Abstract: Towards the goal of carbon neutrality, it is of great significance to leverage and evaluate the dispatching and reserve capacity of the user-side generalized energy storage. In this paper, we focus on distributed energy storage systems, electric vehicles, and heating, ventilation, and air conditioning as examples of user-side broad energy storage resources. A virtual battery (VB) model is initially established to describe the aggregated power feasible domain of their clustered resources. Subsequently, leveraging the VB model, a calculation method is proposed for the upper and lower reserve capacities of cluster resources. On this basis, an optimal scheduling model for user-side generalized energy storage resources, grounded in the VB model, is developed within the framework of power market operation. Furthermore, the non-necessity of the non-convex constraints in the proposed model is demonstrated through a proof of contradiction, thereby transforming the non-convex optimization problem into a convex optimization problem. Finally, the effectiveness of the proposed optimal scheduling model and its superiority in terms of optimization solution efficiency are confirmed through case study. Additionally, a sensitivity analysis is carried out on the factors affecting the reserve capacity of generalized energy storage resources.