This book presents a technical feasibility and economic viability of a wind-solar hybrid renewable energy generation system with rainwater collector for electrical energy production. The power generated would supply part of the energy requirements of the high-rise building where the system is installed. This system is patented as an innovative design, which it integrates and optimizes several green technologies; including urban wind turbine, solar array and rain water collector. This system overcomes the inferior aspect on the low wind speed by guiding and increasing the speed of the high altitude free-stream wind through power-augmentation-guide-vane (PAGV) before it enters the wind turbine at the centre portion. The meteorological data for three sites in Malaysia were evaluated for wind and solar power and the energy saving by using rainwater. Based on recorded data in three sites in Malaysia, extractable energy from wind, solar and rainwater is calculated. Then, the advantages of this system were compared with a similar wind-solar system without PAGV. The economic analysis of the system is performed using the life cycle cost (LCC) and payback period methods.