New solar panel technologies are poised to drive down the cost of solar power even more. Recently, we reported on new technology that makes solar panels out of perovskite modules. In fact, Varun Sivaram, Samuel Stranks, and Henry Snaith have written an article for Scientific American about the wonders of perovskite solar cells, which have achieved stunning results in the laboratory. Sivaram says, “[M]any of us believe this is the field’s biggest breakthrough since the original invention of the solar cell sixty years ago.”
Perovskite Panels Have Faster Payback
One principal advantage perovskite solar panels have over conventional solar technology is that they can be engineered to react to many different wavelengths of light. That lets them convert more of the sunlight that strikes them into electricity.
Now a study by scientists at Northwestern University and the US Department of Energy’s Argonne National Laboratory finds the perovskite based panels pay for themselves much faster than traditional solar panels do, according to a Northwestern University press release.
Employing a cradle-to-grave lifecycle assessment, scientists traced the production costs of both types of solar panels from the mining of raw materials until the end of their useful life. They determined the ecological impacts of making a solar panel and calculated how long it would take to recover the energy invested.
Even though perovskite panels are less efficient that silicon-based panels, they still may be less expensive in the long run. “People see 11 percent efficiency and assume it’s a better product than something that’s 9 percent efficient,” said Fengqi You, corresponding author on the paper and assistant professor of chemical and biological engineering at Northwestern. “But that’s not necessarily true.”
A more comprehensive way to compare solar technology is the energy payback time (or energy return on investment, EROI), which also considers the energy that went into creating the product. Perovskites lag behind silicon in conversion efficiency, but they require much less energy to be made into a solar module. So perovskite modules pull ahead with a substantially shorter energy payback time — the shortest, in fact, among existing options for solar power.
One of the motivations for this study was the need to improve technology so that solar energy can be scaled up in a big way. “Soon, we’re going to need to produce an extremely high number of solar panels,” one of the authors of the study says. “We don’t have time for trial-and-error in finding the ideal design. We need a more rigorous approach, a method that systematically considers all variables.”
“Appreciating energy payback times is important if we want to move perovskites from the world of scientific curiosity to the world of relevant commercial technology,” says Seth Darling, an Argonne scientist and co-author on the paper.
Global energy demand is expected to nearly double by 2050, and Darling says there is no question that solar power must contribute a significant fraction. The real question, he says, is, “How quickly do we have to get a technology to market to save the planet? And how can we make that happen?”