Town Talks: A Look At Solar Energy & Greenhouse Effect

Come learn how the laws of physics are governing climate change and our attempts at green energy  this coming TuesdayJuly 21, 6:00 p.m., Telluride Mountain Village Conference Center. Talk hosted by the Telluride Science Research Center. Admission is free. Cash bar starts at 5:30 p.m.

Joseph Subotnik, Associate Professor of Chemistry at University of Pennsylvania.

Joseph Subotnik, Associate Professor of Chemistry at University of Pennsylvania.

When we think of energy and technology—whether it’s playing solitaire on the computer or harvesting energy through solar panels—we seldom consider what makes things truly work on the subatomic scale.

Joseph Subotnik, Associate Professor of Chemistry at University of Pennsylvania, studies exactly these questions: how atoms move and interact with each other to develop energy processes.

“What we’re interested in,” Subotnik explained, “are the fundamental limitations that we go up against when we’re trying to use solar energy and also at the same time what are the fundamental processes that underlie the greenhouse effect. All of these things can be tied to the second law of thermodynamics.”

As host of Telluride Science Research Center’s Town Talk this week, Subotnik will discuss solar energy and the greenhouse effect at 6:00 p.m. on Tuesday, July 21. Admission is free; cash bar starts at 5:30 p.m.

When using solar energy, there are inherent limitations, the principal one being the second law of thermodynamics, which basically means it’s impossible to use 100 percent of the energy harvested from the sun. There will always be some energy lost in converting solar power to electricity.

“Any energy transfer involves electrons, which are the outer part of an atom. When a photon, or light, hits an atom, it gives it energy, exciting the electron. This process causes the electrons to shoot off. To gather the energy, these excited electrons must be collected. That is fundamentally how solar energy is gathered.

“If you take photons from sunlight and all the ways you can move them and then you excite molecules and electrons to such a degree, the energy can be lost unless you know exactly how to direct it and how to move your electrons precisely in every which way,” Subotnik added.

Because these electrons travel at very high speeds, they lose energy as they hit different objects along their journey. This means that ultimately much less energy will be collected.

“The greenhouse effect can be thought of in the exact same way,” Subotnik said. “Except with solar energy, you don’t want to lose any energy, and for the greenhouse effect, you want to lose all of it.”

Subotnik is studying exactly how these electrons travel, become energized, and lose energy to better understand what goes on in a solar panel and how the earth is warming up from the atmosphere and sun.

“There will always be a limitation with what you can achieve here because of the second law of thermodynamics. So no matter what you try, you’re always at a loss,” concluded Subotnik.

 

 

 

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