We address a BEMS (Building Energy Management System) to guarantee reliability of electric-power supply in dynamic uncertain environments. The building microgrid as the target of BEMS has multiple distributed power sources including a photo-voltaic power system and Electric-Vehicle (EV). EV is regarded as an autonomously-moving battery due to the original means of transportation and is hence a cause of dynamic uncertainty of the building microgrid. The main objective of synthesis of BEMS in this paper is to guarantee the continuous supply of power to the most critical load in a building microgrid and to realize the power supply to the other loads according to a ranking of load importance. We synthesize the BEMS as a reactive control system that monitors changes of dynamic uncertain environment of the microgrid including departure and arrival of an EV, and determines a route of power supply to the most critical load. Also, we conduct numerical experiments of the reactive BEMS using models of power flows in the building and of charging states of the batteries. The experiments are incorporated with data measured in a practical office building and demonstration project of EMS at Osaka, Japan. We show that the BEMS works for extending the time duration of continuous power supply to the most critical load.

This paper introduces a communication system model with renewable power supply. As we assumed a battery-free microgrid system with conventional power as a backup power supply, we propose a method of power state and data transmission scheduling for delay-tolerant communication networks, which reduces conventional power consumption by operating adaptively to changes in renewable power. We found through computer simulations that the proposed method efficiently reduced conventional power consumption.

It is not easy to provide energy supply based on renewable energy enough to satisfy energy demand anytime and anywhere because the amount of renewable energy depends on geographical conditions and the time of day. In order to maximize the satisfaction of energy demand by renewable energy, surplus energy generated with renewable energy should be stored in batteries, and transmitted to electric loads with high demand somewhere in the electricity system. This paper proposes a novel autonomous decentralized mechanism of energy interchanges between distributed batteries on the basis of the diffusion equation and MCMC (Markov Chain Monte Carlo) for realizing energy supply appropriately for energy demand. Experimental results show that the proposed mechanism effectively works under several situations. Moreover, we discuss a method to easily estimate the behavior of the entire system by each node with the proposed mechanism, and the application potentiality of this estimating method to an efficient method working with non-renewable generators while minimizing the dependence of non-renewable energy, and an incentive mechanism to prevent monopolizing energy in systems.