Renewable Energy

March 16, 2014

Kindling the Rivalry Between Silicon and So-called “Fringe Technologies”

Perhaps it is the subtle challenge made by the silicon PV industry that remains most clear in my mind after returning to the SUNLAB after a week of technical presentations at EU-PVSEC 2013.  The rivalry is not new.  In fact, statements asserting silicon’s dominance represent a broad summary of the opinions conveyed about the future of the photovoltaic industry at the conference.   Those statements likely would have slipped transparently through my tired conscience if not for the nagging objection that the arguments for studying alternative PV technologies seem to ring as true today as they did when the price of silicon panels was still at $2.00 per Watt.   So does the emphasis on the plummeting price of flat panels mean that all of us working on so called “fringe technologies” (which include, by deployment volume, higher efficiency CPV and lower efficiency thin film strategies along with pretty well everything else the PVIN funds) should pack it in and start working

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November 18, 2013

PVSC 2013-Tandem CIGS Solar Cells

A subject that caught my attention during the 39th edition of the Photovoltaic Specialist Conference (PVSC) was a poster from Toshiba Corporation [1] about the study of a homojunction CIGS (Copper Indium Gallium Selenium) solar cell. CIGS solar cells are gaining more and more interest in the photovoltaic community as a thin film solar cell due to the material’s high absorptivity, low cost and relatively high power conversion efficiency.  Standard CIGS solar cell consists of a p-type CIGS base, n-type CdS emitter and a ZnO transparent conductive oxide. This heterojunction between CIGS and CdS results in a conduction band offset. The heterojunction structure is used due to the fact that it is hard to get high enough levels of n-type doping in CIGS. P-type doping in CIGS is usually done intrinsically through Cu vacancies, which act as acceptors. To achieve n-type doping, a donor material would need to be introduced into CIGS.  In their poster, the Toshiba corporation group reported

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October 31, 2013

Spectrum Splitting and Thin Film Photovoltaics at PVSC 2013

At the 39th Photovoltaic Specialist Conference in Tampa, Florida, there were two important and interesting topics which were of particular interest to me. The first one was covered by Harry A. Atwater, California Institute of Technology (http://daedalus.caltech.edu/research/thinfilmpv.php) “Full Spectrum High Efficiency Photovoltaics” [1]. He was discussing a new concept: splitting the incident solar spectrum into its constituent wavelengths, guiding these different wavelengths into solar cells with different bandgaps, then absorbing them (shown in Figure 1).

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October 22, 2013

Highlights from PVSC 2013

The IEEE Photovoltaic Specialist Conference (PVSC) is renowned as one of the world’s largest photovoltaics (PV) conferences. It is also probably the oldest conference that is still been held annually. I was fortunate enough to have the opportunity to attend the conference this year, for the second time. As the PV energy market is evolving from niche to mainstream, I’ve noticed some shift of focus in the topics of this year’s conference. The most noticeable would be the emphasis on the long-term reliability of PV systems. The very first plenary session on Monday morning was dedicated to PV reliability issues, with two talks covering both modeling and analysis of data collected from real field operations. While crystalline silicon is still the dominant technology, exploration into new materials and concepts has never been slowed down. It is the same with this year’s conference. It is my area of interest to discover potential new technologies that can bring fundamental improvement to the

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October 15, 2013

PVSC 2013-Discussions on Photovoltaic System Implementation at the 2013 Photovoltaic Specialist Conference

The 39th IEEE photovoltaic specialist conference was held between June 16th and 21st at the Tampa bay convention center in Tampa, Florida. It was a congregation of industry experts, and research giants. Researchers from NREL, Sandia National Laboratories and Universities across the globe graced the occasion to present their latest studies on photovoltaic system design, implementation and reliability of on-sun PV modules.. The program was significantly all encompassing. Besides the presentations, social activities and mixer programs were held to allow attendees to interact, network and share knowledge. Of notable interest was the presentation of the cherry award to Keith Emery. Previously unknown to me, I found that he is renowned for his contribution to photovoltaic research for his design, development and implementation of IV characterization methods. He pioneered the first generation of hardware, software and procedures to measure current-vs.-voltage characteristics as a function of temperature, spectrum and intensity for single and multi-junction cells and modules. Oral and poster presentations at the

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September 22, 2013

PVSC 2013-CdTe thin films progress

I had the opportunity to go to PVSC 39 in Tampa, Florida with fellow Highly Qualified Personnel (HQP). There were a lot of interesting speeches but I will only focus on a couple of them here – particularly those focusing on CdTe thin films progress. CdTe is one of the most attractive materials for production of low cost thin film solar modules [1]. The record efficiency for CdTe solar cells has been established to be 16.7% for 10 years. In the past 2 years, the CdTe record was broken several times and increased from 16.7% to 18.7%. However, there has been no significant change in the open-circuit voltage which was in the range of 840-860 mV for over 20 years. Many arguments have been made to justify the apparent Voc limitation, most frequently: poor hetero-interface with CdS, the difficulty in doping polycrystalline CdTe, midgap defect levels, or non-uniformities at the nano- or micro-scale. Paths for open-circuit voltage above 900 mV

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September 6, 2013

PVSC 2013 in Tampa, Florida

This year, the Photovoltaics Specialists Conference was held in Tampa.  In the middle of June in Florida, you could really feel the sun.  It was hot.  The temperature accounting for humidity was easily into the 40’s each day.   And this was awesome for me, since I almost feel perpetually cold in Ottawa.  An ultra-hot day feels like a blessing so I didn’t mind it at all. We conveniently stayed right across the street from the Tampa Convention Centre, which was also conveniently connected to our hotel with a bridge.  All it took was a quick 30 seconds in the heat and it was back to the frigidity of an air conditioned building.   The actual conference was much more along the interests of the students in the network.  And you could tell.  Students were picking out their sessions as soon as they got their hands on a physical copy of the conference schedule.  I was amazed by the sheer volume of

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August 27, 2013

PVSC 2013-Intermediate Band Solar Cells

I recently had an opportunity to attend the 39th IEEE Photovoltaics Specialists Conference in Tampa, Florida (http://www.ieee-pvsc.org/PVSC39/). Since I am just starting to work in Photovoltaics, it was a great opportunity for me to get immersed in this very quickly developing field by listening to high quality presentations given by the leaders of the field. The presentations were divided into 11 topic areas, with a few sessions taking place at the same time. I really wanted to be in a few rooms simultaneously, but with my background in quantum theory I decided to focus mostly on attending sessions from research Area 1: Fundamentals and New Concepts of Future Technologies. I found a talk by Megumi Yoshida from Imperial College London :“Progress towards Realizing Intermediate Band Solar Cell – Sequential Absorption of Photons in a Quantum Well Intermediate Band Solar Cell” particularly interesting. I was familiar with the concept of introducing the intermediate band (IB) into the solar cell to improve the

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August 15, 2013

PVSC 2013-Exploring Tampa in the Sunshine

The 39th Photovoltaic Specialists Conference in Tampa, Florida was a great conference. Photovoltaic specialists from all over the world gathered at the paradise of recreation, learning the most recent developments in this field delivered by hundreds of high quality presentations and posters. The topics span across eleven general areas from fundamental and new concepts of PV to the supporting of PV innovation with little to none overlap between each area. For me, an organic chemist focusing on developing new polymers to improve the stability of organic photovoltaics (OPV), the area that mostly interested me was, without a doubt, OPV. Thursday of last week was the day for OPVs. In the morning, Professor Christian Körner from Heliatek GmbH gave a talk on the recent progress of organic solar cells [1].  Like a typical general review of this field, the talk started with some fundamental concepts and theories of organic semiconductors, then moved to some developments that aimed at solving the issues

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August 7, 2013

Is there a light at the end of the tunnel for PV in Ontario?

As Ontario’s flagship renewable energy (RE) incentive program, referred to as the Feed-in Tariff (FIT), enters its third review, it is an appropriate point to assess several recent political and policy changes which have implications for the next iteration of RE incentives. In my previous blog, I wrote about the challenges facing Photovoltaics (PV) with respect to the World Trade Organization’s (WTO) initial ruling against Ontario’s domestic content requirements, growing economic turbulence in the RE sector, political adjustments within the provincial Liberal party  as well as other industrial and policy factors that have created uncertainty surrounding the future deployment and development of PV in Ontario. These events have had lasting impacts on the prospects of PV and continue to influence future policy engagement. In conjunction with prior developments, there are new pressures and policy changes which will have serious implications for PV. Do these changes point to positive change for the future of PV? Foremost among these pressures is the

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