Liquid storage of solar energy

Researchers at Chalmers University of Technology in Sweden have demonstrated efficient solar energy storage in a chemical liquid. The stored energy can be transported and then released as heat whenever needed according to a report on Science Daily. The research has been published in scientific journal Energy & Environmental Science.

The team has shown it is possible to convert solar energy directly into stored energy in the bonds of a chemical fluid — or molecular solar thermal system.

According to the research leader, Professor Kasper Moth-Poulsen, "The technique means that that we can store the solar energy in chemical bonds and release the energy as heat whenever we need it. Combining the chemical energy storage with water heating solar panels enables a conversion of more than 80% of the incoming sunlight."

The project commenced more than six years ago, with a successful conceptual demonstration eventuating in 2013. At the time, the solar energy conversion efficiency was 0.01% and the expensive element ruthenium played a major role in the compound. Now, four years later, the system stores 1.1% of the incoming sunlight as latent chemical energy — an improvement of a factor of 100. Ruthenium has been replaced by much cheaper carbon-based elements.

"We saw an opportunity to develop molecules that make the process much more efficient.

"At the same time, we are demonstrating a robust system that can sustain more than 140 energy storage and release cycles with negligible degradation," said Moth-Poulsen.