## 3 Case Study of the Port of Aviles
### Different Modeling Approaches
#### 3.2.1 EMT Modeling  
This section presents the results of two selected consumption profiles after outlining different operational modes. It details the initial energy contributions from generation sources, the energy supplied by the PAT system, and the grid's role in energy provision. The findings support conclusions and guide future improvements by addressing system limitations and developing adaptable operating strategies for enhanced energy performance in port operations.  
* _Scenario 1--EMT Modeling: On-Grid Without Self-Consumption and PAT:_ A comparison of generated and consumed energy revealed a significant surplus, with the hybrid module producing 1449 kWh/year while demand was only 171 kWh/year. This underscored the technology's impact, even without direct interaction between generation and demand. Figure 9 shows the energy balance with substantial surplus energy and the deficit in terms of strategic operation for two sample months.  
The energy profiles for these two representative months of the year were analyzed to evaluate how seasonal variations impacted renewable energy generation and tanked charging and discharging patterns. This analysis was essential for assessing the adequacy of system sizing and understanding how demand distribution affected the overall utilization of energy resources.  
After analyzing the energy profiles throughout the year and conducting an hourly calculation for more accurate results, it was found that a single hybrid energy module covered 60.26% of the current demand, which corresponded to 5506 h out of the 8760 h. A significant amount of energy, totaling 558,431 kWh, had to be imported from the grid.  
Figure 8: Selected energy demand sectors.  
* _Scenario 2--EMT Modeling: On-Grid with Self-Consumption and PAT_: This scenario focused on the interaction between generation and demand, integrating both the energy-generating components and the storage capabilities of one module. A first optimization was focused on the storage capacity that maximized economic benefits, which was 15 m\({}^{3}\). This volume entirely almost eliminated dependence on the electricity grid, covering a total of 8619 h annually, equivalent to 98.39% hours of the year. For the energy demand sector, two representative months of the year, January and August, were selected. These months were chosen to capture the key differences in operation between winter and summer (Figure 10).  
The analysis of data from January revealed that, due to significant surpluses, particularly from renewable sources like wind and solar, the tank was rarely fully discharged. On the other hand, in August, the energy pattern lost regularity, characterized by a series of small peaks throughout the period. This fluctuation was likely due to increased infrastructure usage, typical of the summer months when port activity tended to rise. August's tank loading and unloading profile showed an increased number of cycles due to the solar unit being the primary energy source (Figure 10).  
Figure 9: EMT modeling for Scenario 1: energy balance in (**a**) January and (**b**) August.  
Loading mainly occurred during photovoltaic energy surpluses, while the PAT system was used more consistently to manage peak demand. By implementing the installed technologies, the total cost of purchasing energy from the grid was reduced, reflecting minimal dependency on grid imports. Grid consumption dropped to 2.76 kWh from an initial 171.66 kWh.  
For this combination of energy sectors of the port and given demand profile, the optimized final storage capacity determined to maximize the performance of the hybrid solution was 59 m\({}^{3}\). The estimated optimal storage volume significantly increased the number of hours covered, reaching a total of 4980 h and supplying energy for 60% of the year. Nevertheless, the system still relied on grid support to meet the demand unmet by the hybrid energy system.  
Figure 10: EMT modeling for Scenario 2: energy balance in (**a**) January and (**b**) August.