The new design stores heat generated by excess electricity from solar or wind power in large tanks of white-hot molten silicon and then converts the light from the glowing metal back into electricity when it's needed.
The researchers from Massachusetts Institute of Technology (MIT) in the US estimate that such a system would be vastly more affordable than lithium-ion batteries, which have been proposed as a viable, though expensive, a method to store renewable energy.
"Even if we wanted to run the grid on renewables right now we couldn't because you'd need fossil-fuelled turbines to make up for the fact that the renewable supply cannot be dispatched on demand," said Asegun Henry, Associate Professor at MIT.
Unlike conventional solar plants that use solar panels to convert light directly into electricity, concentrated solar power requires vast fields of huge mirrors that concentrate sunlight onto a central tower, where the light is converted into heat that is eventually turned into electricity.
When electricity is needed, the hot salt is pumped through a heat exchanger, which transfers the salt's heat into steam. A turbine then turns that steam into electricity.
Instead of using fields of mirrors and a central tower to concentrate heat, they propose converting electricity generated by any renewable source, such as sunlight or wind, into thermal energy, via a process by which an electric current passes through a heating element.
The system would consist of a large, heavily insulated, a 10-metre-wide tank made from graphite and filled with liquid silicon, kept at a "cold" temperature of almost 1927 degrees Celsius.
A bank of tubes, exposed to heating elements, then connects this cold tank to a second, "hot" tank.
(With inputs from agencies.)