Self-organization Model for the Formation of Distributed Energy Network

1. Overview Recently, Japan witnessed a serious nuclear power plant accident, owing to which a large amount of CO2 from thermal power plant was emitted into the atmosphere. Given the background of this unfortunate event, at present, there is a need to increase the generation of photovoltaic (PV) power from the viewpoint of saving electricity and reducing the CO2 emission. Therefore, in order to meet this requirement, the legal support required for purchasing the total amount of power generated and for granting the subsidies on PV power generation have been established. Moreover, the Japanese government aims to introduce 53 million kW of PV power in 2030. However, the following technical problems occur when a large amount of PV power is introduced at one time: (1) disparity between the supply and demand for electricity, (2) increase in voltage, and (3) destabilization of frequency. One possible way of solving such technical problems is to use a smart grid technology which is one of the countermeasures to reduce the influence on grid. Moreover, it is necessary to introduce a large number of PV batteries to manage the surplus PV electricity. It should be noted that a distributed energy supply system is expected to reduce both the battery capacity and the influence on grid. The distributed energy network system consists of a network in which electricity and heat can be transferred between the distributed generators and the renewable energy resources, and it can supply stable energy to an urban district. From a long-term point of view, it is thought that it will be difficult to maintain consistency in terms of purchasing the total generated PV power in the case when a large number of PV systems are to be introduced. In addition, the distributed energy system is introduced at random and can be randomly updated by the consumers. Therefore, facilities connected to the distributed energy network will always fluctuate. It is desirable that an optimal energy network emerges while the energy facilities are being constantly updated. Living organism and ecosystem are the example that acquired overall stability and the optimality by local interaction. In the ecosystem, an example of an optimum energy network is a colony populated by living organisms. It is essential for self-organized distributed energy systems such as the “energy colony” shown in Fig. 1 to have high stability and robustness. Carreras et al.(1) studied techniques based on a biological approach to develop a hierarchical energy network, which is also known as an energy web. The Turing model that is famous for the formation of swarm of animal and the formation of the