It's a tall order: Over the next few decades, the world will need to wean itself from dependence on fossil fuels and drastically reduce greenhouse gases. Current technology will take us only so far; major breakthroughs are required.

    What might those breakthroughs be? Here's a look at five technologies that, if successful, could radically change the world energy picture.

    They present enormous opportunities. The ability to tap power from space, for instance, could jump-start whole new industries. Technology that can trap and store carbon dioxide from coal-fired plants would rejuvenate older ones.

    Success isn't assured, of course. The technologies present difficult engineering challenges, and some require big scientific leaps in lab-created materials or genetically modified plants. And innovations have to be delivered at a cost that doesn't make energy much more expensive. If all of that can be done, any one of these technologies could be a game-changer.

    SPACE-BASED SOLAR POWER

    For more than three decades, visionaries have imagined tapping solar power where the sun always shines -- in space. If we could place giant solar panels in orbit around the Earth, and beam even a fraction of the available energy back to Earth, they could deliver nonstop electricity to any place on the planet.

    The technology may sound like science fiction, but it's simple: Solar panels in orbit about 22,000 miles up beam energy in the form of microwaves to earth, where it's turned into electricity and plugged into the grid. （The low-powered beams are considered safe.） A ground receiving station a mile in diameter could deliver about 1,000 megawatts -- enough to power on average about one million U.S. homes.

    The cost of sending solar collectors into space is the biggest obstacle, so it's necessary to design a system lightweight enough to require only a few launches. A handful of countries and companies aim to deliver space-based power as early as a decade from now.

    ADVANCED CAR BATTERIES

    Electrifying vehicles could slash petroleum use and help clean the air （if electric power shifts to low-carbon fuels like wind or nuclear）. But it's going to take better batteries.

    Lithium-ion batteries, common in laptops, are favored for next-generation plug-in hybrids and electric vehicles. They're more powerful than other auto batteries, but they're expensive and still don't go far on a charge; the Chevy Volt, a plug-in hybrid coming next year, can run about 40 miles on batteries alone. Ideally, electric cars will get closer to 400 miles on a charge. While improvements are possible, lithium-ion's potential is limited.

    One alternative, lithium-air, promises 10 times the performance of lithium-ion batteries and could deliver about the same amount of energy, pound for pound, as gasoline. A lithium-air battery pulls oxygen from the air for its charge, so the device can be smaller and more lightweight. A handful of labs are working on the technology, but scientists think that without a breakthrough they could be a decade away from commercialization.

    UTILITY STORAGE

    Everybody's rooting for wind and solar power. How could you not? But wind and solar are use-it-or-lose-it resources. To make any kind of difference, they need better storage.

    Scientists are attacking the problem from a host of angles -- all of which are still problematic. One, for instance, uses power produced when the wind is blowing to compress air in underground chambers; the air is fed into gas-fired turbines to make them run more efficiently. One of the obstacles: finding big, usable, underground caverns.

    Similarly, giant batteries can absorb wind energy for later use, but some existing technologies are expensive, and others aren't very efficient. While researchers are looking at new materials to improve performance, giant technical leaps aren't likely.

    Lithium-ion technology may hold the greatest promise for grid storage, where it doesn't have as many limitations as for autos. As performance improves and prices come down, utilities could distribute small, powerful lithium-ion batteries around the edge of the grid, closer to customers.

    There, they could store excess power from renewables and help smooth small fluctuations in power, making the grid more efficient and reducing the need for backup fossil-fuel plants. And utilities can piggy-back on research efforts for vehicle batteries.

    CARBON CAPTURE AND STORAGE

    Keeping coal as an abundant source of power means slashing the amount of carbon dioxide it produces. That could mean new, more efficient power plants. But trapping C02 from existing plants -- about two billion tons a year -- would be the real game-changer.

    Techniques for modest-scale CO2 capture exist, but applying them to big power plants would reduce the plants' output by a third and double the cost of producing power. So scientists are looking into experimental technologies that could cut emissions by 90% while limiting cost increases.

    Nearly all are in the early stages, and it's too early to tell which method will win out. One promising technique burns coal and purified oxygen in the form of a metal oxide, rather than air; this produces an easier-to-capture concentrated stream of CO2 with little loss of plant efficiency. The technology has been demonstrated in small-scale pilots, and will be tried in a one-megawatt test plant next year. But it might not be ready for commercial use until 2020.

    NEXT-GENERATION BIOFUELS

    One way to wean ourselves from oil is to come up with renewable sources of transportation fuel. That means a new generation of biofuels made from nonfood crops.

    Researchers are devising ways to turn lumber and crop wastes, garbage and inedible perennials like switchgrass into competitively priced fuels. But the most promising next-generation biofuel comes from algae.

    Algae grow fast, consume carbon dioxide and can generate more than 5,000 gallons a year per acre of biofuel, compared with 350 gallons a year for corn-based ethanol.

    Algae-based fuel can be added directly into existing refining and distribution systems; in theory, the U.S. could produce enough of it to meet all of the nation's transportation needs.

    But it's early. Dozens of companies have begun pilot projects and small-scale production. But producing algae biofuels in quantity means finding reliable sources of inexpensive nutrients and water, managing pathogens that could reduce yield, and developing and cultivating the most productive algae strains.

    這是一個離譜的要求：zaijinhoujishinianli
，shijiexuyaozhububaituoduihuashiranliaodeyilai，xianzhejianshaowenshiqiti。muqiandejishuzhinengrangwomenzoudaozheyibule，womenxuyaoyongyouzhongdadejishutupo。

    這些突破可能是些什麼？本文列出了五項技術，如果成功
，它們將會大大改變世界的能源格局。

    zhexiejishunengdailaijudadejiyu。liru，congtaikonghuoqunengliangdejishukenengxunsucuishengquanxindechanye。conghuodianchangbuhuohechucuneryanghuatandejishukenenghuilingjiaoweilaojiudedianchangzhonghuoxinsheng。

    dangran，zhexiejishubingbuyidingnengqudechenggong，tamenmuqiandoumianlinzhebushaonanti，yixiejishuxuyaozaishiyanshichuangzaodecailiaohehuozhuanjiyinzhiwufangmianshixianyixiezhongdatupo。erqie
，chuangxindechengbenbunengrangnengyuanbiandetaigui。ruguonengzuodaozheyiqie，qizhongrenheyixiangjishudoukeyigaibianyouxiguize。

    太空利用太陽能

    30多年來


，夢想家就一直設想在太陽永遠能照耀到的地方──太空中──利(li)用(yong)太(tai)陽(yang)能(neng)。如(ru)果(guo)我(wo)們(men)能(neng)在(zai)環(huan)繞(rao)地(di)球(qiu)的(de)軌(gui)道(dao)上(shang)安(an)置(zhi)巨(ju)大(da)的(de)太(tai)陽(yang)能(neng)電(dian)池(chi)板(ban)，將(jiang)其(qi)中(zhong)哪(na)怕(pa)是(shi)一(yi)小(xiao)部(bu)分(fen)的(de)可(ke)用(yong)能(neng)源(yuan)傳(chuan)回(hui)地(di)球(qiu)，它(ta)們(men)可(ke)以(yi)向(xiang)地(di)球(qiu)上(shang)的(de)任(ren)何(he)地(di)方(fang)提(ti)供(gong)不(bu)間(jian)斷(duan)的(de)電(dian)力(li)。

    這項技術聽起來可能像是科幻小說，但其實很簡單：在22,000英裏之外的太陽能電池板將能源以微波的形式傳回地球，然後轉化為電力並進入到電網中。（低能量的光束被認為是安全的。）直徑1英裏的地麵接收站可以提供約1,000兆瓦電力
，足以供應平均約100萬戶美國家庭的使用。

    jiangtaiyangnengshoujiqisongzhitaikongdechengbenshizuidadezhangai，yinciyoubiyaoshejizhongliangzugouqing，keyijianshaofashecishudexitong。yijingyouxieguojiahegongsixiwangzuizaozaiweilai10年內提供這種太空電力。

    高級汽車電池

    電動汽車可以降低石油消耗量，有助於空氣清潔（如果電力來自於風能和原子能等低碳燃料的話）.但它需要使用更好的電池。

    筆bi記ji本ben電dian腦nao中zhong常chang用yong的de鋰li離li子zi電dian池chi是shi下xia一yi代dai充chong電dian式shi混hun合he動dong力li車che和he電dian動dong車che的de理li想xiang之zhi選xuan。它ta們men比bi其qi它ta汽qi車che電dian池chi的de電dian力li更geng充chong足zu，但dan也ye更geng貴gui，不bu過guo充chong電dian後hou的de行xing駛shi距ju離li仍reng不bu夠gou遠yuan；將於明年上市雪佛蘭（Chevy） Volt混合動力車憑電池可行駛約40英裏。理想情況下
，電動車充電一次最好能行駛近400英裏。盡管仍有改進的空間，但鋰離子電池的潛力有限。

    作為一種替代產品，鋰空氣電池的性能是鋰離子電池的10倍
，可以提供與汽油同等的能量。鋰空氣電池從空氣中吸收氧氣充電，因此這種電池可以更小
、更輕。不少實驗室都在研究這種技術
，但科學家認為
，如果沒有重大突破，要想實現商用可能還需要10年。

    電力儲存技術

    suoyourendouzaizhichifengnenghetaiyangnengjishu
，nizennengzhishenshiwai？danfengnenghetaiyangnengshinazhongyaomeliyongyaomeliushideziyuan。yaogaibianxianzhuang，tamenxuyaogenghaodechucunjishu。

    科學家正在從諸多角度應對這個問題，但各個方麵都麵臨難題。舉例來說

，一項技術是通過風能將地下洞穴內的空氣壓縮產生電能；將空氣輸送至燃氣渦輪機以提高燃燒功效。這其中麵臨的一個障礙是：要尋找到大空間以及可用的地下洞穴。

    leiside，haiyounenggouxishoufengnengdairihoushiyongdejuxingdianchi，dandangqiandeyixiejishuchengbenanggui，qitajishuzebushihenyouxiaolv。jinguanyanjiurenyuanzhengzaixunzhaoxincailiaoyitigaoxingneng，danyaochuxianxianzhejishufeiyuedekenengxingbuda。

    鋰(li)離(li)子(zi)技(ji)術(shu)可(ke)能(neng)是(shi)電(dian)網(wang)存(cun)儲(chu)前(qian)景(jing)最(zui)好(hao)的(de)技(ji)術(shu)，在(zai)這(zhe)個(ge)領(ling)域(yu)內(nei)該(gai)技(ji)術(shu)不(bu)會(hui)麵(mian)臨(lin)像(xiang)在(zai)汽(qi)車(che)業(ye)中(zhong)那(na)樣(yang)多(duo)的(de)限(xian)製(zhi)。隨(sui)著(zhe)性(xing)能(neng)提(ti)高(gao)和(he)價(jia)格(ge)降(jiang)低(di)，公(gong)共(gong)事(shi)業(ye)機(ji)構(gou)可(ke)能(neng)會(hui)向(xiang)電(dian)網(wang)邊(bian)緣(yuan)
，較(jiao)為(wei)靠(kao)近(jin)用(yong)戶(hu)的(de)地(di)方(fang)輸(shu)送(song)小(xiao)體(ti)積(ji)大(da)容(rong)量(liang)的(de)鋰(li)離(li)子(zi)電(dian)池(chi)。

    zheyang，zhexielilizidianchikeyicongkezaishengnengyuanzhongcunchuduoyudenengyuan，youzhuyupingyidiannenggongyingdexiaobodong，tigaodianwangdexiaolv，jiangdiduibeiyonghuodianchangdexuqiu。gongyongshiyejigoukeyiliyongqichedianchideyanjiuchengguo。

    碳捕捉和儲存技術

    繼ji續xu將jiang煤mei炭tan作zuo為wei一yi種zhong主zhu要yao的de能neng源yuan意yi味wei著zhe需xu要yao努nu力li去qu降jiang低di碳tan燃ran燒shao生sheng成cheng的de二er氧yang化hua碳tan。這zhe可ke能neng意yi味wei著zhe要yao建jian設she更geng高gao效xiao的de新xin發fa電dian廠chang。但dan從cong當dang前qian的de電dian廠chang捕bu捉zhuo二er氧yang化hua碳tan（每年大約為20億噸）可能是一個真正能夠改變遊戲規則的技術。

    目(mu)前(qian)已(yi)經(jing)出(chu)現(xian)了(le)小(xiao)規(gui)模(mo)的(de)二(er)氧(yang)化(hua)碳(tan)捕(bu)捉(zhuo)技(ji)術(shu)，但(dan)如(ru)果(guo)將(jiang)這(zhe)些(xie)技(ji)術(shu)用(yong)於(yu)大(da)型(xing)發(fa)電(dian)廠(chang)會(hui)導(dao)致(zhi)發(fa)電(dian)量(liang)減(jian)少(shao)三(san)分(fen)之(zhi)一(yi)
，並(bing)導(dao)致(zhi)發(fa)電(dian)成(cheng)本(ben)增(zeng)長(chang)一(yi)倍(bei)。因(yin)此(ci)，科(ke)學(xue)家(jia)正(zheng)在(zai)尋(xun)找(zhao)既(ji)能(neng)夠(gou)將(jiang)碳(tan)排(pai)放(fang)量(liang)降(jiang)低(di)90%,又能限製成本增長的試驗性技術。

    jihusuoyoujishumuqiandouchuyuchubujieduan，muqianduanyannazhongfangfanenggouzuizhongshengchuhaiweishiguozao。yigeqianjingkanhaodejishushiyijinshuyanghuawudexingshiranshaomeitanhechunjingyang
，erbushizaikongqizhongranshao
；這zhe種zhong方fang法fa會hui產chan生sheng較jiao容rong易yi捕bu捉zhuo的de二er氧yang化hua碳tan集ji中zhong氣qi流liu，幾ji乎hu不bu會hui影ying響xiang電dian廠chang的de效xiao率lv。這zhe種zhong技ji術shu已yi經jing在zai小xiao規gui模mo試shi點dian項xiang目mu中zhong進jin行xing了le展zhan示shi，明ming年nian將jiang用yong於yu一yi個ge裝zhuang機ji容rong量liang為wei一yi百bai萬wan瓦wa的de試shi驗yan電dian廠chang。但dan2020年之前，這種技術可能還難以投入商用。

    下一代生物燃料

    一個令我們逐步擺脫對石油依賴的途徑就是研製出可再生的運輸燃料。這意味著從非食品作物中研製出新一代的生物燃料。

    研究人員正在想辦法將木材、作物廢料、垃圾以及柳枝稷等不可食用植物轉化為具有價格優勢的燃料。但前景最為看好的新一代生物燃料來自於藻類。

    藻類生長迅速，會消耗二氧化碳，一英畝藻類每年可以生成超過5,000加侖的生物燃料，而一英畝玉米每年隻能生產350加侖的乙醇。

    藻類燃料可以直接添加進當前的提煉和分銷係統。理論上來說
，美國可以生產大量的藻類燃料，足以滿足美國所有的交通運輸需求。

    但現在還為時過早。數十家公司已經開始了試點項目和小規模生產。但量產藻類燃料意味著要尋找到可靠的、價格低廉的養分和水資源

，控製可能導致減產的病原體
，研發和培育產量最高的藻株。