Mª Begoña Peris Martínez – Agronomist, Polytechnic University of Valencia (Spain); Master in Natural Environment Defense Techniques, Polytechnic University of Madrid (Spain); Master in Agri-food Economy and Environment, Polytechnic University of Valencia (Spain)

Abstract: The implementation of large-scale biogas and biomethane plants has intensified in Europe as part of energy transition and circular economy strategies. However, numerous scientific studies and territorial analyses document environmental, social, and landscape impacts when these installations are located in rural areas of high agricultural and touristic value. This paper reviews international literature on odor emissions, air quality, digestate effects on agricultural soils, landscape transformation, and social acceptance, incorporating empirical examples from municipalities and viticultural regions in Europe. Based on this evidence, the territorial suitability of the biomethane plant project in San Antonio de Requena (Valencia, Spain) is critically assessed. The results suggest that, in territories where economic value depends on terroir, environmental quality, and sensory experience, implementing such infrastructures presents structural incompatibilities that are difficult to mitigate.

Keywords: biomethane; biogas; viticulture; wine tourism; spatial planning; social acceptance

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1. Introduction

Biomethane production through anaerobic digestion has become a relevant technology in European energy policies. However, the sustainability of these installations depends not only on technical efficiency but also on territorial location, scale, and socio-economic context (Bacenetti et al., 2016; Lupp et al., 2014).

In winegrowing and enotourism areas, soil, landscape, environmental quality, and sensory perception are essential productive assets. The central question arises: is the implementation of large-scale biomethane plants compatible with territories whose economy depends on the balance of soil, landscape, and sensory experience associated with wine?

Experiences from various European municipalities indicate that the impacts associated with these installations are not exceptional but recurrent in certain territorial contexts.

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2. Study Area and Project Location

The project is located in the municipality of Requena (Valencia, Spain), specifically in industrial area 12, plots 202 and 298, according to official documentation published in the Official Gazette of the Generalitat Valenciana (DOGV, 2025).

The proposed plant would be located approximately 1.5 km from the inhabited center of San Antonio de Requena and 6 km from the urban center of Requena, in an environment dominated by wine production and enotourism. These distances are relevant for evaluating odor, landscape, and social perception impacts.

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3. Odor Emissions and Environmental Quality

Odor emissions, mainly hydrogen sulfide (H₂S), are one of the most documented impacts of biogas plants. Zhang et al. (2024) identified H₂S as the main cause of nuisance, with peaks during the reception and handling of slurry.

Wiśniewska et al. (2020) demonstrated that odor dispersion depends on meteorological factors, limiting the effectiveness of mitigation measures even in modern facilities. This phenomenon explains persistent conflicts in municipalities such as Babilafuente (Salamanca, Spain).

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4. Air Quality and Associated Risks

Compounds such as ammonia, H₂S, and siloxanes can be released during operational phases or technical failures (Awe et al., 2022). In touristic territories, these episodes affect perceptions of environmental safety and destination image.

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5. Digestate, Agricultural Soils, and Terroir

Insam et al. (2022) concluded that digestate application may alter soil microbiota, depending on its composition and management. In viticultural regions such as Piedmont (Italy), Riva et al. (2014) documented territorial conflicts arising from biogas plant concentration. Since soil microbiota is a key element of viticultural terroir, these alterations are especially relevant.

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6. Landscape, Tourism, and Social Acceptance

Gaviglio et al. (2017) demonstrated that biogas plant implementation significantly reduces social acceptance in rural landscapes of high aesthetic or touristic value. Lupp et al. (2014) observed similar results in Germany, even in regions with a long biogas tradition.

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7. Integrated Assessment of the Requena Case

Requena combines established viticulture, enotourism, and dependence on landscape and soil. The proximity of the proposed plant to San Antonio de Requena (~1.5 km) and its closeness to productive and residential areas make the location a relevant risk factor.

Compared to European experiences, the associated risks are neither hypothetical nor easily mitigated, especially regarding social perception, landscape, and impacts on high-value agricultural soils.

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8. Comparison Between Centralized Macroplant and Decentralized Plants

Scientific evidence suggests that the location and scale of biomethane plants critically determine their territorial impact, especially in winegrowing and enotourism areas (Bacenetti et al., 2016; Lupp et al., 2014).

8.1 Scale and Waste Management

A centralized macroplant receives large volumes of slurry from multiple farms, concentrating waste management in one point. This results in:

• Higher risk of odor and pollutant emissions (H₂S, NH₃, particles).
• Frequent slurry transport, increasing diffuse emissions, traffic, and spill risks (Zhang et al., 2024).

Decentralized plants at each farm process only local slurry, reducing transport, emission concentrations, and accidental risks.

8.2 Landscape and Social Impact

Macroplants require large industrial buildings and digestate storage, visible from a distance, potentially affecting landscape perception and tourism experience (Gaviglio et al., 2017). On-farm plants are smaller, less visible, and better socially accepted.

8.3 Economic and Energy Efficiency

• Macroplant: high efficiency due to economies of scale, higher biomethane production, significant initial investment.
• Decentralized plants: lower energy efficiency, limited production, lower investment, and reduced risks.

8.4 Section Conclusion

In winegrowing contexts like Requena, where landscape, environmental quality, and sensory perception are strategic assets, a centralized macroplant model increases environmental and social impacts that are difficult to mitigate. Decentralized plants would allow energy valorization of slurry with significantly lower territorial impact, preserving soil, landscape, and enotourism integrity.

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9. Conclusions

Scientific and territorial evidence demonstrates that biomethane macroplants generate impacts on air, soil, landscape, and social acceptance. In winegrowing and touristic territories, these effects become structural, directly affecting economic competitiveness based on terroir and sensory experience.

The implementation of the macroplant in San Antonio de Requena presents structural incompatibilities with the current development model; therefore, its location should be reconsidered in light of scientific and spatial planning criteria.

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References

• Bacenetti, J., et al. (2016). Life cycle assessment of biogas systems. Frontiers in Bioengineering and Biotechnology, 4, 26.
• Capelli, L., et al. (2013). Odour impact assessment in industrial plants. Atmospheric Environment, 79, 731–743.
• Gaviglio, A., et al. (2017). Biogas plants and rural landscape perception. Land Use Policy, 67, 330–341.
• Insam, H., et al. (2022). Digestate effects on soil microbial communities. Environmental Chemistry Letters, 20, 1565–1583.
• Lupp, G., et al. (2014). Public acceptance of biogas plants. Energy Policy, 67, 173–182.
• Riva, C., et al. (2014). Environmental impacts of biogas plants in agricultural areas. Science of the Total Environment, 497–498, 299–309.
• Wiśniewska, M., Kulig, A., & Lelicińska-Serafin, K. (2020). Odour emissions from biogas plants. Applied Sciences, 10(3), 1093.
• Zhang, Y., et al. (2024). Odorous gas emissions from anaerobic digestion plants. Journal of Cleaner Production, 432, 139834.
• DOGV (2025). Proyecto de macroplanta de biometano en San Antonio de Requena. Diario Oficial de la Generalitat Valenciana. Link