The Alqueva Dam is an arch dam and the center-piece of the Alqueva Mutlipurpose Project. It impounds the River Guadiana, on the border of Beja and Évora Districts in south of Portugal. The dam takes its name from the town of Alqueva to its right bank. It creates a large reservoir with an inter-annual regulation capacity from which water may be distributed throughout the region. The dam was completed in 2002 and its reservoir was full in 2012. The 520 MW power station was commissioned in two stages, stage I in 2004 and stage II in 2013. The Alqueva Dam constitutes one of the largest dams and artificial lakes (250 km²) in Western Europe.

In 2004, the first stage of the hydroelectric power station was commissioned, with a capacity of 260 megawatts. The second stage, with an additional 260 MW, was commissioned in 2013. The power station contains four 129.6 MW reversible Francis turbines. With these turbines, the power station is afforded a pumped-storage capability. Power is generated during high demand periods and at times of low demand, the turbines reverse and pump water from a much smaller reservoir below the dam back into the main reservoir. Pedrogao Dam forms the lower reservoir.

Open-loop Pumped Hydro Storage