Optimization of CSP Plants with Thermal Energy Storage for Electricity Price Stability in Spot Markets

Abstract

This research presents a novel optimization strategy for concentrating solar power (CSP) plants with thermal energy storage (TES) systems that aims to stabilize and reduce electricity prices in spot markets. In the current international scenario of initiatives with regulatory changes aiming to reduce climate change effects and therefore CO2 emissions, many countries are reducing the fossil fuel share in their respective electrical systems and increasing electrical renewable energy systems. These carbon free generation systems have inherent problems such as their intermittence which, combined with the lack of high-scale energy storage systems, cause a stability risk in electrical grid systems and require conventional fuel systems to match demand and production. In this research, we analyze spot price markets using a marginal price system that relies on natural gas and is quite sensitive to an increase in fuel prices, causing a direct increase in the final energy cost in systems with a high renewable energy share, and we study how optimally sized CSP plants with TES can be used as manageable solar energy systems and contribute to both price and grid stability. For the Spanish market, we analyze the ongoing market situation and generation mix and we present an optimization scheme using the System Advisor Model (SAM) software that aims to maximize energy availability throughout the day and contribute to peak generation. The results show that the optimization strategy increases the profitability of CSP plants but also ensures a contribution to spot price stability and reduction. A sensibility analysis is presented, and a case study is analyzed in southern Spain. The results show the importance of optimized CSP plants in an energy transition and a strategy is proposed that can be extended to other locations worldwide.