operated safely and continuously throughout the heatwave, NSMO said.
Heavy rain is forecast across northern Vietnam and from Thanh Hoa to northern Quang Tri from the night of August 17 through August 21, with widespread totals of 150-300 mm and more than 450 mm in some areas.
NSMO has urged power operators to closely monitor weather conditions and prepare for possible flooding and landslides to maintain safe electricity supplies.