Optimal Energy Management Of A Grid-Connected Dual-Tracking Photovoltaic System With Battery Storage: Case Of A Microbrewery Under Demand Response

Abstract

Nowadays, the production of craft beer in microbreweries has become very popular all over the world. However, recent studies have demonstrated that the craft beer production process in microbreweries can be considered as energy intensive due to the fact that more to 8% of the production cost is allocated to thermal processes such as heating and cooling. Therefore, most microbreweries have been applying some Energy Efficiency actions to their production processes to decrease the amount of energy consumed and maximize the profits. In cases where the amount of energy consumed cannot be reduced using Energy Efficiency actions, Demand Response measures are implemented to reduce the cost of energy needed to supply the different processes involved. From the available literature, most of the studies based on Demand Response in the microbrewery sector have focused on the use of heating resources for the onsite energy generation to directly support the thermal processes. Very few published studies looked at the onsite “electricity” generation with small scale renewable energy sources and onsite energy storage to assist with energy cost reduction strategies. Therefore, this paper develops an optimal energy management model to minimize the energy cost of a microbrewery, under demand response, supplied with a grid-connected photovoltaic system with battery storage system. As a case study, a microbrewery in South Africa has been selected for simulation purposes. The detailed brewing process’s load profile, the solar resource, the system components’ specifications as well as the Time of Use energy cost structure has been used as input to the developed model with the aim of assessing and analyzing the technical and economic performance of the proposed system under the given operation conditions and constraints. The simulation results have shown that, as compared to supplying the microbrewery exclusively by the grid, the break-even point of the proposed supply option happens after 9.5 years of operation, corresponding to ZAR 398583.18 (USD 22592,09) cumulatively spent. For the considered 20 years’ operation lifetime, the projected savings on the lifecycle cost is ZAR 603490.49 (USD 34206,44) or 40.8%. The result of the discounted payback period analysis indicated that the total investment cost may be recovered in 13.8 years. The microbrewery is selected as a case study just to highlight the fact that some processes are critical and cannot be shifted without compromising the quality of the final product. Therefore, the proposed hybrid system, the developed model and the optimization methodology can be applied to any load in different demand sectors (residential, commercial and industrial) implementing demand response measures in order to reduce their operation energy costs.