MIT's new 'window' on Solar Energy With "Solar Concentrators", An Edge On Solar

Organic solar concentrators collect and focus different colors of sunlight. Solar cells can be attached to the edges of the plates. By collecting light over their full surface and concentrating it at their edges, these devices reduce the required area of solar cells and consequently, the cost of solar power. Stacking multiple concentrators allows the optimization of solar cells at each wavelength, increasing the overall power output. Photo / Donna Coveney

CAMBRDGE, Mass. -- Imagine windows that not only provide a clear view and illuminate rooms, but also use sunlight to efficiently help power the building they are part of. MIT engineers report a new approach to harnessing the sun's energy that could allow just that.

The work, to be reported in the July 11 issue of Science, involves the creation of a novel "solar concentrator." "Light is collected over a large area [like a window] and gathered, or concentrated, at the edges," explains Marc A. Baldo, leader of the work and the Esther and Harold E. Edgerton Career Development Associate Professor of Electrical Engineering.

As a result, rather than covering a roof with expensive solar cells (the semiconductor devices that transform sunlight into electricity), the cells only need to be around the edges of a flat glass panel. In addition, the focused light increases the electrical power obtained from each solar cell "by a factor of over 40," Baldo says.

Because the system is simple to manufacture, the team believes that it could be implemented within three years—even added onto existing solar-panel systems to increase their efficiency by 50 percent for minimal additional cost. That, in turn, would substantially reduce the cost of solar electricity.

In addition to Baldo, the researchers involved are Michael Currie, Jon Mapel, and Timothy Heidel, all graduate students in the Department of Electrical Engineering and Computer Science, and Shalom Goffri, a postdoctoral associate in MIT's Research Laboratory of Electronics.

"Professor Baldo's project utilizes innovative design to achieve superior solar conversion without optical tracking," says Dr. Aravinda Kini, program manager in the Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science, a sponsor of the work. "This accomplishment demonstrates the critical importance of innovative basic research in bringing about revolutionary advances in solar energy utilization in a cost-effective manner."

Solar concentrators in use today "track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain," Baldo and colleagues write in Science. Further, "solar cells at the focal point of the mirrors must be cooled, and the entire assembly wastes space around the perimeter to avoid shadowing neighboring concentrators."

The MIT solar concentrator involves a mixture of two or more dyes that is essentially painted onto a pane of glass or plastic. The dyes work together to absorb light across a range of wavelengths, which is then re-emitted at a different wavelength and transported across the pane to waiting solar cells at the edges.

In the 1970s, similar solar concentrators were developed by impregnating dyes in plastic. But the idea was abandoned because, among other things, not enough of the collected light could reach the edges of the concentrator. Much of it was lost en route.

The MIT engineers, experts in optical techniques developed for lasers and organic light-emitting diodes, realized that perhaps those same advances could be applied to solar concentrators. The result? A mixture of dyes in specific ratios, applied only to the surface of the glass, that allows some level of control over light absorption and emission. "We made it so the light can travel a much longer distance," Mapel says. "We were able to substantially reduce light transport losses, resulting in a tenfold increase in the amount of power converted by the solar cells."

This work was also supported by the National Science Foundation. Baldo is also affiliated with MIT's Research Laboratory of Electronics, Microsystems Technology Laboratories, and Institute for Soldier Nanotechnologies.

Mapel, Currie and Goffri are starting a company, Covalent Solar, to develop and commercialize the new technology. Earlier this year Covalent Solar won two prizes in the MIT $100K Entrepreneurship Competition. The company placed first in the Energy category ($20,000) and won the Audience Judging Award ($10,000), voted on by all who attended the awards.

Written by Elizabeth Thomson, MIT News Office

Photos available upon request

Contact: Teresa Herbert
therbert@mit.edu
617-258-5403
Massachusetts Institute of Technology

Tags: Solar Energy Research, solar energy, solar concentrator, solar power, MIT, Covalent Solar, MIT News

New Dye Technology Converts Ordinary Glass Into A High-tech Solar Concentrator.

Image Credit: Nicolle Rager Fuller, NSF
Revisiting a once-abandoned technique, engineers at the Massachusetts Institute of Technology (MIT) have successfully created a sophisticated, yet affordable, method to turn ordinary glass into a high-tech solar concentrator.

The technology, which uses dye-coated glass to collect and channel photons otherwise lost from a solar panel's surface, could eventually enable an office building to draw energy from its tinted windows as well as its roof.

Electrical engineer Marc Baldo, his graduate students Michael Currie, Jon Mapel and Timothy Heidel, and postdoctoral associate Shalom Goffri, announced their findings in the July 11 issue of Science.

"We think this is a practical technology for reducing the cost of solar power," said Baldo.

The researchers coated glass panels with layers of two or more light-capturing dyes. The dyes absorbed incoming light and then re-emitted the energy into the glass, which served as a conduit to channel the light to solar cells along the panels' edges. The dyes can vary from bright colors to chemicals that are mostly transparent to visible light.

Because the edges of the glass panels are so thin, far less semiconductor material is needed to collect the light energy and convert that energy into electricity.

"Solar cells generate at least ten times more power when attached to the concentrator," added Baldo.

Because the starting materials are affordable, relatively easy to scale up beyond a laboratory setting, and easy to retrofit to existing solar panels, the researchers believe the technology could find its way to the marketplace within three years.

The new technology emerged in part from an NSF Nanoscale Interdisciplinary Research Team effort to transfer the capabilities of photosynthesis to solar technology.

The researchers' approach succeeded where efforts from the 1970s failed because the thin, concentrated layer of dyes on glass is more effective than the alternative--a low concentration of dyes in plastic--at channeling most of the light all the way to the panel edges. However, the current technology still needs further development to create a system that will last the 20- to 30-year lifetime necessary for a commercial product.

For additional information, see the MIT release at: http://web.mit.edu/newsoffice/2008/solarcells-0710.html

-NSF-

Media Contacts
Joshua A. Chamot, NSF (703) 292-7730 jchamot@nsf.gov
Teresa Herbert, Massachusetts Institute of Technology (617) 258-5403 therbert@MIT.EDU

Program Contacts
Rajinder Khosla, NSF (703) 292-8339 rkhosla@nsf.gov

Principal Investigators
Marc Baldo, Massachusetts Institute of Technology (617) 452-5132 baldo@MIT.EDU

Tags: Solar Energy Research, Solar Energy, MIT

MIT and Fraunhofer Cooperate To Design And Build Better Solar Energy Production And To Conduct Other Sustainable Energy Research.

Center aims to significantly reduce cost of solar energy over next five years

April 14, 2008

MIT and Fraunhofer Cooperate To Design And Build Better Solar Energy Production And To Conduct Other Sustainable Energy Research.

MIT and Fraunhofer, a German research organization, have signed an agreement to establish a research center in Massachusetts focused on significantly reducing the cost of solar energy over the next five years. The MIT-Fraunhofer Center for Sustainable Energy Systems will develop cutting-edge technologies and materials for designing and producing better solar modules.

Located adjacent to the MIT campus, the center will be active in other areas of sustainable energy research as well, including developing new technologies to substantially reduce the energy consumption of new and retrofitted structures by adapting state-of-the-art building technology. The center also aims to develop a portfolio of new efficiency and solar technologies that maximize MIT's world-class capabilities in advanced materials R&D and computer simulation.

Professors Ernest Moniz, director of the MIT Energy Initiative (MITEI), and Eicke Weber, director of the Fraunhofer Institute for Solar Energy Systems, announced the agreement that will lead to the creation of the new center Saturday, April 12, at the MIT Energy Conference. Also participating in the ceremony were MIT President Susan Hockfield, German foreign minister Frank-Walter Steinmeier, Karl Weiss, chairman of the board of the Massachusetts Technology Collaborative, and Ian Bowles, Massachusetts secretary of energy and environmental affairs, and Larry Reilly with National Grid.

"This partnership will pair the outstanding basic energy research capabilities at MIT with the world-class applied research capabilities of the Fraunhofer Institute," said Moniz, the Cecil and Ida Green Professor of Physics. "The research focusing on solar energy and on building efficiency address extremely important technologies for both long- and short-term response to global energy challenges. Also, the strong support of the Commonwealth, the Massachusetts Technology Collaborative and National Grid represents the kind of public-private partnership that we will need to succeed."

Start-up costs of the center will be funded with $5 million from the Massachusetts Technology Collaborative. National Grid, the principal member of the Center's Partnership with Industry, also committed to support the center with a pledge of $1 million over five years.

"The Fraunhofer Institute for Solar Energy Systems has been highly successful over 25 years in developing technologies in the areas of renewable energy and energy efficiency, and transferring these innovations to industry," said Weber. "I expect that our new Center for Sustainable Energy Systems at MIT will be as successful here in Massachusetts and help achieve the state's goals in climate protection."

Nolan Browne, MIT alumnus and founder of the MIT Energy Conference, will serve as the center's managing director. In addition, Tonio Buonassisi, assistant professor of mechanical engineering at MIT and the center's planned scientific director, is one of the leading solar technologists in the U.S. today. Roland Schindler, the center's executive director, is a 24-year Fraunhofer veteran who will serve as a liaison between the MIT team and Germany, ensuring that activities are aligned. Four out of the nine members of the board of advisors are MIT professors.

About MITEI

MIT's Energy Initiative (MITEI) is designed to help transform the global energy system to meet the challenges of the future. This Institute-wide initiative includes research, education, campus energy management and outreach activities, an interdisciplinary approach that covers all areas of energy supply and demand, security and environmental impact. For more information, please visit http://web.mit.edu/mitei/.

A version of this article appeared in MIT Tech Talk on April 16, 2008 (download PDF).

tag: Solar Energy Research, MIT, Fraunhofer, Sustainable Energy Systems, solar modules, MIT Energy Initiative, MITEI, Fraunhofer Institute,

NanoPower Solar Window to Address the Energy Crisis .

Octillion Corp.’s NanoPower Solar Window to Address the Energy Crisis

The rapid growth of population as well as economic development in Asia, Eastern Europe and Latin America is driving a rapid expansion of world energy use … The scarcity and non-renewable status of the most important energy sources are making the high energy price environment to become a permanent feature of current reality.

In addressing the energy price challenges, energy technology innovation must play the leading role. Technology advancements can offer a solution to the world energy crisis by offering environmentally friendly and reliable energy source alternatives that meet the world’s basic energy needs and provide sustainable basis for economic development.

Octillion Corp. is a technology incubator currently developing a patent-pending technology that could adapt existing home and office glass windows into ones capable of generating electricity from solar energy without losing significant transparency or requiring major changes in manufacturing infrastructure.
Octillion reported that the process of producing silicon nanoparticles is supported by 10 issued U.S. patents, seven pending U.S. patents, two issued foreign counterpart patents and 19 pending foreign counterpart patents. The company’s current research efforts target refining the process of the deposition of silicon nanoparticles onto glass, quality control and consistent replication of lab-scale samples.
In March 2008, Octillion announced that it succeeded in replacing previously established protocols for producing lab-scale prototypes; a traditionally time-consuming and cumbersome process for depositing nanoparticles onto glass has been successfully replaced with a faster, cost-effective and commercially available deposition technology. This advancement will allow the company to accelerate the NanoPower Window technology development and move from the laboratory to larger-scale testing and production.
Octillion
tag: Solar Energy Research, Solar Energy, NanoPower Solar Window, Energy Crisis, silicon nanoparticles, Octillion,

Thin-Film Solar Cell Research Project Debuts In UK

DURHAM, England, British scientists led by Durham University are starting one of the United Kingdom's largest research projects into photovoltaic solar energy.The $12.3 million, four-year PV-21 program is to focus on making thin-film light absorbing cells for solar panels from sustainable and affordable materials.
A national team of scientists are embarking on one of the UK’s largest ever research projects into photovoltaic (PV) solar energy.The £6.3million PV-21 programme, led by experts at Durham University, will focus on making thin-film light absorbing cells for solar panels from sustainable and affordable materials.The four-year project, which begins in April (2008), is being funded by the Engineering and Physical Sciences Research Council (EPSRC) under the SUPERGEN initiative.Eight UK universities, led by Durham and including Bangor, Bath, Cranfield, Edinburgh, Imperial College London, Northumbria and Southampton, are involved in the project.
They will work together with nine industrial partners towards a “medium to long-term goal” of making solar energy more competitive and sustainable, particularly in light of the recent rise in fossil fuel prices.At present solar cells – used to convert light energy into electricity - are made from key components such as the rare and expensive metal indium which costs approximately £320 ($660) per kilogram.To cut costs in solar cell production the research team will work to reduce the thickness of the cells.Making a solar semiconductor thinner by one millionth of a metre in solar cells generating one gigawatt of power could save 50 tonnes of material.Researchers will also experiment with sustainable low-cost materials which could be used in the manufacturing of solar cells and on the use of nanotechnology and dyes on ultra-thin silicon to capture increased amounts of energy from the sun’s rays.Principal investigator Professor Ken Durose, in the Department of Physics, at Durham University, said: “With the rapid increase in fossil fuel prices and the recent Government announcement about investment in nuclear power it is even more important that we look at long-term future energy generation from solar power.“At present you would need tens of tonnes of very rare and expensive materials for large scale production of solar cells to produce sizeable amounts of power.
“Some of the materials currently used may not be sustainable in 20 years time which is why we have to conduct research into alternative materials that are cheaper to buy and more sustainable. “We are also leading the way in making ultra-thin solar cells that need less material. “Our medium to long-term goal is to make a major contribution to achieving competitive photovoltaic solar energy, which we hope will lead to an uptake in the use of solar power.”

The latest funding follows an initial four-year research project by PV-21 focusing on the development of thin-layer PV cells using compound semiconductors based on the cadmium telluride and chalcopyrite systems.
This work will form the basis for testing new ideas over the next four years.
Chris Pywell, Head of Strategic Economic Change at regional development agency One NorthEast, said: “This project will add substantially to the position of North East England which is already at the forefront of photovoltaic energy research.
“This leading position presents a great opportunity to the region as the world addresses climate change. As well as the strengths of Durham and Northumbria universities that are demonstrated by this success, we have the PV development facilities at NaREC, the new PETEC facilities at NETPark, and great businesses such as ROMAG.
“The Agency, Durham University and our other partners are committed to building on this new project and our many other successes to ensure the region leads the UK in renewable energy.”

tag: Thin-Film Solar Cell, Solar Energy Research, ROMAG, NETPark, PV-21, nanotechnology, Durham University, indium, SUPERGEN, photovoltaic