It produces energy with raindrops

An innovation in renewable energy harvesting sounds too good to be true, but it is—a solar panel that can also operate in the rain. The system is capable of producing electricity even in less than 100% sunlight to the point that it still captures energy from falling raindrops. The new technology bypasses the limitation of conventional solar power generation in that it maintains a consistent supply under different weather conditions, and the potential is generating excitement in the energy industry.

New technology solves the biggest challenge of solar generation

Although practical application is still some way off, scientists from the Soochow University in China, which developed and demonstrated the new tech, are feeling positive about the future. Their groundbreaking device is intended to prevent power output from dropping when it’s not sunny, and although there’s still a lot of work to do in terms of development, efficiency, and scalability, the research team believes the envisioned end result is worth striving for.

The new solar panel technology comes at a time when the global shift towards renewable energy sources is at an all-time high. Now that the costs of solar power systems have dropped 90% in the last 10 years, they’ve become the cheapest form of electricity in many parts of the world.

However, solar electricity generation has one major weakness, and that’s its inability to supply power under any conditions other than sunlight. This means that output plummets when the sun sets or under cloud cover. If this problem can be overcome, the electricity supply will increase dramatically.

This is not the only technology being worked on at the Soochow University. Chinese scientists believe they’ve made a breakthrough with tengs that will enable panels to operate at night.

Groundbreaking solar device harnesses friction energy from raindrops

A demonstration of the new technology was conducted in a laboratory at the Soochow University in Suzhou in China’s Jiangsu Province. The device is constructed by placing two transparent polymer layers on a solar photovoltaic (PV) cell. When raindrops land on the layers and roll off, the friction generates a static electricity charge. Baoquan Sun from Soochow University explained in the journal ACS Nano:

“Our device can always generate electricity in any daytime weather. In addition, this device even provides electricity at night if there is rain.”

Projects in other parts of the world have seen similar devices being added to solar panels called triboelectric nanogenerators (tengs), but the Chinese tech is simpler and more efficient due to one of the polymer layers acting as the electrode for the solar cell and the teng. Sun continued:

“Due to our unique device design, it becomes a lightweight device. In future, we are exploring integrating these into mobile and flexible devices, such as electronic clothes. However, the output power efficiency needs to be further improved before practical application.”

Does the friction-solar device have what it takes to make it into mainstream tech?

Sun says the technology is developing rapidly and he expects a prototype to be produced in three to five years. Other Chinese scientists have also employed tengs on solar cells to gather wind power, an approach Sun believes could be applied to his device as well. Varun Sivaram, a member of the Council on Foreign Relations in the U.S. and the author of a new book on solar power, appreciates the Chinese team’s engineering efforts:

“The idea is interesting – a hybrid device that harvests kinetic energy from water without destroying the output of the solar cell during sunny times. There’s lots of nice engineering, like using one layer to do double duty as a component of the Teng as well as trap light for the solar cell.”

However, while the potential applications of the new device are promising, Sivaram says the power generated from the friction of falling raindrops will have to be significantly higher to make any kind of valuable input to the power generated by the panel:

“It’s really not clear whether this is a big deal or not – I suspect it’s not.”

Other recent innovations in solar panel design have seen femtosecond lasers making their mark in the material science sphere with solar technology that enables glass to be turned into a semiconductor.