**2. Methods**

This paper proposes a case study to evaluate the hybridization degree (HD) of a Solar– Marine Hybrid Energy System (SMHES) in the Cozumel region. The method comprises the following activities: (1) determination of daily and monthly energy storage assessment of the SMHES in the region; (2) comparison of home-load profiles to determine the average energy consumption; (3) identification of the appropriate ESS using Multi-Criteria Decision Analysis (MCDA) with a combination of AHP-TOPSIS methods.

#### *2.1. Solar PV and Marine-Current-Energy Potential in Cozumel*

Figures 2 and 3 show the potential profile to size the solar photovoltaic system (PVS) and the marine-current system (MCS), respectively. For this study, 1 h data resolution was considered for both VREs; solar data were obtained from the Photovoltaic Geographical Information System (PVGIS), and the data analysis was based on Yunez-Cano et al. 2016 [25]. A higher daily potential of solar energy can be obtained using solar-tracking systems as power and efficiency can increase mainly in large-scale solar energy applications [26]; in this work, as the information on this is insufficient, their effect is not included. Marine-current-energy data were provided by the CEMIE-Océano project Mexico [27]; for both systems, data from 2014 were considered. The Köppen–Geiger climate classification of the Cozumel is Aw, which presents a tropical savanna climate characterized by an extensive dry season that is more marked and prolonged than in the monsoon climate and which contrasts with a rainy season with intense rainfall [28,29]. The seasonality analysis considered the spring months (March–May), summer months (June–August), fall months (September–November), and winter months (December–February) [30].

Figures 2a and 3a show the daily standard behavior of solar energy and marine-current energy, where the variations in solar irradiance and marine-current speed are evident at different times (daily variability). Solar potential was obtained via the integration of irradiance data (W/m2) during the day to obtain the irradiation potential (kWh/m2) (Figure 2b). The marine-current seasonal potential is defined as the average of daily measurements of marine-current speed (m/s) for each month (Figure 3b).

**Figure 2.** Standard behavior of irradiance and irradiation in Cozumel: (**a**) daily solar-irradiance profile (W/m2); (**b**) daily irradiation average per month (kWh/m2).

**Figure 3.** Marine-current-speed profile in Cozumel: (**a**) daily standard marine-current-speed profile; (**b**) daily current speed average per month.
