Abstract: Potential energy conversion systems include a movable mass suspended by a line in a non-producing well, in which the line is coupled to a motor operable to lift the movable mass and a generator operable to produce electricity when lowering the movable mass. A fluid fills at least a portion of the non-producing well, and a volume of the fluid is sufficient to immerse or fully immerse the movable mass when the movable mass is raised to an uppermost position in the non-producing well. A storage tank is configured to receive fluid displaced from the non-producing well as the movable mass is lowered from a higher location to a lower location in the non-producing well and to return the fluid to the non-producing well as the movable mass is raised from the lower location.

Abstract: Methods and systems for gravity-based energy storage may utilize various controls. For example, a control system for a gravity well may include an active front end controller (AFE) configured to receive a plurality of reference signals and a plurality of target control parameters. The system may include a rate limiter coupled to the AFE controller and configured to adjust a rate of change associated with each of the plurality of target control parameters based, at least in part, on the plurality of reference signals. The system may include a speed control loop coupled to the AFE controller and configured to communicate with a variable-frequency drive (VFD), the VFD configured to store the plurality of target control parameters. The system may include an AFE component coupled to the AFE controller and configured to communicate with a grid based on the plurality of target control parameters.

Abstract: Potential energy conversion systems include a movable mass suspended by a line in a non-producing well, in which the line is coupled to a motor operable to lift the movable mass and a generator operable to produce electricity when lowering the movable mass. A fluid fills at least a portion of the non-producing well, and a volume of the fluid is sufficient to immerse or fully immerse the movable mass when the movable mass is raised to an uppermost position in the non-producing well. A storage tank is configured to receive fluid displaced from the non-producing well as the movable mass is lowered from a higher location to a lower location in the non-producing well and to return the fluid to the non-producing well as the movable mass is raised from the lower location.