Solar Airplanes: A Flight of Fancy

This article was originally posted on RealClearScience. It was also co-authored with Tom Hartsfield, a Ph.D. candidate in physics at the University of Texas.

Solar Impulse 2, a solar powered airplane that has enough room for exactly one person (the pilot), has made international headlines as it makes its historic trek around the planet. Media outlets from BBC News to Live Science have described the flight as a “revolution.”

Quirky, it is; a revolution, it is not. Continue reading

Dust Devil Power: The Energy of Swirling Wind

This article was originally posted on RealClearScience.

Desert dwellers are familiar with “dust devils,” tornado-like phenomena that range in size from cute to¬†terrifying. When the sun beats down on dry earth, the ground becomes hot. The surface air warms and rises, leaving behind an area of low pressure that draws in more air. Eventually, a circulating vortex of upwelling hot air forms, and the dust devil is born. Because they are fleeting and haphazard, they cannot be harnessed for energy. Instead, scientists have proposed creating their own dust devils. Continue reading

Will Quantum Dots Revolutionize Solar Cells?

This article was originally posted on RealClearScience.

The sun will hopefully be the energy source of the future, but currently, solar power provides less than 1%of global energy. The reason isn’t due to a conspiracy among fossil fuel companies, as some media outlets apparently believe, but because of multiple inherent problems with solar technology. In a nutshell, there is a tradeoff between efficiency and cost.

For example, the current world-record for efficiency (i.e., the ability to convert light into electricity) is 44.7%, held by a multi-junction solar cell used in concentrated photovoltaics. However, for various reasons, such systems are still expensive. Cheaper solar cells, such as the ones you can mount on your roof, are more reasonably priced but have efficiences only around 10 to 20%. Thus, the “holy grail” is to design a solar cell with high efficiency and low cost. Continue reading