Abstract

Small-scale electricity grids, also known as microgrids, integrate consumption with local production, and storage of electrical energy. Microgrids can enhance self-consumption of locally generated electricity and reduce peak power demand, an increasingly vital aspect given the capacity challenges in the Swedish power grid. The choice of control strategy for managing the battery impacts the performance of the microgrid by altering the ability of the system to reduce power peaks, manage battery health and achieve economic viability. This thesis explores the potential of microgrids to mitigate peak power demand through the simulation of a microgrid comprising two industrial-scale buildings, each equipped with a photovoltaic (PV) installation. Additionally, a secondary test case using load data from municipal buildings is included in the appendix to assess the generalizability of the results.

Three different control strategies, each designed with a separate objective, were used to carry out the simulations. The first strategy is forecast-based, using predictions of load and PV production to proactively respond to expected power peaks. The second strategy prioritizes battery health by avoiding harmful microcycling and using the battery mainly for more significant load-demand cycles. Lastly, the third strategy follows a simpler logic that maximizes the self-consumption of solar energy on an hourly basis, without regard for forecast data or battery degradation. The results from the simulations emphasize how each control strategy leads to different trade-offs between peak shaving, self-consumption, battery degradation, and economic performance. Thus, this thesis discusses and analyzes the reasons behind the obtained results as well as potential strengths and weaknesses of the three different control strategies. When combined with an intelligent control system, microgrids have the potential to reduce power peaks. Thus, this study demonstrates that microgrids can play an important role in addressing capacity challenges in the Swedish power system and that the investment can even be economically profitable under favorable conditions. Ultimately, the study emphasizes the importance of aligning the control strategy with the overall goals and characteristics of the microgrid which is crucial regardless of whether the objective with the microgrid is reducing peak loads, maximizing solar self-consumption, or preserving battery health over time.