*3.2. Weather and Environment Data*

The weather data were collected for the year 2022 at the coordinate location of the chosen REC case study site. The model requires accurate measurements of ambient temperature, wind speed, and global horizontal irradiance (GHI) solar conditions to evaluate the hour-by-hour power output of the renewable generation technologies. Figure 4 shows the hourly mean temperature and GHI for each month over one year. A higher GHI is observed in the summer period as expected in the northern hemisphere.

**Figure 4.** Temperature and solar conditions over a one-year period at the island location. The weather conditions are assumed to remain constant year-on-year through the lifetime of the system.

#### *3.3. System Design and Characteristics*

#### 3.3.1. PV Solar Array Model

The Mediterranean region's warm and dry climate promotes the use of PV solar systems to generate clean energy. For the purposes of the study, the solar array was assumed to be installed at 180◦ directly to the south, and at an optimal tilt angle of 38.7◦. The power output of the solar panels *PPV* was modelled using the following governing equation [46]:

$$P\_{PV} = \mathbb{C}\_{PV} d\_f (\frac{G(t)\_{modulle}}{G\_{STC}}) [1 + \mathfrak{a}\_P (T\_\mathfrak{c} - T\_{\mathfrak{c}, STC})] \tag{1}$$

where *CPV* is the generation capacity (kW) of the solar installation under standard conditions, *df* is the derate factor, *G*(*t*)*module* is the direct solar irradiance in W/m2, *GSTC* is the direct solar irradiance under standard test conditions (1000 W/m2), *α<sup>P</sup>* is the thermal power coefficient (%/◦C), and *Tc*,*STC* is the PV cell temperature under standard test conditions (25 ◦C). *Tc* is the PV cell temperature and is calculated by considering the measured nominal operating cell temperature (NOCT). NOCT is the cell measured temperature at a solar irradiance *GNOCT* of 800 W/m2, an ambient temperature *Ta*,*NOCT* of 20 ◦C, and a wind speed of 1 m/s [44]. This known thermal characteristic can then be used to adjust the cell temperature and find the corrected power output using the following equation [47]:

$$T\_c = T(t)\_d + (T\_{c, \text{NOCT}} - T\_{a, \text{NOCT}})(\frac{G(t)\_{modulle}}{G\_{\text{NOCT}}})(\frac{1 - \eta\_{mp}}{\tau a}) \tag{2}$$

where *T*(*t*)*<sup>a</sup>* is the ambient temperature at timestep *t* and *ηmp* is the cell efficiency. The constants *τα* can be assumed to be 0.9 for most cases. Since *ηmp* is not known, the efficiency under standard conditions *ηmp*,*STC* is substituted into the cell temperature equation above and the result yields the following:

$$T\_{\varepsilon} = \frac{T(t)\_d + (T\_{\varepsilon, \text{NOCT}} - T\_{a, \text{NOCT}})(G(t)\_{\text{module}}/G\_{\text{NOCT}})[1 - (\eta\_{mp, \text{STC}}(1 - a\_P T\_{\varepsilon, \text{STC}}))/\pi a])}{(1 + (T\_{\varepsilon, \text{NOCT}} - T\_{a, \text{NOCT}})(G(t)\_{\text{module}}/G\_{\text{NOCT}})[(a\_P \eta\_{mp, \text{STC}})/\pi a]}\tag{3}$$

The GHI input data need to be adjusted based on the local latitude *ϕ* and module tilt *β* to find the module irradiance *G*(*t*, *module*) for the time of day and year. This is found with the following equations [48]:

$$G(t)\_{module} = \frac{G(t)\_{horizontal} \sin(\alpha + \beta)}{\sin \alpha} \tag{4}$$

$$
\alpha = 90^\circ - q + \delta \tag{5}
$$

$$\delta = 23.45^\circ \cdot \sin[360/365(284+d)]\tag{6}$$

where *G*(*t*)*module* is the module irradiance, *G*(*t*)*horizontal* is the GHI data, *α* is the elevation angle, and *δ* is the declination angle which deviates from the earth's tilt of 23.45◦ depending on the day of the year *d*.
