## 3 Results
### Scenario II: Economic Optimization
By contrast, grid electricity is used for local demand (376.9 MWh, 28.6%) without exports. This breakdown reveals the dominance of BG in meeting the system's energy needs, ensuring reliability and continuous operation. At the same time, PV exhibits significant self-consumption, limiting the surplus sold to the grid. The grid plays an essential complementary role, covering nearly one-third of the total energy supply and balancing the system's demand--mainly during insufficient BG or PV output. The annual analysis of Scenario II highlights a consistent and strategic energy management approach that leverages local biomass and solar resources. The biomass input remains relatively steady--up to 400 kg/h--ensuring uninterrupted BG generation. Over the analyzed period, 2225 tons of feedstock were consumed, averaging 6.09 tons/day or about 0.254 tons/h, maintaining reliable biogas production throughout the year. BG generation typically decreases at midday when solar generation is at its peak, while BG output increases (up to 200 kW) during morning, evening, and nighttime. This approach ensures continuous power availability without unnecessary excess generation during peak solar periods. Meanwhile, PV generation reaches its maximum output (up to 125 kW) at midday, especially in summer, effectively meeting daytime loads. Excess PV generation usually occurs around midday in summer, allowing surplus electricity (up to 60 kW) to be sold back to the grid and generating marginal revenue. However, during nighttime and periods of low renewable availability, the system relies on purchased grid power, reaching up to 250 kW and indicating dependence on external sources under less favorable conditions. This coordinated operational strategy balances biogas and PV contributions alongside grid interactions, ensuring year-round cost-effectiveness, system reliability, and operational stability. Figure 16 shows the power distribution of the Proposed System on August 15 th in Scenario II, highlighting the contributions of BG, PV, and grid energy to meet the load demand. BG provides a consistent supply throughout the night, covering a substantial portion of the demand. PV output peaks during midday, reflecting the availability of sunlight, and it drops to zero at night. The grid supplements the system during high demand or low renewable generation periods, ensuring reliability. Occasionally, surplus energy, primarily from PV during midday, is sold back to the grid, although this did not occur on this day. This dynamic balance demonstrates the system's ability to integrate renewable energy while maintaining reliability and economic efficiency. Figure 15: Energy share of the Proposed System in Scenario II. Table 4 highlights the environmental benefits of the Proposed System by showcasing significant reductions in key emissions compared to the Base System. The most notable improvements are observed in sulfur dioxide and nitrogen oxides, major contributors to acid rain, smog formation, and respiratory illnesses. These reductions indicate a cleaner combustion process and a shift toward more efficient energy utilization. Additionally, the substantial decrease in carbon dioxide emissions demonstrates a lower reliance on fossil fuels, reinforcing the system's contribution to mitigating climate change and reducing its carbon footprint. While carbon monoxide levels remain nearly unchanged, the reductions in other pollutants highlight the Proposed System's effectiveness in minimizing harmful environmental impacts. Beyond ecological benefits, these improvements enhance air quality, support regulatory compliance, and may lead to economic advantages such as reduced carbon taxation and improved public health outcomes. The system's ability to lower emissions while maintaining energy efficiency underscores its role in fostering a more sustainable and cost-effective energy solution.