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In recent years, biomethane has transitioned from being an energy development promise to becoming a strategic industrial sector for Spain. The revision of the National Integrated Energy and Climate Plan (PNIEC 2023–2030), the European push derived from the REPowerEU strategy and, especially, the regulatory turning point represented by Royal Decree-Law 7/2026, position biomethane as one of the strategic pieces within the Spanish energy transition.
The relevance of biomethane is explained by its capacity to transform organic waste into renewable energy, reduce greenhouse gas emissions, promote the circular economy, and strengthen energy security using local resources. At the same time, it directly links climate policy with rural development, offering sustainable solutions for the management of agricultural, livestock, and agri-food waste, sewage sludge, and animal by-products not intended for human consumption (ABPs/SANDACH).
Regulatory framework and environmental authorization
From an environmental and social standpoint, it is essential to understand that these facilities are organic waste management infrastructures and, therefore, early and transparent environmental and social planning is vital to ensure a sustainable and socially acceptable deployment of biomethane. Consequently, the commissioning of these projects is subject to various environmental authorization procedures, which vary depending on the facility’s waste treatment capacity.
Specifically, they may require an Integrated Environmental Authorization (AAI) or Environmental License, as well as an Environmental Impact Assessment (EIA) in its simplified or ordinary modality, in accordance with the waste treatment thresholds (tonnes/day) and criteria established in Royal Legislative Decree 1/2016 and Law 21/2013.
Impact management and application of Best Available Techniques (BAT)
Among the main impacts associated with the production process, odor emissions, noise, effluent management, and the potential risk of soil and groundwater contamination stand out. For this reason, it is essential to integrate, from the initial stages of the project, specific odor impact studies, acoustic studies, and atmospheric dispersion models, along with the implementation of preventive and mitigation measures in the design and appropriate operation and maintenance procedures, in addition to the application of Best Available Techniques (BAT).
Critical factors: Location, logistics, and social environment
From a social and territorial point of view, the location of the plants constitutes another critical factor. The availability, type, and proximity of waste condition the size of the facility, its logistics, and its territorial fit. Added to this is the need to ensure land-use compatibility, analyze distances to population centers and livestock farms to avoid social conflicts, and evaluate potential impacts on protected natural areas, the public water domain, and other sensitive environmental elements.
Even so, biogas has also consolidated itself as a key part of the solution to current environmental problems, especially in rural areas. The recovery of livestock manure through anaerobic digestion reduces emissions, prevents foul odors and, above all, decreases aquifer contamination and uncontrolled discharges, a growing social concern. Similarly, the use of pruning remains and agricultural biomass prevents its accumulation in the fields, reducing the risk of fires and management issues.
Sub-product treatment and the digestate challenge
Finally, the management of waste such as ABPs (SANDACH) implies the obligation of prior registration and authorization of the facilities by the competent authority. Likewise, the proper management of digestate—the main sub-product of the process—must be planned and defined from the project design phase, whether through its agronomic application, the restoration of degraded soils, the manufacture of fertilizer products, or the treatment of the liquid fraction for reuse or authorized discharge.
Innovación tecnológica: La metanización y el Power-to-Gas (P2G)
As a leading theme within advanced biomethane best practices, methanation stands out as a key Power-to-Gas (P2G) technology. In this process, captured $CO_2$—sourced from the biogas itself or other industrial origins—is hydrogenated using renewable hydrogen to be transformed into more methane. This results in the generation of synthetic natural gas (SNG), which is fully compatible with the existing gas grid. This practice strengthens the circular economy, utilizes sub-products, and contributes directly to the decarbonization of the energy system.
The added value of EHS Techniques
EHS Techniques can assist biogas plant developers by offering specialized environmental, social, and regulatory consultancy, focused on obtaining environmental permits, ensuring regulatory compliance throughout the project, and the analysis and management of environmental and social impacts. It also provides support in information and dialogue processes with communities and contributes to the design of projects with a positive return for the rural environment.
Their support spans from the initial design phases—defining digestate strategies and environmental requirements—to the processing with authorities and accompaniment during commissioning, ensuring safe, sustainable, and socially responsible development in compliance with current regulations.