Exergoeconomic assessment of the industrial integration of a thermochemical energy storage system with adaptive turbomachinery

Abstract

In recent years, renewable energy generation has experienced unprecedented growth driven by concerns about climate change. Energy storage systems are essential as bridges between renewable generation and integration in sectors such as industry, where efficient systems integration could promote the decarbonisation of processes. Thermochemical storage systems based on turbomachinery are promising, but they still present challenges when operating under off-design conditions. These systems must be studied under these conditions, since their integration into sectors such as industry, where generation and demand fluctuate, can deviate significantly from their rated conditions. In this sense, an exergy study based on off-design models and real data on renewable generation and demand could identify bottlenecks in current configurations. This work presents a comprehensive exergy study of the integration of a novel thermochemical system into a real industrial environment, accounting for variable generation and demand, thereby providing a more realistic scenario. The dynamic study, conducted over an annual cycle, reveals thermodynamic limitations and technological integration challenges in turbomachinery that cannot be detected by simpler analyses. In addition, adaptive compression and expansion systems are proposed to mitigate the fluctuating impact, thereby overcoming these challenges and achieving a remarkable exergy performance of 77.8%. The exergoeconomic evaluation yields competitive values compared to current approaches, including a storage cost of $30 per MWh, an exergy-destruction-based cost rate of $6.35/MWh, and an LCOE for photovoltaic generation of $76.21/MWh.