In Spain, the hydraulic energy Hydroelectric power has been a key element in the country's industrial and social development for over a century. Harnessing the power of water in complex terrain like the Pyrenees has provided access to manageable, renewable electricity. Today, although other sources such as wind and solar have gained ground, hydroelectric plants continue to play a key role. essential role as strategic support in the transition towards a decarbonized energy system.
A good part of the historical success of hydraulics lies in pioneering installations such as the Seira power plant in the Aragonese Pyrenees. Founded over 100 years ago, it was the result of a great technical and human feat: more than 2.000 workers were needed to install its galleries, dams, and turbines, bringing components from several countries. The result was a true industrial cathedral, which even today keeps several of its original turbines in operation and continues to supply electricity to thousands of homes. The plant combines heritage value and innovation, having been modernized in the 37s and adding an installed capacity of 20.000 MW, with an annual production that can supply XNUMX homes.
In the same region, examples such as Eriste power plant reveal the potential of today's hydroelectric plants: water, accumulated in high mountain reservoirs, descends through tunnels to turbines capable of powering an entire medium-sized city. Thanks to the automation and remote monitoring from specialized control centers, these facilities can now be started and regulated in minutes, facilitating a rapid response to grid demands and ensuring supply stability even in critical situations.
Hydraulic power allows to operate both with conventional power plants —which turbine the stored water— as with reversible or pumped storage plantsThe latter have gained prominence in new energy plans, as their function as "natural batteries" makes it possible to store surplus renewable electricity (for example, photovoltaic energy when there is overproduction at midday) and release it when demand requires it. This process is achieved by pumping water to a higher reservoir and then turbiding it in reverse.
Currently, Spain has more than 6 GW of pumped storage power plants., and there are dozens of projects in the pipeline to increase this capacity in the coming years, especially in the Ebro and Miño-Sil basins. The goal is to strengthen storage capacity and reduce dependence on fossil fuels and external energy imports.
Hydraulics are not only relevant for the volume of energy generated, but also for the management capacity that contributes to the electrical system. Unlike other climate-dependent renewables, hydroelectric plants can adjust their production according to demand, helping to maintain the stability and security of the network. Furthermore, these plants help regulate river flows, facilitate irrigation and water supply, and minimize environmental impact thanks to the fact that much of their infrastructure—such as pipelines and power plants—is built underground.
Another fundamental aspect is the technological modernization infrastructure. From turbine replacement and complete automation of operations to the incorporation of advanced monitoring systems—including drones and predictive software—technology has improved the efficiency, safety, and oversight of dams and equipment. Constant monitoring allows for the detection of anomalies and optimization of maintenance, prolonging the lifespan of facilities and preventing more serious incidents.
The role of hydroelectric power plants was particularly highlighted during the major power blackout that affected Spain and Portugal. Thanks to these plants' self-starting ('black start') system, power was quickly restored in many areas, demonstrating their effectiveness. strategic importance in emergencies. The very process of power recovery after a blackout requires systems capable of functioning without external support, and hydroelectric plants fulfill this role reliably, facilitating the gradual reconnection of the national electricity grid.
The large electricity companies Spanish companies, such as Endesa and Iberdrola, are reinforcing their commitment to traditional hydraulics and the development of new pumping systems, aware of the need for flexible storage and the feasibility of converting the peninsula into a "large hydraulic battery." These investments are accompanied by environmental impact studies that seek to minimize the visual and ecological impact, thanks to the underground design of many facilities and the reuse of existing reservoirs.
The role of hydroelectric power plants remains central to Spain's current energy situation, and their contribution is expected to be even more significant in the future. Capable of responding quickly and efficiently to demand, facilitating the integration of other renewables, and providing security and autonomy to the system, hydroelectric power—in its classic and reversible versions—has proven to be an irreplaceable resource in the Spanish energy mix and a guarantee for the energy transition and resilience in the face of crisis situations.