Long duration thermal storage in solid particles - Concentrated Solar Power In fact - CLIMAX
Long duration storage of heat in solid particles. By long duration, we mean many days, or even months, of heat storage.
Some studies have indicated that long-duration energy storage might be needed to accommodate 100% renewable energy generation. Long-duration energy storage can also increase the security and resilience of the electrical grid in the face of increasing natural disasters and other uncertainties.
Inexpensive solid particle storage can accommodate increasing penetrations of renewables by allowing heat to be stored when electricity demand is low, and using that stored heat to produce electricity when demand (and prices) is higher. This time-shifting of energy production and use can increase the flexibility of not just renewables but also conventional baseload power plants.
Solid storage of heat also has the advantage of being inert, inexpensive, non-corrosive, and easy to handle. In addition, many solid materials exhibit a much wider operating temperature range than molten salts.
All these seem to suggest that one can look forward some heavy lifting in the domain of solid particle heat storage.
This article from SolarPACES feels that CSP based on long duration storage in solid particles could even be a game changer - https://bit.ly/2UeA3D7