Different electric thermal energy storage configurations integrated with solar

The addition of an electric heater to an existing thermal energy storage parabolic trough concentrating solar power (CSP) plant can offer a low-cost, large-scale solution for grid electricity storage, albeit with moderate storage efficiency. While previous studies have mainly covered this topic from a techno-economic perspective, this research focuses on the challenge of improving the efficiency of electricity storage. A detailed off -design model, including the solar field and power cycle inertia, is developed and validated for a proposed 50 MW e parabolic trough plant with a solar salt thermal energy storage system. Two electric thermal energy storage (TES) configurations are investigated using this model. In the first configuration, an electric heater is simply added to the entrance of the hot tank in a two -tank TES system without affecting the nominal performance of the power cycle. In the second, novel configuration, an additional (third) tank is introduced. It is primarily charged using electricity -supplied heat for steam superheating. This steam superheating leads to higher power cycle efficiencies without requiring additional modifications to the downstream part of the steam generator. The operation of both storage configurations is examined in three different 7 -day scenarios: no irradiance (when the system functions as a simple Carnot battery), low irradiance, and medium irradiance (when the system functions as a CSP Carnot battery). Results demonstrate that the CSP Carnot battery efficiency is highest in the low irradiance scenario, as the electricity -supplied heat brings the power cycle closer to nominal conditions, enabling better utilization of both solar -supplied heat and electricity -supplied heat. Furthermore, while the superheating configuration exhibits a relative increase of similar to 1 . 9% in power cycle thermal efficiency compared to the normal configuration under nominal conditions, the CSP Carnot battery efficiency is increased