In Indonesia, Coal-Fired Power Plants (CFPPs) dominate electricity generation, prompting initiatives like biomass-coal co-firing to meet renewable energy goals. Utilizing CFPP fly ash in concrete and carbon capture further aids sustainability efforts. Research emphasizes biomass type influence on co-firing efficiency and fly ash's potential in enhancing concrete strength and carbon capture. These findings offer pathways to reduce fossil fuel dependency, mitigate emissions, and advance sustainability goals. Future research should optimize co-firing processes and promote awareness and policy support for broader implementation, positioning Indonesia as a leader in sustainable energy innovation.