豆腐滷水有望降低太陽能成本

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.”

兩項新研究提供的跡象表明，這種狀況有可能會迅速發生改變。其中一項研究提供了一種全新的太陽能電池生產方式，它要比現有方法更便宜，更安全。另一項研究顯示，聚焦式太陽能發電系統（即使用太陽的能量來加熱液體，以驅動渦輪機，簡稱CSP）能夠滿足“目前相當大一部分能源需求。”

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.

《自然》雜誌(Nature)上週三發佈的一份研究報告中，利物浦大學(University of Liverpool)的喬恩o梅傑和其他幾位研究人員宣稱，氯化鎂可以取代生產第二代薄膜太陽能電池所用的氯化鎘。氯化鎂是製作豆腐和浴鹽的原料，還可用來融化冬季道路上的冰雪。

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.

梅傑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，每克成本僅爲0.001美元，遠低於每克0.3美元的氯化鎘。此外，它還能夠消除處理氯化鎘的挑戰和費用——氯化鎘是一種劇毒化合物，需要複雜的安全措施來保護生產工人，廢棄的電池板也需要一道特殊的處理程序。

“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.”

“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來取代這種昂貴且帶有劇毒的原料，而且無需承受任何效率損失，”梅傑說。“對於各種太陽能電池的生產商來說，這是一項巨大的成本收益，有可能推動生產過程發生鉅變。”

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.

由硅製成的面板目前在太陽能市場佔據着主導地位。爲了提升太陽能的競爭力，諸如第一太陽能公司(First Solar)這類企業對開發碲化鎘製成的太陽能電池越來越感興趣。這種材質更有效率，更加靈活，可應用於包括窗戶在內的更多表面。

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.

生產碲化鎘電池需要給太陽能電池添加一層薄薄的氯化鎘，然後在爐中加熱。梅傑說，這個環節被視爲激活過程，可以有效推動電池的效率從大約1%提高到20%。

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.

尋找更安全的替代材料時，梅傑和他的團隊最初考慮的是氯化鈉，但他們發現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，已被國際協議限制使用。

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.

然後，他們轉向氯化鎂，發現這種物質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。

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.”

梅傑說，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，就能獲得產學界的認可。”

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.”

第一太陽能公司企業溝通部主任史蒂夫o克魯姆僅僅表示，氯化鎘仍然是該公司生產過程的“重要組成部分”，它並非“生產過程中主要的成本驅動因素。”

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.

《自然氣候變化》（Nature Climate Change）雜誌本週發表的另一份太陽能研究報告顯示，CSP系統可以解決世界大部分地區很大一部分電力供應。來自奧地利國際應用系統分析研究所(International Institute for Applied Systems Analysis)的研究人員模擬了CSP系統在全球四個地區的建設和運營情況，並充分考慮了天氣、電力需求和成本等因素。他們發現，CSP系統可以滿足地中海地區當前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。

“In order to address climate change we need to greatly expand our use of renewable energy systems,” said IIASA researcher Fabian Wagner, who also worked on the study. “The key question, though, is how much energy renewable systems can actually deliver.”

“爲了應對氣候變化，我們需要加大對可再生能源系統的利用，”這項研究的參與者之一、國際應用系統分析研究所研究員費邊o瓦格納說。“但關鍵問題是，可再生系統真正能夠生產多少能源。”

A huge challenge with deploying solar energy on a large scale is that the sun doesn’t shine all the time. That means that energy must be stored in some way. For photovoltaic (PV) cells, which convert sunlight directly to electricity, this is especially difficult to overcome, because electricity is difficult to store.

大規模部署太陽能的一個重大挑戰是，太陽並不是在所有時間都當空高照。這就意味着，能量必須要通過某種方式存儲下來。對於直接將太陽光轉換爲電能的光伏電池來說，這是特別難以克服的困難，因爲電力很難儲存。