Coordinated usage of distributed sources for energy cost saving in micro-grid

The integration of renewable energy generation into the electric grid is difficult, because of the source intermittency and inconsistency with energy usage. This situation can be improved through a system with energy-storage devices and distributed generators that not only mitigates fluctuations in generation and supply, but also reduces cost. In this paper we present application of energy source control and distributed generator planning in a small micro-grid system to improve energy usage efficiency and cost reduction. The optimized planning strategy is obtained using optimum energy storage and generation scheduling. Three scheduling methods, using real-time actual electricity usage and price, one-day-ahead prediction values and Model Predictive Control (MPC) methods are tested and their performances are compared. Results show that significant cost saving could be achieved with proper planning and coordination of various energy supply sources.