![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() by Staff Writers Sydney, Australia (SPX) May 19, 2016
A new solar cell configuration developed by engineers at the University of New South Wales in Sydney has pushed sunlight-to-electricity conversion efficiency to 34.5% - establishing a new world record for unfocussed sunlight and nudging closer to the theoretical limits for such a device. The record was set by Dr Mark Keevers and Professor Martin Green, Senior Research Fellow and Director, respectively, of UNSW's Australian Centre for Advanced Photovoltaics, using a 28 cm2 four-junction mini-module - embedded in a prism - that extracts the maximum energy from sunlight. It does this by splitting the incoming rays into four bands, using a hybrid four-junction receiver to squeeze even more electricity from each beam of sunlight. The new UNSW result, confirmed by the U.S. National Renewable Energy Laboratory, is almost 44% better than the previous record - made by Alta Devices of the USA, which reached 24% efficiency, but over a larger surface area of 800-cm2. "This encouraging result shows that there are still advances to come in photovoltaics research to make solar cells even more efficient," said Keevers. "Extracting more energy from every beam of sunlight is critical to reducing the cost of electricity generated by solar cells as it lowers the investment needed, and delivering payback faster." The result was obtained by the same UNSW team that set a world record in 2014, achieving an electricity conversion rate of over 40% by using mirrors to concentrate the light - a technique known as CPV (concentrator photovoltaics) - and then similarly splitting out various wavelengths. The new result, however, was achieved using normal sunlight with no concentrators. "What's remarkable is that this level of efficiency had not been expected for many years," said Green, a pioneer who has led the field for much of his 40 years at UNSW. "A recent study by Germany's Agora Energiewende think tank set an aggressive target of 35% efficiency by 2050 for a module that uses unconcentrated sunlight, such as the standard ones on family homes. "So things are moving faster in solar cell efficiency than many experts expected, and that's good news for solar energy," he added. "But we must maintain the pace of photovoltaic research in Australia to ensure that we not only build on such tremendous results, but continue to bring benefits back to society." Australia's research in photovoltaics has already generated flow-on benefits of more than $8 billion to the country, Green said. Gains in efficiency alone, made possible by UNSW's PERC cells, are forecast to save $750 million in domestic electricity generation in the next decade. PERC cells were invented at UNSW and are now becoming the commercial standard globally. The record-setting UNSW mini-module combines a silicon cell on one face of a glass prism, with a triple-junction solar cell on the other. The triple-junction cell targets discrete bands of the incoming sunlight, using a combination of three layers: indium-gallium-phosphide; indium-gallium-arsenide; and germanium. As sunlight passes through each layer, energy is extracted by each junction at its most efficient wavelength, while the unused part of the light passes through to the next layer, and so on. Some of the infrared band of incoming sunlight, unused by the triple-junction cell, is filtered out and bounced onto the silicon cell, thereby extracting just about all of the energy from each beam of sunlight hitting the mini-module. The 34.5% result with the 28 cm2 mini-module is already a world record, but scaling it up to a larger 800-cm2 - thereby leaping beyond Alta Devices' 24% - is well within reach. "There'll be some marginal loss from interconnection in the scale-up, but we are so far ahead that it's entirely feasible," Keevers said. The theoretical limit for such a four-junction device is thought to be 53%, which puts the UNSW result two-thirds of the way there. Multi-junction solar cells of this type are unlikely to find their way onto the rooftops of homes and offices soon, as they require more effort to manufacture and therefore cost more than standard crystalline silicon cells with a single junction. But the UNSW team is working on new techniques to reduce the manufacturing complexity, and create cheaper multi-junction cells. However, the spectrum-splitting approach is perfect for solar towers, like those being developed by Australia's RayGen, which use mirrors to concentrate sunlight which is then converted directly into electricity. The research was funded by the Australian Renewable Energy Agency; and UNSW, in partnership with RayGen Resources, an Australian developer of PV power tower technology; Trina Solar, a PV module manufacturer; and the U.S. National Renewable Energy Laboratory.
Related Links University of New South Wales All About Solar Energy at SolarDaily.com
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |