Vietnam Hydropower Could Lose 18.5 Billion kWh in 2026

Estimated reading time: 6 minutes · Last updated: 9 November 2026

Vietnam's hydropower plants could generate about 18.5 billion kWh less electricity in 2026 than in 2025, based on figures from NSMO, the operator of the national electricity system and market. El Nino is the main driver. Since the second half of October 2026, water flowing into hydropower reservoirs has reached only about 80% of the multi-year average. Valued at the current average retail electricity price, the shortfall is worth nearly 40,000 billion VND, or about 1.6 billion USD. The drop comes after ten months in which the Middle East crisis and the conflict in Ukraine broke supply chains and pushed up primary energy prices. Dr. Nguyen Huy Hoach argues that preparation for the 2027 dry season should begin now, using several risk scenarios.

Why El Nino Is Squeezing Vietnam's Hydropower in 2026

The National Electricity System and Electricity Market Operation Co., Ltd. (NSMO) says the weather turned against the power system late in the year. Starting in the second half of October 2026, El Nino reduced the water reaching hydropower reservoirs to roughly 80% of the multi-year average. A reservoir that fills with a fifth less water than usual has a fifth less fuel to burn through the dry months that follow.

The forecast built on that inflow data puts 2026 hydropower production about 18.5 billion kWh below 2025. That is a full-year comparison. The weakness in inflows only began in late October, so much of the pressure falls on stored water that must now stretch into the next dry season.

The hydrological problem did not arrive alone. NSMO notes that for the past ten months, Vietnam's electricity supply has absorbed several shocks at once. The crisis in the Middle East and the conflict in Ukraine disrupted supply chains and drove up primary energy prices, and Vietnam felt both effects. When cheap water runs short, the usual substitute is thermal generation, which depends on exactly the fuels those shocks made dearer.

What the 40,000 Billion VND Figure Really Measures

The headline value of nearly 40,000 billion VND, or about 1.6 billion USD, comes from a simple multiplication. The lost 18.5 billion kWh is priced at the current average retail electricity tariff. Dividing the value by the volume implies an average retail price of roughly 2,160 VND per kWh.

That makes the figure a yardstick of scale rather than a bill anyone will receive. A retail tariff is what consumers pay at the end of the chain. It is not the cost of the water that failed to arrive, and it is not the cost of the power that will replace it.

The more useful question is what fills the gap. If coal, gas or oil-fired plants step in, the real expense depends on fuel prices and delivery schedules over the coming months. That links the valuation directly to the geopolitical pressures NSMO describes. The 40,000 billion VND estimate tells readers the shortfall is large; it does not settle who pays or how much.

Hoach's Four Scenarios for the 2027 Dry Season

Dr. Nguyen Huy Hoach, of the Scientific Council of Vietnam Energy Magazine, says supply for the 2027 dry season should be prepared in advance across several operating scenarios, each matched to a different level of risk. The basic case starts from the newest forecasts for climate, hydrology, load and fuel. From those, planners would fix how much water can be drawn, what capacity each type of plant can offer and where the transmission grid hits its limits.

That baseline then feeds weekly, monthly and seasonal operating plans. Hoach also wants monitoring indicators that flag early when real conditions drift away from the forecast.

The hydrological scenario assumes things get worse: inflows below expectations, a rainy season that ends early, or rising demand for water downstream. In that case Hoach says reservoir regulation, thermal dispatch, flexible generation and load management should be revised together. The fuel scenario tests high prices, late deliveries and supply that falls short of plan. Its recovery plan should name replacement fuels, set inventory levels, rank which plants run first and define when schedules change.

Why Hoach Says a Stress Test Is Not a Shortage Forecast

The hardest case is the double-risk scenario, where poor hydrology and fuel supply trouble strike together. Hoach says this case is meant to measure the resilience of the whole power system rather than any single plant.

He is explicit that modelling such a case does not mean a power shortage is bound to happen. In his framing, the exercise is a test that exposes weak points early enough to prepare a response. That distinction matters: a dire scenario on a planning desk is not a prediction, and readers should not treat it as one.

Hoach puts heavy weight on coordination. The system dispatcher, EVN, generation and transmission companies and state management agencies need to work from one shared database covering load forecasts, hydrology, fuel availability and grid condition. Scenarios should also be reviewed on a regular schedule, he says, whenever new climate bulletins arrive, fuel markets move, or new plants and grid projects run ahead of or behind plan.

Can Vietnam's grid absorb the hydropower shortfall?

The bottom line

The 18.5 billion kWh hydropower shortfall is a water problem that quickly becomes a fuel problem. With reservoir inflows near 80% of the multi-year average since late October 2026, Vietnam must lean harder on other sources at a time when NSMO says primary energy prices have already been pushed up by the Middle East crisis and the conflict in Ukraine. The nearly 40,000 billion VND valuation shows the scale, but the true cost will depend on what fuel replaces the lost water and at what price. Hoach's scenario plan is a reasonable response. Its value will show only if EVN, the dispatcher and state agencies actually share data and revise plans as forecasts change.

What to watch

• Watch how reservoir inflows hold up through the rest of 2026 against the roughly 80% of multi-year average NSMO has recorded since late October.
• Watch whether EVN and the system dispatcher adopt scenario-based operating plans before the 2027 dry season begins; no start date has been set.
• Watch for new climate forecast bulletins, which Hoach says should trigger a review of the operating scenarios; no publication date has been given.