## 8 Results and Discussion
### Environmental Impact and Sustainability  
The impact on the environment and long-term sustainability of the HEMS are crucial considerations for its overall effectiveness. This section examines the system's contribution to reducing greenhouse gas emissions, its role in promoting renewable energy usage, and the long-term sustainability benefits. The integration of REs such as PV and WTs significantly reduces the reliance on fossil fuels. This reduction leads to a decrease in greenhouse gas emissions. In the baseline scenario without any DR programs, the system heavily relies on renewable sources during daylight hours, with PV generation peaking at 910 W and wind generation peaking at 880.1 W. By optimizing the use of these renewable sources through DR programs, the system further minimizes the need for fossil fuel-basedpower, thus reducing emissions. The 20% DR scenario effectively shifts energy consumption to off-peak periods, reducing the load on backup systems like FCs and batteries that might otherwise rely on non-renewable energy. This shift not only lowers operational costs but also contributes to a significant reduction in carbon footprint. The more aggressive 30% and 40% DR scenarios enhance this effect by further smoothing out energy consumption peaks, ensuring that RESs are utilized to their maximum potential.  
The HEMS promotes the usage of RESs by integrating PV and WTs into the residential energy grid. In Liaoning Province, where the case study is based, solar irradiation reaches up to 895.16 Wh/m\({}^{2}\), and wind speeds peak at 8.89 m/s, making it an ideal location for renewable energy generation. The system's design ensures that these renewable sources are the primary contributors to meeting the household's energy needs. Throughout the day, PV and wind energy are prioritized, with PV generation starting as early as 6:00 a.m. and peaking at midday. Wind energy complements PV generation by providing steady power throughout the day and peaking in the late afternoon. By leveraging these renewable sources, the HEMS reduces dependency on conventional power sources, promoting a cleaner and more sustainable energy mix.  
The long-term sustainability benefits of the HEMS are multifaceted. Firstly, the system's reliance on RESs contributes to the reduction of fossil fuel consumption and greenhouse gas emissions. This reduction is crucial for combating climate change and promoting environmental health. Secondly, the HEMS enhances energy resilience by incorporating diverse energy sources and storage solutions. The integration of batteries, FCs, and EVs maintains a dependable power supply even during periods of reduced RES generation. For example, during the highest load demand of 1658 W at 9:00 p.m., the system effectively utilizes battery discharge and wind generation to satisfy the energy needs, demonstrating its robustness and reliability.  
The economic savings achieved through DR programs translate into long-term financial sustainability. By reducing operational costs and achieving quick payback periods, the HEMS provides an economically viable solution for residential energy management. These savings can be reinvested into further improving the system or into other sustainable initiatives, creating a positive feedback loop for environmental and economic benefits. The environmental impact and sustainability of the HEMS are significant. By reducing greenhouse gas emissions, promoting renewable energy usage, and providing long-term sustainability benefits, the system proves to be an effective solution for modern residential energy needs. The integration of DR programs further enhances these benefits, making the HEMS a model for sustainable and environmentally friendly energy management.