Harnessing the natural power of the wind is by no means a new concept. Asides from sailing, wind power has been utilised for many thousands of years, principally for agricultural purposes. Basic windmills are thought to have been used in Persia (now Iran) as early as the 7th century AD. Their ability to make use of otherwise untapped energy sources without the needs and costs of other alternatives, ensured that they remained the machines of preference in several industries throughout both agricultural and industrial revolutions.
Whilst their basic concepts have remained true to the basic origins, technological advances have enabled engineers to adapt the mechanics of the mill to enable a more functional and useable source of power. In the 18th C, engineers developed spring sails, a device incorporating shutters onto the sails, to enable the mill to be run at constant speed during variable wind speeds automatically. The development of the fantail in 1745 also ensured the mills ran in the face of the wind and along with airbrakes meant that the mill could run at its most efficient at all times without the risk of doing itself damage in strong winds. Uses developed into water pumping, wood sawing, papermaking, pressing oil seeds and a variety of grinding uses.
American colonists used windmills to grind wheat and corn, to pump water, and to cut wood at sawmills. As late as the 1920s, Americans used small windmills to generate electricity in rural areas without electric service. When power lines began to transport electricity to rural areas in the 1930s, local windmills were used less and less,
The use of wind turbines for generating electricity was pioneered in Denmark late in the 1890s. The concept was made a reality by Poul la Cour, 1846-1908, who had originally trained as a meteorologist. He built the world’s first electricity generating wind turbine in 1891 and although his project was a success, decided the greatest problem lay in storage of the electricity. As a result he used the electricity from his turbines for electrolysis in order to produce hydrogen for the gas lighting in his school.
Wind is one of the simplest gifts of nature, it is air in motion. It is caused by the uneven heating of the earth’s surface by the sun. Since the earth’s surface is made of very different types of land and water, it absorbs the sun’s heat at different rates.
During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating winds. At night, the winds are reversed because the air cools more rapidly over land than over water.
In the same way, the large atmospheric winds that circle the earth are created because the land near the earth’s equator is heated more by the sun than the land near the North and South Poles.
Today, wind energy is mainly used to generate electricity. Wind is called a renewable energy source because the wind will blow as long as the sun shines.
In order for this to happen, windmills are used. How does it work? Like old fashioned windmills, today’s wind machines use blades to collect the wind’s kinetic energy. Windmills work because they slow down the speed of the wind. The wind flows over the airfoil shaped blades causing lift, like the effect on airplane wings, causing them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.
With the new wind machines, there is still the problem of what to do when the wind isn’t blowing. At those times, other types of power plants must be used to make electricity.
This type of energy production is done on a wind farm. Wind power plants, or wind farms as they are sometimes called, are clusters of wind machines used to produce electricity. A wind farm usually has dozens of wind machines scattered over a large area. The world’s largest wind farm, the Horse Hollow Wind Energy Center in Texas, has 421 wind turbines that generate enough electricity to power 220,000 homes per year.
Unlike power plants, many wind plants are not owned by public utility companies. Instead they are owned and operated by business people who sell the electricity produced on the wind farm to electric utilities. These private companies are known as Independent Power Producers.
Operating a wind power plant is not as simple as just building a windmill in a windy place. Wind plant owners must carefully plan where to locate their machines. One important thing to consider is how fast and how much the wind blows.
As a rule, wind speed increases with altitude and over open areas with no windbreaks. Good sites for wind plants are the tops of smooth, rounded hills, open plains or shorelines, and mountain gaps that produce wind funnelling. Wind speed varies throughout the country. It also varies from season to season.
New technologies have decreased the cost of producing electricity from wind, and growth in wind power has been encouraged by tax breaks for renewable energy and green pricing programs. Many utilities around the country offer green pricing options that allow customers the choice to pay more for electricity that comes from renewable sources.
Most of the wind power plants in the world are located in Europe and in the United States where government programs have helped support wind power development. The United States ranks second in the world in wind power capacity, behind Germany and ahead of Spain and India. Denmark ranks number six in the world in wind power capacity but generates 20 percent of its electricity from wind.
Wind energy is an economical power resource in many areas of the country. Wind is a clean fuel, wind farms produce no air or water pollution because no fuel is burned. Growing concern about emissions from fossil fuel generation, increased government support, and higher costs for fossil fuels, especially natural gas and coal, have helped wind power capacity in the United States grow substantially over the last 10 years.
This is how a wind farm is set up;
1 – Study of wind regime
2 – Selection of suitable sites
3 – Negotiation of land rights
4 – Design of generator arrays (placing within the site)
5 – Building
And the investments needed are;
1. Wind Turbines
2. Grid Extension
3. Modifications to control equipment of Grid controllers
4. Additional water turbines on hydro stations
In Kenya wind farming may be a new advancement. According to the Energy Act of 2006 which was signed into law in 2007 the permanent secretary of the Energy ministry will have to perform several duties, wind farming being one of many.
It may be the best alternative for the thousands of Kenyans that live without electricity. How many places do we have in our country side that fits the requirements of tapping wind energy? There are many hillsides that aren’t even being used. Many communities would indeed benefit if the government supported projects fully like the Lake Turkana Wind Power Consortium, located North West of Kenya near Lake Turkana, which would supply the national power grid with up to 30% of clean electricity once it commences.
A wind farm consisting of 353 wind turbines, each with a capacity of 850 KW will be constructed. The total foreseen power generated by the initial phase of this wind farm is expected to start production in June 2011 and reach full production of 300 MW by July 2012, adding 30% or more to the total existing installed capacity available in Kenya. Wind turbine technology has seen recent rapid improvement with the development of turbines.
The people of the Lake-side plains lands of Kenya live within a potential source of power more useful than an oilfield. Although they have no significant sources of water power or coal they live in what can be described as a giant natural heat engine. This is the wind circulation system caused by the difference in temperatures of the sun-baked Kano Plains and the cooler waters of the Lake. Air rises from the plains from about 11.00 a.m. as they heat up; this pulls in air from the lake and a substantial wind blows throughout the area until the land cools down and temperatures equalise at about sunset. Unlike an oilfield this will not be exhausted as long as the sun shines.
However in order to start construction of such projects one major set back is the state of the roads leading to such remote areas that are suitable for wind farming. Machinery and equipments all need to be transported to various parts of the country from the port of Mombasa, in this case to North West near Lake Turkana. Many roads are a mess and bridges not strong enough to allow Lorries to access it.
Another factor as to why wind power production is not so common both internationally and locally is its financial implications, turbines are expensive and in order to generate enough electricity as compared to hydro electric turbines one must invest in a large number of machinery to do so. Land is another factor that must be considered due the importance of location. Highlands are a more suitable area for harnessing wind power however research has shown that areas with vast numbers of turbines generate turbulence with in turn affects the growth of crops, according to the Science daily report. The most serious environmental drawbacks to wind machines may be their negative effect on wild bird populations and the visual impact on the landscape. To some, the glistening blades of windmills on the horizon are an eyesore; to others, they’re a beautiful alternative to conventional power plants. The noise created by wind turbines is often cited as an issue, although the noise of large turbines is far less than of smaller turbines.
Of late there have been many prospective investors looking to Kenya to venture in wind power production. African Clean Energy, the British firm and Wind Flow, a local partner, will initially set up a wind farm in Marsabit to provide an alternate power source for the country. They will then sell the power they generate to KenGen for distribution into the local power grid. Currently, country mainly relies on hydroelectric power that can be disrupted by unreliable rain patterns.
Wind will provide an alternative source for the country at a time when the national power distributor, Kenya Power and Lighting Company is on a recruitment drive to attract more customers to the national grid. Just eight per cent of the population has access to power, and as the Government pushes forward its promise to supply power to more citizens, alternative sources are expected to shore up supplies. Other countries have already gone for wind power as soaring oil prices and fears of climate change drive the need for less petroleum-based power sources. Wind is the fastest growing source of electricity in the world, though it remains a minor player compared to more common fossil fuels and other alternatives such as geothermal, hydro and nuclear power. Wind power uses natural air movements to drive giant windmill blades, turning turbines that convert the kinetic energy into electrical power. Wind turbine sales are projected to rise from .1 billion to almost double that amount by 2011, according to research firm BTM Consult.
In conclusion Kenya seems to be looking at more efficient and cleaner means of producing electricity. With new bills that have been passed regarding renewable energy and the introduction of new foreign investors to tap into this energy shows us that Kenya and the government are ready and willing to take a new challenge to harnessing wind power. So yes it can be done but I do think that there is still potential for more to be done, like educating people, especially those in rural areas on the benefits of wind power and how to do it. There are still many places outside Nairobi that live without electricity, Kogelo was once one of those places. Politicians need to campaign for such projects. They are the ones who could make a greater impact for the benefit of such projects.