Energy from shadows

By Eliabel Legrand



Introduction


Your best friend that follows you around when the sun comes out - your shadow- it doesn’t serve an important function unlike your heart or brain, but what if you could use shadows to create electricity?


When using renewable power sources that are powered by light such as solar panels, shadows can be a nuisance as it means electricity isn’t being created. However, researchers from the National University of Singapore have engineered a way to create power from the omnipresent shadows.



Dr. Swee Ching Tan uses a remote controlled vehicle to test the shadow effect generator device at a lab in the National University of Singapore (Credit: Reuters)


Explanation


A team from the NUS Department of Materials Science and Engineering and NUS Department of Physics created a device that can harvest energy from shadows. “We can harvest energy anywhere on Earth, not just open spaces,” says Swee Ching Tan, a materials scientist at the National University of Singapore.


The cell is created by placing a thin coating of gold onto silicon.Like in a normal solar cell when exposed to light, the silicons electrons become energized and the energized electrons then jump from the silicon to the gold. The voltage of the part of the device that is exposed to the light increases relative to the shaded part and the electrons in the device flow from high to low voltage. They are sent through an external circuit creating a current that can be used to power another gadget. The greater the contrast between light and dark, more energy is provided by the device.


Next Steps


The team is working on boosting the performance of the device, borrowing strategies from solar cells to gather light. Increasing the amount of light the devices can absorb allows them to better harness shadows, as well as developing shadow energy harvesting panels that can efficiently harvest from indoor lighting.


The team is also investigating the use of other materials other than gold to decrease the price of the device, meaning they would be more cost effective and easier to implement in society. Another pathway they are looking at is making the device wearable or attachable to clothing to exploit energy during normal everyday activities.


Conclusion


Shadows are omnipresent and perhaps one day in the future we will be able to harvest energy from them by placing the shadow-effect energy generators around the world in places that have been deemed unfit for solar panels to work, or indoors. “A lot of people think that shadows are useless,” Tan says, but “anything can be useful, even shadows.”


References


  1. “Novel Device Harnesses Shadows to Generate Electricity.” ScienceDaily, 21 May 2020, www.sciencedaily.com/releases/2020/05/200521102108.htm. Accessed 7 June 2020.

  2. Wilke, Carolyn. “A New Device Can Produce Electricity Using Shadows.” Science News, 3 June 2020, sciencenews.org/article/new-device-can-produce-electricity-using-shadows. Accessed 1 June 2020.


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The Scientific Teen 2020.