Researchers from Sweden’s Chalmers University of Technology designed an energy system that stores solar energy in liquid form for up to 18 years, a press statement reveals.

With the help of scientists from China’s Shanghai Jiao Tong University, the Chalmers team has tested its device, called the Molecular Solar Thermal system (MOST), by connecting it to a thermoelectric generator, proving that it can produce electricity on-demand.

The Chalmers team has been working on its technology for more than a decade, and it believes it may soon be a viable option for charging low-power electronics devices.

The system was designed using specially-developed molecules of carbon, hydrogen, and nitrogen. When these are hit by sunlight, the atoms within the molecules are rearranged, turning them into an energy-rich isomer that’s stored in liquid form. Impressively, the researchers say their system stores energy in this liquid form for up to 18 years. It is then released using a special catalyst that returns the molecules to their original shape, releasing the stored energy as heat.

A closed system that produces no carbon emissions

The Chalmers researchers collaborated with scientists from China’s Shanghai Jiao Tong University, who brought a thermoelectric generator to the table. This allowed them to produce a small amount of electricity, though the collaborators believe this could be improved by future models.

“The generator is an ultra-thin chip that could be integrated into electronics such as headphones, smart watches, and telephones,” said researcher Zhihang Wang from the Chalmers University of Technology. “So far, we have only generated small amounts of electricity, but the new results show that the concept really works. It looks very promising.”

According to research leader Kasper Moth-Poulsen, Professor at the Department of Chemistry and Chemical Engineering at Chalmers, the MOST system “means that we can use solar energy to produce electricity regardless of weather, time of day, season, or geographical location. It is a closed system that can operate without causing carbon dioxide emissions.”

The proof of concept’s current output stands at a relatively small 0.1 nW, though the researchers say their system could be used to address the issue of solar energy being intermittent by storing energy for months on end and deploying it just when it’s needed. A finished model could be used to power small electronic devices. Next, the Chalmers team aims to improve their system’s performance and also are also working on building an affordable commercial version of their system that could potentially be used in homes.