Optimal energy management of a rural microgrid system using multi-objective optimization

Electrification of rural areas has always been a challenge. In addition, large livestock farms such as dairy farms, also face environmental problems due to inappropriate treatment of animal wastes. Therefore, improvement of the electrical system in farms vis-a-vis efficient waste management is of great importance to industry. In this paper, a combined cooling, heating, and power (CCHP) microgrid model was built to improve system efficiency of energy utilization and lessen environmental problems caused by animal wastes based on multi-objective optimization. In this proposed model, the animal manure is used to produce biogas, which is used to feed internal combustion engines (ICEs), gas boilers, and absorption chillers. The generated electricity would offset that would otherwise be bought from main grids. PV generation is introduced to further increase the renewable fraction of energy contents. The electrical storage is also included to balance power demand and power supply. To increase system efficiency of energy utilization, coolant water from ICEs, plus their exhaust, could be utilized based on the thermal storage modeled, by inclusion of absorption refrigerator and heat exchanger. The final goal is to maximize energy output from distributed energy resources (DERs) and meanwhile minimize daily system operating cost. Extra electricity generated beyond the load demand could be used to charge battery storage. In this way, system energy cost is reduced with energy system improvement and reconfiguration, and surrounding environmental problems due to animal wastes are also lessened.