Wind Energy: The Basics
Wind energy, or wind power, is a potentially limitless yet largely untapped source of clean, non-polluting electricity. A single, strategically placed 750 kW wind turbine can prevent the emission of 5,000 tons of carbon dioxide into the earth's atmosphere each year. It would take approximately 500 acres of forest to absorb that much CO2. Wind energy is one of the world's fastest-growing energy sources and with the support of the human race worldwide, is capable of powering industry, businesses and homes with clean, renewable electricity for many years to come.
Wind is created by the unequal heating of the Earth's surface by the sun. Wind is actually a form of solar energy; winds are caused by the heating of the atmosphere by the sun, the rotation of the earth, and the earth's surface irregularities. The wind is slowed dramatically through it's exposure to the Earth's surface, however, the power of the wind may be five times greater at the height of a 40-story building than the ground-level breeze on your face. Therein lies some of the challenges associated with wind power; in order to compete with conventional energy generation sources, it must be similarly competetive on a cost basis.
Wind energy is harnessed using mechanical devices called wind turbines, which are used to generate electricity from the kinetic power of the wind. A wind turbine is basically a machine which converts kinetic energy to electrical energy through its three main components. First, the blades which catch the wind which makes it rotate. The blade is then attached to a shaft which would spin when the blades rotate. The shaft is then connected to a generator which turns the mechanical energy to electrical energy. There are different types of wind turbines, which we discuss in more detail in this article.
Wind Energy: The Challenges
Even though the cost of wind power has decreased dramatically in the past 10 years, the technology still requires a higher initial investment than fossil-fueled generators. The major challenge associated with using wind as a source of power is that wind is intermittent and it does not always blow when electricity is needed. Wind energy cannot be stored (unless batteries are used); and not all winds can be harnessed to meet the timing of electricity demands.
Summary of Challenges:
- The most effective locations for harnessing wind power are often in remote locations, far from the areas where the electricity will ultimately be utilized. Additionally, wind resource development may compete with alternative uses for the land, and those uses may be more "highly valued" than electricity generation. Although wind power plants have relatively little impact on the environment compared to other conventional power plants, there is some concern over the noise produced by the rotor blades, the aesthetic (or visual) impacts, and the issue that birds have been killed by flying into the rotors. Although many of these problems have been resolved or significantly reduced through technological development and proper site planning, they are still considerations that must be factored in when considering wind energy.
- Hourly forecasting difficulty. Despite continuing improvements in wind forecasting techniques, actual wind generation in each hour can vary substantially from forecast levels. Generally, the geographic areas with the best wind potential are not part of any organized regional transmission organization with centralized dispatch. Instead, each transmitting utility schedules out-of-region deliveries of wind generation based on forecasts and may impose substantial charges for deviations between forecast and actual generation.
- Intra-hour swings in generation. Wind generation, even if produced over an hour on average in the amount forecast, may vary greatly within the hour. The within-hour output swings can be particularly noticeable as weather fronts pass through. Although the Federal Energy Regulatory Commission’s (FERC) Open Access Transmission Tariff does not address the cost of such intra-hour variations, transmission providers are beginning to assess sometimes substantial new transmission ancillary service charges to cover the supposed cost of such generation swings.