Analysis and inter-comparison of energy yield of wind turbines in Pakistan using detailed hourly and per minute recorded data sets

Within Pakistan the rather ease of availability of hydrocarbon gas reserves in Balochistan had the effect of delaying the work on feasibility of renewable energy and installation of appropriate pilot projects. However, with a clear sign of depletion of fossil fuels the present government has initiated a major programme of wind speed measurement and installation of large wind farms at locations that have been deemed fit for this purpose. The key force behind the present resurgence of renewable energy activity within Pakistan is the creation of the Alternative Energy Development Board (AEDB), established by the Government of Pakistan in 2003. Under the aegis of AEDB wind speed data have been measured over a period of 4 years at a minute’s frequency for Southern Pakistan at Gharo. The period of measurement was May 2002–June 2006. The present work aims to explore the potential for using hourly- as opposed to minute-by-minute data for the design of wind energy systems, the former set being much more widely available for a larger number of locations within the developing world. This work has therefore centred on finding the difference in the wind energy production by using: (a) a measured long-term, minute-by-minute data, and comparing this with (b) a concurrent hourly data set. Furthermore, a comparison of the cumulative frequency of wind speed from the latter data sets has also been carried out. It was found that the difference between the annual energy outputs from the latter two data sets was in close agreement with only a % difference. The two cumulative frequency functions were also found to be closely related. These results may be of use for locations close to the equatorial belt where the wind regime is noted for its stable and seasonal character.