Intense summer sun can spike temperatures of solar panels, causing their electrical production to plummet.
Like humans, solar panels don’t work well when overheated. Now, researchers have found a way to make them “sweat”—allowing them to cool themselves and increase their power output.
It’s “a simple, elegant, and effective [way] to retrofit existing solar cell panels for an instant efficiency boost,” says Liangbing Hu, a materials scientist at the University of Maryland, College Park.
Today, more than 600 gigawatts of solar power capacity exists worldwide, providing 3% of global electricity demand. That capacity is expected to increase fivefold over the next decade. Most use silicon to convert sunlight to electricity. But typical silicon cells convert only 20% of the Sun’s energy that hits them into current. Much of the rest turns into heat, which can warm the panels by as much as 40°C. And with every degree of temperature above 25°C, the efficiency of the panel drops. In a field where engineers struggle for every 0.1% boost in power conversion efficiency, even a 1% gain would be an economic boon, says Jun Zhou, a materials scientist at Huazhong University of Science and Technology.
Decades ago, researchers showed that cooling solar panels with water can provide that benefit. Today, some companies even sell water-cooled systems. But those setups require abundant available water and storage tanks, pipes, and pumps. That’s of little use in arid regions and in developing countries with little infrastructure.