Yahoo News Generating energy from shadows
It's called the shadow-effect generator.
Scientists at the National University of Singapore have developed a new technology that harnesses energy from shadows and converts it into electricity.
The team's lead, Dr. Swee Ching Tan says, "So as we all know, solar panels need to be based in open areas, they cannot be based in places where light has been obstructed or where shadows are being cast. So our shadow-effect generator comes in handy. It can be based in those areas to harvest obstructed light, for example."
The device is similar to a silicon solar panel cell.
But instead of extracting energy from light, the technology relies on voltage differences between illuminated and obstructed parts of the object to generate energy.
(SOUNDBITE) (English) ASSISTANT PROFESSOR OF MATERIALS SCIENCE AND ENGINEERING AT NATIONAL UNIVERSITY OF SINGAPORE, DR. TAN SWEE CHING, SAYING:
“The voltage difference between the illuminated part and the shadow region create a voltage difference, and therefore driving the electrons from the bright side to the dark side, and therefore creating electricity.”
The device is small, currently confined to a size of 6 square centimeters.
It can produce around 0.25 volts.
So around 20 of the panels could produce 5 volts, enough to power a light bulb or charge a mobile phone.
But the team already envisions other uses.
(SOUNDBITE) (English) ASSISTANT PROFESSOR OF MATERIALS SCIENCE AND ENGINEERING AT NATIONAL UNIVERSITY OF SINGAPORE, DR. TAN SWEE CHING, SAYING:
“So our shadow energy-effect generator can also be used as a motion detector. So as the car passes over the first piece, the blue LED light will light up and if the car passes over the second piece, the green LED light will light up.”
In order to work, the device needs to be partially covered in shadow.
(SOUNDBITE) (English) ASSISTANT PROFESSOR OF MATERIALS SCIENCE AND ENGINEERING AT NATIONAL UNIVERSITY OF SINGAPORE, DR. TAN SWEE CHING, SAYING:
“Like cities where we have lots of buildings, so shadows will be everywhere, so therefore, it’s not practical to place solar cells in such cities. So the device might come in handy in places like very densely populated cities where skyscrapers are everywhere, where shadows are always persistent.”
Dr. Tan says he and his team are still perfecting the device. Future plans include founding a company to make the shadow-effect energy available for home use.
