豆腐鹵水有望降低太陽能成本
????兩項新研究提供的跡象表明,這種狀況有可能會迅速發(fā)生改變。其中一項研究提供了一種全新的太陽能電池生產(chǎn)方式,它要比現(xiàn)有方法更便宜,更安全。另一項研究顯示,聚焦式太陽能發(fā)電系統(tǒng)(即使用太陽的能量來加熱液體,以驅(qū)動渦輪機,簡稱CSP)能夠滿足“目前相當大一部分能源需求。” ????《自然》雜志(Nature)上周三發(fā)布的一份研究報告中,利物浦大學(University of Liverpool)的喬恩?梅杰和其他幾位研究人員宣稱,氯化鎂可以取代生產(chǎn)第二代薄膜太陽能電池所用的氯化鎘。氯化鎂是制作豆腐和浴鹽的原料,還可用來融化冬季道路上的冰雪。 ????梅杰在哥本哈根參加一個電視電話會議時表示,氯化鎂源自海水,每克成本僅為0.001美元,遠低于每克0.3美元的氯化鎘。此外,它還能夠消除處理氯化鎘的挑戰(zhàn)和費用——氯化鎘是一種劇毒化合物,需要復雜的安全措施來保護生產(chǎn)工人,廢棄的電池板也需要一道特殊的處理程序。 ????“所以,我們完全可以用一種完全良性而且成本低得多的物質(zhì)來取代這種昂貴且?guī)в袆《镜脑希覠o需承受任何效率損失,”梅杰說?!皩τ诟鞣N太陽能電池的生產(chǎn)商來說,這是一項巨大的成本收益,有可能推動生產(chǎn)過程發(fā)生巨變。” ????由硅制成的面板目前在太陽能市場占據(jù)著主導地位。為了提升太陽能的競爭力,諸如第一太陽能公司(First Solar)這類企業(yè)對開發(fā)碲化鎘制成的太陽能電池越來越感興趣。這種材質(zhì)更有效率,更加靈活,可應用于包括窗戶在內(nèi)的更多表面。 ????生產(chǎn)碲化鎘電池需要給太陽能電池添加一層薄薄的氯化鎘,然后在爐中加熱。梅杰說,這個環(huán)節(jié)被視為激活過程,可以有效推動電池的效率從大約1%提高到20%。 ????尋找更安全的替代材料時,梅杰和他的團隊最初考慮的是氯化鈉,但他們發(fā)現(xiàn)它的效率大約只有氯化鎘的一半。另一種選擇是氯二氟甲烷,但它跟臭氧層枯竭有關,已被國際協(xié)議限制使用。 ????然后,他們轉(zhuǎn)向氯化鎂,發(fā)現(xiàn)這種物質(zhì)的效率完全可以跟氯化鎘相媲美,而且不需要昂貴的安全設備。 ????梅杰說,氯化鎂目前還沒有得到應用,但他希望“一旦這項研究工作獲得關注,就能獲得產(chǎn)學界的認可?!?/p> ????第一太陽能公司企業(yè)溝通部主任史蒂夫?克魯姆僅僅表示,氯化鎘仍然是該公司生產(chǎn)過程的“重要組成部分”,它并非“生產(chǎn)過程中主要的成本驅(qū)動因素。” ????《自然氣候變化》(Nature Climate Change)雜志本周發(fā)表的另一份太陽能研究報告顯示,CSP系統(tǒng)可以解決世界大部分地區(qū)很大一部分電力供應。來自奧地利國際應用系統(tǒng)分析研究所(International Institute for Applied Systems Analysis)的研究人員模擬了CSP系統(tǒng)在全球四個地區(qū)的建設和運營情況,并充分考慮了天氣、電力需求和成本等因素。他們發(fā)現(xiàn),CSP系統(tǒng)可以滿足地中海地區(qū)當前70-80%的電力需求,而且跟燃氣電廠相比,它無需支付額外費用。 |
????Two new studies offer signs that this could be changing quickly. One offers a new way to produce solar cells more cheaply and safely than current methods. The other indicates that concentrating solar power, which uses the sun’s energy to heat up a liquid that drives a turbine, could supply “a substantial amount of current energy demand.” ????In a study released Wednesday in journal Nature, University of Liverpool’s Jon Major and several other researchers announced that they had found that magnesium chloride, which is used in making tofu, bath salts and applied to roads in the winter could replace cadmium chloride in the making of second-generation, think-film solar cells. ????Speaking in a teleconference from Copenhagen, Major said magnesium chloride, which is extracted from seawater, would cost $0.001 per gram compared to $0.3 for cadmium chloride. It would also eliminate the challenges and expense of handling cadmium chloride, a highly toxic compound that requires elaborate safety measures to protect workers during its manufacture and a special disposal process when panels are no longer needed. ????“So what we have done without any loss of efficiency is to replace expensive and highly toxic material with one that is completely benign and much lower cost in the process,” Major said. “This offers a great cost benefit for production of these kinds of solar cells and could help make a step change in the production of them.” ????The solar market is currently dominated by panels made with silicon. In a bid to make solar more competitive, there is growing interest from companies like First Solar in developing solar cells using cadmium telluride, which is more efficient and more flexible so it could be applied many more surfaces including windows. ????To make these cadmium telluride cells, a thin layer of cadmium chloride is applied to the solar cell, and then heated up in a furnace. This is considered the activation process, Major said, helping boost a cell’s efficiency from around 1 percent to as much as 20 percent. ????In a bid to find a safer alternative, Major and his team first looked at sodium chloride, but found the efficiency was about half of cadmium chloride. Another option was difluorochloromethane but that has been linked to ozone depletion and its use has been restricted by international agreements. ????They then turned to magnesium chloride and found that it was just as efficient was comparable and could be applied without any expensive safety equipment. ????Major said magnesium chloride isn’t being used at the moment, but was hopeful it “would be taken up by research and hopefully by industry once this work is publicized.” ????Steve Krum, the director of corporate communications for First Solar, would only say cadmium chloride remains “critical part” of its production process and that it was not a “major cost driver in our manufacturing process.” ????In the other solar study, researchers writing in Nature Climate Change this week said concentrating solar power or CSP could supply a large fraction of the power supply in much of the world. The researchers from the Austria-based International Institute for Applied Systems Analysis simulated the construction and operation of CSP systems in four regions around the world taking into account weather, electricity demand and costs. They found that CSP in the Mediterranean region, for example, could provide 70-80% of current electricity demand, at no extra cost compared to gas-fired power plants. |