OFFSHORE WIND ENERGY POTENTIAL ALONG INDIAN COAST

International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 7, July 2018, pp. 1480 1486, Article ID: IJCIET_09_07_157 Available online at http://www.iaeme.com/ijciet/issues.asp?jtype=ijciet&vtype=9&itype=7 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 IAEME Publication Scopus Indexed OFFSHORE WIND ENERGY POTENTIAL ALONG INDIAN COAST Jobil Varghese Karunya Institute of Technology and Science, Karunya Nagar, Coimbatore 641114, India Freeda Christy Karunya Institute of Technology and Science, Karunya Nagar, Coimbatore 641114, India Katta Venkattaramana National Institute of Technology Karnataka, Surathkal, Mangalore 575025, India ABSTRACT India being a fast developing over populated country requires energy in huge quantity to keep pace with its aspirations. The Offshore wind energy is the source of clean and economical energy of the future. This energy requires higher power capacity wind turbine installed offshore. A study of various offshore locations of west and east coast of India was conducted. Total coast line length of 7500km is available together with Arabian sea in the west, Indian ocean in the south and the Bay of Bengal in the east. The offshore locations Jamnagar, Bombay, Mangalore, Cochin, Madras, Vishakhapatnam, Paradeep and Calcutta were studied with respect to the variation in wind velocity both horizontally and vertically. Power generation potential at 90m height for various locations were evaluated and compared considering a 5 Mega Watt wind turbine developed by the National Renewable energy Laboratory USA. Key words: offshore, wind energy, power capacity, potential. Cite this Article: Jobil Varghese, Freeda Christy and Katta Venkattaramana, Offshore Wind Energy Potential along Indian Coast. International Journal of Civil Engineering and Technology, 9(7), 2018, pp. 1480-1486. http://www.iaeme.com/ijciet/issues.asp?jtype=ijciet&vtype=9&itype=7 1. INTRODUCTION India being a fast developing over populated country requires energy in huge quantity to keep pace with its aspirations. It is also indebted to address the environmental concerns arising during the production of energy using the various sources. [2] The availability of a very long coastline almost 7500 kilometers running along Arabian sea in the west, Indian ocean in the south and Bay of Bengal in the east makes it almost indispensable to consider development of offshore wind farms. Wind energy is considered to be the clean and renewable energy of the future, worldwide and India have the potential to make significant contribution as is evident from its present onshore installations. It will be a blessing in disguise for the mostly http://www.iaeme.com/ijciet/index.asp 1480 editor@iaeme.com

Jobil Varghese, Freeda Christy and Katta Venkattaramana underdeveloped coastal area to have a power source nearby for faster development. The wide gap in living standard of people in coastal and interior India in the past has resulted in political unrest and formation of new state even. 1.1. Power Available with Wind The energy available in the wind is basically kinetic energy. The blades of the wind turbine are subjected to this energy and it is transformed into electrical energy. Therefore, when the feasible location for installation of wind turbine is considered, the most important aspect to be considered is the wind characteristics of the region. The main characteristic of the wind its velocity is very important since a minimum velocity of 5-5.5m/s is required for wind energy development. In olden days wind information were extracted from synoptic weather charts published at regular intervals, weather charts are mostly prepared by using ship observations and assuming continuity in the pattern over the oceanic regions. [5] The Indian Metorological Department (IMD) New Delhi wind data from 1961 to 70 was obtained and utilized in the present study, wind data distribution for the Indian seas (IMD 1961-70) over one degree square grids. It is also necessary to study the wind turbulence of the region, extreme wind speed, average wind speed and wind shear. In addition to these the marine protected areas, coastal regulation zone and the navigation area have to be set aside. The methodology adopted was to collect the available wind velocity data onshore and offshore for the regions making due corrections. From these data, generated power was evaluated and compared. 1.2. Offshore Wind Energy Offshore wind energy is the energy of the future. The wind velocity is higher in the offshore environment. The kinetic energy of a stream of air with mass m and velocity v is given by Considering a wind rotor of cross sectional area A, subjected to a wind stream, kinetic energy of the air stream available for the turbine can be expressed as Where the density of air and v is the volume of the air parcel available to the rotor. The air parcel interacting with the rotor per unit time has an area equal to area of the rotor and thickness equal to wind velocity. Therefor power that is equal to energy per unit time can be expressed as The power available with the wind spectra has a cubic relation with the wind velocity. This will ensure more energy making the power generation economical. Turbulence of the wind is less in offshore due to lack of obstructions. This will reduce the impact loads on the turbine components and increase the life. Some disadvantages of installing wind turbines onshore like sound pollution and visual pollutions can be avoided if the turbines are installed offshore. 1.3. Indian Coast A study of various offshore locations of west and east coast of India was conducted. Total coast line length of 7500km is available together with Arabian sea in the west, Indian ocean in the south and the Bay of Bengal in the east. The offshore locations selected were Jamnagar, (1) (2) (3) http://www.iaeme.com/ijciet/index.asp 1481 editor@iaeme.com

Offshore Wind Energy Potential along Indian Coast Bombay, Mangalore, Cochin, Madras, Visakhapatnam, Paradeep and Calcutta. The coastline and the locations are shown in the figure 1. [5] Figure 1 Major s along Indian Coast The locations selected are of great significance being port, harbors and shipping routes. These locations cannot be considered for installation, of wind turbines for generation of wind energy, but are considered since the data pertaining to these regions were readily available and reliable too. A macro analysis of the locations will give a general behavior along the Indian coastline and will be of considerable help for locating offshore wind turbines. The latitudes and longitudes of the locations are furnished in Table 1. The offshore locations Jamnagar, Bombay, Mangalore, Cochin, Madras, Vishakapatanam, Paradeep and Calcutta were studied with respect to the variation in wind velocity horizontally and vertically. Wind velocities pertaining to the various locations along the coastline are furnished in Table 2. Now the above data are obtained for offshore locations 50km from the shore. To correlate distance with longitudes and latitudes, the distance between two longitudes at equator is considered as 111.321km and the distance between two latitudes at equator is considered as 110.567m. Table 1 Latitudes and Longitudes of onshore and offshore locations Onshore Offshore Latitude Longitude Latitude Longitude Jamnagar 22.5 o North 70 o East 20 o North 68 o East Bombay 18.5 o North 73 o East 18.5 o North 71 o East Mangalore 13 o North 75 o East 11 o North 73 o East Cochin 9.5 o North 77 o East 8.5 o North 74 o Eas Madras 13 o North 80 o East 13 o North 83 o East Vishakhapatnam 17.5 o North 83 o East 16 o North 85 o East Paradeep 20 o North 86 o East 18 o North 88 o East Calcutta 22 o North 88 o East 20 o North 89 o East http://www.iaeme.com/ijciet/index.asp 1482 editor@iaeme.com

Jobil Varghese, Freeda Christy and Katta Venkattaramana Table 2 Wind velocity near shore for various months of the year Jamnagar Bombay Mangalore Cochin Madras Vishak Paradeep Calcutta January 3 2 2 2 3 3 2 2 February 2 3 2 2 2 2 1 1 March 3 3 2 2 2 2 2 3 April 3 3 3 3 4 5 3 5 May 3 3 3 3 5 5 5 5 June 6 6 6 6 8 8 8 8 July 9 9 8 6 6 8 8 8 August 8 6 5 5 5 6 5 5 September 4 4 4 4 4 4 3 3 October 2 2 2 2 1 1 2 2 November 2 2 1 1 3 3 3 2 December 3 3 2 1 5 5 3 3 Table 3 Wind velocity offshore for various months of the year Jamnagar Bombay Mangalore Cochin Madras Vishak Paradep Calcutta January 4 4 3 3 5 5 4 3 February 3 3 2.5 2.5 3 2 2 2 March 3 3 2.5 2 2 2 2.5 3 April 3 3 3 3 3 4 4.5 4 May 5 4 4 5 6 5 5 5 June 6 6 7 7 8.5 6 8 8 July 10 9 7 6 8 6 8 8 August 8.5 7 6 5.5 6 7 6 6 September 5.5 5.5 4.5 4.5 5.5 5 4 3.5 October 3 3 2.5 2 2 2 2 2 November 4 3.5 2 2 4 4 3 3 December 4 4.0 2.5 2 6 5.5 3.5 3 From the national hurricane center site interaction application map application enabled to obtain distance between two points by inputting GPS coordinates of latitudes and longitudes. The wind velocities offshore are given in the Table 3. 1.4. Wind Shear Velocity of the wind is specified at 10m from the ground surface. This wind velocity goes on increasing with height in a logarithmic pattern, the aerodynamic roughness length of the land beneath through which wind blows also influence the wind Velocity. The two corrections involved, one for height and other for roughness had been incorporated in the following formula, Stull 1999, where the values for r 2 and r 1 are respectively 0.002 and 0.005, the aerodynamic roughness surface length for sea and beach was given as in Eq. 4. M 2 = M 1 x ( ) ( ) (4) Where M 1 is the wind velocity at height z 1 and M 2 is the new wind velocity at height z 2 and roughness length r 2. The variation in wind velocity with height is given in the table 4. http://www.iaeme.com/ijciet/index.asp 1483 editor@iaeme.com

Offshore Wind Energy Potential along Indian Coast Table 4 Wind velocity 90m height offshore Jamnagar Bombay Mangalore Cochin Madras Vishak Paradeep Calcutta January 4.98 5.64 4.23 4.23 7.05 7.05 5.64 4.23 February 4.23 4.23 3.53 3.53 4.23 2.82 2.82 2.82 March 4.23 4.23 3.53 2.82 2.82 2.82 3.53 4.23 April 4.23 4.23 4.23 4.23 4.23 5.64 6.35 5.64 May 8.46 5.64 5.64 7.05 8.46 7.05 7.05 7.05 June 8.64 8.46 9.87 9.87 11.99 8.46 11.28 11.28 July 14.1 12.69 9.87 8.46 11.28 8.46 11.28 11.28 August 11.99 9.87 8.46 7.76 8.46 9.87 8.46 8.46 September 7.76 7.76 6.35 6.35 7.76 7.05 5.64 4.94 October 4.23 4.23 3.53 2.82 2.82 2.82 2.82 2.82 November 5.64 4.94 2.82 2.82 5.64 5.64 4.23 4.23 December 5.64 5.64 3.53 2.82 8.46 7.76 4.94 4.23 1.5. Power Variation for Different s Modern wind turbine blades consist of airfoil section. The blades are subjected to lift force and drag force by the wind impinging on the blades at an angle called the angle of attack. The lift forces are responsible for the rotation of the turbine. The theoretical power available with the wind is given by the equation (3). A part of the energy available with the wind cannot be exploited and it is carried away with the leaving wind. Therefore the actual power produced by the wind turbine was obtained by multiplying the available power with power coefficient. The density of air decreases with the increase in site elevation and temperature but air density may be taken as 1.225 for most of the practical cases. The wind turbine considered is 5MW wind turbine developed by the national renewable Energy Laboratory, United States of America, of which the diameter of the rotor is 126m. The wind power generated by this turbine had been evaluated for the different offshore locations along the coast of India for all the twelve months of the year and furnished in Table 5 Table 5 Wind power (MW) variation offshore, location, month Jamnagar Bombay Mangalore Cochin Madras Vishak Paradeep Calcutta January 0.55 0.55 0.23 0.23 1.07 1.07 0.55 0.23 February 0.23 0.23 0.13 0.13 0.23 0.07 0.07 0.07 March 0.23 0.23 0.13 0.07 0.07 0.07 0.13 0.23 April 0.23 0.23 0.23 0.23 0.23 0.55 0.78 0.55 May 1.85 0.55 0.55 1.07 1.85 1.07 1.07 1.07 June 1.85 1.85 2.94 2.94 5.26 1.85 4.38 4.38 July 8.56 6.24 2.94 1.85 4.38 1.85 4.38 4.38 August 5.26 2.94 1.85 1.42 1.85 2.94 1.85 1.85 September 1.42 1.42 1.78 0.78 1.42 1.07 0.55 0.37 October 0.23 0.23 0.13 0.07 0.07 0.07 0.07 0.07 November 0.55 0.37 0.07 0.07 0.55 0.55 0.23 0.23 December 0.55 0.55 0.13 0.07 1.85 1.42 0.37 0.23 http://www.iaeme.com/ijciet/index.asp 1484 editor@iaeme.com

Velocity in m/s Velocity of Wind in m/s Jobil Varghese, Freeda Christy and Katta Venkattaramana 2. RESULT AND DISCUSSION A comparison of the wind velocities for different locations near shore and offshore were made and it was observed that Jamnagar experience the maximum wind velocity followed by Bombay and Madras. Cochin experiences lowest wind velocity among the chosen locations followed by Mangalore and Vishakhapatnam. The wind velocities experienced at Paradeep and Calcutta were almost the same. For all the other locations selected, the wind velocity 50km away from the near shore location was observed to be greater all the months of the year except for couple of months have same velocity. The wind velocities near shore and offshore for Jamnagar is shown in the fig. 2. 12 10 Wind velocity near shore Wind Velocity Offshore 8 6 4 2 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec of the Year Figure 2 Variation in Wind Velocity near shore and offshore at Jamnagar for various months of the year The variations in wind velocity with height for the different offshore location were calculated by using equation 4. For each location the wind velocity showed a logarithmic increase with height. A comparison of the wind velocity at 10m height and 90m height for location Jamnagar for the twelve months of the year shown in the figure 3. 16 14 12 10 8 6 4 2 0 velocity at 10m height Velocity at 90m height Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec s of the Year Figure 3 Variation in wind velocity at 10m and 90m for offshore location Jamnagar for various months of the year. The generated power for various locations had been evaluated and variation during different months of the year is shown in figure 4. For obvious reason, cubic relation between wind velocity and generated power, Jamnagar showcased the maximum power. http://www.iaeme.com/ijciet/index.asp 1485 editor@iaeme.com

Generated Power in Mega Watt Offshore Wind Energy Potential along Indian Coast 9 8 7 6 5 4 3 2 1 0 Jamnagar Bombay Madras Paradeep Calcutta Vishakapatanam Mangalore Cochin Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec of the Year Figure 4 Variation in Power Generated at Various Offshore s during for various months of the Year. 3. CONCLUSIONS The wind velocity near the coast and 50km into the sea from the coast were analyzed and found that wind velocity at offshore has logarithmic increase than the wind velocity near the coast in all the selected locations. From the comparison of power generated at the various locations along the coastline, it was inferred that Gujarat have maximum offshore wind generation potential followed by Maharashtra and Tamil Nadu. West Bengal and Orissa s power generation potential are comparable. The least amount of wind power generated from the study was Kerala followed by Karnataka and Andhra Pradesh. REFERENCES [1] Garlapati Nagababu, Surendra Singh Kachhwaha, Vimal Savsani and Ranajit Banerjee. Evaluation of offshore wind power potential in the western coast of India: A preliminary study, Current Science 112(1), January 2017 [2] Mani Murali, R, Vidya, P. J., Poonao Modi, Seelam Jaya Kumar, Site selection for offshore wind farms along the Indian Coast, Indian Journal of Marine Sciences 43(7), July 2014 [3] Sukhatme, S. P., Can India s future needs of electricity be met by renewable energy sources? A revised assessment, Current Science 103(10), pp.1153-1161, 2012 [4] Stull, R. S., Meteorology today for scientists and engineers, a technical companion book to Ahrens meteorological today (2 nd ed.)1999 [5] Swain, J., Simulation of wave climate for the Arabian sea and Bay of Bengal, Doctor of Philosophy in Physical Oceanography Dissertation, Cochin University of Science and Technology, 1997. [6] Central Electricity Authority, All India installed capacity (in MW) of power stations http://www.cea.nic.in/reports/monthly/installedcapacity/2016/installed_capacity_ 03.pdf [7] S.Munisekhar, O.Hemakesavulu And Dr.M.Padmalalitha, Wind Energy Conversion Systems Using Fuzzy Controlled Statcom For Power Quality Improvement. International Journal of Electrical Engineering & Technology, 4 ( 4 ), 201 3, pp. 108 117. [8] M. Thirupathaiah, P. Venkata Prasad and V. Ganesh, Analysis of Various Compensation Devices For Power Quality Improvement In Wind Energy System. International Journal of Electrical Engineering & Technology, 7 ( 3 ), 2016, pp. 25 39 http://www.iaeme.com/ijciet/index.asp 1486 editor@iaeme.com