Construction of the first utility-scale pumped storage project in Vietnam Bac Ai Pumped Storage Hydropower Plant is progressing into its peak construction phase in 2026, with underground works and powerhouse development now underway. Following the commencement of Phase 2 in early 2025, the project has since gained momentum, with tunnelling, access infrastructure, and auxiliary systems largely completed and excavation works advancing ahead of schedule. Notably, the main underground powerhouse construction began in January 2026, marking an important milestone as the project transitions from preparatory works into core civil construction.

Backed by new financing agreements including a €76 million credit facility signed in late 2025, the 1,200 MW scheme is expected to play an important role in Vietnam’s grid stabilization strategy. It is also expected to support large-scale renewable energy integration under the national power development framework as the country continues to plan for more clean energy deployment such as the 500 MW offshore wind project being advanced by Pacifico Energy.

Bac Ai Pumped Storage Hydropower Plant Development Status: 2026 Update

Phase 2 construction: Started February 2025

Main powerhouse excavation: Began January 2026

Tunnel works: 3.1 km completed out of 17 km total

Construction pace: Exceeding initial excavation targets

Current phase: Peak construction, covering underground works and core infrastructure

Key Milestones Ahead

First unit commissioning: December 2029

Final unit commissioning: December 2030

Full project completion: May-June 2031

Project Fact Sheet for Bac Ai Pumped Storage Hydropower Plant

Location: Bac Ai District in Ninh Thuan Province, Vietnam

Capacity: 1,200 MW

Technology: Pumped storage hydropower

Developer: Vietnam Electricity (EVN)

Total Investment: VND 21.1 trillion ( Over $800 million)

Construction Period: 2025 – 2031

Current Stage (2026): Main construction underway. Underground works also are underway

First Power: December 2029

Completion: Mid-2031

Function: Grid stabilization, energy storage

Project Scope

The project is a large-scale underground pumped storage facility with the following features:

Installed Capacity: 1,200 MW from four, 300 MW units

Technology: Pumped-storage hydropower (Francis-type pump-turbines)

Reservoir System:

• Lower reservoir: existing Tan My irrigation reservoir
• Upper reservoir: newly constructed with no natural inflow

Infrastructure: Underground powerhouse, tunnels, water conveyance systems

Transmission: 500 kV double-circuit connection to the national grid

Project Cost

Total Investment: VND 21.1 trillion

Funding Sources:

• EVN equity
• International loans
• Multilateral financing

Recent Financing Update

€76 million credit facility signed with the Agence Française de Développement (AFD) in December 2025.

The project is also supported by a pool of international lenders and development finance institutions.

Project Team

Developer: Vietnam Electricity (EVN)

Project Management: EVN Power Project Management Board No. 3 (EVNPMB3)

Engineering and Consulting: Power Engineering Consulting Joint Stock Company 4

Contractors: Vinaconex

Financiers: Agence Française de Développement

Government Stakeholders:

• Vietnam Ministry of Industry and Trade
• Government of Vietnam for PDP8 oversight

1.2 GW Bac Ai Pumped Storage Hydropower Plant Project Awards Construction Contract to Consortium

Reported February 15, 2025 – Vietnam Electricity (EVN) together with a consortium of contractors have been awarded contracts for the construction of the 1.2 GW Bac Ai Pumped Storage Hydropower Plant Project. The project, worth US$826 million is expected to begin construction later this year. It is located in Bac Ai district, Ninh Thuan province and has four turbine generators. The consortium of contractors awarded include Song Da Corporation, Lung Lo Construction Corporation, LILAMA 10 JSC, SCI E&C JSC and Construction JSC 47. Additionally, Truong Son Construction Corporation, and Vietnam Construction and Import – Export Joint Stock Corporation also featured in the award.

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Bac Ai Pumped Storage Hydropower Plant completion date

If construction goes as scheduled, operations will begin in December 2029. The full project will be competed in May 2031. This is because the project will be completed in units. The first unit will begin operation in December 2029 and the second in April 2030. The third unit will go on in August 2030, and the fourth in December 2030.  Additionally, each of the generators will have a capacity of 300 MW. The prime minister of Vietnam also approved the Bac Ai Pumped Storage Hydropower Plant Project in Ninh Thuan Province in the National Power Development Plan for 2021 – 2030, with a vision to 2050.

Project Overview

Location: Bac Ai district, Ninh Thuan province

Capacity: 1.2 GW

Number of turbines: 4

Developer: Vietnam Electricity

Completion date: May 2031

Details on the Project

Details on the other construction processes include constructing and installing of main project equipment. This includes the pressure tunnel, upstream pressure tower, underground factory and 500 kV distribution station. Moreover, downstream valve tower, the discharge tunnel, downstream pressure tower. Underground construction tunnels and alleys and roads serving construction and operation will also be built.  Furthermore, a 22 kV construction power supply system will also be required to be constructed. Other works include the construction and domestic water supply system, auxiliary works and construction camps.

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