Introduction
Energy extraction from wind is one of the oldest energy-harvesting technologies that is being used for centuries. Winds are caused by the rotation of the earth and the heating of the atmosphere by the sun. The total annual kinetic energy of air movement in the atmosphere is estimated to be 3 x 105 kWh or 0.2% of the solar energy reaching the Earth. The maximum Technically usable potential is estimated to be theoretically 30 trillion kWh Per year, or about 35% of the current world total energy consumption. The power in wind blowing at 25.6 km/h is about 200 W/m2 of the area swept by a windmill. Approximately, 35% of this power can be captured by windmills and converted to electricity. The kinetic energy of the air can be transformed to mechanical and then to electrical form of energy using fans, gears, turbine, and generator system. Windmills a modern world's electricity harvesting technology accounts for more than 2 GW of installed capacity worldwide. Electricity generation from wind is directly proportional to the air density, swept area of blades, and cube of the wind velocity. Since wind velocity is more tentative, hence optimizing the blade area, maximum energy can be extracted for particular wind speed at a given place.
| where, |
P =(1/2)*
*A*V∧3 |
(1) |
| P: Wind power |
p: Air mass density |
| A: Swept area |
V: Wind (area of wind velocity flow) |
The annual wind speed at a location is useful as an initial indicator of the value Of the wind resource. The relationships between the annual mean wind speed and the potential value of the wind energy resource are listed below:
| Annual Mean wind speed @ 10 m Ht. (m/s) |
Indicated value of wind resource |
| <4.5 |
Poor |
| 4.5-5.4 |
Marginal |
| 5.44-5.7 |
Good to Very Good |
| >6,7 |
Exceptional |
Uttara Kannada, a district located in the west coast and in the region of Western Ghats region of Karnataka, is blessed with good wind potential.Since electricity supply is unreliable at most times, harnessing of wind energy could play a prominent role in meeting the energy demand in the region since electricity supply is unreliable in most of the times. Wind energy potential in the district could meet the regional electricity demand through wind energy conversion system (WECS) avoiding plenteous greenhouse gas (GHG) emission and fossil fuel. This can be harnessed locally in a decentralized manner for applications in rural areas and remote areas, such as water Pumping for agriculture and plantations. Wind- driven electric generators could be utilized as an independent power source and for purposes of augmenting the electricity supply from grids. In coastal, densely populated taluks, Such as Karwar, Kumta, and Bhatkal in Uttara Kannada District, decentralized production of electricity would help local industries, especially seasonal agro processing industries, such as cashew, etc.WECS can be hybridized with solar, biomass, and any other available local energy resources to provide 100% Reliable power since wind flow is at its maximum during monsoon when solar insolation and dry biomass availability is comparatively lesser.
Wind resource assessment: Wind resource assessment is the primary step towards understanding the local wind dynamics of a region. Wind flow developed due to the differential heating of the earth is modified by its rotation and further influenced by local topography. This results in an annual (Year to year), seasonal, synoptic (passing weather), diurnal (day and night), and turbulent (second to second) changes In wind pattern. Increased heat energy generated due to industries and escalating population in urban areas result in heat islands which also affects the wind flow as well.
2.1. Objective
The objective of the present study is to assess the taluk wise annual wind Potential in Uttara Kannada district and assess techno-economic feasibility of wind energy harvesting options, to meet the regional electricity demand.
