Techno-Economic Assessment of Renewable Energy Communities and Biomethane Valorization in a Medium-Sized Agricultural Enterprise

The promotion of energy from renewable sources is a key objective of the European Union's energy policy, as outlined in Directive (EU) 2018/2001, known as the Renewable Energy Directive II. This directive introduces the concept of Renewable Energy Communities (RECs), which are groups of citizens and/or small and medium-sized enterprises that produce and share electricity generated from renewable sources. Additionally, its amendment, Directive (EU) 2023/2413, sets a further goal of achieving an annual sustainable biomethane production of 35 billion cubic meters by 2030. Within this context, Northern Italy emerges as one of the European regions with the highest potential for biogas production. This thesis presents a techno-economic feasibility study for a medium-sized agricultural enterprise located in Piedmont, evaluating three possible configurations: 1.??A Renewable Energy Community featuring a photovoltaic system installed on the farm’s rooftop; 2.??A Renewable Energy Community incorporating both a photovoltaic system and an anaerobic digester, owned by the farm, for the production of biogas from bovine manure and its subsequent combustion in a cogeneration plant; 3.??Upgrading of biogas to biomethane through a pressure-swing adsorption (PSA) CO₂ capture process, followed by injection into the gas grid. The analysis begins with the assessment of hourly electrical and thermal load profiles for the farm, along with the electrical load profiles of REC participants. A parametric analysis is then conducted to determine the optimal photovoltaic system size—identified as 150 kWp—based on the comparison of key energy and economic performance indicators (KPIs). The anaerobic digestion plant and hourly biogas production, along with associated energy consumption, are subsequently dimensioned. Starting from a minimum cogeneration plant size of 100 kW and an initial photovoltaic installation of 50 kWp, the combustion engine size is gradually increased while the photovoltaic capacity is reduced, maintaining a maximum total production limit of 150 kW. Finally, the CO₂ capture process based on hourly biogas production is designed and simulated using PSA technology, and the associated economic KPIs are evaluated. Incentives for shared electricity within RECs are considered according to the CACER Decree, while biomethane injection incentives are referenced through the Biomethane Decree. Among the REC configurations, the photovoltaic-only option proves most economically advantageous, as the high capital and maintenance costs of the anaerobic digester render the payback period and net present value less competitive. Conversely, configurations including cogeneration demonstrate superior performance in terms of self-consumption and energy self-sufficiency. Regarding biomethane production and sale, the analysis highlights that financial incentives are essential to ensure investment viability, as the market price of natural gas, as established by the Energy Market Operator (GME) on the Day-Ahead Market, is insufficient to guarantee economic return. In conclusion, under current incentive schemes, biomethane production and sale represent the most economically viable renewable energy strategy for a medium-sized agricultural enterprise.