Swedish researchers have developed a new breed of molecule which could make storing solar energy all the more efficient.
Researchers at the Chalmers University of Technology in Gothenburg have developed a new compound which they hope can help solve the many issues with storing renewable energy.
The molecule, which is a compound of nitrogen, carbon and hydrogen, is designed to be used as part of the team’s Molecular Solar Thermal Energy Storage (MOST) system. When placed in sunlight in its liquid form, the bonds between its atoms change, turning it into an energy-rich isomer capable of storing solar energy.
How The System Works
In the researcher’s prototype system, the Sun’s energy is trapped using a satellite dish-like device which follows the motion of the sun and condenses its sunlight into a single point containing the isomer. The isomers are then stored at room temperature to better maintain the energy potential of the molecule and minimise energy loss.
To release the energy, the isomer is then filtered through a special catalyst that can control the release of the pent up energy. The reaction which takes place within the catalyst heats up the isomer by 63 degrees celsius, releasing the energy and simultaneously returning the molecule to its original state to be reused.
This means solar energy caught on one day can be preserved and later used during periods where generating traditional solar power is not feasible - such as at night or on overcast days.
The team behind the project believe their invention could be used in domestic heating systems, which could pass the molecules from roof to heating system in a circular process. What's more, the reaction that takes place within the MOST does not damage the molecule, allowing them to be reused indefinitely for emissions-free heating.
The Chalmers team is not the only group eying a molecular solution to energy storage, with MIT developing a similar system. However, according to research team leader, Kasper Moth-Poulsen, the MOST system is already operating better than expected:
“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.”
It is hoped the MOST system can overcome the renewable energy storing issues which have long dogged the concept. The main problem with renewable power source is that they are often intermittent, meaning they are poorly placed to respond to the fluctuating power demands of users. Whereas fossil fuel power stations can simply burn more or less fuel to generate electricity, renewable power stations either fail to meet demand, or in some cases, have to wastefully use up electricity to avoid overloading the grid.
Solar energy is often stored in large lithium-based batteries, but these are impractical for domestic use due to their size and expense. Furthermore, they begin to lose charge as soon as they are disconnected from the solar panels, potentially losing all their charge in a matter of weeks. This mean they are poor choices for preserving energy between seasons which may feature extremely different levels of energy production and need.
Moth-Poulsen and his team aren’t quite ready to claim victory in this battle just yet. Firstly, they need to further develop the concept into a coherent whole, as well as increase the heat output of the molecule. The team aims to eventually boost output to 110 degrees celsius before making a commercial release - which it hopes to achieve in the next decade.