Solar Energy Autopilot (SOLEA): A Holistic System Architecture for Autonomous Concentrated Solar Thermal Plants and Its Evaluation in an Operational Power Tower Facility

Concentrated solar thermal (CST) plants can provide dispatchable renewable energy but remain complex and costly to operate due to tightly coupled subsystems, dynamic environmental conditions, and high safety requirements. This work presents the Solar Energy Autopilot (SOLEA), a holistic four-layer architecture that transforms a traditional solar power tower plant into an autonomous cyber-physical system (CPS). The architecture integrates plant hardware and control systems, advanced optical and meteorological measurement systems, a CPS middleware platform with a standardized digital twin, and a multi-agent automation layer for operation planning and control. SOLEA is implemented and evaluated at an operational research facility, where intelligent agents autonomously plan operating days, start and shut down the plant, and regulate the receiver flux and outlet temperature under varying environmental conditions. A dualsided evaluation quantifies benefits in terms of efficiency, robustness, and cost-related indicators and assesses the system's autonomy using a multi-dimensional maturity model. The results show substantial reductions in operational and investment costs, highly robust operation despite challenging environmental conditions, and efficiency gains in plant operation enabled by an increased autonomy level of the plant. Overall, the study demonstrates that the layered modular SOLEA architecture can effectively bridge the gap between isolated automation solutions and plant-wide autonomous CST operation and provides a reusable blueprint for advancing autonomy in future CST plants and comparable industrial environments.