What works for hay — you can’t make it if the sun doesn’t shine — also works for solar power.

Now, researchers may be close to overcoming the major shortcoming of solar panels — their inability to generate power at night — by tapping into the planet’s infrared light.

The panels work by absorbing the sun’s heat with photovoltaic cells to generate energy. Once the sun sets, “anti-solar panels” can be pointed toward the ground to capture the Earth’s invisible infrared light, researchers at the University of California, Davis, said in the journal ACS Photonics. This could reduce the need for batteries and natural gas generating plants during the nighttime hours.

“You have heat energy coming from the sun toward the Earth, and that normal solar cell picks off that energy as it’s transmitted from the sun to the Earth,” Jeremy Munday, an author of the paper and a professor in the Department of Electrical and Computer Engineering at UC Davis, told Inverse. “Basically you need these two different temperature bodies and some way of converting that power.” 

The paper states that an “anti-solar panel” could generate about 25% of the electricity during the night that a solar panel produces in the daytime. Researchers at Stanford are also working on solar that would work at night. 

Technological gains such as “anti-solar panels” and higher-capacity batteries will be needed if greenhouse gas emissions are to be curbed, reducing the worst-possible consequences of global warming. Renewables are responsible for a growing share of the world’s electricity generation but need to be adopted at a faster rate to check rising temperatures. Researchers are pushing to develop a high-capacity battery capable of long-term power storage at an affordable cost. 

An improved battery would give the solar and wind sectors a boost, by allowing power to continue flowing when the sun sets and the wind dies down. Not all promising energy technologies have proven profitable. Angel investor Tom Blum says he doesn’t know many people who have made money on backing battery technology and tells those considering them to “run away,” according to Business Insider.

The UC Davis team is working on developing prototypes to see how well they can make this concept work. Solar panels usually are made of silicon, which is good at capturing light that’s in the visible spectrum, while this device would be made of a substance such as mercury alloys that can capture long-wavelength light.

A solar system that can deliver clean energy 24 hours a day could be a gamechanger, keeping electricity flowing while slashing greenhouse emissions.

  • Researchers at Australia’s Curtin University are developing a thermal battery that would be a key component to a solar power system that could produce electricity at night.
  • The American solar sector is attracting investment from unlikely sources. Capital Dynamics, a Zug-Switzerland-based asset manager has seen its solar portfolio surge over the last decade, and now owns seven of the 20 largest U.S. solar projects.