Understanding the Structural Challenges of Energy Autarky in Biomass-Based Cogeneration: A System Dynamics Analysis of Sugar Industry

Biomass-based cogeneration enables sugar mills to achieve energy autarky by utilizing bagasse for steam and electricity generation. However, the long-term sustainability of this system remains uncertain due to fluctuations in biomass supply and quality. This study employs a System Dynamics approach to identify the structural factors limiting energy autarky in sugar mills. The model was validated with error rates of 0.01 - 4.78% and error variances of 0.13 - 27.21%, indicating adequate representation of real-system behavior. A multivariate Monte Carlo simulation (200 runs) was conducted by varying bagasse moisture content, boiler efficiency, and sugarcane productivity. The baseline simulation (2012-2035) shows that Total Sugarcane Production and Gross Bagasse Production decline by 72.7% and 71.9%, respectively, reducing Thermal Energy generation from 372.5 B kJ to 103.2 B kJ. Consequently, Energy Autarky Stress (EAS) remains persistent within a range of 0.084-0.214. Monte Carlo results indicate that uncertainty affects Gross Bagasse Production 16.3% and Thermal Energy 9%, but does not alter the overall behavior of EAS. These findings reveal that energy autarky limitations are primarily driven by structural dependence on biomass supply and endogenous feedback mechanisms rather than operational uncertainty. The study contributes by demonstrating the importance of structural resilience and biomass supply sustainability, shifting the focus from technical efficiency optimization toward long-term energy autarky in sugar mill cogeneration systems.