## 7 The Case Study
### Kinetic Energy Harvesting Materials Assessment
#### 7.4.3. Cellulosic Materials  
Due to their flexibility and ease of deployment, cellulose-based nanogenerators have shown promise in high-foot-traffic environments, including urban walkways, shopping centers, and public transportation hubs [49]. This study found that cellulose-based TENGs could generate sufficient electricity from pedestrian movements to power low-energy devices such as environmental sensors and LED lighting. Integrating cellulose materials into flooring surfaces enables low-profile, non-intrusive installations that continuously capture energy as people walk. Additionally, the natural biodegradability of cellulose makes these devices suitable for temporary or semi-permanent installations, such as at music festivals, sporting events, and other high-traffic events where temporary power solutions are needed [54]. Innovative flooring solutions represent another promising application for cellulose-based nanogenerators. Embedding cellulosic TENGs within mats or floor tiles allows public spaces to harness energy from human motion to power lighting, digital displays, or environmental sensors. Ref. [116] examined the use of cellulose-based TENGs in illuminated flooring systems for indoor spaces, confirming their effectiveness in capturing energy from footsteps to power indoor lighting and signage. Outdoor applications have also demonstrated potential. [PERSON] et al. [63] reported on cellulose-based TENG mats embedded into flooring surfaces to capture energy in outdoor, high-traffic areas such as park walkways and sports arenas. This study emphasized the device's durability in harsh weather conditions, including rain and high temperatures, showcasing its adaptability and robustness for continuous outdoor use. Cellulosic nanogenerators, particularly those based on triboelectric and hybrid technologies, could be highly suitable for harvesting energy from foot traffic at the Al-Haram Mosque in Saudi Arabia. The mosque experiences constant high-density pedestrian movement, especially during daily prayers, Hajj, and Ramadan, providing significant mechanical energy that can be converted into electricity using cellulosic nanogenerators. Integrated beneath walkway surfaces, these devices could continuously capture kinetic energy reliably in dense traffic areas. Cellulose is derived from natural plant fibers, making these devices environmentally friendly and biodegradable--attributes aligned with the eco-friendly aspirations of modern architectural initiatives, including sustainable practices at religious sites. Furthermore, cellulose materials can be sustainably sourced and safely replaced over time without negative environmental impacts. Cellulosic TENGs can be integrated into soft flooring materials, carpets, or mats, ensuring comfort, particularly in spaces where visitors are frequently barefoot or wearing soft footwear. The flexibility of cellulosic materials allows seamless integration into flooring or carpets, maintaining the mosque's spiritual ambiance without intrusive design features. While cellulosic TENGs currently produce modest energy outputs, they are well-suited to powering low-energy applications within the mosque, such as:  
LED pathway lighting improves visibility without burdening the main power supply. Environmental sensors monitor air quality, temperature, or crowd density, thus enhancing comfort and safety. Emergency indicators or small signaling systems are beneficial during high-traffic events. Recent advances in surface treatments and hybrid configurations have significantly enhanced the durability of cellulosic TENGs, increasing their resistance to wear and tear caused by frequent pedestrian traffic. Protective coatings or combining cellulose with more robust materials can extend their lifespan and maintain efficiency, even under continuous mechanical stress. Despite their potential, implementing cellulosic nanogenerators in a high-traffic environment such as the Al-Haram Mosque presents several challenges. Current cellulosicTENGs primarily support low-power applications.