A method for planning evolutive design of isolated renewable microgrids with multi-objective optimisation

Isolated renewable microgrids represent one promising solution to reach objectives of rural electricity access. Optimising cost and reliability of these systems is however crucial and there exists an inherent trade-off between environmental, economic and reliability objectives. Furthermore, investments are often fixed at the beginning of the project, although repowering can be made during the project life. The method presented in this paper allows for evolutive sizing of isolated microgrids and uses a genetic algorithm to return the set of optimal solutions under the three objectives of long-term cost, renewable integration, and reliability. As a case study, we consider a rural microgrid currently in the process of being deployed in Mali. The results show that there is an opportunity to improve system cost and reliability on renewable microgrids by considering evolutive sizing. The results enable us to observe the trade-off between all design objectives.