# Influencing Factors of Solar-Powered Electric Vehicle Charging Stations in Hail City, Saudi Arabia
## 4 Results and Discussion
### Charging Stations
#### 4.2.2 Factors Affecting the Number of Stations  
Impact of Average Car Consumption Rate (R) and Charger Power (CP) on Station Numbers  
The data show that the average R significantly influences the number of EVCSs needed. Figure 2 demonstrates the precise relationship between vehicle efficiency and the need for charging infrastructure through a step-by-step increase in the NS' as R values climb. For example, the station requirement increases from 6 to 41 when comparing the extremes of R values (0.05 vs. 0.40) for a mid-range CP of 45 kWh. This significant disparity highlights that vehicle efficiency is essential when developing urban EV infrastructure. In some circumstances, the link is described in depth as follows. * Lowest R = 0.05 kWh/km: At this optimal efficiency level, the NS' required started at 13 for the lowest CP of 20 kWh. As CP increases, a notable decrease in station requirements is observed. For instance, at CP values of 40 and 45 kWh, the NS' drops to seven and six, respectively. The highest CP of 75 kWh requires the fewest stations, with only four needed. * Medium R = 0.20 kWh/km: With moderate efficiency, the station requirement escalates noticeably. At a CP of 20 kWh, the NS' almost quadruples to 46 compared to the lowest R. Even at higher CP levels, such as 60 and 75 kWh, the numbers are significantly higher than in the lowest R scenario, requiring 16 and 13 stations, respectively. * Highest R = 0.40 kWh/km: This scenario demands the most substantial infrastructure and represents the least efficient EVs: the station requirement at a CP of 20 kWh skyrockets to 91. Even at the highest CP of 75 kWh, the requirement remains high at 25 stations, highlighting a more than sixfold increase from the most efficient scenario. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Share of Private Charging (\%)** & **0** & **20** & **40** & **60** \\ \hline Zone 4 & 7 & 6 & 5 & 4 \\ \hline Zone 6 & 6 & 5 & 4 & 3 \\ \hline Zone 7 & 6 & 5 & 4 & 3 \\ \hline Zone 8 & 5 & 4 & 3 & 3 \\ \hline Zone 9 & 3 & 2 & 2 & 2 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Expected number of stations at different private charging rates in Hail City [41]. Effects of Car Slots (CSs) per Station and Average Car Consumption Rate (R)  
Analyzing the relationship between CSs and the required NS' reveals significant insights, particularly concerning vehicle efficiency. For vehicles with an R-value of 0.05 kWh/km, the NS' needed decreases sharply from nearly 13 stations at 50 CSs to 5 stations at 100 CSs, as shown in Figure 3. This trend is consistent across different R values, although less efficient vehicles (e.g., R = 0.40 kWh/km) show a more significant reduction under the same conditions. The diminishing returns on increasing the number of CSs become apparent beyond 200 slots, where the NS' plateaus, suggesting an optimal range for station capacity depending on the average vehicle efficiency in the fleet. Figure 3: Impact of CSs per station and average car R on adjusted number of stations. Figure 2: Impact of average car R and CP on adjusted number of stations. Car Battery Capacity's Role in Charging Infrastructure Needs  
Figure 4 presents the required NS' as a function of BC for EVs, stratified by different R values. It illustrates the response of charging infrastructure needs across a BC range of 25 kWh to 100 kWh, with R values varying between 0.05 and 0.40 kWh/km. Vehicles with an R = 0.40 kWh/km show a generally increasing trend in the required NS' as BC increases until 65 kWh. Notably, there is a sharp decrease in station requirements between 80 and 95 kWh, indicating a potential threshold beyond which significantly less infrastructure is needed to support larger BCs in highly efficient vehicles. It is also evident from the figure that the same effect applies to the required NS' with an increase in R, where a greater NS' required. Additionally, the impact of increasing BC on the NS' at low R values is almost constant, at 0.05 and 0.10 kWh/km for 7 and 13 stations, respectively.