The deployment of biogas and biomethane plants has become one of the most controversial issues in Spain's energy transition. On paper, these facilities allow for the transformation of organic waste into renewable gas and fertilizers, but on the ground they are generating a wave of neighborhood protests, municipal vetoes, and intense technical and environmental debate.
While the European Union and the central government are promoting biogas as a key element in reducing emissions and dependence on fossil fuels, doubts are accumulating in many towns and cities about odors, pollution risks, truck traffic and, ultimately, about the rural development model that is desired for the coming decades.
What are biogas plants and why are they multiplying?
Biogas plants are based on large, closed digesters where organic waste from agriculture, livestock farming, the food industry, wastewater treatment plants, or municipal solid waste is decomposed anaerobically. This process yields biogas (a mixture of methane and CO₂ that can generate heat or electricity) and a solid or semi-liquid byproduct, digestate , which can be used as fertilizer if managed properly.
Biogas can be used to produce biomethane , a purified, high-purity gas that is injected into natural gas networks. In Europe, more than 19.000 biogas plants and around 1.700 biomethane plants are already operating , integrated into energy systems that, according to the industry, have demonstrated their technical and economic viability.
Until recently, Spain has been a minor player in this field, but that is changing rapidly. The government's Biogas Roadmap aims to almost quadruple production by 2030, and the gas industry association highlights that the country has one of the greatest biomethane potentials in the EU. There are already 24 operational plants, and hundreds of projects are under development, with estimated investments of several billion euros.
In parallel with the European ( REPowerEU plan) and Spanish regulatory push , communities such as Valencia and Catalonia have designed their own roadmaps to use biogas in the energy recovery of waste , with the aim of reducing the enormous amount of garbage that ends up in landfills and complying with the limits set by Brussels.
The clash between environmental potential and social alarm
On paper, biogas plants fit into the circular economy narrative : they transform waste that currently generates uncontrolled emissions into usable energy and fertilizers. However, in Spain, a strong social movement against their deployment is consolidating, which is not limited to poorly designed projects but often questions the technology as a whole.
One example is the growing opposition in Castile and León . In the province of Burgos, the Stop Biometano Villangómez platform has organized protests and collected thousands of signatures against a biogas plant planned about 2,5 kilometers from several villages, denouncing that rural areas are being filled with facilities that, in their view, threaten their quality of life and their territorial model.
In Segovia , the municipality of Cuéllar is processing up to four applications for new biogas plants that would use livestock and fruit and vegetable waste. Concerns about their proximity to the town center have prompted political groups like United Left to promote objections, informational meetings, and the possible creation of a neighborhood platform . Their criticisms focus on potential odors, traffic, noise, and the devaluation of homes.
Protests have also increased in Castilla-La Mancha . The 'No to Biogas in La Sagra' platform has been organizing demonstrations for months against a biomethane plant in Villaluenga de la Sagra . They fear digestate leaks into the soil, streams, and wells, especially after periods of heavy rain, and warn of a potential "environmental disaster" for which they hold the regional government, the town council, and the Hydrographic Confederation responsible.
In the regional political sphere, the Minister of Economy, Business and Employment of Castilla-La Mancha herself has stated that, when there is a clear rejection at the municipal level , the regional government will not promote these projects, although she points out that there is also an obligation to comply with international decarbonization goals.
Municipal rejection and administrative obstacles
The opposition to biogas isn't coming solely from neighborhood or environmental groups. Several city councils are using the urban planning and public interest tools at their disposal to halt the construction of new plants within their jurisdictions, citing issues of territorial suitability or environmental concerns.
In Mengíbar (Jaén), the town council has issued an unfavorable report on the building permit application for a biomethane plant promoted by the company Naturmet. After reviewing the documentation, the local government has announced that it will use all administrative and legal means to prevent this project, as well as two other biogas or biomethane projects planned for the municipality, insisting that its priority is to protect the public interest and guarantee maximum transparency with citizens.
The city of Jaén is also taking a stand. The Jaén City Council is considering declaring a lack of public or social interest in order to halt a planned biogas plant on the Fuerte del Rey road. The Councilor for Urban Planning, África Colomo, maintains that it is a private, for-profit business initiative focused on the economic valorization of waste, without a clear and positive impact on the city as a whole.
According to this argument, the lack of a specific and protective regional regulatory framework prevents the city council from requiring detailed studies on the actual impacts on the environment and the population, which, in its view, clashes with the territorial, urban, and environmental model it intends to implement in Jaén. The Urban Planning Department plans to formalize this position in a resolution.
In San Javier (Murcia), the mayor has announced he will sign a resolution opposing the declaration of public interest for a biogas plant in the village of El Mirador. He argues that the project is not territorially, environmentally, or economically compatible with the municipality, emphasizing that there are no pig farms in the area to justify the installation and that the management of pig slurry has been met with resistance from the outset.
The Murcia councilor also points to the lack of information and transparency towards the residents and considers the initiative closed in that location, although he distinguishes between his opposition to this specific case and his general support for biogas and biomethane as technologies of the future, as long as they are not imposed on local communities.
The vision of the experts and the environmental movement
Amid the controversy, environmental organizations are displaying nuanced positions. Ecologistas en Acción (Ecologists in Action) recently published a guide for evaluating biogas projects, calling for an individual analysis of each case . Their representative, Marina Gros, insists that the problem is not the technology itself, but rather “poorly designed projects,” and admits that within the organization there are disagreements and internal debates about the role these plants should play.
The Ecologists in Action guide highlights some key criteria. Firstly, that the facilities be located near the waste generation points to reduce transport and its impacts, preferably in a local area with a stable and affordable supply of raw materials. Secondly, that the resulting digestate be used as fertilizer and not become a new problem, so that a true circular economy can be achieved.
The organization also warns of projects competing for the same waste in the same region, or of large plants located next to gas pipelines rather than near waste sources. Regarding input materials, it favors the use of sewage sludge and biodegradable fractions currently destined for landfills, and is critical of the use of cover crops or large volumes of slurry and other livestock waste.
Marina Gros points out that industrial livestock farming is not sustainable in the long term from a climate, environmental, or dietary perspective, and warns that an energy system cannot be designed that depends on the continuous generation of such waste, because that would mean consolidating a livestock model that many consider unsustainable. In her view, it is essential to reduce overall waste production, not just to find new uses for it.
In contrast, some environmental engineering experts see the widespread rejection of biogas plants as a difficult-to-understand contradiction . Professor Emeritus Xavier Flotats, with decades of experience in the sector, argues that it is preferable to channel livestock and urban waste into biogas plants, rather than allowing it to freely emit methane in landfills or ponds . In his view, the digestate produced by the plants, while retaining much of its original weight, has a more mineralized composition and can be managed more safely.
Plant design: odors, digestate and emissions
One of the main concerns of the public is the bad smells and possible leaks or seepage from these facilities. Flotats and other specialists agree that, if the plant is well designed and built , anaerobic fermentation in closed digesters should not generate significant odor problems.
The critical point, they emphasize, is the waste reception and handling area . Opening concrete pits in the open air to unload organic waste is, according to these experts, a recipe for social conflict. Instead, they recommend closed-loop systems : direct pipe connections to sealed tanks for liquid waste, or unloading of solids into enclosed buildings with air treatment using specific filters.
Digestate management is another key aspect. Upon leaving the digester, this material can continue to emit residual methane if left in uncovered ponds. Therefore, in much of Europe, the practice of covering digestate storage facilities and recovering this remaining gas is becoming widespread. This slightly increases production while simultaneously reducing odors and fugitive emissions.
Regarding the potential risks of soil or water contamination , proponents of these technologies point out that the plants must comply with stringent waterproofing and monitoring regulations, similar to those applied to other energy infrastructure. Even so, complaints from neighborhood associations about alleged leaks following periods of heavy rainfall reflect a persistent lack of trust and oversight at the societal level.
This clash is also evident in the debate surrounding slurry and livestock waste . For Flotats, it is contradictory to oppose processing in digesters a waste stream that already causes emissions and management problems on farms. From a more critical environmental perspective, the focus should be on the food and livestock system as a whole, rather than on the specific biogas technology.
Andalusia and olive groves: biomethane, emissions limits and rural employment
In Andalusia, the debate on biogas is intertwined with the future of olive groves and the olive oil industry . In olive-growing areas of Córdoba and other provinces, movements have emerged opposing new plants, concerned about their environmental and landscape impact. However, business projects have also appeared that argue the exact opposite: that biomethane is essential for the sector's viability within the new European regulatory framework.
One of the most ambitious plans comes from the alliance between Oleícola El Tejar, Greenar, and Vorn Bioenergy , which aims to build a network of eight biomethane plants linked to existing olive pomace processing facilities in the region. The planned investment is around €350 million and is envisioned with a long operational horizon, tied to the emissions limits that the EU will impose on industrial facilities starting in 2030.
According to its proponents, the current model for managing olive pomace (the byproduct remaining after olive oil extraction) relies on drying and burning it, which emits large quantities of pollutants. They explain that with the upcoming regulations, many facilities would face severe restrictions that could force them to drastically reduce their activity if they do not adopt new treatment technologies.
In this context, biogas emerges as a solution that combines emissions reduction with economic viability . By transforming olive pomace and other waste products like chicken manure into biomethane and fertilizers, the aim is to give a second life to materials that are currently a management problem, while simultaneously generating renewable energy and strengthening the profitability of traditional olive groves , especially small farms already struggling with rising costs and pressure on olive oil prices.
The promoters also emphasize the potential impact on rural employment and population retention . Each biomethane plant of this type could create between ten and twelve direct jobs, plus around twenty indirect jobs related to logistics and maintenance, with investments of between 30 and 40 million euros per facility. They assert that the aim is not to establish industries foreign to the region, but rather to strengthen existing value chains surrounding olive groves.
Lleida, bio-industrial parks and the race for biomethane
In Catalonia , the province of Lleida is establishing itself as a key player in the race for biomethane in Spain. Energy companies and local institutions see its strong agricultural and livestock sector as fertile ground for developing projects that integrate the production of renewable gas, biofertilizers, and other bioproducts.
The company Moeve, for example, has incorporated Lleida into its Positive Motion 2030 strategy , which envisions a €600 million investment to deploy up to 30 biomethane plants in Spain with a target portfolio of 4 TWh, equivalent to the annual consumption of more than one million households. The company has joined the public-private collaboration ecosystem 'Lleida Alimenta', which brings together agri-food entities, research centers, and innovation projects in the circular bioeconomy.
In parallel, the idea of a bio-industrial park is being promoted : an industrial area where different companies would share infrastructure to convert organic agricultural, livestock, forestry, or food waste into biogas, biomethane, biofertilizers, and bioproducts . For such a hub to function, a network is needed between raw material producers, energy converters, R&D centers, and innovative companies committed to circular solutions.
Other energy groups already operate in the area. Naturgy has two of its six biomethane plants in the province, one in Torrefarrera and the other in Vila-sana, where 140.000 tons of agricultural and livestock waste are processed annually to produce approximately 60 GWh of renewable gas. In addition, there are projects promoted by international funds, such as the La Sentiu de Sió plant, which has received authorization from the Generalitat (Catalan government) and anticipates an investment of up to 90 million euros, with an estimated annual production of 227 GWh and several dozen direct jobs.
The vision of local and provincial administrations is that the development of the circular bioeconomy can improve the sustainability of primary production, increase the added value of the agri-food industry and generate skilled jobs in rural areas, preventing waste from being seen only as a cost and turning it into a strategic resource.
At the national level, data from industry associations indicate the existence of approximately 685 biomethane plant projects spread across the country, which would mobilize nearly €12.000 billion if they were to materialize. The shared objective of companies and some government bodies is for Spain to fully participate in what is being defined as a biomethane revolution on a European scale.
Divided communities, participation and access to information
The deployment of biogas is forcing a rethink of how citizen participation is managed in projects with a strong technological and territorial component. In many cases, the tensions revolve not only around the plant itself, but also around the feeling that decisions are being made behind the backs of local residents , without clear processes for information and debate.
Platforms like Stop Biometano Villangómez and 'No to Biogas in La Sagra' insist that their villages “are not sacrifice ground” and demand that their proposals for the local economic and energy model be respected. Their statements criticize both the companies promoting the projects and the regional and national governments, which they accuse of prioritizing corporate interests over the demands of rural communities.
In Cuéllar, the United Left party has denounced the Castile and León regional government for hindering the submission of objections against biogas plants by requiring citizens to formally prove their status as "interested parties." The party points out that the Transparency and Administrative Procedure laws recognize the public's right to participate in environmental processes and maintain that being a resident of an area where potential odors, pollution, or increased heavy traffic are anticipated is sufficient grounds for intervening in the proceedings.
These dynamics have led to the creation of new neighborhood platforms in various regions, which seek to coordinate efforts, share legal and technical information, and gain influence with local councils and regional governments. They are often inspired by previous movements that have already halted similar projects in other municipalities, generating a kind of "contagion effect" in the opposition to biogas.
From the institutional perspective, regional officials such as the Director General of Education and Environmental Quality for the Valencian Government point out that much of the resistance stems from widespread misinformation , sometimes fueled by conflicting interests. They maintain that the plants that successfully complete the permitting process have comprehensive reports on environmental impact, emergency response, waste management, and water resources, and that when problems arise, they are usually due to specific mismanagement , not structural flaws in the technology.
In this context, the idea is gaining ground that the key lies not only in approving or rejecting projects, but in strengthening transparency , improving public consultation mechanisms, and raising minimum technical standards to ensure that the plants built respond to both climate objectives and the concerns of the communities that host them.
What is emerging on the horizon is a scenario in which biogas and biomethane plants will continue to multiply in Spain and Europe, driven by the demands of decarbonization and waste management, but in which their acceptance will depend largely on how current conflicts are resolved: which projects are considered truly sustainable, how their size, location and design are regulated, and to what extent they are integrated into a territorial model that citizens perceive as their own and not as an external imposition.
