CEE Oct-Dec 2012

l a higher wind energy output. Therefore, offshore wind farms are expected to offer higher economic viability. Europe has taken the lead in this space, with about 1,500 grid-connected offshore turbines aggregating 4,300 MW across 10 countries (as on June 30 , 2012). Countries like Canada, the US, China and India are also showing interest in offshore wind technology. Moreover, turbine manufacturers such as Alstom, Siemens and Vestas have launched floating wind towers. In these towers, the turbine is mounted on a floating structure and is held by wires or chains attached to weights on the seabed. These towers do not require permanent anchoring to the seabed, thereby reducing their installation costs. Key factors to be considered in the structural design of towers Turbine over speed: At very high winds, turbines and rotors run into over speed, which puts excessive loads on towers. Fatigue failure: After being subjected to cyclical loads over a long period, the tower material suffers fatigue, which causes it to gradually degrade and reduces its strength. Steel welds can crack due to the built-up residual stress caused by long-term fatigue. Rotor and blade imbalance: Rotors and blades have a built-in imbalance. Blade rotation during snowfall or heavy rainfall puts additional loads on the tower. Seismic loads: Since a wind turbine is a dynamic structure, the inherent load puts pressure on towers located in high seismic zones. The challenges are multiplied in the case of offshore projects, which are more prone to seismic activities. The way forward The trend towards the use of large-sized turbines will gain momentum with developers looking to exploit low-wind sites and governments announcing/planning higher tariffs for such sites. To develop such turbines, manufacturers are using innovative techniques for lower construction. Though some manufacturers have devised innovative strategies, the viability of these options is yet to be establ ished. Greater innovation in tower design and construction is expected as several manufacturers apply the lessons learnt from the current developments in this space and modify techniques to supply towers at reduced costs. Courtesy: Renewable Watch, Oct. 2012, Pp 56- 60. VESTAS TO FOCUS ON MAINTENANCE f'"' 'ICES 1" 1 1'\IOIA Denmark-based wind turbine manufacturer Vestas, which is currently implementing a global reorganization and cost-cutting plan, is reportedly planning to scale down its turbine sales operations in India in order to increase its focus on providing value-added and maintenance services to existing and upcoming wind power plants in the country. The company is targeting to cut its costs by Euro 250 million by December 2012. Courtesy: Renewable Watch, Oct. 2012. P6. The cost of wind power has dropped below the price of coal-fired energy in parts of India for the first time as improved turbine technology and rising fossil-fuel prices boost its competitiveness, Greenko Group Pic (GKO) said. "Today we're able to supply energy below the cost of conventional power,' said Mahesh Kolli, president of Greenko, which is building wind projects with General Electric Co. (GE) (GE) in India. "That's the key development for this year." The cost of wind has closed in on coal thanks to more advanced turbines, which can produce more electricity from lower wind speeds . The shift means new wind farms in India will be able to survive without state subsidies, potentially attracting investors to a country where 57 per cent of installed capacity is coal-based and 31 per cent renewable, including hydropower. The company, based on the Isle of Man, has signed agreements for more than 1,000 megawatts of wind capacity and a three-year contract to buy at least 450 megawatts of GE turbines. State power distributors in places such as Karnataka, Rajasthan, Maharashtra and Andhra Pradesh have a "market incentive to buy wind power because we're cheaper," Kolli said. Courtesy: Total Energy, Jul.-Aug. 2012. P20. w· · ~ ~ H: c r 1 ' .. 1 t- j'"' T 1\1111 I A"'' 1 When wind energy met over one-third of Tamil Nadu's energy demand, has proven the ability of renewable energy to consistently meet utility-scale energy supply, according to the Indian Wind Power Association. This illustrates the need for the policy makers at the State and Centre to restore the incentives to support the wind energy sector, said the Association. 37