Forward-Looking Book on Concentrating Photovoltaics (CPV) Published (Super User) | Sun Sep 10, 2017

Book Explores Future Pathways for CPV to Become Viable and Affordable Solar Power Technology

Dr. Matteo Chiesa, Professor of Mechanical and Materials Engineering, and Harry Apostoleris, Class of 2015 MSc graduate and current PhD student, are supporting the advancement of concentrating photovoltaics (CPV), which is a type of photovoltaic technology that concentrates sunlight to generate electricity, with a new book that explores how emerging CPV technologies could overcome challenges that have limited CPV generation and deployment.

Dr. Chiesa and Apostoleris co-authored the book titled Concentrating Photovoltaics (CPV): The Path Ahead with Dr. Marco Stefancich,Senior Researcher at the Dubai Electricity and Water Authority (DEWA). The book was envisioned, designed and commissioned by the research team and was published earlier this month by Springer, one of the leading international science and technology publishers.

“Silicon-based solar photovoltaics (PV) are dominating the solar market right now, but these basic solar panels are not very efficient, converting roughly 15% of sunlight into electrical energy. CPV, on the other hand, can reach conversion efficiencies upwards of 40%, but they have not been successful from a market perspective. This book looks at what is contributing to CPV’s low uptake and poor market performance, and how we can fix this problem with existing CPV technologies and those that are on the horizon,” Apostoleris explained.

CPV maximizes efficiency by using multiple optical elements, such as mirrors and lenses, to reflect light into a super concentrated beam that is aimed at solar cells. The optical elements enable the use of small, high-efficiency solar cells. Mechanical systems move the panels throughout the day, tracking the path of the sun so that the solar cells are exposed to a maximum amount of direct sunlight.
Although CPV is still in its nascent stage of development, its high sunlight-to-electricity efficiency makes it a unique solution for large-scale commercial and utility-scale power generation, underscoring the pressing need to bolster research and development of the powerful solar energy harnessing technology. However, there are many obstacles hindering CPVs wider uptake, including high costs and heavy machinery, which is the focus of the first part of the book.

Part two of the book explores the CPV innovations that are on the horizon in terms of technology development that could help overcome the current market challenges holding CPV back. The authors surveyed several review papers on CPV to identify areas in the field being targeted for innovation, including high-efficiency cells, low-cost systems, high performance concentrator optics, and integrative sun tracking.

The focus of Apostoleris’ Master’s and PhD research was especially relevant to this part of the book. He has been developing innovative tracking integration and spectral splitting technologies to help make CPV systems smaller, lightweight and more affordable. In fact, it was the research papers his team published on tracking integration and spectral splitting that attracted Springer’s attention and prompted their request for a book publication on CPV.

“During my Master’s studies, I developed a system that concentrated and directed sunlight onto a transparency-switching material that was able to track the sun without using mechanical devices to collect concentrated sunlight on a small solar cell,” Apostoleris explained.

This technology avoids the use of heavy and expensive mechanical tracking machinery, which would enable CPV systems to be extremely lightweight and small, opening up their potential to be placed on rooftops.

As part of his PhD dissertation, Apostoleris is developing an optical device that disperses and concentrates visible and infrared light and feeds each slice of the solar spectrum to spectrally-matched solar cells. This technology would avoid the need to use expensive multi-junction solar cells typically required of CPV systems, thereby reducing the costs significantly.

Emerging technologies that could transform the way CPV systems are used, like Apostoleris’ integrated tracking system and spectral splitting concentrator, are considered in detail in the second part of the book.

Part three looks at how the emerging technological developments discussed in the previous section have enabled a new range of possibilities for CPV deployment across several potential applications.

“The best way forward for CPV is to expand current thinking about how CPV technologies can be used. That is, we should not just aim to make CPV solar panels that can compete with extremely low-cost PV panels. Instead, we must shift our thinking towards how we can employ emerging CPV technologies in different ways for different applications,” Apostoleris remarked.
Applications like building integration for daylighting or heating are just a couple examples cited in the book.

“Solar panels convert sunlight into electricity and then that electricity is turned back into something we use, like a light. CPV can skip one step and provide light directly, thereby minimizing the amount of energy needed to generate light,” he added.

The authors referenced many technological innovations to demonstrate how CPV can be transformed into useful, affordable and viable options for generating clean energy.

“We believe this book has expanded the space researchers have to play with in terms of developing and deploying solar energy solutions in all sorts of setting,” Dr. Chiesa asserted.

Although CPV only entered the market in the mid-2000s as a utility scale solar power generation option, it is expected to reach US$1.9 billion by 2023. This underscores the potential of CPV technology, if the economic and technical challenges that the technology faces can be overcome, and the relevance of the work highlighted in this book, which aims to position CPV as a potentially valuable contributor in the global push for clean energy.

Erica Solomon
News and Features Writer
11 September 2017