University researchers work to make solar energy more affordable

By Emily Scott, Staff writer

In the ongoing search for reliable renewable energy sources, two University professors are working to make a form of solar power technology more affordable.

Mechanical science and engineering professors Kimani Toussaint and Placid Ferreira, along with researchers from the University of Michigan and the National Renewable Energy Laboratory, were recently selected to receive a grant from the U.S. Department of Energy’s SunShot Initiative. This initiative, which is comparable with President John F. Kennedy’s “Moon Shot” initiative, aims to support research that will make renewable energy more cost competitive with traditional energy sources.

Toussaint and Ferreira’s project involves developing a specific type of solar power technology called concentrating solar power collectors, which use reflective surfaces to focus light at point of absorption and convert that energy into electricity.

Although concentrating solar power has been in the industry for decades, it hasn’t been able to compete with photovoltaics, the type of technology used in solar panels that creates an electric current when exposed to light. The team’s goal is to reduce the cost of concentrating solar power so it can compete with solar panels and be a part of the broader renewable energy portfolio.

“The challenge is that the cost of photovoltaics . . . has become so inexpensive that the attraction to concentrating solar power is not as strong from a financial perspective,” Toussaint said.

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    But concentrating solar power has specific advantages over photovoltaics. One of the main challenges with photovoltaics is storage, as it relies on the presence of sunlight to keep its battery charged.

    With concentrating solar power, heat can be stored for much longer periods of time and accessed during nighttime operations.

    “When you do want to have access to power where there is no more sunlight, concentrating solar power becomes extremely attractive,” Toussaint said.

    Ultimately, their goal is to create a new technology that can be put to market and used in the industry, and they hope to achieve this in a way that hasn’t been done before.

    They proposed a flat structure for collecting sunlight, which is different from the traditional concentrating solar power collector that is curved, almost like a bowl. Making the structure flat uses less material, but aslo brings about a new set of challenges — which is where Toussaint and Ferreira’s expertise in nanotechnology comes in.

    Toussaint leads a lab in photonics research of bio/nano environments, and said the lab has done a lot of work in nanotechnology, which deals with dimensions less than 100 nanometers. But in this project, they’ll use techniques from nanotechnology to attempt to focus over long distances.

    “People have shown . . . that you can take nanostructures and arrange them in such a way that you can focus over distances that are shorter than the thickness of human hair,” he said. “No one has shown that you can do that over centimeters, or meter distances, much longer distances . . . so if we could pull that off, it would be a big deal, actually.”

    Ferreira said using nanotechnology in this type of way is something that isn’t normally done.

    “[This research] is taking emerging technology, that’s nanotechnology, and using our understanding of phenomena that occur at the nanoscale to address problems of the environment and energy,” he said. “So that’s kind of a rather challenging thing to do, and that’s what makes it interesting and special.”

    The multiple skill sets they are using in this research — such as in energy and energy conversion, manufacturing and fabrication of materials, and in Toussaint’s case, optics and nanotechnology — are not usually used in collaboration, Ferreira said.

    The project is Toussaint’s first foray into solar energy research, but he said it’s something he’s always wanted to do. He hopes this work will make solar power more viable in the face of a future that needs it.

    “We’re a planet that has a sun. So being able to access some of the energy from that sun in a waste-free way would be a huge plus,” he said. “I think that it’s only a matter of time that we don’t have any choice but to embrace more renewable energy forms. And you can’t talk about renewable energy . . . without thinking about solar energy. Simply because we have sunlight.”

    Solar power has become more feasible over time, especially with the decreased cost of photovoltaics. Toussaint said he doesn’t expect concentrating solar power to completely replace solar panels, but he does expect the two technologies to become complementary to each other.

    “I think if we’re successful, it’ll point us in a certain direction that will allow us to harness phenomena at the nanoscale to actually increase the efficiency of energy conversion devices,” Ferreira said.

    Toussaint’s ultimate hope is that this research will add to the vast amount of research in solar technology that has already been done.

    “We’re hoping to be able to at least contribute to that body of work in a way that makes this a lot more viable,” he said. “If we’re successful, it’s not that it’s just good for concentrating solar power, it would be good for the entire solar industry.”

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