Wind power describes the process by which the wind is used to generate mechanical power or electricity. Wind is also one of the oldest known sources of power used by humans and today it is the most established and efficient renewable energy source.
Renewable energy is energy drawn from a source that does not deplete when used. The academic term for wind power, Eolic energy, is a term derived from the name of the Greek mythological figure Aeolus, the keeper of the winds.
Wind energy does not contaminate, it is inexhaustible and reduces the use of fossil fuels which are the origin of greenhouse gasses that cause global warming. Wind power is the most efficient technology to produce energy in a safe and environmentally sustainable manner. It produces zero emissions, it is local, inexhaustible and is available practically everywhere on the plant, which contributes to reducing energy imports and to creating wealth and local employment.
The worldwide total cumulative installed electricity generation capacity from wind power has increased rapidly since the start of the third millennium, and as of the end of 2019, it amounts to 651 Gw.
Wind energy currently supplies over 3 % of global electricity consumption and this is expected to exceed 5 % by 2020. In the longer term (by 2040), the International Energy Agency forecasts that wind energy could meet 9 % of global electricity demand and more than 20 % of demand in Europe.
In Sri Lanka, we have about 100 Mw wind power installed capacity at present and this will be increased up to 200 Mw with the commissioning of the Mannar, Thambapavani wind power project and he Government plans to increase the capacity up to 1200 Mw by the year 2037.
Maximum power demand in Sri Lanka is about 2600Mw and the annual power demand is at about 16000 Gwh out of which Solar/wind installed capacity 216 Mw produced 600 Gwh in 2018. According to above data, we produce less than 2% of our power requirement from wind energy.
According to wind resource map of Sri Lanka, the total windy area on land is around 700km2. The windy land represents about 6% of the total land area of 65,600km2 of Sri Lanka. With the total usage of windy areas, around 20,000 Mw can be generated with the 5 Mw per 1km2 conservative value.
This is very much higher than our power requirement in the country. For these reasons, producing electricity through wind energy and its efficient use contributes to sustainable development. Unlike fossil fuels and nuclear power plants, wind energy has one of the lowest water-consumption footprints, which makes it a key for conserving hydrological resources.
The wind will never run out. The technology will improve, and the current wind turbines may be superseded by even more better units, but the wind will always be there. The source of wind power is inexhaustible.
With a free energy source, land-based wind turbines produce some of the cheapest electricity on the planet.
According to CEB it is less than Rs. 9 per kilowatt-hour in Sri Lanka and because the power produced by wind farms is sold over a long period at a fixed price, there are none of the sudden hikes in price that often affects electricity produced by fossil fuels.
In general, once erected and commissioned, wind turbines require little in the way of maintenance. The technology might be sophisticated, but the mechanics are straightforward and reliable. Low operational costs will lead to lower electricity costs for the consumer as more people adopt it.
As disadvantages, wind turbines produce noise, and if you live near them, this may be an inconvenience. The sound they produce can travel up to 2 km according to some estimates, but they aren’t any noisier than a busy highway and aren’t situated near populated areas.
The sound will also carry depending on the direction of the wind that day, and if there’s no wind, there’s no noise. Aesthetically, it has been argued that they are not attractive to look at, but compared to the extensive damage mining and fracking causes, this should be a minor concern.
Wind farms built at sea nearly eliminate both of these negatives, and this is becoming more common. There have not been enough studies to be sure about the amount of birds killed every year due to wind turbines. It is very much less than the birds killed due to other human activities.
Even though the impact of wind turbines on birds is comparatively less, scientists and researchers are continuously working to reduce, and ideally eliminate, the impact on birds and other wildlife. The Mannar, Thambapavani wind power plant in Sri Lanka consists of a Bird Radar system to minimize the impact on birds.
Another disadvantage of wind power is that wind is not constant. In fact, it fluctuates both in strength and direction. Technologies such as anemometers that automatically measure the speed of wind in order to provide wind speed and direction measurements help to reduce wasted wind. Those measurements are then used to rotate and fine-tune the direction the turbine faces to directly face wind and generate the most amount of energy as possible.
When the ability to store electricity improves, this will become much less of a problem, and the use of other clean and renewable energy sources can help maintain clean energy at all times. Of course, placing wind farms in high-wind areas also helps negate this negative.
To achieve maximum benefit and usage of wind energy, it is proposed to construct and operate semi-dispatchable wind farms in the identified significant areas. The Mannar Island has been selected to construct wind farms in the north-western and northern regions due to constant availability throughout the past years wind analysis.
Its first phase, the 100Mw wind farm is now being constructed at the southern coast of the Mannar Island. The facility is expected to power up the national grid with 30 Nos of 3.45 MW Wind turbines which produce 103.5Mw of power.
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Content Submitted by
Mr. Achala Kalinga
Project Manager – PMD II