首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Usually alternating current (AC) transmission suffers lower losses than direct current (DC) , and thus, AC became the industry s
Usually alternating current (AC) transmission suffers lower losses than direct current (DC) , and thus, AC became the industry s
admin
2019-05-09
44
问题
Usually alternating current (AC) transmission suffers lower losses than direct current (DC) , and thus, AC became the industry standard. Some people, however, question that standard because over long distances high-voltage DC lines suffer lower losses than AC. Not only does that
make them better in their own right
, but employing them would allow electricity grids to be restructured in ways that would make wind power more attractive. That would reduce the need for new conventional(and polluting) power stations.
Wind power has some problems. You don’ t always get it where you want it and you don’ t always get it when you want it. The question of where the wind is blowing would no longer matter because it is almost always blowing somewhere. If it were windy in Spain but not in Ireland, current would flow in one direction.
Dealing with when the wind blows is a subtler issue
. For instance, an important part of Dr Schmid’ s continental grid is the branch to Norway. It is not that Norway is a huge consumer. Rather, the country is well supplied with hydroelectric plants. These are one of the few ways that energy from transient sources like the wind can be stored in grid-filling quantities. The power is used to pump water up into the reservoirs that feed the hydroelectric turbines. That way it is on tap when needed. The capacity of Norway’ s reservoirs is so large, according to Dr Schmid, that should the wind drop all over Europe—which does happen on rare occasions—the hydro plants could spring into action and fill in the gap for up to four weeks.
Put like this, a Europe-wide grid seems an obvious idea. That it has not yet been built is because AC power lines would lose too much power over such large distances. Hence the renewed interest in DC. Dr Schmid calculates that a DC grid of the sort he envisages would allow wind to supply at least 30% of the power needed in Europe. Moreover, it could do so reliably—and that means wind power could be used for what is known in the jargon as base-load power supply.
Though wind power has its opponents, too, its environmental virtues might be enough to swing things in its favour if it were also reliable. Indeed, a group of Norwegian companies have already started building high-voltage DC lines between Scandinavia, the Netherlands and Germany, though these are intended as much to sell the country’ s power as to accumulate other people’ s. And Airtricity—an Irish wind-power company—plans even more of them. It proposes what it calls a Supergrid. This would link offshore wind farms in the Atlantic Ocean and the Irish, North and Baltic seas with customers throughout northern Europe.
By saying"Dealing with when the wind blows is a subtler issue" (Line 4, Paragraph 2) , the author actually implies that______.
选项
A、it is more difficult to predict the time when the wind blows
B、it is more intricate to deal with the wind since it is always transient
C、it is more complex to control the wind in the temporal sense
D、it is more complicated to utilize the wind power
答案
C
解析
语义题。文章第二段指出利用风能存在很多问题,包括风向的时间和地点。而哪里有风的问题相对比较容易解决,但是风在什么时候吹则是一个更加微妙的问题,也就是说,在时间意义上控制风能是比较困难和复杂的,因此C选项符合题意。
转载请注明原文地址:https://kaotiyun.com/show/e1Cd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
Leadersof16nationspaidapoignanttributetosurvivingveteransandthosewhodiedduringtheD-Daylandings60yearsagoth
ACanadianresearcherhasdiscoveredthatsoundtravels【21】______airmorethanone-halfkilometeranhourslowerthanhadb
ACanadianresearcherhasdiscoveredthatsoundtravels【21】______airmorethanone-halfkilometeranhourslowerthanhadb
Industrial【21】______doesnotjusthappen.Companies【22】______lowaccidentratesplantheirsafetyprograms,workhard
Fathersexposedtopoisonoussubstancesareprobablyjustaslikelytobethecauseofdefectsintheirunborninfantsasmother
AnewlypublishedAIDSstudycouldopenanotherfrontinthebattleagainstHIVinfectionbyshowingthatgenetherapycanbeus
TheStudents’Unionofyouruniversityisplanningtoholdanartsfestivalnextsemester,andtheyareinvitingstudentstocon
ItwasaverygoodyearfortheGlobal500,new-comersandold-comersalike.Butcanitlast?ThinkofFORTUNE’sGlobal50
Thebuildingcrane,whichhasbecomethemoststrikingfeatureoftheurbanlandscapeinSwitzerland,isbeginningtoalterthe
Theideaofhumanoidrobotsisnotnew,ofcourse.TheyhavebeenpartoftheimaginativelandscapeeversinceKarlCapek,aCze
随机试题
简述盂子的仁政思想。
水底电缆单独充气,常年水深在5~10m时,最高充气气压应()KPa。
运用管理理论与实践的历史文献,全面考察管理的历史演变、重要的管理思想和流派的方法是()
与药物剂量无关的不良反应有()
资本市场要求进入资本市场融资的公司按照规定向投资者披露信息,提高生产运营的公开性和()。
建设工程中采用的投标保函、履约保函等方式,属于我国《担保法》中的()。
客户身份资料自业务关系结束当年计起至少保存()年。
简述孔子教育思想的历史影响。
A、Ann’sfather.B、Tom’ssister.C、Ann’ssister.B
IfJohnnycan’twrite,oneofthereasonsmaybeaconditioningbasedonspeedratherthanrespectforthecreativeprocess.Spe
最新回复
(
0
)