Within the context of carbon control strategies, the development and utilization of renewable energy emerge as indispensable pathways to addressing the energy crisis and environmental challenges. The substantial increase in the share of electricity generated from renewable sources introduces issues such as instability and intermittency, posing significant challenges to the stability of the electrical grid. Consequently, enhancing the flexibility of coalfired power units is of paramount importance for maintaining the balance of supply and demand within the power system and managing grid fluctuations. Ammonia energy storage, as an innovative chemical storage solution, is regarded as an effective approach to augment the power system's capability to incorporate renewable energy generation and enhance the flexibility of coal-fired power plants. This paper summarizes three carbon reduction technologies and methodologies within the framework of carbon control strategies, elucidating the advantages and value that ammonia contributes to the process of increasing power plant flexibility. It proposes a method for coupling green power with conventional thermal power through electrolytic ammonia production, tailored for power plants. Additionally, it identifies two principal applications of ammonia within power plants as a carbon-free fuel and absorbent. Finally, it anticipates the future development trends and challenges of ammonia's role in enhancing power plant flexibility.