Gouvães is the only one of the three dams in the complex where a pumping system has been installed, the "only technology that allows to efficiently store large amounts of energy."
One of the phases of the “Tâmega’s Giga Battery” project is concluded, a set of three dams and three power plants that constitute one of the largest European hydroelectric projects of the last 25 years. The dams of Daivões and Gouvães are the two infrastructures of the Tâmega Electricity Production System that are inaugurated this Monday, leaving only the Alto Tâmega dam missing, which Iberdrola, the concessionaire in charge of the project, expects to complete by June 2024.
The project has a planned investment of €1.5 billion in the three dams and corresponding hydroelectric plants, which, according to the head, José Maria Otero, remains unchanged at this stage of the project. It will be possible to supply 440,000 homes with the capacity of the production system.
Once construction is complete, the complex will employ 40 people permanently, after around 20,000 were needed to erect the complex, José Maria Otero explained.
Gouvães is the “star” of the project as it is the only one of the three dams where a pumping system has been installed, the “only technology that allows for large amounts of energy to be stored efficiently,” and in this case, “the largest in Portugal,” explained José Maria Otero, who received journalists at the complex on Sunday. The “Tâmega’s Giga Battery” can store up to 40 gigawatt-hours of energy.
In this way, the Tâmega’s project contributes to secure the national electricity system, constituting a reserve for risky situations.
Besides having this safety mechanism, the Gouvães dam has the advantage of not depending on the same river as the others: while the Alto Tâmega and Daivões dams are fed by the waters of the Tâmega, the Gouvães dam rather uses the bed of the Torno river.
This dam, with only 30 metres high, which compares to the 77.5 metres of Daivões and the 106.5 metres, to be built, of the Alto Tâmega dam, has an installed power of 880 megawatts, above the 118 megawatts of Daivões and the 106.5 MW that are projected for Alto Tâmega. The power of Gouvães benefits from the higher position that this structure has, which allows the water to give a higher fall, of 657 metres, which compares to the 87 metres of the Alto Tâmega dam and the 64.5 metres of Daivões.
The future of the complex, for example regarding its use for other activities such as tourism, has yet to be determined. The Portuguese Environment Agency is responsible for drawing up the Reservoir Management Plan, which will provide for the possible alternative uses of these waters.