Stanford researchers develop nighttime solar panels Powered by radiative cooling
World’s first solar panel that works at night. In a groundbreaking development, researchers at Stanford University have unveiled a technology that allows solar panels to generate electricity at night by harnessing the phenomenon of radiative cooling. This innovative approach could revolutionize sustainable energy, particularly for off-grid applications, although it remains in its early stages of development.
Radiative cooling occurs naturally on clear nights when heat escapes from the Earth’s surface, allowing infrared energy to radiate into space. The temperature difference between an object and the surrounding air can be utilized to produce electricity. By attaching thermoelectric generators to commercial solar panels, Stanford researchers have enabled the panels to collect dissipating heat, generating small amounts of power. While the energy output is modest—about 50 milliwatts per square meter during the night—this is enough to power low-energy devices such as LEDs and environmental sensors.
Shanhui Fan, the lead researcher, emphasized that although the energy generation is much lower than the 200 watts per square meter that typical solar panels generate during the day, the technology shows great potential for improvement. As the design and efficiency of these panels evolve, they could complement traditional solar energy, offering a reliable source of power during nighttime hours.
A Game-Changer for Off-Grid Communities
This breakthrough could be a game-changer for the 770 million people around the world who live without access to electricity. Nighttime solar panels could provide essential lighting and power, especially in remote regions, without the need for expensive and polluting batteries. The technology can also be retrofitted into existing solar cells, offering an affordable way to enhance the reliability of renewable energy in underserved areas.
In addition to providing electricity, this innovation reduces the environmental impact associated with battery production and disposal, which involves mineral extraction and contributes to ecological waste. By powering low-energy devices like environmental sensors and IoT devices, this technology could reduce reliance on batteries, further advancing sustainability goals.
Expanding Applications and Overcoming Challenges
The concept of radiative cooling is not limited to electricity generation. It has broader applications, such as zero-energy cooling systems developed by companies like SkyCool Systems and potable water extraction in drought-prone areas by researchers at ETH Zurich. These diverse uses highlight the potential of radiative cooling to advance sustainability across multiple sectors.
Nighttime solar panels also offer promise in regions with fluctuating cloud cover or limited sunlight, where traditional solar power has been less viable. This could lead to greater adoption of solar energy in areas previously unsuitable for conventional systems, broadening the impact of renewable energy.
However, experts like Geoff Smith, emeritus professor of applied physics, caution that practical challenges remain. These include improving thermoelectric materials, reducing costs, and overcoming the complexity of integrating the technology into existing energy grids and storage systems. Addressing these hurdles will be key to scaling up the technology and making it widely accessible.
Despite these challenges, the potential of nighttime solar panels is vast. As research continues and innovations emerge, this technology could play a pivotal role in solving global energy challenges, making renewable energy more reliable and accessible for communities around the world.
