‘Sun in a box’ system can beat Li-ion batteries over store renewable energy: Study

Scientists at MIT have devised a groundbreaking system capable of storing renewable energy, like solar and wind power, for subsequent release into the electric grid as needed. Featured in the journal Energy and Environmental Science, the system is designed to supply power to a small city continuously, overcoming the intermittency associated with solar and wind energy sources.

The innovative design involves storing excess electricity from solar or wind power in large tanks containing white-hot molten silicon. Subsequently, the light emitted by the glowing metal is converted back into electricity when demand arises. MIT researchers believe this system could be significantly more cost-effective than lithium-ion batteries, often considered for renewable energy storage, and estimate it to be approximately half as expensive as pumped hydroelectric storage, the most economical form of grid-scale energy storage.

Asegun Henry, an Associate Professor at MIT, emphasized the critical challenge of renewable energy storage, stating that the new technology aims to address this fundamental problem in energy and climate change. The concept emerged from a project focused on enhancing the efficiency of concentrated solar power, a form of renewable energy that differs from conventional solar plants by utilizing vast mirrors to concentrate sunlight onto a central tower, where it is converted into heat and subsequently electricity.

The proposed system, named TEGS-MPV (Thermal Energy Grid Storage-Multi-Junction Photovoltaics), diverges from traditional concentrated solar power methods. Instead of relying on mirrors and a central tower, the system converts electricity generated by any renewable source into thermal energy. The process involves passing an electric current through a heating element, which could be paired with existing renewable energy systems, such as solar cells, to capture and store excess electricity.

The system comprises a 10-meter-wide tank made of graphite, filled with liquid silicon, maintained at a “cold” temperature of nearly 1927 degrees Celsius. A network of tubes, exposed to heating elements, connects this cold tank to a second, “hot” tank. When electricity from the town’s solar cells enters the system, it is converted to heat in the heating elements, offering a promising solution to the storage challenges associated with renewable energy.