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  3. Widespread adoption of plug-in electric vehicles could dramatically cut greenhouse gas pollution and reduce U.S. dependence on f

Widespread adoption of plug-in electric vehicles could dramatically cut greenhouse gas pollution and reduce U.S. dependence on f

admin2023-02-20  46
问题     Widespread adoption of plug-in electric vehicles could dramatically cut greenhouse gas pollution and reduce U.S. dependence on foreign oil. But results of an electric-car pilot project presented recently at the annual meeting of the American Association for the Advancement of Science provide added incentive to go electric: Car owners could return unused electricity back to the grid (输电网) and make real money while doing it.
    Electric cars need big, powerful batteries to accelerate to highway speeds and travel scores or even several hundred kilometers on a single charge. But because most drivers drive just a few dozen kilometers a day, most of that battery capacity sits unused. To take advantage of that storage capacity, Willett Kempton, director of the University of Delaware’s Center for Carbon-Free Power Integration in Lewes, teamed up with an electric car maker, several utilities, a software company, and PJM Interconnection, one of 10 regional organizations that coordinate and control the U.S. electrical grid.
    To ensure that electricity flows steadily and without interruption, the U.S. government requires PJM Interconnection and its counterparts to have reserves of power in case a generator goes down and other electrical reserves to maintain the 60-Hz frequency of alternating current that our appliances and devices are accustomed to dealing with. Today, PJM Interconnection and its counterparts pay conventional power plants to maintain this reserve power. But as renewable energy sources such as wind and solar, which provide energy cleanly but intermittently, come online, these grid operators need to increase their storage capacity to ensure a steady electricity supply. So Kempton and his colleagues set out to provide some of the backup power from a fleet of parked electric cars.
    Kempton’s team used an electric car from AC Propulsions, a California car company, which was custom-built to provide electricity back to the grid. They used commercially available software and hardware that companies such as PJM Interconnection use to monitor and control energy flow. In November, the company hooked the grid up to the car, and Kempton’s team’s electric car became the first car in the world to earn its keep as a backup electric power source. At the rates that PJM Interconnection pays today to maintain power reserves, a hooked-in electric car could generate $1,800 a year for its owner.
    "I think it’s tremendously exciting," says Kathryn Clay, director of research for the Alliance of Automobile Manufacturers. "The extra dollars an electric car provides will not be enough by themselves to get consumers to adopt grictenabled vehicles—for that we also need better and less expensive batteries and tax incentives to give the market an encouragement" Nevertheless, "it’s an incentive to push in the right direction."  
What is true about renewable energy sources such as wind and solar?
选项 A、They reduce the dependence on backup power.
B、They are the main sources of backup power.
C、They increase the necessity for backup power.
D、They are regarded as the best back power.
答案B
解析 原文该句开头的as…表明本句中存在着一对因果关系，原文表明：因为使用了不稳定的可再生能源，导致对后备电力有了更高的需求，因此，本题应选B。原文该句除了因果关系很关键外，intermittently一词也很重要，intermittently正好表明可再生能源的供应时常中断，这就造成了对储备电力的需要，经过这样的分析，就可以知道其他干扰项都没有正确描述可再生能源和储备电力之间的关系。
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