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Newsletter and Technical Publications Costs The costs for the construction, operation and maintenance of this technology is closely related to the economic feasibility of utilizing wind energy. It is noted that the notion that wind energy is free is not exactly true. In fact, the wind is free, but not the energy. From a scientific and economic perspective, wind energy becomes free after the system is purchased, installed and generated sufficient quantities of energy to have covered its cost. In fact, it is not easy to accurately determine the cost of wind energy because of the following considerations:
Nevertheless, one of the following two approaches is typically used to estimate wind energy costs, as follows: First Approach This approach is based on determination of the cost of one kilowatt of the nominal capacity for the wind energy system. Most manufacturing companies try to reduce this cost by using simpler designs and following large-scale, serial production techniques. Second Approach This approach is based on determination of the cost of one square meter of the area of the system rotor. Most manufacturing companies also try to reduce the costs further through facilitating optimal design and use of the system. The first approach is recommended, as it give a better idea of the system’s benefits in regard to its design and output. It also assists the user to avoid purchasing a system with a large rotor, but a low capacity. Experiments and information obtained from the use of small wind energy systems have demonstrated that the cost of a fully successful wind energy system (including system, tower, batteries and converters), being used independently of any other power source, is between US$ 2.50-5.00/watt of the system’s nominal capacity. This cost is reduced to US$ 1.50-2.50/watt when the batteries and converter are not used. Thus, the price of one kilowatt of wind energy with this system ranges between US$ 1,500-5,000. Using this value, the price of a ten kilowatt capacity wind energy system can range between US$ 15,000-50,000, depending on the system type, quality and needed equipment. It is noted that the price of good batteries can total up to 40% of the price of the total system. The initial cost to construct a submerged electric pump unit utilizing wind energy (7 m diameter rotor) is US$ 40,000 in the Sultanate of Oman. The following simplified computation is presented for estimating the cost of pumping water using traditional wind energy systems, as well as modern systems having similar production characteristics in regard to pumping water:
The cost is increased with modern systems, due primarily to the required system accessories for pumping the water (pump, cables, electrical fixtures, etc). The cost is about US ½ cent/m3 of water for traditional systems and about US 1 cent/m3 for modern systems. This cost is competitive with other technologies typically applied in remote areas far from sources of electrical power or oil. This is particularly the case if it is considered that the actual lifetime of conventional systems is unlimited, whereas some maintenance and replacement of batteries is required for the modern systems that depend on the generation of electric power. Effectiveness of the Technology On one hand, the efficiency of this technology is dependent on its quality, and the quality of the conventional multiple blade systems has proven effective over many years. This technology is easy to maintain and has a negligible wear factor. Depending on the water purity, only the pump seals must be replaced every 3-5 years. The modern two- and three-blade systems are considered experimental, being duplicated from European designs. Thus, there has not yet been sufficient time to evaluate their effectiveness over long durations of 10 years or longer. On the other hand, the effectiveness of this technology also is dependent the availability of wind energy to satisfy their operational requirements. It obviously is pointless to install a system requiring a certain minimum wind speed in areas where this wind speed does not occur for long durations over a given year, or where it never occurs. Even if the needed minimum wind speed occurs during certain periods over the annual cycle, lower wind speeds for the remainder of the year result in a lower return for the wind energy system. Thus, in addition to the nominal capacity of the system, the occurrence and frequency of different wind speeds also must be considered. This includes computing the system efficiency and productivity, based on the results of wind speed measures carried out at its designated installation site over at least a five-year period. A review of the available wind measurements from some of the meteorological stations in the countries of West Asia clearly indicates that there are several locations enjoying appropriate wind speeds for efficient operation of this technology. Suitability This technology is best utilized in areas with suitable wind activity throughout the year, and with shallow groundwater depths. It encourages the wise use of groundwater resources, because of its limited pumping capacity controlled by its technical specifications and wind speed patterns. The technology is ideal for remote arid and semi-arid areas located far from electric power sources. Nevertheless, it also can be used in an effective and economically- feasible manner in areas where electric power is available, primarily because of constant increases in energy prices. The technology is not only utilized to withdraw water from wells, but also from canals, rivers and dams to reservoirs above ground level, as well as to convey the water to remote areas. The technology also is used to improve the aquatic environment for fisheries, by increasing the dissolved oxygen content of the water by pumping it from fish farms and conveying it back to the tank. It also is suitable for protecting the environment and reducing air pollution caused by the exhaust from other types of energy that utilize oil derivatives. Advantages The advantages of this technology are as follows:
Disadvantages There are no specific disadvantages to the use of this technology, except its dependence on the availability of wind. This means that the well discharge is sensitive to fluctuations in wind speed. This disadvantage can be overcome, however, if a pre-study is undertaken to determine the character of the prevailing wind patterns in a given location. A well-prepared farmer can install a suitable system, taking into consideration such factor as the wind patterns and characteristics, farm size and the types of vegetation and their irrigation requirements. Such information also will assist the farmer to select the appropriate size for the system(s) needed, as well as ensuring that the water reservoirs can store water volumes that can fully meet the farm’s water requirements. It is noted that the system susceptibility to changes in wind speeds can be overcome with modern systems that use electrical submerged pumps. The wind energy systems generate the needed electricity and store it in batteries, to be used later to run the pumps during periods of little or no wind. Cultural Acceptance The initial response to the use of this technology in countries in the Arab region was very encouraging. A subsequent decline in interest can be attributed to hydrogeological (fall of water table) and financial (increased installation costs) reasons. Nevertheless, the technology is relatively popular because of its low environmental impacts. Its comeback also is attributed to its ability to generate electrical power that can be used to pump water via electric pumps. The electric pumps can withdraw water from greater depths than can the initial mechanical pumps. Further Development of the Technology Many experiments with the development and use of this technology have been carried out in the industrial countries of Europe, United States of America and the Russian Federation. In the Arab region, few experimental efforts have been undertaken, although some efforts to develop the technology and to establish testing laboratories were undertaken in Syria, Jordan and some Gulf countries. These latter developmental effort have generally concentrated on the following topics:
Information Sources Contacts Al-Nozom Al-Tabeaya Company Controller General Information and Public Awareness Center Workshop of Mohammed Wahib Al-Nafori References ACSAD. Syria country report: Study and development project of Arab water technologies. ACSAD, Damascus, Syria. ACSAD. 1983. General report: Study and development project of Arab water technologies. ACSAD, Damascus, Syria. ACSAD. 1983. The use of wind energy: Studies of Al-Hamad Basin. ACSAD, Damascus, Syria.
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