Mas Roig mini-grid: A renewable-energy-based rural islanded microgrid

This paper presents a microgrid project, named Basic Distributed Nodes (NoBaDis), deployed in a stand-alone farm in Girona, Spain. NoBaDis is based on intensive use of information to maximize the penetration of renewable energy through two main strategies: anticipation and opportunity. The loads are classified in four different types according to priority and are controlled by intelligent sockets interconnected in a mesh network. Each socket measures the main electric parameters, communicates to the local computer bidirectionality by using ZigBee communications, and is able to switch on/off the loads. The power system is composed by low-density energy sources (renewable) and high-density cogeneration engine. These elements can be interconnected in two different configurations to test different scenarios. After 5 years of operation, the results have shown the importance of real-time management system to reduce the operational costs of the microgrid. In addition the project has highlighted the importance of distributed generation and control to assure the energy supply in terms of quality and quantity even in extremely weather conditions as it was in March 2010 during a snow storm that generated a black out that affected more than 250,000 consumers in this area during one week.