大規模的太陽能電力系統不但能滿足未來長期的能源需求,還能減少碳排放。不過美國麻省理工學院能源計畫(MITEI)上週提交給美政府高層的報告指出,要實現這個願景,還需開發成本更低的技術,政府也需要推行更有效的政策。
投資創新技術 降低太陽能發電成本
這份名為〈太陽能的未來〉的報告提到,美國要大規模部署太陽能發電,必須在電力系統方面做出預先規畫,因為一天當中,太陽能發電量難以正確預測。
報告作者指出,聯邦政府應該重新考慮如何提高成本效益,並盡快投入經費資助創新技術,尤其是能降低成本與大規模儲存電力的技術,同時必須更加重視獎勵生產太陽能電力。
「我們的目標是持續評估太陽能源當前和潛在的競爭優勢,並確認美國政府哪些政策的改變,長期來看更能有效支持大規模部署太陽能電力系統,我們認為這是相當關鍵的。」主持MITEI、麻省理工學院的化學工程學教授阿姆斯壯(Robert Armstrong)表示。
該研究小組在本週將調查結果提交給國會議員和華盛頓的政府高層官員。
美國透過再生能源配額制度支持利用再生資源發電,研究團隊也建議將該制度整合成統一的國家計畫,放寬各州進行信用額度交易,降低達到設定目標的成本。
新型太陽能電池 盼突破35%發電效率
麻省理工學院的研究人員目前正在開發數種新的太陽能技術。麻省理工學院和史丹佛大學的科學家已經開發出新型太陽能晶片(solar cell,俗稱太陽能電池),結合兩種吸收太陽光的材料,用以捕捉範圍更廣的太陽能量。
初版太陽能晶片的光電轉換效率雖然只有13.7%,不過研究人員表示,已經找到低成本又能提高效率到30%的方法,將能大幅改善目前以矽為基礎的商業太陽能晶片。研究人員表示該技術最終將能突破35%的發電效率。
這種新型太陽能晶片採用目前廣為使用的矽,再加上一層半透明的鈣鈦礦(perovskite),它可以吸收更高能量的光子。
非廉價勞力 中國太陽能板靠完善供應鏈壓低成本
因為低廉的勞動力成本與政府的大力支持,截至2011年,中國生產的太陽能板佔全球63%,而咸信是全世界最主要的太陽能板製造商。
但是,麻省理工學院和美國能源部再生能源實驗室於2013年的報告指出,美國可望在生產光伏(photovoltaic)領域再次擁有成本競爭力。
然而,詳細分析光伏的生產成本,發現中國較低價的光伏產品,主要源自經濟規模與完善的供應鏈,而並非廉價的勞動力。
「我們開發了由下而上(bottom-up)的模式,」該研究的共同作者、麻省理工學院機械工程副教授博納西西(Tonio Buonassisi)表示。該報告發表於《能源與環境科學》期刊。研究人員也評估生產光伏的成本,包括所有材料、人工、設備和製造過程中的間接費用。
博納西西表示,重點在於讓目前製造光伏組件的區域價格差異「恢復彈性,不再是因為國家特定的介入才擁有優勢」。因此,技術創新就有機會迅速帶動一個平等競爭環境。
Solar energy on a grand scale could meet humanity’s future long-term energy needs while cutting carbon emissions, but lower-cost technologies and more effective government policies are needed to achieve this potential, finds a new study released Tuesday by the Massachusetts Institute of Technology’s Energy Initiative (MITEI).
“The Future of Solar Energy” says that America needs to prepare its electricity systems for very large-scale deployment of solar generation, which tends to vary unpredictably throughout the day.
The authors point to an urgent need for federal R&D dollars to be invested in new technologies, especially low-cost, large-scale electricity storage, with greater emphasis on rewarding production of solar energy.
“Our objective has been to assess solar energy’s current and potential competitive position and to identify changes in U.S. government policies that could more efficiently and effectively support its massive deployment over the long term, which we view as necessary,” said MITEI Director Robert Armstrong, the Chevron Professor in Chemical Engineering at MIT.
The study group is presenting its findings to lawmakers and senior administration officials this week in Washington.
Richard Schmalensee, the study’s chair and Howard W. Johnson Professor Emeritus of Economics and Management at the MIT Sloan School of Management, said, “What the study shows is that our focus needs to shift toward new technologies and policies that have the potential to make solar a compelling economic option.”
Today’s federal and state subsidy programs designed to encourage investment in solar systems should be reconsidered, to increase their cost-effectiveness.
The group also recommends that state renewable portfolio standards, which support increased power generation from renewable resources, be brought under a unified national program that would reduce the cost of meeting set targets by allowing unrestricted interstate trading of credits.
Several new solar technologies are being developed by MIT researchers.
Scientists at MIT and Stanford University have developed a new kind of solar cell that combines two different layers of sunlight-absorbing material in order to harvest a broader range of the sun’s energy.
The new cell uses a layer of silicon, which forms the basis for most of today’s solar panels, but adds a semi-transparent layer of a material called perovskite, which can absorb higher-energy particles of light.
In this initial version, the efficiency is 13.7 percent, but the researchers say they have identified low-cost ways of improving this to about 30 percent, a big improvement over today’s commercial silicon-based solar cells. They say this technology could ultimately achieve a power efficiency of more than 35 percent.
It’s widely believed that China is the world’s dominant manufacturer of solar panels because of its low labor costs and strong government support. But a 2013 study by researchers at MIT and the U.S. Department of Energy’s National Renewable Energy Laboratory indicates that the United States could once again become cost-competitive in photovoltaic (PV) manufacturing.
As of 2011, manufacturers in China accounted for 63 percent of all solar-panel production worldwide. But a detailed analysis of all costs associated with PV production shows that the main contributors to that country’s lower PV prices are economies of scale and well-developed supply chains, not cheap labor.
“We developed a bottom-up model,” explains Tonio Buonassisi, an associate professor of mechanical engineering at MIT and a co-author of the report, published in the journal “Energy and Environmental Science.”
The researchers estimated costs for virtually all the materials, labor, equipment and overhead involved in the PV manufacturing process.
The bottom line, Buonassisi says, is that today’s regional price differences in making photovoltaic modules are “not inherent [and] not driven by country-specific advantages.” As a result, technological innovations could rapidly level the playing field.
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