The design of future energy automation and management systems requires Distribution System Operators (DSOs) to analyse and compare different technical solutions for determining which of these could be best implemented in their networks. This paper presents a methodology that helps DSOs carry out such a complex task. The methodology is based on the Smart Grid Architecture Model (SGAM) framework. It was implemented using a web-based application that facilitates editing and automatic analysis of SGAM architectures. The methodology was successfully evaluated in the context of DISCERN European research project.