The call brought together Thousands of residents of Colmenar Viejo and Tres Cantos to express their opposition to the biogas plant planned next to the municipal landfill. While the organization estimated the attendance at around 7.000 people, the Civil Guard put it at around 1.700, a dance of numbers common in this type of protests.
At the center of the debate are the proximity to residential and educational areas, the potential odors and increased heavy traffic, as well as the impact on air, water, and soil quality. The neighborhood movement frames this opposition as a broader discussion in Spain on the biogas plant model and its fit in the circular economy.
Chronicle of the protest
The march, promoted by the Colmenar–Tres Cantos (3CV) Stop Biogas Platform, toured the streets of the city center from mid-morning, reading a manifesto and receiving support from local officials from other areas where similar facilities already operate. The attendees chanted slogans critical of the municipal government, the location and volume of the plant, focusing on the smells and the proximity to housing.
Collectives such as neighborhood associations of both municipalities and the Sierra Norte Clean Air Platform participated prominently. According to the organizers, the infrastructure would affect a potential population of more than 110.000 people due to its radius of influence and the traffic of trucks.
What the neighbors demand
The spokespersons claim public technical reports, transparency, holding a referendum, and reviewing the location. They argue that the reference model in Europe prioritizes smaller, local plants, which is why they see the project next to the Colmenar Viejo landfill as oversized.
They also ask for a "fair distribution" of waste management, recalling that the landfill of Colmenar Viejo receives waste from more than 75 municipalities and has chained successive expansions. Its message: the climate transition cannot be achieved at the expense of quality of life from the nearby neighborhoods.
Technical issues and the judicial route
Members of the academic community integrated into citizen platforms maintain that the current waste treatment model It is outdated and concentrates its inconvenience and impacts in a few municipalities. The risks mentioned include operational episodes such as fires or torrential rain events, in addition to emissions associated with transportation and treatment.
In parallel, several associations have taken the matter to court. declaration of public utility of plots linked to the project. The first instance has admitted the procedure, but the court has requested additional information before deciding whether the case continues or is closed, according to sources from the Clean Air Platform.
Opponents also refer to a recent guide by the Representative, prepared with the gas industry association, from which they conclude that the proposed design may not meet several criteria. This reading is under discussion and is part of the technical exchange between platforms and developers.
The position of the development companies
PreZero and Enagas Renovable They assure that the plant will occupy around 6.200m², an area smaller than the municipal football field, and will incorporate biofilters and activated carbon capable of eliminating up to 99% of odors. To this they add a double lock and vacuum system in the unloading bay to prevent leaks to the outside.
The companies emphasize that they will not employ slurry throughout the useful life, even if the regulations allow it in the future, and which will deal exclusively organic fraction of urban and industrial origin, with priority given to waste from Colmenar Viejo and its surrounding area. According to its data, the plant will process around 75.000 annual tons and biomethane will be injected into the gas network, with an energy equivalent to the consumption of almost 30.000 people.
After removing the composting ship, the design has been compacted and a treatment is proposed using pasteurization, which, according to the promoters, would facilitate its integration into the environment and reduce inconvenience compared to more extensive alternatives.
Next steps and context in Spain and Europe
The neighborhood platform plans to maintain mobilizations and information actions, while the administrative and judicial process continues. The Local government of Tres Cantos has requested a review of the location, and the one from Colmenar Viejo maintains that the file would comply with the regulations, with strict supervision.
On a broader level, in recent years there has been an increase in Spain reluctance to macroplants biogas, while in several European countries they are investing in biogas installations smaller scale linked to local waste. Local entities ask the Ministry for Ecological Transition for more information and guarantees so that climate goals do not compromise the well-being of nearby neighborhoods.
The pulse in Colmenar Viejo concentrates two visions: those who fear the impact of a plant they consider large and close, and those of companies that maintain that the project is compact, technologically controlled, and aligned with the circular economy. Pending technical definitions and the judicial process, neighborhood participation and institutional transparency will mark the following movements.
