A Scalable Design Methodology for a Self-Sufficient Circular Farm Integrating Food Production, Water Management, Renewable Energy, and Biomass Pyrolysis

Abstract

Climate change, increasing resource depletion, food insecurity, water scarcity, and growing energy demand have intensified the need for sustainable and resilient living systems. Existing studies have mainly focused on individual aspects of sustainability, such as renewable energy, sustainable agriculture, water management, or biomass valorization, while comprehensive design methodologies integrating these components into a single autonomous system remain limited. This study proposes an integrated framework for designing a self-sufficient circular farm capable of achieving high levels of food, water, and energy autonomy while minimizing environmental impacts through closed-loop resource management. The proposed methodology combines nutritional requirement assessment, crop planning, livestock integration, water balance, solar photovoltaic generation with battery storage, and slow biomass pyrolysis for biochar production and organic waste valorization. A reference case corresponding to one person over a five-year operational period was developed to establish the design methodology and system sizing procedures. The results indicate that approximately 0.7–1.0 ha is required per person, with an estimated annual water demand of approximately 3,545 m³ and an annual electricity demand of 9.25 MWh. The energy system can be supplied by an approximately 8 kWp photovoltaic installation coupled with 60–70 kWh of LiFePO₄ battery storage. Approximately 2.5 tonnes of dry biomass could be mobilized annually for slow pyrolysis, generating about 750 kg of biochar per year. The estimated initial investment ranges from €84,000 to €153,000, excluding land, while the environmental assessment indicates approximately 18.5 tonnes of CO₂ avoided and 10 tonnes of CO₂ additionally sequestered over five years. The proposed framework is scalable and adaptable to households and larger communities by adjusting key design parameters, providing a quantitative methodology for the development of resilient autonomous farms and circular resource management systems in Mediterranean climates.