Optimal Design of Hybrid Solar Power Systems: A Case Study in the Chinese Market

Abstract

The global energy industry is shifting towards a net-zero energy system to achieve climate neutrality, leading to significant growth in distributed renewable energy generation. This reshapes market dynamics and presents challenges in balancing supply and demand, increasing the risk of midday oversupply and variability in renewable generation, potentially compromising grid reliability. Concentrated solar power (CSP) offers a viable solution for grid decarbonization by integrating large-scale renewables and providing ancillary services like peak shaving and load shifting, frequency control, and energy storage, complementing the intermittent supply of photovoltaics (PV). The synergy between low-cost PV and dispatchable CSP fosters a resilient and sustainable system. Demonstration projects, especially in China, emphasize the relevance of hybrid CSP systems. CSP plants are built alongside large-scale PV installations to address the growing challenges associated with the electrical grid. The study explores hybridizing high-performance collectors, specifically Ultimate Trough (UT) collectors using molten salt as a heat transfer fluid, with PV to identify optimal solar field sizing and operational strategies. The techno-economic optimization framework integrates in-house cost models with thermodynamic and optical models derived from the System Advisor Model (SAM). A case study in Shichengzi, China, evaluates a hybrid CSP + PV plant with integrated thermal storage. High-performance collectors and better synergy in UT and PV production profiles lead to a 17% and 35% reduction in the power purchase agreement (PPA) price compared to conventional large aperture troughs not optimized for molten salt operation and linear Fresnel devices. This research supports informed decision-making and design solutions for sustainable and economically viable renewable energy production.