Hybrid solar panels gather energy from sun and rain

Researchers in China have developed solar panels with an integrated electrode that can also harvest energy from the power of falling rain.

Researchers at China’s Soochow University developed an electrode that harvests energy from rain falling on solar panels. A number of innovators focus their work on ways to make solar panels smarter by making them multi-use. Another team of researchers in China used graphene to produce hundreds of solar cell microvolts from simulated rainwater. Because rain contains salts as well as water, when used on a solar cell, graphene attracts the positive ions in the salts. That results in two completely separate layers of ions – one positive and one negative. Energy generated by the impact of the rain can then be stored between the two layers of ions. Scientists found the solar-to-electric conversion efficiency of rainwater on a graphene-covered solar cell to be up to 6.53 percent. That is enough to generate hundreds of microvolts of electricity.

A United States’ startup designed solar panels that absorb water from the air and cleans it, producing renewable drinking water. Specifically for use in arid regions, the water is available from a faucet on the back of each panel. The panels clean air-borne moisture with a special material and the solar electricity. The potable water then gets pumped to the faucet. One solar panel produces enough water to support a family of four.

The Soochow University team’s device generates electricity even at night, as long as it is raining. It does this via a triboelectric nanogenerator (TENG). TENGs convert mechanical energy into electricity. Researchers say they are three to five years away from a prototype. However, if widely adopted, the hybrid panels would greatly increase the consistency of solar panel output. This, in turn, would further reduce the cost of solar power and the structures themselves. The Soochow University’s development focuses on increasing the efficiency of the output power. How might new materials and integrations increase the numbers of hybrid sustainable power options?