In groundbreaking research, solar panels have been created that generate electricity when there is no sun… at night! The solar cells were developed by researchers at Stanford university and work by generating electricity from the temperature difference between the cells and the air around them.
The possibilities for this technology are boundless, and bring hope to the 770 million people without access to electricity. It is also promising in the wake of global supply issues of electricity, due to the conflict in Ukraine.
Solar energy has come a long way since photovoltaic cells were created in 1954. Since that time solar energy has become more affordable, allowing households to generate their own electricity. Currently, solar electricity generated during the day can only be used at nighttime by using batteries. However, batteries are expensive and current batteries have a limited lifespan and will end up in landfill. Researchers have been working for years to discover a way to utilise solar cells at night, and now they are one step closer.
So how exactly do the new solar panels work?
The device uses a thermoelectric generator, which harvests electricity from the temperature difference between the cells and the air. It does this through a process called thermal radiation, which occurs at night when heat leaves objects and radiates toward outer space. This causes objects to cool down, which then become cooler than the ambient air. The researchers at Stanford published a paper that explained how they used the thermoelectric generator to turn those temperature differences into electricity.
Presently, the solar cells that the researchers developed can generate 50 milliwatts per square meter. It would take about 20 square meters of solars cells to power conventional lights. However, the technology is new and still in development, and the solar device was built using store-bought parts. Once the technology improves, it is expected the output will rapidly improve too.