A team of researchers at Chalmers University of Technology in Sweden has designed an energy system that stores solar energy in liquid form for up to 18 years.

According to the Zap aeiou portal, the process relied on scientists from Shanghai Jiao Tong University in China to test its device, the so-called molecular solar thermal system (MOST), by connecting it to a thermoelectric generator and proving that it can produce electricity on human demand.

The system is designed using specially developed carbon, hydrogen, and nitrogen molecules. When these are hit by sunlight, the atoms within the molecules are repositioned, transforming into an energy-rich isomer that is stored in liquid form. Impressively, the researchers say that the 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 form, releasing the stored energy in the form of heat.

Collaboration with scientists at Shanghai Jiao Tong University in China brought a thermoelectric generator into the research, which produced a small amount of electricity, although the collaborators believe this could be improved by future models.

"The generator consists of an ultra-thin chip that could be integrated into electronic devices such as headphones, smart watches and phones," said researcher Zhihang Wang from Chalmers University of Technology. "So far, we have generated only 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 in the Department of Chemistry and Chemical Engineering at Chalmers University, 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."

According to Interesting Engineering, the current proof-of-concept output is a modest 0.1 nW, although the researchers say their system could be effectively used to address the issue of solar energy being intermittent, storing energy for months on end and deploying it precisely when it is needed.

A finished model could be used to power small electronic devices. Now, the Chalmers team wants to improve the performance of the system and is also working on building an affordable commercial version of their system that could potentially be used in homes.