## 5 Methodology Validation
### Scenario 4: Solar Photovoltaic, Batteries Storage System, and Combined Heat and Power  
This scenario is a combination of the three previous scenarios. The objective is always the same: to supply the critical loads. In the case of the combination of PV, energy storage and CHP, the installed capacity of each resource changed. It is important to mention that for this scenario the MG operated in islanding mode, and only considered energy for critical loads. To test the behavior of the system according to the design, the CHP always supplied its maximum capacity. The PV system supplies the energy depending on the solar radiation. The battery is in charge of supplying the necessary energy for the load when the total energy from CHP and PV systems are not enough, or to absorb the excess energy from \begin{table}
\begin{tabular}{c c} \hline \hline
**Component** & **Cost [8/kWh]** \\ \hline Operational and maintenance & 0.013 \\ \hline Installation & 0.006 \\ \hline Fuel & 0.003 \\ \hline Total cost & 0.022 \\ \hline \end{tabular}
\end{table} 
Table 7: Estimated cost for CHP. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Capacity Installed [kW]** & **8/kW** & **Estimated Cost [USD]** \\ \hline
800 & 2091.27 & 1,673,016 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Estimated cost per kW. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Component** & **Cost [8/kW]** \\ \hline Operational and maintenance & 0.013 \\ \hline Installation & 0.006 \\ \hline Fuel & 0.003 \\ \hline Total cost & 0.022 \\ \hline \end{tabular}
\end{table} 
Table 7: Estimated cost for CHP. CHP and PV systems while the state of charge of the battery is less than 95%. Depending on whether it is necessary to supply additional energy or absorb excess, the battery will function accordingly. When CHP and PV systems generate energy higher than the necessary energy for the critical loads, and if the SOC of the battery is higher than 95% a new load is connected to conserve the energy balance. If the state of charge of the battery is less than 20%, the load is disconnected and the energy from CHP will be used to charge the battery, thus the load will be reconnected when the state of charge of the battery is at least 25%. According to the CHPs available on the market and the required average energy for the critical loads (630 kWh), one CHP of 420 kW was selected. The CHP will produce approximately 50% due to the mechanical limitations. The other 50% will be produced from the PV system during the day and the excess energy stored for use during the night. Hence, the capacity of the PV system selected is 1.4 MW, and considering 5h of average solar radiation, approximately 7 MWh will be produced. The parameters considered the simulation are shown in Table 10.  
To calculate the area needed for each system, the dimensions provided for the manufacturer available in the datasheet was used. The configuration and location for PV system  
The days of austerity to supply the critical loads is almost two days, considering that the main grid was disconnected around 2:00 a.m., as observed in Figure 18. This could be observed when the load was disconnected for around 90 min or 1.5 h. This disconnection occurs due to the state of charge of the battery being 20% and the CHP not being able to supply the energy required for the load. The energy of CHP is used to charge the battery. Then the charge is reconnected when the battery reaches a state of charge equivalent to 25%. The load interruption as observed in the beginning of the second day is blinker, which occurs due to lack of solar radiation and only the CHP has available power to supply the critical loads. However, the CHP cannot supply sufficient energy for the total demand. On the other hand, the voltage profile in the substation in the low voltage side is shown in Figure 19, which indicates that the MG installation does not affect the correct functioning of the system, thus the voltage profile is improved. In the same figure, it is observed that the voltage in p.u does not present violations.