题型:阅读理解 题类:常考题 难易度:普通
北京市海淀区2018-2019学年高一下学期英语期中考试试卷
The day will come when renewable energy such as wind, solar, geothermal and others replace fossil fuels as the major source of world energy. However, most analysts insist that this day will not arrive for many decades to come—certainly well past the middle of the century. Systems of fossil fuels have already been firmly set up, and it is too costly or impractical to replace the existing systems with renewables. But there are good reasons to believe that the transition (转变) to renewables will come much faster than previously thought.
It is hardly surprising that many experts say we will see a relatively slow transition from fossil fuels to renewables, given what is known about previous energy changes of this sort. "Energy transitions take a long time," observed Vaclav Smil of the University of Manitoba in Scientific American. It took more than 50 years for coal to replace wood as the world's leading source of energy and another 50 years for oil to replace coal; the change from fossil fuels to renewables, he argued, is not likely to come any faster.
Under ordinary circumstances, Smil's forecast would no doubt prove accurate. But these are not ordinary times. Growing concern over climate change is leading to increasingly strict controls on CO2 and other greenhouse gas (GHG) emissions (排放), while the development in renewables technology is lowering their price and speeding their installation.
There are, of course, many difficulties in the effective control of carbon emissions, as demonstrated by coal companies to block the introduction of new rules by the US Environmental Protection Agency. Nevertheless, it is impossible to dismiss the progress being made at the local and international levels to promote the use of renewables. The European Union (E. U), for example, is well on the way to achieving a 20% reduction in GHG emissions from 1990 levels by 2020, along with a 20% increase in the use of renewable energy.
The transition to renewables will be faster due to dramatic improvements in the pricing and performance of such systems. As a result of the steady increases in the efficiency of wind and solar systems, together with the savings achieved through large-scale manufacture, the price of renewables is falling globally. With prices dropping this fast, solar energy is now proving competitive with fossil fuels for generating electricity in many areas.
The change from fossil fuels to renewable energy will not come overnight, and it will not escape many setbacks. Nevertheless, renewables are likely to replace fossil fuels as the main source of electrical power well before mid-century.
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