Solar power might be better for the environment than other forms of energy, but its use is stymied by issues such as device installation costs and the fact that it relies on sunlight.

However, a team of researchers from Stanford University have proposed a solution to the latter problem. According to a study published this week in the Applied Physics Letters journal, they designed a solar power device that can “extend power generation into the night.”

Typically, photovoltaic (PV) cells – nonmechanical devices that convert sunlight directly into electricity – are used to generate solar power. Some PV cells can also convert artificial light into electricity.

“Standard photovoltaic (PV) cells can provide a renewable off-grid source of electricity but only produce power from daytime solar irradiance and do not produce power at night,” said the Stanford researchers.

A recent Forbes Advisor article listed this as one of the “cons” consumers should consider before using solar energy to power their homes.

“If your home doesn’t receive adequate sunlight, either because of the climate or shade, the solar panels may not be a viable option,” the outlet said.

When the sun is shining, PV cells function as a “heat engine” using it as a heat source, according to the study. At the same time, it uses the “the ambient surroundings of Earth as the cold sink, converting solar radiation illuminated on the PV cell into electrical power.”

While this is going on, there is an “outgoing radiative heat flow from Earth to outer-space,” that occurs during the day and at night.

“Harvesting such outgoing heat flow is, therefore, of interest for nighttime power generation,” said the study. However, this would not be possible using the silicon cells usually used for solar cells.

That’s where a thermoelectric generator (TEG) module enters the picture. This device “generates power from the temperature difference between the radiative cooler and the ambient,” or the radiative cooling of a solar device during the night.

“A PV cell with a TEG module should provide all-day power generation,” researchers said.

One of the aims of the study was to find an energy source that could be used by the large numbers of people around the world who do not have access to the power grid. According to the International Energy Agency, 770 million people live without access to electricity, mostly in Africa and Asia.

The agency said that power generation from solar PV in 2020 grew by 23% growth from 2019 to 2020.

“Solar power is more affordable, accessible, and prevalent in the United States than ever before,” and California is currently the largest distributed PV market in the nation, according to the U.S. Office of Energy Efficiency and Renewable Energy.