Introduction
Solar panels are usually associated with rooftops, deserts and open fields. But researchers in China are testing a very different idea: generating solar electricity underwater.
Researchers from Yunnan University have demonstrated a perovskite-based solar system operating at a depth of around 10 metres (33 feet) in the South China Sea. The work was published in Joule.
Why Put Solar Panels Underwater?
Sunlight becomes weaker as it travels through water, particularly because water absorbs much of the red and infrared part of sunlight. This makes conventional silicon solar cells less suitable for underwater applications.
The Chinese researchers addressed this by using wide-bandgap perovskite solar cells, designed to make better use of the wavelengths of light that can penetrate water. In laboratory testing under simulated 10-metre underwater conditions, the cells achieved a power-conversion efficiency of 34.71%.
How Much Energy Can They Produce?
The researchers tested larger modules in real seawater conditions. At 10 metres depth, the system generated around 324 mWh in two hours.
While this is nowhere near the output of a conventional utility-scale solar farm, the objective is different. The technology could provide a continuous local power source for underwater sensors, cameras, communications equipment and marine monitoring systems.
The Perovskite Advantage
Perovskites are emerging photovoltaic materials that can be engineered to absorb particular portions of the solar spectrum. This makes them interesting for environments where conventional solar technologies struggle.
The researchers also estimated a T80 lifetime of about 5.49 years under simulated 10-metre underwater illumination—meaning the cells could retain 80% of their initial performance for that period under those conditions.
What Are the Challenges?
Commercial deployment is still some distance away. Underwater solar systems must deal with saltwater corrosion, pressure, water ingress, biofouling and reduced sunlight. Marine organisms growing on the panels could gradually block light and reduce performance.
Why It Matters
The significance of the technology may not be about replacing land-based solar. Instead, it could create a new category of autonomous underwater energy systems.
If future versions become cheaper, more durable and scalable, underwater solar could reduce the need for frequent battery replacement or cables in remote marine infrastructure—helping power the growing network of sensors and equipment needed to monitor our oceans.
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