Patent ID: 8952563
Filing Date: 2015-02-10
Classification: B60L,B61C,H02J,Y02E,Y02T,Y04S

Abstract:
1. A method for utility scale energy storage employing a rail system having upper and lower storage yards with interconnecting track connecting the upper and lower yards and a plurality of control elements for configuring track routing in the system with a plurality of shuttle units having a support structure and integral transfer mechanism for removably carrying masses, each shuttle unit operably connected to an electrical motor and an electrical generator comprising: connecting the rail system to an electrical grid; upon receiving a command for energy storage, controlling a selected set of the plurality of shuttle units to each load a mass from a selected storage track in the lower storage yard; connecting the storage track to a power track; driving the motor operably connected to each shuttle unit to lift the mass up the power track to the upper storage yard by accelerating the motor to a synchronous operating speed, bypassing rectifier/inverter circuits employed for asynchronous operation and directly connecting the motor to the electrical grid for synchronous operation; controlling the selected set of shuttle units to unload the masses to a selected storage track in the upper storage yard; upon receiving a command for energy return, controlling a selected set of shuttle units each to load a mass from a selected storage track in the upper storage yard; connecting the storage track to a power track; regeneratively braking the generator operably connected to each shuttle unit to carry the mass down the power track to the lower storage yard; controlling the shuttle unit to unload the mass to a selected storage track in the lower storage yard.