Using alternative energy resources and developing these resources are of great importance in order to prevent pollution of the environment and global warming, which have recently been imposing serious threats to the world. Limited reserves of fossil fuels and their negative effects the environment lead institutions, organization and governments to find technologies that more efficient and new and renewable energy resources to be used for producing energy in the natural environment. Today, the use of wind energy technology has been developing very fast.
Given that wind power is a local resource and that is a clean and environmentally friendly resource, it is vital to conduct the required technical and economical feasibility researches in order to make use of this energy to overcome the current energy problems.
Jordan like other developing countries depends entirely on imported oil for meeting its needs of commercial energy and pays more than 10% of its GDP for the energy bill. Since the energy resources discovered locally are limited, and considering the big burden that the imported energy has on the national economy; the Government gives special attention towards renewable energy for the purpose of assessing, developing and planning of the local energy demand.
1.1 Wind Potential and Use in Jordan
1.1.1 Wind Potential (Wind Data)
Jordan possesses high potential of wind energy resources where the annual average wind speed exceeds 7 m/s (at 10 m height) in some areas of the country. The long term climatic data are available at the Jordan Meteorological Department (JMD). Some other institutions like the Ministry of Energy and Mineral Resources (MEMR) and the Royal Scientific Society (RSS) have some measurements of such data especially wind and solar data for the purpose of assessing the potential of these resources for power generation and other applications in Jordan.
1.1.2 Wind Utilization
Wind energy in Jordan is used mainly for electricity generation. There are two wind farms connected to the grid in the northern part of the country; one with a capacity of 320 kW in Al-Ibrahimyya, consisting of 4 stall regulated wind turbines of 80 kW each, established in 1988 in co-operation with a Danish firm and considered as the pilot project. The other most recent one, has a capacity of 1125 kW in Hofa, consisting of 5 pitch regulated wind turbines of 225 kW each, established in 1996 in co-operation with
the German Government under the so-called ELDORADO program.
Wind energy is used successfully, through a Hybrid Power System to electrifying a remote village in the southern part of the country called Jurf El-Darawish. This system was constructed in 1987 and consists of 2 wind energy converters of 20 kW each, a 10 kW peak Photovoltaic field, storage battery system of 330 kWh capacity, and a back up diesel generator of 65 kW.
Water pumping in remote areas using mechanical and electrical Wind mills is also used intensively in Jordan. There are more than 20 pumping stations in this field using mechanical wind mills manufactured locally. There exist also some attempts for local manufacturing of electrical wind turbines especially the blades and the tower.
This study gives a preliminary investigation of the potential of wind power generation employing average wind speed data for Al-Mafraq city assuming it has the same climate as the Hashemite University.
1.2 Literature Review
The wind power potential has never been considered as an alternative source of energy in Cameroon. For that reason many researches take place to utilize renewable energy especially wind energy in a full-fledged manner. In 2002 Tchinda and Kaptouom , discussed the prospect of wind power in the Adamaoua and Northern Cameroon provinces. It was observed thaqt the northen province has annual mean wind speeds that are equal to or exceed 2 m/s for over 53% of the time, while the Adamaoua province has annual wind speeds that’s are equal to or exceed 1 m/s for over 29% of the time. Calculations of the mean wind power density from a hypothetical aerogenerator or water pumping system and the mean wind power from circular areas were also made. In the north province, a very fruitful result would be achieved if windmills were installed for producing wind energy for drinking water, irrigation and electricity for small household.
 Techinda R, Kaptouom E. wind energy in Adamoua and North Cameroon provinces. Energy Convers Mgmt 2003;44:845-857.
Data and Methodology
Generation of power from a windmill requires continuous flow of wind at a rated speed. This is difficult to accomplish because wind by its very nature is not constant and does not prevail at a steady rate, but in fact fluctuates over short periods of time. The speed of wind is also dependent on height above the ground. In order to estimate the wind speed at any height, we employ the Hellman exponent law:
V(h)/V10 = (h/10)αWhere V(h) is the wind speed at height h, and V10 is the wind speed at 10 m height and α is the Hellman exponent. for flat and open areas, α=1/7. The available power in the wind per unit area at any wind speed may be estimated as,
Whereρis the air density which was assumed to be 1.225 kg/m3 and V3 is monthly mean wind speed in m/s. this available power can not be totally extracted by any wind machine. The maximum extractable power from any wind machine is limited by the Betz relation, which assigns thepower coefficient Cp = 16/27 for the maximum performance of a wind machine.
Maximum extractable power per unit area is given as,
Pmax = 1/2 ρ CpV3 (W/m2)
Because a wind-turbine wheel cannot be completely closed, and because of spillage and other effects, practical turbines achieve some 50 to 70 percent of the ideal efficiency. The real efficiency η is the product of this and ηmax and is the ratio of actual to total power,
Pactual =η Ptot = η 1/2ρ V3
Where η varies between 30 and 40 percent for real turbines.