Past Present and Future: Understanding Wind Power
Abstract
In recent years
due to diminishing fossil fuels and environmental concerns wind power has again
become a popular renewable energy source.
In this paper I outline the history of wind power and its uses as well
as the future potential for wind power.
The goal is to make readers aware of the ease at which the power of the
wind can be harnessed as well as outlining suitable locations for “wind
farming” and giving a basic understanding of the technology/mechanisms that
generate electricity from the wind. It
is important to realize that although our non-renewable resources are not yet
depleted one day they will be and we can not afford to wait until then to begin
planning for our future without fossil fuels.
Wind power has been the fastest growing energy source since 1990
(eere.energy.gov) and in all reality it could become our most reliable energy
source in the near future. It is
important for us to reduce our reliance on fossil fuels and wind power is one
of the easiest most viable renewable energy sources available that we must
utilize today and in the future.
Introduction
The history of wind power dates back over a thousand years to the first documented windmills used for grain-grinding and water-pumping in Persia around 500-900 A.D. (Kovarik, Pipher, Hurst) Over the next 1,000 years the apparatus used for harnessing the power of the wind changed drastically from primitive “vertical-axis” windmills (fig. 1) used in Persia and China to the modern-day wind turbines scattered across the globe (Hunt). Similarly, changes in use of wind power have also occurred over the years from grinding grain and pumping water to creating electricity to power a city (telosnet.com). Though the history of wind power is important it is the less distant past, present and future that I will discuss in detail. Fossil fuels will run out but as long as the sun is shining and the earth is spinning the power of the wind can be harnessed. Wind power has quickly become the most abundant and fastest growing resource in the world since 1990 and given the depletion of fossil fuels it is important that we continue to take advantage of such a prominent renewable resource and consider the various options and locations for capturing the wind (windturbinecompany.com)
Fig 1 (telosnet.com)
History
The first electricity generating windmill system was assembled in Cleveland, Ohio in 1888 but was very inefficient producing only 12 kilowatts (telosnet.com). The subsequent attempt to harness the wind for electricity occurred in 1891 and was relatively successful throughout Europe prior to the onset of WWI and the use of fossil fuels (Park). The European design incorporated 4 aerodynamic rotor blades capable of producing 25 kilowatts but as aforementioned the cheaper more practical fossil fuels put the mills out of business (telosnet.com). During the 1920’s and 1930’s following the creation of the first wind turbines 1-3 kilowatt wind generators were installed across the Midwest of the United States (eere.energy.gov). These systems provided electricity for lighting farms and powering refrigerators, power tools, washing machines and freezers. Once again, however, the low cost of fossil fuels combined with the Great Depression put an end to small scale wind generators fueling farms across the Great Plains (telosnet.com).
Though small scale wind generation ended for the most part during the 1930’s, large scale projects were already under way around the world (Park). Two notable primitive large-scale wind generators were the Balaclava generator on the Black Sea and the Smith-Putnam generator in Vermont. The Balaclava generator produced 200,000 kilowatt hours of electricity in just over 2 years of operation (Park). These primitive generators main application was connection to an electric power grid and their short-lived success proved large-scale wind generation possible (telosnet.com). The downfall of the first large-scale generators was their intermittent electricity production because they required strong gusts that were not always present (Hunt). As before the periodic low price of fossil fuels ended the need for large scale wind generation – a trend that will be seen throughout the history of wind power and a major component of the renewed interest in wind generation (eere.energy.gov). The 1960’s and 1970’s were rife with experimentation and innovations in wind turbine design and the most successful design used light weight blades with high efficiencies (fig 3) based on an early concept incorporated in this country by Sandia National Laboratories after the Federal Wind Energy Program was put into place during the Nixon administration (sandia.gov).
Fig 3
(telosnet.com)
Where to Capture the Wind
As is suspected the best location for a wind turbine is the place with the highest average wind speed (Brown). However, there are several factors determining which places are best suitable for installation of wind turbines. In general, sites with an average wind speed of 20 km/hr or greater are best (wikipedia.com). Coastal areas and regions that fall within the belt of strong westerly winds offer the greatest potential as wind power sites on the large scale. However, on a local scale it is important to know wind patterns since prevailing winds from one direction are more beneficial in wind production than a site with winds from varying directions (Kovarik, Pipher, Hurst). Another important factor in choosing a site for constructing wind turbines is avoiding terrain and man-made obstructions that will interfere with the flow of wind (Kovarik, Pipher, Hurst). The most common method for the initial selection of a wind power site is to look at the meteorological records of a country or location (fig 4).
Fig
4 (eere.engery.com) 
(6 % of the
Once potential areas have been
found, on-site investigation occurs to gain a better understanding of the
terrain and places the wind blows hardest most often (Kovarki, Pipher,
Hurst). The importance of choosing a
good site is remarkable since an average wind speed just a few mph greater has
the potential to create much more energy (Hunt). For example, there is 338% more power
available from wind blowing at 12 mph than from wind blowing at 8 mph (Kovarki,
Pipher, Hurst). Although average wind
speed is important in determining a possible site it is still the consistency
at which the wind blows at those speeds that is most important in determining
what sites will be most productive (Kovarik, Pipher, Hurst). Once a site has been chosen the wind turbines
are hoisted high above the ground because of the different ways wind moves at
ground level and above ground - near the ground wind is slowed by friction
whereas high above the ground wind flows freely and more quickly (Hunt).
Mechanics and Electricity Production
As discussed the design of wind generators has undergone many changes over the centuries but the turbines in use today are either horizontal-axis (fig 3) or vertical-axis wind machines (Park). The horizontal-axis wind machines are also classified as either down-wind or up-wind depending on whether they face into the wind (up-wind) or away from the wind (down-wind) (Kovarik, Pipher, Hurst). In either case the power produced by the wind turbine is proportional to the cube of the wind speed (wikipedia.com). Therefore as wind speed doubles the power production increases eight fold (British Wind Energy Association). However, regardless of design mathematic theory shows that only 59% (Betz limit) of the wind flowing through the blades can be captured (British Wind Energy Association). The blades of a wind turbine are specifically designed to create lift - much like the wings of an airplane – but since the blades are connected to gears which in turn are connected to a shaft, the lift created by the wind causes the blades to spin which turn the gears which turn the shaft which connects to a generator and makes electricity (fig 5) (eere.energy.com). The turbines are designed to face into the wind
Fig 5 (eere.energy.com)
(or away from the wind) to utilize as much energy as possible from a direct flow hitting the blades (Park). Of course the amount of energy generated depends on the speed of the wind but a current problem with wind energy is the storage of electricity for later use (Kovarik, Pipher, Hurst). Unlike fossil fuels that are burned at a rate determined by the amount of electricity needed the power of the wind is unpredictable (Kovarik, Pipher, Hurst). Currently the best way to solve this problem is to connect wind turbines to a power grid which is in turn connected to a power company (fig 6) (eere.energy.com).
In this situation the power company uses the wind energy to supply its customers with electricity and if necessary they are also able to burn fossil fuels to make up the difference when wind energy is below the demanded amount (Kovarik, Pipher, Hurst). In situations where the turbine(s) is more rurally located and not connected to a power grid the energy can be stored in DC batteries and later converted to AC using a synchronous inverter which connects a wind generator to the utility grid and the house wiring system (Park). There are other methods to store electricity but in the future if wind energy becomes more prevalent it is most likely that wind farms will be connected to grids connected to power companies for minimal energy loss.
Economic Issues
As mentioned before, though wind energy seems like the best energy source available it is the low cost of fossil fuels that has kept production of wind power low over the years (eere.energy.gov). In the same sense it is the rising prices of fossil fuels and their eventual depletion that has made wind energy economically cost-effective over the past decade (windustry.com). There are many factors influencing the cost of a wind energy system whether it is personal or commercial. Construction costs, the cost of the turbine itself, connection fees, metering equipment, maintenance, repairs and consulting fees all must be factored in. Depending on what state you live in there might also be taxes and other fees to be paid on energy produced or sold. If you are a resident of Arizona, Iowa, Massachusetts, Minnesota, New Jersey, Ohio or Vermont there will be no sales tax on wind energy system purchases (windustry.com). Other states have instituted other benefits and incentives to switch to wind power and the federal government offers grants to help defer costs (eere.energy.gov). In owning a wind energy system benefits will come from one of three sources; tax savings, free electricity or revenue from excess energy produced (windustry.com). The figure below shows the calculation of annual costs for a personal energy system in 1980.
Fig 6 (Park)
|
Purchase
Price |
4,000 |
|
|
|
Installation
Cost |
1,000 |
|
|
|
Maintenance/Insurance |
4,000 |
|
|
|
|
|
9,000 |
|
|
Resale
Value |
-500 |
|
|
|
|
|
$8,500 |
|
|
Include
per annum Simple Interest at 10 % |
|||
|
|
|
|
|
|
1.10 x
$8500/20 = $467.50/yr |
|
||
|
|
|
|
|
|
Divde by
enery produced in one year |
|||
|
$467.50/3,000
kWh = $0.16/kWh |
|||
|
|
|
|
|
|
Factoring
in tax credits reduces annual cost |
|||
|
to
$357.50 and unit cost to $0.12/kWh. This |
|||
|
price is
still higher than power companies |
|||
|
rates. |
|
|
|
Judging from the above chart it becomes apparent that the prices a power company has to offer are still cheaper in the short run than owning your own wind turbine. When talking about large scale wind turbines connected to power grids the prices are unbelievable. A turbine designed by NASA rated at 200 kW costs 1.7 million dollars total installed. This does not include maintenance fees and comes with no warranty (Hunt). Comparable turbines are just as expensive and the lack of a guarantee that the machine will work deters many investors especially after the minimal success of turbines in the past throughout California (Hunt). The expenses related to wind energy are becoming more and more competitive with energy produced from fossil fuels; in 1980 it cost $.80/kWh to produce large-scale wind energy and by 2002 the price had fallen to $0.04/kWh. By 2002 global wind energy capacity reached 31, 000 MW and it is speculated that wind energy will become the biggest bulk-energy production source in the world in the coming years (www.eere.energy.gov). The EPA and their Wind Energy Development plan have already proposed several wind energy ideas. Their most promising plan consists of a 20-year program to produce the most wind energy possible at the lowest cost and the greatest economic benefits for industry as well as communities (windeis.anl.gov).
Conclusion
Though the power of the wind has been used since before the time of Christ it is in the past century and especially the past 30 years when true potential for wind energy to generate electricity has been tapped in to (Park). The diminishing supply of fossil fuels and the environmental concerns associated with their burning have been the biggest concern leading to the necessity for cleaner renewable sources such as wind power (windustry.com). Through continued research and technological advancements beginning around the turn of the century the viability of large-scale wind energy production has become more easily attainable. More efficient systems are constantly under construction in an effort to make wind power the biggest bulk energy system in the world in the near future (eere.energy.gov). Assuming governments invest as much or more than they currently do and continue to promote wind energy through tax breaks, land grants and other incentives our reliance on fossil fuels should decline (windustry.com, telosnet.com). It is important to realize the necessity of a switch to renewable resources and the great importance of wind energy in this scheme as it is the most abundant renewable resource in the world (eere.energy.gov).
Sources
EERE.ENERGY.GOV.
Energy Efficiency and Renewable Energy; Wind Energy. 2 March. 2005 http://www.eere.energy.gov/RE/wind.html.
Kovarik, Pipher and John Hurst. Wind Energy. Northbrook, IL: Quality Books Inc., 1979.
Hunt, V. Daniel. WINDPOWER: A Handbook on Wind Energy Conversion Systems. New York:
Van Nostrand Reinhold, 1979.
Sandia.gov.
September 2003. Wind Energy. 2 March, 2005 http://www.sandia.gov/wind/WPA.htm.
Park, Jack. The
Wind Power Book. Palo Alto, CA: Cheshire Books, 1981.
Lipman, Musgrove, et al.
Wind Energy for the Eighties:
British Wind Energy Association.
Exeter, England: Short Run Press
Ltd., 1981.
United States, California.
Windustry.com. Wind
Energy Economics.
Wikipedia.com. Wind
Energy.
Windeis.anl.gov.
2005. Wind Energy
Development.
“About Wind Energy”. Windturbinecompany.com.
2000-2005. http://windturbinecompany.com/windenergy/index.html.