Researchers at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia have learned how to produce electricity from Earth’s excess heat through quantum tunneling. Quantum tunneling is a phenomenon in which particles are able to tunnel through a barrier that, under the rules of classical mechanics, they are usually unable to pass through. First predicted in the early 20th century and generally accepted by mid-century, quantum tunneling plays an important applied role in devices such as the tunnel diode, quantum computing, and the scanning tunneling microscope. Using quantum tunneling to harvest electricity from Earth’s radiant heat involves a specifically designed antenna that can identify this excess heat as high-frequency electromagnetic waves, and then transform the signals into a direct electrical charge.
The heat produced by sunlight hitting the Earth results in a constant flow of infrared radiation that, if untapped, is essentially free energy gone to waste. It is estimated that the global output of infrared radiation may be as much as millions of gigawatts per second. Since the infrared wavelengths are so short, scientists at KAUST needed to design micro-antennas suited to catch this heat. “There is no commercial diode in the world that can operate at such high frequency,” said lead researcher Atif Shamim. “That’s why we turned to quantum tunneling.”
Via a tunneling device known as a metal-insulator-metal (MIM) diode, electrons are able to pass through a small barrier, despite lacking the energy classically required to do so. As the electrons pass through this barrier, they are converted into an electrical direct current. The technology could be applied to solar panels, which currently only harvest a small percentage of the potential heat and light energy available for electrical power. While there is work to be done, the potential for how we gather and use energy is huge. “This is just the beginning – a proof of concept,” said Shamim. “We could have millions of such devices connected to boost overall electricity generation,”