Although it has been exploited for thousands of years, the re-emergence of wind energy for electric power generation in the grid-connected mode is of relatively recent origin. Since the mid-seventies, when work began in earnest on harnessing wind, the development of wind energy technology has made significant progress. Modern wind turbines are far removed from their historic predecessors. They are highly sophisticated machines built on aerodynamic principles. These principles were developed from the aerospace industry, incorporating advanced materials and electronics. Modern wind turbines are designed to deliver energy across a range of wind speeds. The technical feasibility of using wind as a major source of energy has now been established, and wind energy today ranks as one of the most promising of the renewable energy technologies for generating electricity. Today, wind power is a truly global phenomenon and is beginning to figure in national energy plans as an important source of energy, income and employment.

    The world’s total wind turbine capacity has reached 8,500 MW in 1998. The United States set the pace in the early eighties. A total wind power capacity of 1,700 MW has been installed in the U.S. Several European countries, especially Germany, Denmark, the Netherlands, United Kingdom and Spain now have national wind energy programmes. The present installed wind power capacity in Europe is about 5,500 MW. The total installed capacity in Germany has gone up to nearly 2,400 MW, and now leads the world in the production of electricity from wind. A capacity of about 1,300 MW has been installed in Denmark. 600 MW of wind power capacity has been installed in Spain and about 350 MW in the Netherlands. In U.K.., the installed capacity stands at 330 MW. Sweden and Italy have initiated wind installations and 150 MW has already been installed in each country. Elsewhere in the world, India has emerged as a leading wind power, with 992 MW of installed capacity. This puts India in the fourth position in the global hierarchy. Similarly, the Chinese programme is becoming active with 190 MW installed so far.

  Wind is one of the most cost-effective of the renewable energy technologies, and the resource is widely distributed around the world. The capital costs have halved and now average about $ 1,000/KW. They are expected to decline to $ 750-850/KW, within the next few years. Operation and maintenance (O&M) costs have dropped four-fold over the last decade to 1-1.5 c/KWh, and are likely to drop to less than 1 c/KWh by the year 2005. Availability factors have increased from 60 percent to over 95 percent, and generation can be predicted with certainty on a long-term basis. Capacity factors now vary from 20-30 percent, and are expected to increase to 30-45 percent by the year 2005. With the output from a modern turbine in a good wind area now averaging 800-1,000 KWh/year/Sq.m. of rotor swept area, the specific energy yield has nearly doubled. The annual energy output is generally about 2 million KWh/MW. The construction lead-time is less than six months, and wind turbine installations are highly modular. The new variable speed wind turbine technology is expected to improve energy capture, reduce stresses and lengthen turbine life. The evolving wind turbine technologies employ flexible, lightweight blades and larger rotor diameters (gone up to 66m), improved ailerons, teetering attachments; direct drive transmission; increased height (up to 68 m) and aerodynamic tower design; and advanced electronic controls. The trend towards higher sizes is continuing, and commercial prototypes of up to 1.5 MW unit capacity have now been introduced. These technological developments will help to break the 5 c/KWh barrier, down from the present cost of 7-9 c/KWh, and drop to below 3 c/KWh by the year 2005. In terms of land area, with installation of 8 MW per sq. km., the output is typically 1,60,000 KWh/ha/year.

    The experiences of other countries have provided useful information on policy initiatives, technology development institutional linkages, legislation, pricing, etc., which are necessary for successful programme development, particularly in developing countries. India has taken up a fairly ambitious programme, faced as it is with growing shortage of power and energy. The interest stems not only from the fact that wind power is proving to be cost-effective, but also because it is modular, has short gestation, and is environmentally benign.

    The Wind Power Programme in India was initiated towards the end of the Sixth Five Year Plan, in 1983. A market oriented strategy was adopted from the very beginning of the programme. This has led to the successful commercial development of the technology. The key elements of the strategy are:-

    implementation of a comprehensive Wind Resource Assessment Programme

    induction and demonstration of state-of-the–art wind turbine equipment

    association of the State Electricity Boards and the industry from inception

    The broad based National Programme includes wind resource assessment activities; research and development support; implementation of demonstration projects to create awareness and opening up of new sites; involvement of utilities and industry; development of infrastructure capability and capacity for manufacture, installation, operation and maintenance of wind electric generators; and policy support. The programme aims at catalysing commercialisation of wind power generation in the country.

    The Wind Resource Assessment Programme is being implemented through the State Nodal Agencies, Field Research Unit of the Indian Institute of Tropical Meteorology (IITM-FRU) and Centre for Wind Energy Technology (C-WET). The cost in respect of the wind monitoring stations is shared between the Ministry of Non-Conventional Energy Sources (MNES) and State Nodal Agencies. Under the programme, 80% of the cost of the monitoring stations, determined in accordance with the norms set by the MNES, is provided as grant-in-aid to State Nodal Agencies. The concerned States meet the remaining 20% cost.

    Demonstration Wind Power Projects are implemented through the State Governments, State Nodal Agencies or State Electricity Boards, 60% of the full cost of the WEG, including spares and erection/commissioning, is met by MNES, while the balance cost and other local civil/electrical costs are met by the concerned State. A benchmark of Rs. 3.2 crore/MW has been fixed for the determination of the MNES support for Demonstration projects. The concerned State/Agency meets all expenses towards the cost of the project over and above the eligible cost including escalations, if any.

    The MNES also supports projects in developing and neighbouring countries, wherein the full cost of wind turbine equipment, including spares and erection/commissioning, is provided by MNES, with local works being undertaken by the recipient country. For wind-diesel projects, full cost of the wind-turbine & control equipment is provided by the MNES, with the cost of the DG set or its upgradation, and local works, being met by the recipient country.

    Research and Development activities are undertaken through Research Institutions, National Laboratories, Universities and Industry, for development of cost-effective and systems for improvement in quality of power generation from wind power projects.