Abstract: A modular pumped storage hydropower system may include a shaft having a first end located opposite a second end. A reservoir is connected to the first end of the shaft. The second end of the shaft is configured to be located under a surface of ground. The second end of the shaft has a first compartment and a second compartment. The first compartment retains a pump assembly having an inlet in hydro communication with the second compartment. The second compartment is configured to retain water. A pipe has a first end connected to the pump assembly located opposite a second end extending through a cover of the first end of the shaft. The second end of the pipe is in hydro communication with the reservoir. The pipe of the pump assembly transfers water from the second compartment of the second end of the shaft to the reservoir.

Abstract: Underground facilities built for storing electric energy in the form of gravity and buoyant energy are described herein. In one embodiment, the facility is disposed in a thixotropic fluid beneath the ground surface and houses water to maintain a positive buoyancy and a piston having a bulk density greater than the water. In another embodiment, the underground facility is configured as a buoyant capsule arranged in a cylinder filled with water, where the cylinder is sealed except for openings in a bottom half of the cylinder to allow near unimpeded water flow from a location inside to a location outside of the cylinder. In another embodiment, the underground facility is configured as a negatively buoyant capsule.

Abstract: A modular pumped storage hydropower system may include a shaft having a first end located opposite a second end. A reservoir is connected to the first end of the shaft. The second end of the shaft is configured to be located under a surface of ground. The second end of the shaft has a first compartment and a second compartment. The first compartment retains a pump assembly having an inlet in hydro communication with the second compartment. The second compartment is configured to retain water. A pipe has a first end connected to the pump assembly located opposite a second end extending through a cover of the first end of the shaft. The second end of the pipe is in hydro communication with the reservoir. The pipe of the pump assembly transfers water from the second compartment of the second end of the shaft to the reservoir.

Abstract: A modular pumped storage hydropower system may include a shaft having a first end located opposite a second end. A reservoir is connected to the first end of the shaft. The second end of the shaft is configured to be located under a surface of ground. The second end of the shaft has a first compartment and a second compartment. The first compartment retains a pump assembly having an inlet in hydro communication with the second compartment. The second compartment is configured to retain water. A pipe has a first end connected to the pump assembly located opposite a second end extending through a cover of the first end of the shaft. The second end of the pipe is in hydro communication with the reservoir. The pipe of the pump assembly transfers water from the second compartment of the second end of the shaft to the reservoir.

Abstract: Underground facilities built for storing electric energy in the form of gravity and buoyant energy are described herein. In one embodiment, the facility is disposed in a thixotropic fluid beneath the ground surface and houses water to maintain a positive buoyancy and a piston having a bulk density greater than the water. In another embodiment, the underground facility is configured as a buoyant capsule arranged in a cylinder filled with water, where the cylinder is sealed except for openings in a bottom half of the cylinder to allow near unimpeded water flow from a location inside to a location outside of the cylinder. In another embodiment, the underground facility is configured as a negatively buoyant capsule.