Economics

Remote wind power systems often incorporate additional generating systems such as diesel generators and solar arrays. These "hybrid" systems provide improved reliability of power supply and operational flexibility. When the power from the wind turbine is not sufficient to operate the load, the alternate power source comes on-line. The alternate source is used far less frequently in a hybrid system than if the wind system were not present.


Wind Power Environment:

Introduction

Wind energy, as a partial solution to environmental problems, has received high praise from energy and environmental experts. The Electric Power Research Institute has stated that "Alone among the alternative energy technologies, wind power offers utilities pollution-free electricity that is nearly cost-competitive with today's conventional sources." More than 20,000 commercial-sized wind turbines have been errected worldwide over the last decade with capacity of more than 2,000 MW. About 80 per cent of these machines are located in California. They already supply one per cent of the states electricity. This is enough to serve the needs of cities over 900,000 people. Further more, the turbine performance ans reliability have improved. The cosequence is, that costs have fallen considerably so that the wind power energy is nowadays a competitive energy source. One reason for the price development is the fact that the machines are operating for more than 95 per cent of the time.

In 1991, for example, California's wind power plants offset the emission of more than 2.8 billion pounds of carbon dioxide, even assuming they replaced relatively clean-burning gas-fired power plants. These same wind plants offset 16 million pounds of nitrogen oxide, sulfur dioxide, and particulates.

One environmental concern about wind power is land use. While a single wind turbine does not use much space, large scale applications such as utility wind farms require significant acreage. However, one advantage of wind farms is that the wind turbines occupy only about 5% of the land, and since the turbines are high in the air, the bulk of the land is available for agriculture, grazing, or other uses. The next page is How much energy does it take to build a wind system in relation to the energy it produces?.

Wind Power Applications


Wind turbines range from small residential systems to large utility systems. Wind power systems are modular and can be scaled easily to any application. The size range has increased from around 60 KW to around 200 KW. The majority of these commercial machines have two or three blades which rotate about a horizontal shaft sweeping an area 20 to 30 meters across.
There is some interest in developing vertical axis machines. They have two important advantages: First they don't need equipment to turn the rotor into the wind. Another advantage, perhaps more important, is the fact, that they are less subject to gravity, which is a major consideration in big horizontal axis machines.
However, there are problems in trying to achieve a steady output because each blade continually passes through the others wind shadow.


Remote

Small wind turbine systems are often the most inexpensive source of power for remote sites. The turbines for this system are very simple and can operate unattended for long periods at harsh sites. Common applications include telecommunications, rural residences, and water pumping. Remote power systems using U.S. small wind turbines have been installed in more than 70 countries around the world.