Let there be light: UT researchers leading the way in solar panel science
Solar power, or photovoltaics, have been around for nearly a century and a half. It's estimated that solar panels now provide up to 2% of worldwide electricity. The technology is becoming increasingly efficient, thanks in no small part to the efforts of local researchers.
"Sunlight consists of particles of light called photons," explains Dr. Randy Ellingson, physics professor at the University of Toledo. "Every photon generates an electron, which builds into an electrical current and creates a voltage much like a battery."
Lately, however, direct sunlight has been rather hard to come by. Dr. Ellingson says solar power generation in Toledo is down about 10% this season, but even on cloudy days, "you might end up getting 60-70% of the normal amount of power from a clear-sky day."
Silicon panels are the industry standard -- making up about 90% of it -- running at an average of 17-18% efficiency (with higher results in lab studies). UT researchers have used a combination of lead and tin, among other elements, to bump that number up to 23 percent, providing quite a potential boost for the industry.
That mixture allows for cells to draw from two different parts of the sun's spectrum to generate more power. With zero emissions outside of building and installing the array, the environmental benefits would be great, yet one current hurdle involves the new panel materials themselves.
"You don't want to put technologies in the field that are susceptible to contaminating the environment," says Ellingson. "In this case, you need to demonstrate that the lead is stable and sealed and cannot leach out."
Other UT projects include mitigating that sun-cloud variability, and using buildings and even vehicles for solar energy storage.
As far as initial cost, Dr. Ellingson says the average break-even point for payback comes in less than a year now, explaining that "energy inputs required are relatively low, and the energy outputs are improving every year as the efficiency climbs."
With costs being driven down as the technology improves, global industry growth has been exponential, and it's only a matter of time before U.S. demand catches up. Dr. Ellingson offers an example from overseas.
"Toledo is 25-30% higher than the typical insolation in Germany, and yet Germany has about 4x as much solar energy per person installed in their country than the U.S. does, so there's certainly a lot of room for growth."
Current estimates put U.S. annual solar power generation at 67 gigawatts, or enough to power nearly 13 million homes -- and that figure is expected to nearly double in the next 5 years.