Energy storage systems and methods

Abstract

The technical description relates to energy storage systems and methods. Specific examples described herein relate to in-ground energy storage systems and methods of selectively discharging electrical energy from an energy storage system. An example energy storage system comprises a first fluid storage tank, a second fluid storage tank, a first fluid disposed in the first fluid storage tank, a second fluid disposed in the second fluid storage tank, a heating unit operably connected to the first fluid storage tank and adapted to heat the first fluid, a cooling unit operably connected to the second fluid storage tank and adapted to cool the second fluid, and an energy conversion unit exposed to the first fluid and the second fluid. The energy conversion unit is adapted to convert a temperature difference between the first fluid and the second fluid directly to electrical energy or indirectly to electrical energy through intermediate mechanical work, such as rotational motion.

Dependencies are inferred from the claim text.