It would increase from 2.6 billion kilowatt-hours this year to 8.6 billion kWh, monopoly distributor Vietnam Electricity (EVN) said in a note Wednesday.
Water levels in hydropower dams in the north and central regions have fallen to their lowest in years, it said. Hydropower production this year would be 13 percent less than the target, it added.
Dwindling supply of gas and coal adds to the challenge, while renewables only account for 2.5 percent of total production though the designed capacity is 9 percent.
Vietnam is facing difficulties in producing enough power to fuel a fast-growing economy.
With power shortages expected from 2021 onwards, the country might need to import 3.6 billion kWh of power from Laos and China, rising to 9 billion kWh in 2023, the Ministry of Industry and Trade had said in July.
The World Bank has estimated that Vietnam needs $150 billion for energy sector development by 2030, with electricity demand growing by 8 percent a year in the next decade.