tidal
Autor: RG Serviços | Publicado: 2009-07-02T12:31:00-07:00

tidal energy tidal is the generation of electricity through the use of energy contained in the entry of water bodies due to tides. Two types of tidal energy can be obtained: kinetic energy of current due to tidal energy potential by difference between a height of the tides high and low.Anywhere the surface ocean oscillates between high and low points, called tides, each 12h and 25min. In certain bays and estuaries, as next to Mount Saint - Michel, in the estuary of river Rance, France, or in São Luís, Brazil, these tides are quite amplified, and may reach heights of the order of 15 metres. The unbulk water bodies covering two thirds of the planet constitute the largest solar collector imaginable. The tides, caused by the attraction Lunar, also represent a seductive energy source. Together, the temperature of the oceans, the waves and tides could provide much more energy than humanity would be able to spend today — or in the future, even if the overall consumption simply fold every ten years. [citation needed] Energy marés is similarly of hydroelectricity.This is a complex hydraulic engineering. Built a dam, a reservoir seacoast. When the tide is high, water fills the tank, passing through the turbine hydraulic type bulbo, and producing electric power. At low tide, the reservoir is flushed and the water tank passes again through the turbine conflicts, producing electrical power. This source type is also used in Japan, France and England. The first plant tidal built in the world for electricity generation was de La Rance, in 1963 and before 1500 in lameiras municipality of Sintra for direct use in moendas.OECD and FAO are questioning biofuelsAccording to the report of the Organisation for economic cooperation and development (OECD) and the United Nations for the food and Agriculture (FAO) on prospects for agriculture world in the next decade, published on Wednesday, 4 July 2007, if a high price for some products, particularly for cereals.Analyzing what has happened so far, the drought in some countries cereal farmers and the reduction of surpluses due to demand Chinese and the reform of the common agricultural policy (Cap) explain the recent spikes in prices of some raw materials. "But, looking to the long-term, structural changes that are occurring will maintain high prices for many agricultural products in the next decade," says the report. What changes are these? "The reduction of surpluses and a decline of export subsidies contributing to these changes, but the most important is the growing use of cereals, sugar, oil and vegoils to produce substitutes for fossil fuels, i.e. ethanol and biodiesel." Which will lead to higher prices of cultures, malignancy.this, drift, which will reflect in the final costs.According to the report of the European Union, the quantity of oil used for biodiesel should increase from the current ten million tonnes to 21 million within ten years. In the United States, ethanol from corn will double by 2016, while in Brazil, the 21 billion litres today produced saltarão for forty - four billion.The report emphasises that, in most countries temperate, ethanol and biodiesel is not economically viable without public support. Which means that political decisions taken in the short term may modify the scenario described in the study. The introduction of new technologies and the price of oil are two other variables that also contribute to remaining many unknowns about the future of this new market.