Энергетические ресурсы — страница 4

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its ability to be used widely and in specialized situations. For instance, "Small systems can be installed on the roofs of homes to heat water for domestic use. Moderate-size systems can supply hot water, steam, and hot air to schools, hospitals, businesses, and industries. Large solar thermal electric installations can generate electricity in quantities comparable to those generated in intermediate-size utility generating plants (that is, 100 to 200 megawatts [MW] of electricity)." One myth about solar power is that it requires large areas of land in order to be deemed useful. One example of this falsity is "Solar collectors covering less than half of Nevada could supply all of the United States' energy needs." While that seems like a lot of land, that area

divided my 50 states and spread out could almost go unnoticed. One of solar powers biggest advantages is cost. For 1% of the construction cost on a building, solar panels installed could save up to 50% on heating bills. In addition, at a more consumer level, a resident of a home could save almost $500 within just the first year of installation. As an added bonus, the savings are likely to increase over the years due largely to increase in electrical bills. Thus, a solar heating system is capable of paying for itself in less than 10 years. The answer to the energy crisis the world is seeing could be to simply return to that with we depends on already, the Sun. Flowing water creates energy that can be captured and turned into electricity. This is called hydropower. The most common

type of hydropower plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. But hydropower doesn't necessarily require a large dam. Some hydropower plants just use a small canal to channel the river water through a turbine. Another type of hydropower plant – called a pumped storage plant – can even store power. The power is sent from a power grid into the electric generators. The generators then spin the turbines backward, which causes the turbines to pump water from a river or lower reservoir to an upper reservoir, where the power is stored. To use the power, the water is released from the upper reservoir back down into the river or lower

reservoir. This spins the turbines forward, activating the generators to produce electricity. The ocean can produce two types of energy: thermal energy from the sun's heat, and mechanical energy from the tides and waves. Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors. The sun's heat warms the surface water a lot more than the deep ocean water, and this temperature difference creates thermal energy. Just a small portion of the heat trapped in the ocean could power the world. Ocean thermal energy is used for many applications, including electricity generation. Ocean mechanical energy is quite different from ocean thermal energy. Even though the sun affects all ocean activity, tides are driven primarily by the gravitational pull of

the moon, and waves are driven primarily by the winds. As a result, tides and waves are intermittent sources of energy, while ocean thermal energy is fairly constant. Also, unlike thermal energy, the electricity conversion of both tidal and wave energy usually involves mechanical devices. A barrage (dam) is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a generator. For wave energy conversion, there are three basic systems: channel systems that funnel the waves into reservoirs; float systems that drive hydraulic pumps; and oscillating water column systems that use the waves to compress air within a container. The mechanical power created from these systems either directly activates a generator or transfers to a working

fluid, water, or air, which then drives a turbine/generator. Conclusion. Thus, humanity uses many kinds of energy: renewable and non-renewable. To make sure we have plenty of energy in the future, it's up to all of us to use energy wisely. We must all conserve energy and use it efficiently. It also up to those of you who will want to create the new energy technologies of the future. One of you might be another Albert Einstein and find a new source of energy. It's up to all of us. The future is ours but we need energy to get there. The world has changed dramatically over the last 200 years, thanks largely to fossil fuels – coal, oil and natural gas. These have provided us with cheap and convenient energy, which we use to heat and cool our homes and to run our cars, appliances