Therefore,alternative sources of energy have become very important and relevant to today's world.These sources,such as the sun and wind,can never be exhausted and therefore arc called renewable.They cause less emission and are available locally.Their use can. to a large extent,reduce chemical,radioactive, and thermal pollution. They stand out as a viable source of clean and limitless energy.These are also known as non-conventional sources of energy.Most of the renewable sources of energy are fairfy non-polluting and considered clean though biomass,a renewable source,is a major polluter indoors.

　　Solar Energy

　　Solar energy is the most readily available source of energy.It does not belong to anybody and is,therefore,free.It is also the most important of the non-conventional sources of energy because it is non-polluting and,therefore.helps in lessening the greenhouse effect.

　　Solar energy has been used since prehistoric times.but in a most primitive manner.Before 1970,some research and development was carried out in a few countries to exploit solar energy more efficiently,but most of this work remained mainly academic.After the dramatic rise in oil prices in the 1970s,several countries began to formulate extensive research and development programmes to exploit solar energy.

　　When we hang out our clothes to dry in the sun,we use the energy of the sun.In the same way, solar panels absorb the energy of the sun to provide heat for cooking and for heating water.Such systems are available in the market and are being used in homes and factories.

　　Solar energy can also be ursed to meet our electricity requirements.Through Solar Photovoltaic(SPV)cells,solar radiation gets converted into DC electricity directly.This electricity can either be used as it is or can be stored in the battery.This stored electrical energy then can be used ac night.

　　Hydro Power

　　Hydro power is one of the best,cheapest,and cleanest source of energy,although,with big dams,there are many environmental and social problems.Small dams are,however,free from these problems.This is in fact one of the earliest known renewable energy sources.in the country(since the beginning of the 20th century).

　　In fact,for the last few hundred years,people living in the hills of the Himalayas have been using water mills.or chakki,to grind wheat.Besides being free from the problem of pollution.small hydropower plants are also free from issues and controversies that are associated with the bigger projects.namely affecting the lives of thousands of people living along the banks of the rivers.destruction of large areas under forest.and seismological threats.

　　New environmental laws affected by the danger of global warming have made energy from small hydropower plants more relevant.These small hydropower piants can serve the energy needs of remote rural areas independently.The real challenge in a remote area lies in successful marketing of the energy and recovering the dues.Local industries should be encouraged to use this electricity for sustainable development.

　　It is a technology with enormous potential.which could exploit the water resources to supply energy to remote rural areas with little access to conventional energy sources.It also eliminates most of the negative environmental effects associated with large hydro projects.

　　Energy From the Sea-Ocean Thermal,Tidal and Wave Energy

　　On an averaige,the 60 million square kilometre of the tropical seas absorb solar radiation equivalent to the heat content of 245 billion barrels of oil.Scientists feel that if this energy can be tapped a large source of energy will be available to the tropical countries and to other countries as well.The process of harnessing this energy is called OTEC(ocean thermal energy conversion).It uses the temperature differences between the surface of the ocean and the depths of about lOOOm to operate a heat engine.which produces electric power.

　　Energy is also obtained from wavcs and tides.In some countries such as Japan small scale power generators run by energy from waves of the ocean,have been used as power sources for channcl marking buoys.

　　Biomass

　　Biomass is a renewable energy resource derived from the carbonaceous waste of various human and natural activities.It is derived from numerous sources,including the by-products from the timber industry.agricultural crops,raw material from the forest,major parts of household waste and wood.

　　Biomass does not add carbon dioxide to the atmosphere as it absorbs the same amount of carbon in growing as it releases when consumed as a fuel. Its advantage is that it can be used to generate electricity with the same equipment of power plants that are now burning fossil fuels.Biomass is an important source of energy and the most important fuel worldwide after coal,oil and natural gas.

　　Traditional use of biomass is more than its use in modern application.In the developed world biomass is again becoming important for applications such as combined heat and power generation.In addition,biomass energy is gaining significance as a source of clean heat for domestic heating and community heating applications.In fact in countries like Finland.USA and Sweden the per capita biomass energy used is higher than it is in India.China or in Asia.

　　Geothermal Energy

　　We live between two great sources of energy,the hot rocks beneath the surface of the earth and the sun in the sky.Our ancestors knew che value of geothermal energy;they bathed and cooked in hot springs.Today we have recognized that this resource has potential for much broader application.

　　The core of the earth is very hot and it is possible to make use of this geothermal energy(in Greek it means heat from the earth).These are areas where there are volcanoes.hot springs,and geysers,and methane under the water in the oceans and seas. n some countries,such as in the USA water is pumped from underground hot water deposits and used to heat people's houses.

　　The utilization of geothermal energy for the production of electricity dates back to the early part of the twentieth century.For 50 years the generation of electricity from geothermal energy was confined to Italy and interest in this technology was slow co spread elsewhere.In 1943 the use of geothermal hot water was pioneered in lceland.

　　Co-generation

　　Co-generation is the concept or producing two forms of energy from one fuel.One of the forms of energy must always be heat and the other may be electricity or mechanical energy.In a conventional power plant,fuel is burnt in a boiler to generate high-pressure steam.This steam is used to drive a turbine.which in turn drives an alternator through a steam turbine to produce electric power.The exhaust steam is generally condensed to water which goes back to the boiler.

　　As the low-pressure steam has a large quantum of heat which is lost in the process of condensing,the efficiency of conventional power plants is only around 35%.In a cogeneration plant,very high efficiency levels,in the range of 75%-90%,can be reached.This is so,because the low-pressure exhaust steam coming out of the turbine is not condensed,but used for heating purposes in factories or houses.

　　Since co-generation can meet both power and heat needs, it has otber advantages as well in the form of significant cost savings for the plant and reduction in emissions of pollutants due to reduced fuel consumption.

　　測試題

　　1.High concentrations of harmful gases are resulted from______________.

　　A) ozone depletion B) global warming

　　C) the consumption of fossil fuels D) serious water and air pollution

　　2.The sun and wind are called renewable energy because they are____________.

　　A) natural B) inexhaustible

　　C) newly-found D) clean

　　3.Biomass,though a renewable energy,mainly causes_______________.

　　A) indoor pollution B) outdoor pollution

　　C) industrial pollution D) agricultural pollution

　　4.In the l970s,some countries began to be concerned about solar energy because of___________.

　　A) economic recession B) sharp rise in oil prices

　　C) reduced oil production D) increased research funds

　　5.In the hills of the Himalayas,“chakki”are used for_____________.

　　A) purifying water B) keeping animals

　　C) producing power D) exchanging goods

　　6.What is recommended to be used by the remote rural areas with little access to conventional energy sources?

　　A) Small hydropower plants. B) Solar energy heaters.

　　C) Wind power mills. D) Hot spring thermal energy.

　　7.It is mentioned that,between the surface and the depth of the ocean,there are great differences in_____________.

　　A) dissolved substance B) natural resource variety

　　C) marine life species D) water temperature

　　8.After coal oil and natural gases,the fourth most important fuel is_____________.

　　9.ICeland was the first counfry that______________.

　　10.In the conventional power plants,a large quantum of heat is lost in the process of condensing______________.

　　答案詳解

　　1.[C][定位]根據(jù)題干中的high concentrations of harmful gases查找到第1段第2句。

　　解析：選項C與題干組成的因果關(guān)系與原文該句中的因果關(guān)系雖然表述不同，但內(nèi)容相同，因此選項C為本題答案。選項A和選項B是high concentrations of harmful gases造成的結(jié)果，而非原因，因此不能選。

　　2.[B][定位]根據(jù)題干中的sun,wind，renewable等詞查找到第2段第2句。

　　解析：選項B與原文該句中的can never be exhausted同義，為本題答案。選項A和選項C的內(nèi)容沒有在原文提及，選項D不能與題干構(gòu)成相應(yīng)的因果關(guān)系。

　　3.[A][定位]根據(jù)題干中的biomass查找到第2段最后一句。

　　解析：原文該句中的a major polluter indoors表明biomass主要引起室內(nèi)的污染，選項A表達了與此相同的內(nèi)容，故為本題答案。

　　4.[B][定位]根據(jù)題干中的數(shù)字1970s查找到第1個小標題Solar Energy下第2段最后一句。

　　解析：在四個選項中，只有選項B在原文該句中提及，其他選項都是無中生有。

　　5.[C][定位]根據(jù)題干中的大寫名詞Himalayas和專有名詞“chakki”查找到第2個小標題Hydro Power下第2段第1句。

　　解析：原文該句以居住在喜馬拉雅山的人們?yōu)槔f明人們很早就開始“利用水力發(fā)電”了，因此，本題應(yīng)選C。

　　6.[A][定位]根據(jù)題干中的remote rural areas和conventional等詞查找到第2個小標題Hydro Power下第4段首句。

　　解析：原文該句中的It指代hydro power，該句還是圍繞“水力發(fā)電”這一話題，由此可排除B、C和D選項，正確答案為A。

　　7.[D][位]根據(jù)題干中的surface，depth，ocean等詞查找到第3個小標題Energy From the Sea-Ocean Thermal,Tidal and Wave Energy下首段末句。

　　解析：在原文該句中，只有選項D的內(nèi)容有提及，其他內(nèi)容均沒有原文依據(jù)，因此選項D為本題答案。

　　8.[biomass]

　　[定位]根據(jù)題干中的coal，oil，gases和fourth等詞查找到笫4個小標題Biomass下第2段末句。

　　解析：空白處應(yīng)為名詞詞組。題目只是將原文的主語和表語的位置倒轉(zhuǎn)，由此可見，原文中的主語biomass為本題答案。

　　9.[used geothermal hot water]

　　[定位]根據(jù)題干中的專有名詞Iceland查找到第5個小標題Geothermal Energy下末段末句。

　　解析：空白處應(yīng)為定語從句的謂賓部分。原文該句中的pioneered表明冰島是首個使用地?zé)釡厝牡胤剑诨卮饐栴}的時候，注意that后應(yīng)該是定語從句的謂語，由于事情發(fā)生在l943年，該謂語動詞應(yīng)為過去式。

　　10.[the low-pressure steam]

　　[定位]根據(jù)題干中的conventional power plants和quantum of heat等詞查找到最后一個小標題Co-generation下第2段首句。

　　解析：空白處應(yīng)為名詞詞組。在原文該句中，condensing后面并沒有帶任何賓語，但該段末句中的the low-pressure... is not condensed提示了首句中condensing的賓語應(yīng)該是該句開頭的the low-pressure steam，這也就是本題答案。

　　參考譯文

　　可再生能源

　　在上個世紀人們看到，消耗不可再生能源對環(huán)境造成的損害比任何其他人類活動都大。[1]從煤炭、原油等化石燃料中產(chǎn)生的電能使大氣中積聚了高濃度的有害氣體，這反過來導(dǎo)致了許多人們今天需要面對的問題，如臭氧層的減少以及全球氣候變暖等。汽車污染也是個主要問題。

　　因此，替代性的能源非常重要，與當今的世界密切相關(guān)。[2]這些能源(如太陽能和風(fēng)能)用之不竭，因此稱為可再生能源。它們減少了排放物，并且可以就地利用。它們的使用可以在很大程度上減少化學(xué)污染、輻射污染和熱污染。作為可行的清潔能源，它們用之不盡，具有突出的優(yōu)勢，還被禰為非常規(guī)能源。[3]盡管生物作為可再生能源是室內(nèi)污染的主要來源，但大多數(shù)可再生能源基本上不污染環(huán)境，因而被看做是清潔能源。

　　太陽能

　　太陽能是遍布最廣的隨地可用的能源。它不屬于任何人，因此可以免費使用。它也是非常規(guī)能源中最重要的能源，因為它無污染，因而有助于減輕溫室效應(yīng)。

　　自從史前時代起人們就開始使用太陽能了，不過，其使用方式極為簡單。1970年以前，在一些國家人們?yōu)榱烁行У乩锰柲芏隽艘恍┭邪l(fā)工作，但大多數(shù)的研發(fā)工作主要停留在學(xué)術(shù)研究上。[4]20世紀70年代石油價格急劇上漲后，有些國家為了利用太陽能開始展開廣泛的研發(fā)工作。

　　我們把衣服掛到太陽底下曬干，就是在利用太陽能。同樣地，太陽能電池板吸收太陽能為煮飯燒水提供熱能。這樣的設(shè)備如今市場上已有銷售.正在為家庭和工廠所使用。

　　我們還可以利用太陽能滿足對電力的需求。通過太陽能光電板。太陽輻射可以直接轉(zhuǎn)化為直流電。這種電可以直接使用，也可以在電池中儲存起來。這樣儲存起來的電能就可以在夜晚使用。

　　水電

　　水電是最好、最廉價、最清潔的能源之一，雖然建造大壩帶來了許多環(huán)境和社會問題。但小水壩就不存在這些問題。在這個國家，這實際上是最早為人所知的可再生能源之一(從20世紀初開始)。

　　[5]事實上，在過去的幾百年里，居住在喜馬拉雅山的人們一直都在利用水磨(或稱為chakki)來磨小麥。小水電站除了沒有污染問題，也不存在大型項目所帶來的種種問題和矛盾-----大水壩影響了住在河岸的成千上萬居民的生活，破壞了大面積的森林，并帶來地震的危險。

　　地球變暖的危險使得人們通過了新的環(huán)境立法，這些新的立法使小水電廠產(chǎn)生的電能更加具有實際價值。這些小水電可以獨立地為偏遠鄉(xiāng)村地區(qū)供電。在偏遠地區(qū)建設(shè)小水電的實際挑戰(zhàn)在于有效地推銷電能并收回電費。為了可持續(xù)發(fā)展.應(yīng)該鼓勵當?shù)仄髽I(yè)使用這種電力。

　　[6]這是一種具有巨大潛力的技術(shù)，它可以利用水資源向難以采用常規(guī)能源的偏僻鄉(xiāng)村地區(qū)提供電力。它還避免了大型水利工程對環(huán)境所帶來的負面影響。

　　海洋能源——海洋熱能，潮汐能和波浪能

　　6000萬平方公里的熱帶海洋吸收的太陽輻射平均相當于2450億桶石油的能量。科學(xué)家們覺得，如果這種能量可以得到開發(fā)的話，就可以為熱帶國家以及其他國家提供巨大的能源。利用這種能源的過程叫做“海洋熱能轉(zhuǎn)換”。[7]它利用海洋表面海水和大約lOOO米深處的海水的溫差來推動熱力發(fā)動機來發(fā)電。

　　人們還從波浪和潮汐中獲得能量。在一些國家，比如日本，波浪或海洋能量推動的小規(guī)模發(fā)電機被用來向標記航道的浮標提供電能。

　　生物能

　　生物能源是種可再生能源，來自各種人類活動或自然活動的含碳廢棄物。它有許多來源，包括木材工業(yè)的副產(chǎn)品、農(nóng)作物、森林中的原材料、生活垃圾的主要部分以及木頭。

　　生物能源不會給大氣增加二氧化碳，因為它用作燃料焚燒時釋放的碳和在生產(chǎn)過程中吸收的碳一樣多。這種能源的優(yōu)勢是，可以利用目前焚燒化石燃料的發(fā)電廠的同樣設(shè)備來發(fā)電。[8]生物能源是一種重要的能源，世界范圍內(nèi)，其重要性僅次于煤炭、石油和是然氣。

　　傳統(tǒng)上時生物能源的利用遠遠超出它在現(xiàn)代社會的利用程度。在發(fā)達國家，生物能源現(xiàn)在變得再次重要起來，被用于輔助供熱、發(fā)電。此外，生物能源作為一種家庭和社區(qū)供熱設(shè)施的清潔熱源現(xiàn)正益發(fā)重要。事實上，在芬蘭、美國和瑞典等國，人均使用的生物能比在印度、中國或亞洲其他國家都多。

　　地?zé)崮?/p>

　　我們居住在兩大能源之間：地表下是滾燙的巖石，天上是太陽。我們的祖先知道地?zé)岬膬r值，他們在溫泉里沐浴，用溫泉煮東西。如今我們意識到，這種能源擁有更廣泛的應(yīng)用前景。

　　地板很熱，利用地?zé)崮?希臘語中表示“來自地球的熱”)是可能的。這些地方包括那些有火山、溫泉和間歇泉的地方，還包括海洋水底下的甲烷。在一些國家，比如在美國，人們從地底下的熱水池中把水抽出來給房子供暖。

　　利用地?zé)崮馨l(fā)電的歷史可以追溯到20世紀早期。有50年的時間里只有意大利在利用地?zé)岚l(fā)電，其他地方的人們過了很久才漸漸地對這種技術(shù)感興趣。[9]1943年，首先是冰島開始著手開發(fā)地?zé)釡厝?/p>

　　熱電聯(lián)產(chǎn)

　　熱電聯(lián)產(chǎn)是指利用一種燃料同時產(chǎn)生兩種形式的能量。其中一種能量一定是熱能，另一種能量可以是電能，也可以是機械能。在傳統(tǒng)的發(fā)電廠，燃料在鍋爐里燃燒以便產(chǎn)生高壓蒸汽，蒸汽推動渦輪，渦輪又通過蒸汽輪機推動交流發(fā)電機發(fā)電。廢汽通常凝結(jié)成水，又回到鍋爐里。

　　[l0]因為低壓蒸汽含有大量的熱能，這些熱能在蒸汽凝結(jié)的過程中損耗了，因此傳統(tǒng)發(fā)電廠的熱效率只有大約35%。在熱電聯(lián)產(chǎn)的發(fā)電廠卻可以達到很高的效率水平，在75%-90%之間。[10]這是因為從渦輪冒出的低壓廢汽并不用來冷凝成水，而是用來為工廠或房屋供暖。

　　因為熱電聯(lián)產(chǎn)可以同時滿足供電、供熱的需求，它還有其他一些優(yōu)點：可以為工廠大量節(jié)省成本：因為減少了燃料的消耗，可以減少污染物的排放。