## 7 The Case Study
### Sustainability and Future Directions for Al-Haram  
The Al-Haram Mosque's energy strategy is shifting towards a more sustainable model, aligning with broader Saudi initiatives to adopt renewable and eco-friendly energy sources [87]. Several sustainable practices have already been implemented or are under consideration [103; 112]:  
1. LED Lighting Upgrades: The shift from traditional lighting to LED technology has significantly reduced the mosque's lighting energy consumption [88]. LEDs are more energy-efficient and have a longer lifespan, making them particularly suitable for high-use environments [87].
2. Cooling Innovations: To address the high energy demands associated with cooling, the mosque may consider adopting district cooling systems or high-efficiency chillers to lower electricity usage [113]. Additionally, advanced air distribution and heat exchange systems could help manage cooling more efficiently [87].
3. Energy Storage Solutions: Battery energy storage could enhance the integration of renewable sources, especially solar power, by storing excess energy generated during the day [100]. This stored energy can then be utilized during peak demand periods or at night when solar energy is unavailable.  
Despite the potential benefits of renewable and self-powered systems, several challenges hinder the complete adoption of these technologies at the Al-Haram Mosque:  
First, the Scale of Energy Demand: The mosque's enormous energy requirements, particularly for cooling and ventilation, make it difficult for renewable and self-powered systems alone to fulfill the entire demand [101]. Supplementary renewable systems may be feasible, but traditional energy sources will likely remain essential for meeting the primary load [109; 112].  
Second, Aesthetic and Spatial Constraints: Given the mosque's historical and religious significance, any new installations must be carefully considered [102; 103]. Large-scale solar panels [110] or visible piezoelectric systems could conflict with the mosque's aesthetics [113], requiring creative and unobtrusive integration methods.  
Third, Cost and Maintenance: Implementing and maintaining renewable energy systems, especially in a high-traffic environment, can result in substantial costs [100]. Advanced energy-harvesting technologies such as TENGs and piezoelectric flooring may also require frequent maintenance due to wear and tear, potentially disrupting mosque operations [114].  
Fourth, Environmental Conditions: The harsh climate in Mecca, characterized by high temperatures and dust, poses durability challenges for solar and piezoelectric systems [115]. Ensuring these technologies can withstand environmental conditions without frequent replacement or repairs is essential for their long-term viability [116].  
The Al-Haram Mosque's energy consumption is immense because of its scale, continuous operations, and the comfort and safety requirements of millions of pilgrims [101]. Although traditional fossil fuel-based energy sources have reliably powered the mosque, there is an ongoing shift towards renewable and self-powered energy systems [117]. Therefore, further exploration of solar power, piezoelectric energy harvesting, and hybrid systems combining solar and kinetic energy is necessary to reduce reliance on non-renewable sources and enhance sustainability.  
While current self-powered technologies such as piezoelectric flooring and TENGs might not fully satisfy the mosque's extensive energy needs, they provide valuable supplementary solutions that could alleviate demand on the primary grid, particularly for low-power applications. As these technologies continue to advance, the potential for renewable and self-powered systems to significantly contribute to the mosque's energy infrastructure will likely increase, supporting Saudi Arabia's vision for a sustainable future [118].