Grolier Multimedia Encyclopedia - 0 views
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basic laws of physics dictate that energy is conserved and can only be changed from one form to another or into matter.
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If the supply of fuel is finite, not only will there be no energy supply when the fuel is exhausted
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coal, oil (petroleum), natural gas, uranium, and fuel wood—is limited and insufficient to sustain rapid rates of development.
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debate about the exact length of time available before the effects of a worldwide shortage become apparent
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geothermal energy, hydroelectric power, peat, ocean thermal energy, solar energy, tidal energy, wind power, and fuel wood.
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ocean currents and winds are results of the uneven distribution of solar radiation over the Earth's surface
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ocean thermal energy, solar heating of the upper layers of the ocean produces temperature gradients that can be harnessed to generate electricity
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Sun also powers the hydrologic cycle, in which ocean water is evaporated, transported over the continents, and precipitated as rain or snow to form rivers
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energy locked in such renewable fuel sources as wood and peat is derived from the Sun by the process of photosynthesis.
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over the entire surface of the Earth at a very low average rate, leakage is much higher in certain locations.
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Nonrenewable resources originate from two processes: (1) photosynthesis, which occurred many millions of years ago, followed by the fossilization of the plant and animal life that resulted, and (2) the formation of the Earth itself.
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A cleaner-burning fuel than oil, natural gas seemed to be in abundant supply at the turn of the 21st century and, with the greatly enlarged network of gas pipelines, was rapidly growing in use.
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nearly total dependence on fossil fuels and hydroelectricity ensures that efforts to solve energy problems by switching to alternative sources will have to overcome a great deal of inertia, both economic and psychological.
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sources as solar power, wind power, and synthetic fuels suffer from the serious drawback that few major installations now exist.
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solar energy reaches the top of the atmosphere in amounts 10,000 times greater than all human production of energy, it reaches the Earth's surface at rates of only about 80 to 250 W/m2, and considerably less on cloudy days.
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arge-scale system based on solar-collector panels will be physically huge, causing problems of maintenance and land use
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