The earth’s energy crisis has long been a topic among scientists, climatologists, and researchers worldwide. While advancements in solar technology have offered a hopeful alternative to fossil fuels, the problem of long-term storage remains. This problem may soon find a solution thanks to the recent development of a unique fluid: solar thermal fuel.
Ground-Breaking Research
Researchers in Sweden developed a unique molecule in 2018 that changes the way it behaves when exposed to sunlight. This simple composition of carbon, hydrogen, and nitrogen changes when exposed to the sun. The molecule becomes an isomer – the same molecules with a different structure. Full of energy, this liquid is then capable of heating.
Kasper Moth-Poulsen, the leader of the research team, explains the exciting benefits to the Chalmers news team. “The energy in this isomer can now be stored for up to 18 years. And when we come to extract the energy and use it, we get a warmth increase which is greater than we dared hope for.” (1) This solar thermal fuel could be a game-changer for the earth’s atmosphere. Unlike natural gas, coal or oil, this liquid’s energy does not release carbon dioxide or greenhouse gases into the environment. Reusable and environmentally friendly, the potential uses of solar thermal fuel are limitless. (2)
The Catalytic Cycle That Builds Up Heat
The research group at Chalmers created a prototype system to test the applications of this ground-breaking molecule. Housed on the university’s rooftop, a solar thermal collector, catalyst, pump and a series of tubes propel the transformation. As the fluid flows and collects ultraviolet light from the sun through transparent ducts, its molecular structure changes.
The molecular compound, known as norbornadiene, rearranges itself into the energetic isomer, quadricyclane. The unique bonds of quadricyclane allow for energy to stay trapped between the atoms, retaining solar power even when the isomer cools down. The liquid then passes over a cobalt-based catalyst where the solar energy is captured. As the quadricyclane converts back to norbornadiene, released heat raises the liquid’s temperature by 113 degrees F. This means that when it pumps through the filter, not only does it provide enough heat to warm a house or power a water heater, it also returns to its original form to repeat the process. (2)
Modern Applications
This circular process of extracting solar energy is far from perfect, but the implications are meaningful. From domestic needs—like heating your home or washing and drying clothes—to larger industrial applications, thermal solar energy could significantly impact society for good. Moth-Poulsen’s team has been able to run the solar fuel through 125 cycles without any significant degradation. Ideally, this process could repeat for years without ever needing to replace the fuel. (2)
Years of development are still ahead for Moth-Poulsen and his team. He and the researchers at Chalmers have already worked diligently to create multiple versions of the fuel, but other iterations are forthcoming. Testing for long shelf life, high density, and the best recyclability will allow them to create the best version available. To make this fuel work as efficiently as possible, Moth-Poulsen is also working on adapting it to respond to a broader spectrum of the sun’s wavelengths.
He and his team of researchers are hopeful that this technology could be available commercially in as little as 10 years. Considering our current climate crisis and the need for renewable energy, this timeline is a hopeful one.
“There is a lot left to do,” Kasper commented to Chalmers. “We have just got the system to work. Now we need to ensure everything is optimally designed.” (1)
