Wind energy

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Wind energy

  1. 1. Renewable Energy Sources for the Cayman Islands and Other Caribbean SIDS © M. L. Anderson, 2007 Part 2: Wind Energy
  2. 2. Part 2. Wind Energy Caribbean Islands have substantial wind resources.  Wind turbines erected in areas that receive strong winds, both along the coast and offshore, have the potential to generate non-polluting electricity to support most SIDS growing demand for energy.  Wind power does not contribute to global warming and produces no air pollution wastes.
  3. 3. Wind Energy Basics      Wind is the natural movement of air across the land or open water caused by the uneven heating of cooling of the earth’s rotation. Both land and water absorb and release energy gained from the sun. Also when warm air rises, cooler air rushes in to take its place causing local winds. The rotation of the earth changes the direction of the flow of air producing prevailing winds including the Caribbean’s trade winds. Wind turbines capture the wind’s energy with two or three propeller-like blades, which are mounted on a rotor, and connected to a generator, to generate electricity.
  4. 4. Wind Energy Basics      The turbine blades sit high atop towers taking advantage of the stronger and less turbulent wind at 100 feet or more aboveground. When the wind blows, a pocket of lowpressure air forms on the downward side of the blade and pulls the blade toward it, causing the rotor to turn. Similar to an airplane wing, this is called lift. The force of the lift is much stronger than the wind force against the front side of the blade (drag). The combination of lift and drag cause the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity.
  5. 5. Wind Energy    Wind conditions over areas of water are considerably better than over land: 1. The average wind speed is unobstructed. Wind speed over water is typically 1m/s higher than over the land; resulting in approximately 40% more wind energy. 2. The wind is less turbulent over water than over land. This also contributes to increased wind turbine performance.
  6. 6. Wind Energy Basics     The amount of energy produced by a wind turbine is dependent on the wind speed and the size of the blades. When the wind speed doubles, the power produced is increased eight times. In addition, the larger the blade, the more wind is captured. As the diameter of the circle formed by the blades doubles, the power generated increases four times.
  7. 7. Types of Wind Turbines  Vertical Axis turbine, Horizontal Axis turbine, Double bladed, Multi-bladed water pump
  8. 8. Wind Energy   Every unit of electricity generated from a wind turbine replaces one that would otherwise be generated from fossil fuels, and thus prevents the emission of several greenhouse gasses including carbon dioxide, sulfur dioxide and nitrous oxide. The Renewable Obligation places a value on the ‘greenness’ of electricity that is higher than the price of power itself.
  9. 9. Wind Energy     Technological advances in turbine and blade designs over the past 20 years have reduced the cost of producing electricity with wind as much as 80%. The larger the turbine, the less are required for a given size wind farm. By moving turbine size from 250kW size range to 1MW machines, site construction costs are reduced by up to 30%. The price of wind turbines of about 45meters rotor diameter is approximately US$770/kW.
  10. 10. Wind Energy    Operational costs also vary according to turbine size and average wind speed: while 250kW machines cost US$25/kW annually, it only costs US$14/kW per year for a 750kW turbine. Plant costs are about 10 cents/kW hour for wind speeds at 5mph, with much more efficient energy production at 3.6cents /kW hour at wind speeds of 10mph. Spacing between wind turbines normally ranges from 3 to 7 rotor diameters, depending on turbine size, number of units and their spatial pattern. Lattice vs. tubular steel.
  11. 11. Can we rely on the wind?     Wind turbines generate electricity for 70-85% of the time, but not always at full output. Most wind turbines start generating power with wind speeds at 4m/s, maximum power is at 15m/s and units are shut down at 25m/s, to prevent storm damage. No power plant is operational 100% of the time. Plants are routinely shut down for maintenance and for other reasons, with other power sources picking up the slack in a grid system.
  12. 12. What happens when the wind stops blowing?      Wind is not available all of the time and many critics of wind power cite the intermittent nature of the wind as a detriment of wind energy. When the wind stops blowing, electricity continues to be generated from other sources, such as gas or nuclear, all a part of a large energy grid. The system is used to dealing with fluctuations in demand, and it is possible to have well over 15% of a country’s needs met by intermittent energy sources without having to make any changes to the way the system operates. The output from a wind farm is smoother than the output from a single machine, and the output from a dispersed wind system, with wind farms scattered across a large area is smoother still making large changes in output highly unlikely. In addition, wind farms are typically operating at high output when the demand is the highest, especially in the winter months.
  13. 13. What is the cost of wind?     The price of wind turbines of about 45 meters rotor diameter is approximately US $770/kW. In addition, the larger the turbine, the less it will cost to run /kWh. By moving the turbine from the 250 kW size range to 1MW size turbines, both site construction and operational costs are reduced by 30%. Operational costs range from US$25/kW/year for 250kW machines, to about US$14/kW/year for 750kW turbines.
  14. 14. What is the Cost of Wind?    Average energy prices are also inversely proportional with wind speed. For example: prices from a 10MW wind farm with 500kW turbines, corresponds a plant cost of $900/kW yielding a price of about 10 cents/kWh at 5 m/s wind speed, whereas if the wind speed increases to 10 m/s, the price of power decreases to 3.6 cents/kWh. Construction costs, electrical equipment and transmission costs account for about 25 to 40% of the project cost.
  15. 15. Wind Resources in the Caribbean    The wind patterns in the region are dominated by the northeast trade winds. They are controlled largely by the pressure gradient across the region, created by the location and intensity of the sub-tropical region of high pressure located between Bermuda and the Azores Islands located in the North Atlantic. The trade winds are a persistent feature of the region blowing throughout the year
  16. 16. Wind Resources in the Caribbean    Due to the trade winds, exposed areas of the smaller islands and costal regions of the larger islands have a very low incidence of meteorologically calm conditions. The Caribbean islands are ideally suited for wind power deployment. Wind speeds are greatest in the eastern Caribbean and lower in the western Caribbean and the Bahamas.
  17. 17. Windmill History  Northern Europe has harnessed the power of wind for centuries.
  18. 18. Windmill History  Wind power was abundant about 175 years ago, when five million water-pumping windmills were at one time spread across the American West.  At 1 KW per machine, they represented 5000MW of distributed power.
  19. 19. Windmill History  Two centuries ago, Americans relied on the winds along the shores of New England to power salt farms and gristmills. By the 1830’s 1,260 “salt mills” along with 39 wind-powered gristmills had been emplaced along the coast of Cape Cod providing energy for industry.  The advent of steam power caused the end of the windmills.
  20. 20. Global Wind Development      In the U.S. wind is expected to provide at least 6% of the nation’s electricity by 2030. In Denmark, windmills are currently generating 20% of electricity. Scotland is projected to have 18% of all electricity generated by renewable sources by 2010, and will increase to 40% by 2020. Spain will have 15% of its electricity from wind power by 2011. Europe is the leader in wind power with a total capacity of 35,000MW, or the equivalent of 35 coal-fueled power plants.
  21. 21. Caribbean Wind Development Through the Latin American and Caribbean Initiative for Sustainable Development, these countries have committed to alter their energy mix so 10% of their primary energy supply will come from renewable sources by 2010. The thrust for renewable energy development in the Caribbean is being led by the Caricom Secretariat through the Caribbean Renewable Energy Development Project (CREDP) that seeks to increase the use of renewable energy in the region and reduce implementation costs of these projects that would reduce the region’s dependence on oil.
  22. 22. Caribbean Wind Development     Wind turbines for grid electricity generation are presently operational in Cuba, Curacao, Guadeloupe, Jamaica and the Dominican Republic. The wind turbines on Monsterrat have been put out of commission due to volcanic activity on the island. The turbines on Antigua, Barbados, Trinidad and Tobago are currently non-operational. Wind power is used for water pumping on the islands of Aruba, Bonaire, Curacao, Cuba, Dominican Republic, Guyana and Jamaica.
  23. 23. Caribbean Wind Development Curacao has had beach wind generators for over twenty years, located on the windy, non-commercial side of the island As with most Caribbean Islands, there is a windy side of the island, where waves and rip tides are known to be hazardous, whereas the leeward side of the island has much calmer waters, and lends itself for tourist activities such as swimming, diving, fishing and other water based activities. KODELA, the utility company of Curacao, installed the first wind turbine in 1983, with an initial investment of US$1million that also included infrastructure for a 25MW expansion. The 1983, a 3MW Tera Cora wind farm consisted of 12 Nedwind 250 kW turbines. It has been an unqualified success, performing well above expectations, and is the standard bearer for all other Caribbean wind farm projects.
  24. 24. Curacao, Netherlands Antilles  Has the most experience with wind generation.  The 1983, a 3MW Tera Cora wind farm consists of 12 Nedwind 250 kW turbines. It has been an unqualified success, performing well above expectations, and is the standard bearer for all other Caribbean wind farm projects.  When oil prices dropped in 1986, the expansion project was no longer viable, however from 1986 to 1991, wind turbine manufactures made significant strides in improving efficiency and lowering costs.  KODELA has since improved on the standard European design, especially in terms of corrosion and high wind speed resistance, and built what is still the largest wind farm in the Caribbean.
  25. 25. Curacao Wind Farm      The 3 MW wind farm has been able to maintain a power penetration factor of 94% with a 38% capacity factor. Wind speeds measured at the wind farm site from 1995 – 2000 have averages 8.6 m/s (19.2 mph) and have very little diurnal variation, enabling the wind farm to operate as a base-load plant. The 12 turbines sit atop simple reinforced concrete foundations and are spaced 1225 meters apart in a line following the contours of the land. The rotors have three blades and have a diameter of 23.5 meters. The 3 MW wind farm has been able to maintain a power penetration factor of 94% with a 38% capacity factor. KODELA arranged for the instillation of an additional wind farm in 2000 with a 9 MW wind capacity, upgrading to 500 kW turbines from Nedwind.
  26. 26. Dominican Republic The International Finance Corp., (IFC) a private sector group within the World Bank, signed an agreement to provide $10 million and a guarantee of $13 million to Consorcio Energentic Punta Cana-Macao (CEMP), a privately owned utility in the Dominican Republic to support an 8.25MW wind power plant. This wind power plant is the first of its kind in the Dominican Republic, replacing part of the utility’s diesel generation. The plant will serve resort areas in Punta Cana and its surrounding communities, which contribute about half of the country’s tourism arrivals.  This is the first time that the IFC has collaborated with DANIDA, the Danish government’s development agency, through a program that provides subsidies to economically sound wind power projects in developing countries.
  27. 27. Jamaica Wind Development The Petroleum Corporation of Jamaica is constructing a wind farm at Wigton with a capacity of 20.7 MW of power. It is expected to supply the Jamaica Public Service Company (JPS) with an average of at least 7MW. This is a 20MW wind power plant with technology supplied by the Dutch firm: Nedwind, the same company that has been so successful in Curacao. The Wigton site is located on the Manchester Plateau, with an elevation of between 900- 1000 meters above sea level. The Wigdon Wind Farm project involves the instillation of 27 wind turbines with a capacity of 750 kW each, for a total capacity of 20.2 MW. This project, when completed, will represent 3.5% of Jamaica’s power capacity. The farm is expected to run at an average capacity of 35%. The turbines have a projected design life of 20 years.
  28. 28.  The Jamaica – The Price of Oil Jamaican Power sector is dominated by oil-fired power generated by steam turbines and reciprocating engines, which emit significant quantities of nitrous oxide and sulfur dioxide.  In addition to the pollutants, the cost of oil imports is a significant expense for most Caribbean nations.  In 1998 the oil import bill in Jamaica was $440 million, however oil prices have more than doubles since then, also with increased consumption, the bill is estimated at over $1billion annually.  The high cost of the oil imports drains away the hard earned money made from tourism in Jamaica.
  29. 29. Jamaica – The Price of Oil      The reliance on oil for the majority of power in the Caribbean region is also the reason for unusually high electricity prices of over 20 US cents per kWh, compared to 5 – 10 cents per kWh in North America or Europe. At these prices, many renewable energy applications are competitive, particularly wind power, which can generate electricity below 10 cents, depending on wind conditions and the technology deployed. The potential for wind power in Jamaica is 70MW by 2010. Because the only source of energy for the power plant will be wind power, the Wigton plant will be generally CO2-free energy. The entire output of the plant will generate potential emission reduction credits for each kWh of output.
  30. 30. Implementation Problems      Problems restricting the implementation of wind power projects in the Caribbean are both infrastructure and logistics. The large 400-ton cranes necessary to erect the towers and assemble the turbines are not readily available, and moving the cranes, which are 40-50 meters high, around on limited access roads is a problem. Also the frequency of hurricanes in the region creates the very real possibility that some turbines could be damaged by the strong winds beyond repair. Another problem is the electric grids on many of the islands are for primarily diesel and heavy fuel oil generation and wind is perceived to be limited to a penetration of only 10-12%. Although this fact has been proven false, a complicating factor is that the grids on some islands are laid out in a complex, haphazard manner, and may have frequent power cuts, unless the entire grid is remade, a prohibitively expensive venture for most SIDS.
  31. 31. LIOW Wind Project Long Island, N.Y., View from Jones Beach In New York, the Long Island Power Authority (LIPA), a public utility, has granted FPL Energy, a subsidiary of General Electric energy a contract for construction of a wind farm off the South shore of Long Island. The facility will consist of 40 wind turbines in a cluster design, 3.6 miles from the nearest shoreline, to minimize visibility.
  32. 32. Long Island Power Authority        The turbines will be sited SE of Jones Beach State Park and SW of Robert Moses State Park and will also be visible from the shores of Cedar Beach. The 8-square mile area wind park will be one of the largest renewable offshore energy parks in the country. The 40 turbines will produce 140MW of electricity for LIPA, enough to power 44,000 homes. Each turbine rotor has three blades approx. 182’ long and the tubular steel towers are approx. 260’high. The turbines can produce electricity at wind speeds as low as 8mph and are at peak production from 26-36 mph. The turbines shut down at wind speeds beyond 56 mph. It has been found that in many cases where wind farms are located, tourism and public education on wind energy also increases.
  33. 33. LIOW Wind Project  Long Island, N.Y., View from Moses and Cedar Beaches
  34. 34. Wind Energy        Key points to final site selection must include: wind resource assessment such as ambient temperature, pressure, humidity and precipitation, lightning, hail, winter icing, soil resistively and groundwater level. Wind turbine specs should be tailored to site conditions. Ensure good grounding and shielding.
  35. 35. Wind Energy      Public opposition to wind farms in nearshore waters is based on worries that: They will spoil the seascapes Have detrimental effect on: birds, fisheries, marine mammals Increase sedimentation and habitat disturbance Any specific wind project will have impacts, whether it is coastal, offshore or land based.

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