To advance global solar adoption and overcome the challenges of intermittent energy production, researchers have introduced a hybrid device. This innovative system merges two cutting-edge technologies—molecular solar thermal energy storage and traditional silicon-based photovoltaic cells.
Photovoltaic solar energy plays a crucial role in renewable energy production, converting sunlight directly into electricity. However, its effectiveness is hampered by the fluctuating nature of sunlight and varying energy demands. “Photovoltaic solar energy still presents challenges due to intermittent solar production and fluctuating energy demand,” the researchers emphasized.
One of the biggest hurdles has been the gap between when energy is generated and when it is needed. To ensure a continuous power supply, highly efficient energy storage systems are vital. However current solutions often fall short.
“These technologies do not perform optimally, mainly due to the heating they experience, which affects energy production and the durability of photovoltaic systems,” explained ICREA professor Kasper Moth-Poulsen from the Barcelona East School of Engineering (EEBE), who led the research team.
Moreover, existing storage technologies, like batteries, rely on unsustainable materials, further complicating their long-term use.
To address these issues, the team developed the first-ever hybrid solar device combining silicon-based photovoltaic cells with a groundbreaking molecular solar thermal energy storage system (MOST). The MOST technology uses organic molecules that change structure when absorbing high-energy photons, such as ultraviolet light. This unique feature enables the system to capture solar energy and store it for future use.
What sets the MOST system apart is its ability to provide cooling for the photovoltaic cells. “These molecules also act as an optical filter, blocking photons that would otherwise cause heating and reduce system efficiency,” the team noted. This cooling effect not only enhances the efficiency of the solar cells but also contributes to the sustainability of the system.
Unlike traditional storage methods, the MOST system is built from abundant materials like carbon, hydrogen, oxygen, and nitrogen. “Unlike other technologies that rely on scarce materials, the MOST system uses common elements,” the team mentioned in a press release, highlighting the system’s environmentally friendly design.
In practical tests, this hybrid device achieved remarkable results, setting a new record for energy storage efficiency. The device demonstrated an efficiency rate of 2.3% specifically for storing molecular thermal solar energy.
Additionally, the system’s cooling capability reduces the temperature of photovoltaic cells by up to 8°C, minimizing heat-related energy losses and boosting the cells’ overall efficiency by 12.6%.
“The combined device operates with a solar utilization efficiency of up to 14.9%, which represents an improvement over the two hybrid solar systems operating independently,” emphasized the research team.
By seamlessly integrating photovoltaic energy with molecular thermal storage, this device offers enhanced performance and reliability, while also addressing the environmental impacts of traditional energy storage methods. Batteries, often used for energy storage, depend on rare and harmful materials, but this hybrid solution moves away from such reliance, reducing the carbon footprint and enhancing sustainability.