# Stateflow-Based Energy Management Strategy for Hybrid Energy System to Mitigate Load Shedding
## 6 Conclusions  
This work presented a Stateflow (SF)-based energy management strategy (EMS) for a renewable-based hybrid energy system (HES) that experiences regular load shedding. The EMS controls HES operation during both modes of operation, i.e., grid-connected mode and islanded mode. It optimizes the energy production and utilization in addition to achieving uninterrupted power supply during load shedding. The performance of the system is investigated using a real data set of irradiance, temperature, and load shedding schedule for a small residential community in the city of Quetta, Pakistan. The simulation results proved the resiliency of the HES in different weather and load shedding conditions. Furthermore, the superiority of the control strategy is confirmed in terms of reduced grid  
Figure 21: Contribution of different energy sources in summer and winter seasons.  
Figure 20: The annual energy generation mix of HES and the load demand.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Contributor** & **Energy (kWh)** & **\% of Demand** \\ \hline Net energy from grid (to satisfy the load) & 95,053 & 79.6 \\ Net energy from PV (to satisfy the load) & 8688 & 7.2 \\ Net energy from ESU (Fraction of PV and grid) & 14,674 & 12.3 \\ Net energy from both Gen & 1110 & 0.9 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Annual contribution from different energy sources.  
burden by prioritizing the utilization of PV energy. Additionally, the research has found that the application of SF minimizes the computational complexity of the problem solving and advantageously demonstrates the behavior of an event-driven system.  
To improve the research, future work should focus on the following key areas. First is to develop a more refined control strategy for the HES pool (i.e., the interconnection of several HES) and to study its effectiveness in handling the load shedding issue. Second is to extend the SF utilization by considering the multi-layer control design for HES that will contain a prediction layer (to forecast demand, PV, and grid vulnerabilities), energy management layer (to improve energy efficiency), and operational layer (for current and voltage control). The third key area is to focus on the techno-economic performance of HES by studying the impact of various HES configurations and energy management strategies on the energy yield of the system.  
Conceptualization, Z.S.; Methodology, M.P.B. and Z.S.; Formal analysis, M.P.B. and Z.S.; Investigation, M.P.B. and Z.S.; Funding acquisition, Z.S., S.A.K., W.A., A.R.B. and N.K.; Resources, Z.S.; Software, M.P.B., N.K. and S.A.K.; Supervision, Z.S. and A.R.B.; Validation, Z.S. and W.A.; Visualization, W.A. and S.A.K.; Writing--Review & editing, M.P.B., Z.S. and A.R.B. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Higher Education Commission, Pakistan, under the HRDi-UESTP Scholarship Program and Ministry of Higher Education, Malaysia, under the Malaysia Rising Star Award grant. The grant was managed by Universiti Teknologi Malaysia under Vot. No.R.J130000.7823.4F919.  
The data that support the findings of this study were derived from the openly available data in a public repository at [[https://solcast.com/](https://solcast.com/)]([https://solcast.com/](https://solcast.com/)), (accessed on 14 May 2021) and [[http://ccms.pittc.com.pk/FeederDetails](http://ccms.pittc.com.pk/FeederDetails)]([http://ccms.pittc.com.pk/FeederDetails](http://ccms.pittc.com.pk/FeederDetails)) (accessed on 14 May 2021) by providing required information.  
This article has been made possible by the support of the Centre of Electrical Energy Systems (CEES), School of Electrical Engineering, Universiti Teknologi Malaysia (UTM). The authors would like to thank Ministry of Higher Education, Malaysia and Higher Education Commission, Pakistan for providing resources and the financial support.  
The authors declare no conflict of interest.