*3.2. Hourly Power and Water Flows*

Figure 11 shows the power flows of a representative day associated with each desalination technology coupled with hybrid energy systems on both islands. The power flows confirm that systems on Camasusu Island are diesel-favored, while those on Lubang Island are RE-favored. An exception is the RO system on Camasusu Island, which uses an RE-favored system because of its high turndown capability. The diesel-favored systems have batteries that drain to 20% outside of sun-hours, which result in diesel generation to meet the baseload. In contrast, the RE-favored systems only utilize diesel generation during days with low solar irradiation.

Figure 12 compares the power consumed by the different desalination units and demonstrates how water is stored. In MED and MSF, water output is continuous because of the low turndown, increasing water level over time. In RO systems, however, water storage is drained until it reaches the minimum water level. After this, the RO plant will start producing water to meet the demand, explaining the uneven energy demand profile. Because of this, the RO system behaves as an additional load during the day. This is evidenced by the monthly average water level shown in Figure 13 wherein MED and MSF water storage tanks are full, while RO water storage is minimum.

**Figure 11.** Hourly power output of electrical components and Li-ion BESS state of charge (SOC) on Camasusu Island (**top**) and Lubang Island (**bottom**). Li-ion BESS usage is high on Lubang Island.

**Figure 12.** Hourly desalination energy consumption and water storage fraction on Camasusu Island (**top**) and Lubang Island (**bottom**). Power consumption is uneven in the RO system on Camasusu Island.
