There is an increasing awareness that there are limits to the availability of non-renewable resources, while there is an increasing energy demand throughout the world. This demand is expected to be satisfied through the efficient renewable energy in the near future. However, the world is facing the challenge of variable renewable energy outputs due to a stochastic feature of the energy sources. Thermal energy storage (TES) can be a good option for mitigating the effects of intermittent renewable resources on the networks. It can not only allow the increased renewable energy and night time low price electricity utilization, but also provide flexibility and ancillary services for managing future electricity supply/demand challenges. In this paper, various TES forms, including sensible, latent and sorption are explained and summarized for their performance enhancement. More importantly, from the perspective of sustainability, various integration forms for different applications are systematically introduced, such as TES integration with hot water supply, air conditioners and heat pumps, TES integration with building construction systems, and TES integration with power production cycles, cogeneration, food transport, solar cookers and vehicle systems for thermal comfort. Therefore, this study is beneficial to designing more sustainable thermal systems by the researchers and engineers.