有关风力发电或太阳能发电文章的英文

【专家解说】：Fossil energy and nuclear energy are considered nonrenewable energy types. Nonrenewable energy is obtained from sources at a rate that exceeds the rate at which the sources are replenished. For example, if the biogenic origin of fossil fuels is correct, we could consider fossil fuels renewable over a period of millions of years, but the existing store of fossil fuels is being consumed over a period of centuries. Because we are consuming fossil fuels at a rate that exceeds the rate of replenishment, we consider fossil fuels nonrenewable. Similar comments apply to nuclear fuels such as uranium, as we observe in later chapters. Solar energy is considered a renewable energy for the following reasons.1 Renewable energy is energy obtained from sources at a rate that is less than or equal to the rate at which the source is replenished. In the case of solar energy, we can use only the amount of energy provided by the sun. Because the remaining lifetime of the sun is measured in millions of years, many people consider solar energy an inexhaustible supply of energy. In fact, solar energy from the sun is finite, but should be available for use by many generations of people. Solar energy is therefore considered renewable. Energy sources that are associated with solar energy, such as wind and biomass, are also considered renewable. Solar radiation may be converted to other forms of energy by several conversion processes. Thermal conversion relies on the absorption of solar energy to heat a cool surface. Biological conversion of solar energy relies on photosynthesis. Photovoltaic conversion generates electrical power by the generation of an electrical current as a result of a quantum mechanical process. Wind power and ocean energy conversion rely on atmospheric pressure gradients and oceanic temperature gradients to generate electrical power. In this chapter we focus on thermal conversion.We first discuss the source of available solar energy, and then consider solar energy technology in two of its three forms: passive solar, and active solar. The third form of solar energy, solar electric, is discussed in the next chapter. We end this chapter with a discussion of solar power plants.