Энергетические ресурсы — страница 3

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international black market. Sooner or later, extremists will accumulate enough of this to build a crude device, which could easily be carried by a vehicle, driven into a major city and detonated. The prospects are frightening. As in any industry, accidents happen. Serious accidents can mean the spreading of dangerous radioactivity into the environment. Several serious accidents have occurred, as everyone knows. Several other less well-known accidents associated with the race to build nuclear weapons occurred in the former Soviet Union, causing the contamination of hundreds of square kilometers of land. Renewable sources - Renewable energy sources have long been energy's Cinderella. Today, wind power is finally coming into its own. Denmark, already employing 12,000 people in its

wind industry, intends wind power to produce half its total electricity needs by 2030. Several major wave power projects are now underway and solar energy is booming in Germany, the western USA and, in a smaller way, in remoter parts of the South. Equally important in cold climates is the design of buildings to capture 'passive' energy and retain it through insulation. Other minor renewables include geothermal power in volcanically active countries like Iceland, while tidal barrages remain a possibility in the UK and eastern Canada. People use some kinds of renewable sources. At first, it is wind energy. We have been harnessing the wind's energy for hundreds of years. From old Holland to farms in the United States, windmills have been used for pumping water or grinding grain.

Today, the windmill's modern equivalent – a wind turbine – can use the wind's energy to generate electricity.  Wind turbines, like windmills, are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more aboveground, they can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor. A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the

blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity. Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. Stand-alone wind turbines are typically used for water pumping or communications. However, homeowners or farmers in windy areas can also use wind turbines as a way to cut their electric bills. For utility-scale sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant. Several electricity providers today use wind plants to supply power to their customers. At second, it is bio energy. We have used bio energy

– the energy from biomass (organic matter) – for thousands of years, ever since people started burning wood to cook food or to keep warm. And today, wood is still our largest biomass resource for bio energy. But many other sources of biomass can now be used for bio energy, including plants, residues from agriculture or forestry, and the organic component of municipal and industrial wastes. Even the fumes from landfills can be used as an energy source. The use of bio energy has the potential to greatly reduce our greenhouse gas emissions. Bio energy generates about the same amount of carbon dioxide as fossil fuels, but every time a new plant grows, carbon dioxide is actually removed from the atmosphere. The net emission of carbon dioxide will be zero as long as plants continue

to be replenished for bio energy purposes. These energy crops, such as fast-growing trees and grasses, are called bio energy feedstocks. The use of bio energy feedstocks can also help increase profits for the agricultural industry. I think, that it is very important to use sun energy. The Sun is the center of our solar system and the source of life on the planet earth. Moreover, as petroleum continues to pollute and destroy the earth, what better way than to look to the Sun for a solution? The earth and either being used or simply bouncing off are always capturing the heat from the Sun. Solar technology utilizes this heat energy and converts it to electrical energy, which is then fed into the power grid for users. That, albeit, is not all. One of the benefits of solar energy is