Wind Turbine Systems
A wind turbine is a device that converts mechanical energy into electricity. The wind turbine, is installed on top of a tall tower, harvests wind energy and converts it into electricity. This electricity is used to charge batteries, reduce the fuel consumption on a diesel generator, or drive a pump. Since the wind is intermittent, some sort of storage (batteries) is usually incorporated into the system or a back-up generator may be used.

Small wind turbines are primarily used for remote energy applications. Rural electrification of homes, schools, health centers villages, farms and small industries can often be done less expensively and more quickly with renewable energy, such as wind power, than by extending the utility grid. Using newly developed wind-electric pumping technology, wind turbine systems are also being used for village water supply and irrigation. These new wind pumps provide an alternative to the traditional diesel powered pump.

Wind systems are better than grid extensions or diesel generators because they are more sustainable and require little maintenance. Wind systems are smaller, modular and have a shorter lead-time than grid extension. For grid extension distances as short as one kilometer a wind system can be a lower cost alternative for small loads. While they cost more initially than diesels they are much better from the user’s point of view. Donor agencies, for example, typically supply diesels at no cost, but leave operational costs (fuel, maintenance and replacement) to the local people. This requires scarce hard currency and usually results in limited utilization and a shortened life of the diesel because of inadequate maintenance. Many countries must also import their fossil fuels, further magnifying the burden imposed by diesels.

 Wind power in comparison to other renewable energy technologies is very competitive. In the big picture, wind power complements these other power sources by providing a least cost approach under certain conditions. In many situations the lowest cost centralized system will be a hybrid system that combines wind, photovoltaics and diesel power.

The economies of scale in small wind turbines make them particularly competitive in cost for sizes above 250 watts. For daily loads as small as one kilowatt-hour per day a wind turbine will be less expensive than diesels, grid extension, or photovoltaics for virtually any wind resource above 4 m/s (9 mph). This wind resource is available in most of the developing world. For larger daily load requirements the economics of wind power get progressively better. For a 10 kW wind turbine a wind resource of only 3-3.2 m/s (6.7-7.2 mph) will usually make wind the least cost option. There are not many areas of the world that have average wind speeds below 3 m/s (6.7 mph).

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