Energy management of grid-interconnected multi-microgrids based on adjustable power and greenhouse gas credits

This paper presents a novel hierarchical energy management system (EMS) to minimise the operational greenhouse gas (GHG) emission of grid interconnected multi-microgrid (IMMG) systems. The peer-to-peer energy trading strategy (ETS) integrated optimisation is implemented with three levels for the IMMG test system: MGs, the utility grid, and community power distribution agents (CPDAs). The ETS employs the “adjustable power” concept to harness the underutilised controllable DGs by considering the per-unit emission of the DGs involved. Further, “GHG credits”, inspired by the carbon markets prevalent in European nations, are introduced in the ETS. This serves as an offset for the GHG emissions produced or as an incentive. The three levels of the proposed EMS approach include local optimisation at the MG level, followed by ETS-integrated global optimisation at the IMMG level, and lastly, settlement of GHG credits using the Bid-based Hamilton Allocation approach. A comparative study using two alternative approaches validates the efficacy, robustness, and scalability of the proposed approach in promoting environmental sustainability and improving decarbonisation of the network. Furthermore, two other recent and widely adopted ETS approaches are implemented on the test IMMG system, and a comparative analysis further highlights the superior performance of the novel ETS-integrated EMS approach.