Introduction
Renewable energy power generation has gained acceptable level of attention in the present day energy sector, even though the majority contribution to the energy sector is from fossil fuels like-coal, natural gas and other fossil fuels1. Among renewable power generation, wind energy has gained its importance and marked as cheapest and freely available energy resource. It is a clean source with almost negligible greenhouse gas emissions leading to the sustainable energy generation2, 3. Wind energy industries has great impact on climate change, wind power generation is most essential in the present environmental condition of rising global warming, pollution levels etc.4 Understanding the wind energy conversion is much simpler. Uneven heating of the atmosphere by the suns solar energy results in wind flow. Wind movement i.e., the kinetic energy present in the wind is converted in to the mechanical energy using aerodynamically designed wind turbines. This mechanical energy present in the turbine shaft is converted into electrical energy using alternators5. Evolution of wind turbine technology was dated back to 7th century BC in the Afghan highlands6. The first recorded wind turbines are vertical axis and later horizontal axis wind turbines (HAWT) recorded their appearance in the historical documents of Persia6.However, horizontal axis wind turbines became more popular and widely acceptable in modern wind energy farms7. VAWTs are lags behind horizontal axis wind turbines in development even though, they are aerodynamically efficient. Research and development on VAWTs started in early 1980s8 . There were lot differences between HAWT and VAWT which were clearly explained8-10, this comparative study reveals that design, installation and performance of VAWT would be more effective, therefore this would serve better in meeting present day increasing energy demand.