Researchers at Columbia University, led by biophysicist Ozgur Sahin, have developed an “evaporation engine” that uses bacterial spores that expand in the presence of humidity and contract when the humidity is low.
While this technology was first described in a 2015 paper in Nature, the group recently made headlines again when they wrote a paper describing the potential for natural evaporation from U.S. lakes and reservoirs to generate 325 gigawatts of power! That represents nearly 70 percent of the electricity currently generated by the United States. Their analysis, published in Nature in Sept 2017, revealed that the energy potential available from evaporation is comparable to that of wind and solar power but unlike wind and solar is characterized as low-intermittency. According to the authors, these findings “motivate the improvement of materials and devices that convert energy from evaporation.”
This is the just kind of innovation that I believe needs to make its way into classrooms to inspire the next generation of scientists and engineers. This new technology also provides an opportunity to invite your students to evaluate the challenges that will need to be studied in order to use this technology on large bodies of water. For example, the authors cite that “using evaporation driven materials and devices on lakes or reservoirs could affect freshwater resources” but that this technology could reduce evaporative losses in regions characterized by water stress and scarcity. The authors conclude that “these materials and devices could potentially contribute toward solving energy and water related challenges.”
Below I have listed some classroom-ready resources should you want to introduce this technology to your students:
Renewable Energy from Evaporating Water (5 minute video with Ozgur Sahin)
Evaporation-powered devices in action (4 minute video)
A miniature car driven by evaporation (Under 1 minute video)
ScienceTake | The Spore Machine (1:36 minute video from the New York Times)
Engineering Evaporation (6 minute conversation between Ozgur Sahin and Ira Flatow on NPR’s Science Friday)
Evaporation could power most of the U.S. — study
Greenwire, September 26, 2017
Water evaporation could be a promising source of renewable energy
The Verge, September 26, 2017