风能英语阅读雅思托福

Fossil energy and nuclear energy are considered nonrenewable energytypes. Nonrenewable energy is obtained from sources at a rate that exceedsthe rate at which the sources are replenished. For example, if the biogenicorigin of fossil fuels is correct, we could consider fossil fuels renewableover a period of millions of years, but the existing store of fossil fuels isbeing consumed over a period of centuries. Because we are consumingfossil fuels at a rate that exceeds the rate of replenishment, we considerfossil fuels nonrenewable. Similar comments apply to nuclear fuels suchas uranium, as we observe in later chapters. Solar energy is considereda renewable energy for the following energy is energy obtained from sources at a rate that is lessthan or equal to the rate at which the source is replenished. In the caseof solar energy, we can use only the amount of energy provided by thesun. Because the remaining lifetime of the sun is measured in millionsof years, many people consider solar energy an inexhaustible supply ofenergy. In fact, solar energy from the sun is finite, but should be availablefor use by many generations of people. Solar energy is therefore consideredrenewable. Energy sources that are associated with solar energy, such aswind and biomass, are also considered radiation may be converted to other forms of energy by severalconversion processes. Thermal conversion relies on the absorption of solarenergy to heat a cool surface. Biological conversion of solar energy relieson photosynthesis. Photovoltaic conversion generates electrical power bythe generation of an electrical current as a result of a quantum mechanicalprocess. Wind power and ocean energy conversion rely on atmosphericpressure gradients and oceanic temperature gradients to generate electricalpower. In this chapter we focus on thermal first discuss thesource of available solar energy, and then consider solar energy technologyin two of its three forms: passive solar, and active solar. The third form ofsolar energy, solar electric, is discussed in the next chapter. We end thischapter with a discussion of solar power plants.