More and more interconnections between European countries to ensure better security of supply, the increasing difficulty of balancing the network, globally and locally, due to the development of intermittent energy sources, the increasing involvement of cities in the energy and sustainable development, energy optimization that can be implemented locally by linking various “energy networks and systems” are factors that argue for the development of energy systems and energy distribution networks at multiple levels.
These levels are structured like Russian dolls and are all interconnected for a consistent grid and energy systems operation, at which a balance has to be achieved:
– Transcontinental level: For electricity, it is the European Supergrid level that is a connection between countries to limit the overall reserve capacity by avoiding the duplication of national reserve capacities and to access to more efficient means of production.
– National level managed by the TSO: the balance is assured at this level by conventional adjustment mechanisms, possibly stimulated by capacity markets that may involve various aggregators (production and demand response). This level is where are connected the traditional “centralized” power plants.
– Level of a metropolis or city: this level is where some distributed power sources are connected, where the interface with heat networks is managed, where the unavoidable energy derived from waste incineration or industry can be used. In the future, it may be necessary to consider the overall balance management at this level, but at this time, nothing exists in this area.
– Level of a neighbourhood or a large consumer (microgrid): This level is where the smallest distributed power sources are connected, where the interface with transport systems is managed. In the future, it may be necessary to consider the overall balance management at this level, but at this time, nothing exists in this area.
These different levels of network management define Fractal Grids, clusters and mesh networks of microgrids. Some of these microgrids, organized through a parent-child hierarchy, may momentarily work independently to ensure maximum security of supply to major consumers and maximum resilience to the economic world.
So it is very interesting to consider the evolution of the network topology in this direction to meet security of supply needs, to face malicious acts, to optimize the management of distributed generators and storage units and to master the complexity of balancing mechanisms.
There is a safe bet that Smart Grids never reach the stage of full maturity if they fail to move towards Fractal Grids type of architecture.