Gouvães, Alto Tâmega and Daivões dams and hydroelectric power plants.

Tâmega River, Portugal

The Government of Portugal awarded Iberdrola the DBO (Design, Build and Operation) contract for a unique and outstanding project.

What did the project involve?

The project involved three hydraulic utilization systems:

1. Gouvães hydropower system – Dam on the Torno River (a tributary of the Tâmega) and a (mainly underground) channel connecting to the Daivões reservoir.

• It includes a pumping station and a reversible hydropower plant built into the mountain.
• The dam is a concrete gravity type, 30 m high and 232 m long at the crest, with a reservoir surface area of 175 ha.
• The channel has a length of over 7 km, and the hydropower plant has a capacity of 880 MW.

2. Alto Tâmega hydropower system – Dam on the Tâmega River:

• Located just upstream of the Daivões reservoir.
• It includes a non-reversible hydropower plant.
• The dam is a double-curvature concrete arch type, 106 m high and 334 m long at the crest, with a reservoir surface area of 466 ha.
• The hydropower plant has a capacity of 2 × 80 MW.

3. Daivões hydropower system – Dam on the Tâmega River:

• Located with the purpose of creating a reservoir downstream of the Daivões dam.
• It includes a conventional hydropower plant.
• The dam is a concrete gravity-arch type, 77.5 m high and 265 m long at the crest, with a reservoir surface area of 341 ha.
• The hydropower plant has a capacity of 2 × 57 MW.

Additionally, the project included the generators and transformers, high-voltage lines, electrical substations, mechanical equipment, access roads, auxiliary buildings, and other necessary facilities and equipment, with a total budget of €1.074 billion.

Risk assessment by Ineria

A major international insurance group had to carry out a risk assessment of the project related to civil liability, third-party damages, and environmental liability.

To carry out this work, the company hired Ineria Management to perform a Desktop Project Review, with the aim of obtaining useful information to help identify certain project risks.

Ineria provided the client with a team of consultants specialized in infrastructure risk analysis, who completed their mission within the tight timeframe required.