Evaluating energy and greenhouse gas emission footprints of thermal energy storage systems for concentrated solar power applications

Abstract

Abstract Greenhouse gas emissions from the power generation sector contribute significantly to climate change. The use of thermal energy storage systems can reduce the sector's impact depending on factors such as plant energy performance and environmental friendliness. In this study, an Excel-based model was developed to evaluate the greenhouse gas emissions and net energy ratio for thermal energy storage technologies used in concentrated solar power applications. Five thermal energy storage systems were considered: two-tank indirect sensible heat storage, two-tank direct sensible heat storage, one-tank direct sensible heat storage, latent heat storage, and thermochemical storage. To capture the uncertainties in the results for each type of storage, a Monte Carlo simulation was performed by varying key operational and model parameters. With uncertainty taken into consideration, it was determined that the mean greenhouse gas emission values for two-tank direct sensible heat storage and one-tank direct sensible heat storage are 15 gCO2-eq/kWh and 11 gCO2-eq/kWh, respectively. The two systems offer higher energy performances and lower emissions than the other storage systems and thus the potential to be implemented commercially for concentrated solar power applications.