Optimal sizing of RES and BESS in networked microgrids based on proportional peer-to-peer and peer-to-grid energy trading

Networked microgrids emerged from the growing deployment of microgrids in the distribution network. The coordinated operation of networked microgrids offers technical and economical benefits to microgrid owners, customers, grid/utility, and other stakeholders. The optimal capacity sizing of renewable energy sources and battery energy storage systems allows microgrids to minimize costs and maximize reliability. A multi-objective optimization problem is developed for optimal sizing in a networked microgrid consisting of four different microgrids. The annual energy costs and loss of power supply probability index are taken as objectives. Peer-to-peer and peer-to-grid energy trading approaches are employed. The peer-to-peer energy trading among microgrids employs the proposed "proportional trading method" via a networked microgrid manager or aggregator. The multi-objective optimization problem formulated is solved using Multi-Objective Particle Swarm Optimization. The individual objective optimization results for annual energy cost and loss of power supply probability are also analyzed. The proposed method decreases the interaction between the grid and the MGs, and the usage of renewable energy sources is enhanced. The capacity of battery energy storage systems is lowered by 96%, 53.2%, 48.86%, 21% for respective microgrids in networked microgrids. The results of proportional peer-to-peer energy trading-based multi-objective optimization show that trading energy among microgrids minimizes annual energy cost by 0.75% while maintaining system reliability.