Review of grid-tie micro-generation systems without energy storage: Towards a new approach to sustainable hybrid energy systems linked to energy efficiency

This paper reviews the literature on the subject albeit approaching hybrid micro-generation power systems from a systems thinking (ST) and cybernetics standpoint, viewing them as dynamically complex adaptive systems (CAS) coupled with and supplying to a set of homes termed a sustainable block in a rural setting. Here homeostatic regulation (HR) and control play a vital role in reaching efficient equilibrium towards reconciling power supply and demand response management. Unlike most of the work reviewed in the literature, the focus here is on supervisory control of grid-connected micro-generation systems without energy storage, aiming towards building energy efficiency, thriftiness and sustainability in energy consumption. Building on homeostatic control (HC) principles first introduced by F.C. Schweppe in 1979, the paper explores the concepts of sustainability and sustainable hybrid energy systems (SHES) applied to micro-generation, focusing on operational aspects rather than on socio-economic, environmental or regulatory ones. A concrete theoretical model for building a SHES is presented for a proposed grid-connected renewable microgrid. The model seeks to reconcile power supply and demand towards efficient equilibrium (homeostasis) proposing reward-based criteria for controlling renewable electricity supply and consumption in rural communities in Chile. Discussion and recommendations are also offered stating that energy sustainability (ES) is essentially a systems issue, and one where ES is first and foremost a structural, organizational and operational property which is in the very nature of the system itself - it is built into it - rather than explained by exogenous factors.