This part of IEC 62257 provides a method for describing the results to be achieved by the electrification system independently of the technical solutions that could be implemented. The purpose of this part of IEC 62257 is to provide a method to assist project contractors and project developers to select and design the electrification system for isolated sites while matching the identified needs, such as those described in IEC TS 62257-2. IEC TS 62257-2 assesses the needs of the users and the different power system architectures which can be used for meeting these needs. In relation to the needs of the different participants to the project, functional requirements that shall be achieved by the production and distribution subsystems are listed. In Clause 5, energy management rules to be considered are described. These are key issues as they have a great influence on the sizing of the electrification system. In Clause 6, the informations provided by the system sizing process to allow the participants to select the equipment or component able to fulfil the functional requirements are listed. To allow and facilitate the management of the micro-power plant and the maintenance of the whole electrification system, some information is collected and monitored. Clause 7 is dedicated to defining the parameters and specifying rules for data acquisition.