# Making Optimal Location-Sizing Decisions for Deploying Hybrid Renewable Energy at B&Bs
## 5 Results and Discussion
### Analysis of the Base Case
#### 5.1.1 100% Self-Sufficiency in the Base Case
In the hybrid solar-wind system (hybrid RE), solar energy is only available during daytime hours, while wind energy may be available throughout the day. As the hybrid RE can take advantage of the complementarity between solar and wind energy, the annual costs of the hybrid RE are 17.2% lower than the annual costs of the solar-only system. Compared to prior studies (Table 1), the cost of the energy of the hybrid RE in this study (USD 1.838/kWh) is competitive, although it also depends on the cost setting of each technology. According to Table 3, wind energy contributes 10,287 kWh (8.8%) to the annual RE generation. However, as shown in Table 4, the volume of solar and wind energy generation varies depending on the season, which affects their percentage share. For example, the percentage of wind energy for each season is as follows: 4.8%, 1.3%, 13.2%, and 22.1% in spring, summer, autumn, and winter, respectively. In the summer, solar contributes the most to RE generation (98.7%), as solar radiance reaches its maximum. In the spring and autumn, solar is still preferred, but not as much as in summer. Finally, when the wind speed reaches its maximum in the winter, the model prefers a more significant wind allocation than in other seasons. Further details on total energy generation in each time period for each season-representing month for hybrid RE are presented in Table A4 (in Appendix C). Although solar energy completely dominates RE generation in Pingtung, the model still relies on wind energy to simultaneously supply power. In addition to seasonal variations, solar is only available during daytime hours and wind may be available throughout the day. Considering B&Bs receive energy supply from RE that depends on local weather and B&Bs also have to cope with the fluctuations in energy demand due to peak peri \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Energy (kWh)** & **April (Spring)** & **July (Summer)** & \
\begin{tabular}{c} **October** \\ **(Autumn)** \\ \end{tabular} &
\begin{tabular}{c} **January** \\ **(Winter)** \\ \end{tabular} \\ \hline Solar & 9719 (95.2\%) & 10,853 (98.7\%) & 8771 (86.8\%) & 6988 (77.9\%) \\ Wind & 490 (4.8\%) & 145 (1.3\%) & 1336 (13.2\%) & 1984 (22.1\%) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Energy generation (kWh) and percentage share of solar/wind for each season-representing month. ods/seasons, determining the specific size of the batteries becomes a critical decision. However, there are significant differences between the LCOEs for generating and saving energy (Section 4.3.1). This condition leads to different decisions regarding surplus energy. Sometimes it is more cost-effective to save that surplus for later use, resulting in greater battery capacity and higher annual costs. However, it is more cost-effective to let it be unused at other times. In terms of emissions, most of Taiwan's electricity generation is provided by Taipower, a state-owned power company that uses fossil fuels to generate electricity. However, generating one kWh of electricity from the power grid is also responsible for 0.532 kgCO\({}_{2}\)e (kilograms of carbon dioxide equivalent) [85]. If the B&B is able to run its business with 100% RE, this would result in the avoidance of CO\({}_{2}\) emissions of 26,715 kgCO\({}_{2}\)e or 26.7 tCO\({}_{2}\)e (tons of carbon dioxide equivalent) per year. Compared to per capita CO\({}_{2}\) emissions in Taiwan (11.02 tCO\({}_{2}\)e/person) [86], the reduction may appear insignificant. However, if half of Taiwanese B&Bs switch their primary energy sources to RE, they could potentially reduce emissions by 94,010 tCO\({}_{2}\)e per year. It is worth mentioning that there are approximately 7042 B&Bs in Taiwan [66]. Taiwan is still in the process of formulating appropriate policies to govern CO\({}_{2}\) emissions. Therefore, the following analysis is based on the average carbon tax rate in Europe, that is, USD 42.29/tCO\({}_{2}\)e [87].