There is growing interest in Energy Storage Systems (ESS) and other distributed energy resources (DER) as non-wires alternatives to resolve distribution issues while also providing valuable services to the grid and to energy customers. One such use is to defer distribution capacity investments required due to load and/or DER growth. Selecting ESS power and energy ratings for capacity deferral requires time-series load profile data. This paper is a part of a longer-term objective of making it easy for utilities to consider energy storage systems within distribution planning. This paper proposes a practical planning-based approach to screen ESS (both power and energy ratings) to defer distribution capacity investments. More specifically, an approach is presented here that leverages linear power flow approximation to quickly perform many time-series ESS dispatch simulations enabling rapid ESS project screening for a large number of distribution feeders. This paper also illustrates intuitive ways to visualize optimal ESS power and energy ratings for different peak clipping objectives. The proposed ESS project screening approach is demonstrated on a real Hydro One distribution feeder.