With the global shift towards carbon neutrality by 2050–2060, renewable energy sources are increasingly being incorporated into energy management plans. However, the variability of renewables presents challenges for integration into power plants, leading to the exploration of innovative energy storage technologies. The P2G technology is emerging as a solution that leverages green hydrogen production to bridge renewables with existing fossil fuel power plants, enabling diverse applications and storage options. By blending green hydrogen into natural gas, researchers are exploring more environmentally friendly energy production methods, albeit with a current limitation of 10% hydrogen blending. In the building sector, Multi-Generation Hybrid Energy Systems (MGHESs) are playing a key role in reducing fossil fuel dependence and striving towards Net Zero Energy Buildings (NZEB). Recent studies demonstrate the benefits of coupling renewable resources like PV panels, wind turbines, and biogas generators in MGHES configurations, showcasing cost and emission reductions. Researchers are also investigating optimized designs for waste-to-energy systems and exploring the potential of biogas-driven MGHES with multiple energy outputs including hydrogen and water desalination. The integration of biogas-fueled engines and solar technologies in MGHES designs is a key focus, highlighting the innovation and sustainability goals driving advancements in energy systems for buildings.