In the bowels of the Bierzo region of León, where coal was the absolute king for decades, the silence of the abandoned and flooded galleries is about to be broken. But this time there will be no pickaxes, no minecarts, no black ore. The new gold of the mining basin is water, and those in charge of extracting its potential come from the Alps. The Swiss energy company Alpiq has set its eyes on this ruined industrial legacy to transform it into a colossal natural “battery” that promises to be the energy engine of the future in Spain. A million-dollar purchase in El Bierzo. The news that has shaken the local and international energy panorama is the acquisition of the “CDR Navaleo” macroproject by the Swiss multinational Alpiq, as detailed in their press release. However, as local media describethis pumped hydroelectric energy storage project had initially been developed by Erbiergía, a company promoted and controlled by the well-known mining businessman Manuel Lamelas Viloria. Despite the sale, the Bercian promoter will maintain a stake in the company to continue collaborating and supporting its development on the ground. The project figures are colossal. Although two years ago the project has already obtained a powerful grant Of 35.5 million euros from the Ministry for the Ecological Transition (Miteco), the total investment necessary to build this megastructure is much greater. Now, as advanced in ElDiario.esthe estimated budget exceeds 300 million euros, but other sources raise the investment figure above 400 million, placing it in a range of between 420 and 450 million euros. And why Spain? To understand the magnitude of Navaleo, you have to look at the sky. Spain has very ambitious goals of penetration of renewable energies, such as solar and wind, but these sources are intermittent: it is not always sunny or the wind blows when we turn on the switch at home. Therefore, the electrical system urgently needs “storage and flexibility to guarantee the stability of the network,” explained by the Swiss company. That is where this plant comes in, which will contribute 535 megawatts (MW) of flexible capacity to the Spanish grid, according to local media. To get an idea of its size, the current third vice president, Sara Aagesen, noted during a visit to the area that “all residential buildings in the province of León could be supplied with the annual production of this CDR from Navaleo”, as they have collected in The Economist. The impact transcends Spanish borders. To understand the phenomenon, the importance of infrastructure must be configured. The European Commission has included Navaleo on its list of Projects of Common Interest (PCI)highlighting its strategic value for the energy security of the entire continent, which also opens the door to better financing through the European Investment Bank. For the Swiss company, which has been operating in the Spanish market for 25 years, this is a major milestone: This is its first large-scale hydroelectric project outside of Switzerland. The engineering behind the “battery”. The technical mechanism is as fascinating as it is colossal. The facility will operate through a closed-circuit pumped hydroelectric energy storage system. In practice, it consists of taking advantage of groundwater from old mining operations, as explained in the local media. The system will pump water from the Tremor River area to a higher elevation, where it will be stored in a pond. When the country needs electricity, that water will be released through a large pipe so that it passes through a turbine and generates energy. This closed-loop design will provide the electrical grid with at least eight hours of uninterrupted energy storage, literally acting as an immense rechargeable water battery. But an abandoned mine? Used old coal mine poses obvious doubts about toxicity. Currently, abandoned mines are flooded and their waters contain minerals and contaminants. Far from being a problem, this is one of the greatest added values of the project. The plant is called “CDR” precisely because it is a Reversible Treatment Plant. “Through our asset we are going to offer flexibility and storage, but we are also going to offer an environmental benefit. We are going to drain the contaminated water from the mines and purify it,” explains Amédée Murisier, director of Alpiq in statements to The Economist. In this way, an environmental liability and degraded land is transformed into a clean energy asset. Furthermore, viability is assured: the company already has a water concession granted for a period of 75 years, which guarantees long-term operational continuity. Forecasts and deadlines. The macroproject will extend through the Bercian municipalities of Torre del Bierzo, Castropodame, Congosto and Molinaseca, areas hard hit by the closure of mining. As for the deadlines, there are certain nuances. While the Viloria Group I hoped to start construction this year, the new Swiss owners apply their well-known precision and caution. Amédée Murisier warns that there is still a year and a half of work ahead to refine the geological studies and detailed engineering before making the final investment decision. What is certain, and what all actors agree on, is that the plant will enter commercial operation in the early 2030s. Where before Leonese miners went down into the bowels of the earth to extract coal with their pickaxes, in a few years thousands of liters of purified water will flow, pushed by Swiss technology. The Navaleo project is not only a work of pharaonic engineering; It is the perfect metaphor for the energy transition. A textbook circular economy that demonstrates how the old industrial ghosts of Bierzo can be reconverted, given a facelift and end up being the master key to ensuring the green and electric future of Spain. Image | freepik Xataka | Far from Grazalema and the reservoirs, Andalusia has another serious problem: completely collapsed mining ponds
