The study delves into the critical necessity of long-duration energy storage to ensure the consistent reliability of electricity derived from renewable sources. Numerous technologies have emerged to address this need, enabling the storage of surplus energy generated by renewables in diverse materials, taking the forms of sensible or latent heat. The comprehensive analysis explores these various techniques in detail, providing a thorough examination of their respective advantages and disadvantages. High-temperature TES emerges as a pivotal component, particularly within CSP. This storage capability becomes imperative for maintaining a seamless and predictable power generation process, especially during periods of limited or intermittent sunshine, coinciding with high electricity demand and costs. Presently, CSP plants predominantly employ sensible energy storage in molten salt, which requires substantial salt volume, two large tanks, or a single tank system. A detailed study is conducted on a similar type of TES system using a PCM as an insulation to minimize the heat losses from the storage tank. The impact of the PCM layer in minimizing the heat loss is analyzed via an analytical model and CFD simulations. The cost incurred for the PCM is further compared with the cost of electrical heating.