Systems and methods are provided for charging a pumped thermal energy storage (PTES) system. A system may include a compressor or pump configured to circulate a working fluid within a fluid circuit, wherein the working fluid enters the pump at a first pressure and exits at a second pressure; a first heat exchanger through which the working fluid circulates in use; a second heat exchanger through which the working fluid circulates in use; a third heat exchanger through which the working fluid circulates in use, a turbine positioned between the first heat exchanger and the second heat exchanger, configured to expand the working fluid to the first pressure; a high temperature reservoir connected to the first heat exchanger; a low temperature reservoir connected to the second heat exchanger, and a waste heat reservoir connected to the third heat exchanger.

Systems and methods are provided for generating electricity via a pumped thermal energy storage (PTES) system. A system may include a pump configured to circulate a working fluid within a fluid circuit, wherein the working fluid enters the pump at a first pressure and exits at a second pressure; a first heat exchanger; a second heat exchanger; a turbine positioned between the first heat exchanger and the second heat exchanger, configured to expand a first portion of the working fluid to the first pressure; a heat rejection heat exchanger configured to remove thermal energy from a second portion of the working fluid; a high temperature reservoir connected to the first heat exchanger; and a low temperature reservoir connected to the second heat exchanger.

A steam turbine system including a steam source for generating a steam flow, a high pressure turbine providing a first steam exhaust, a low pressure turbine fluidly coupled to the high pressure turbine, and, a steam storage system having an inlet for receiving a portion of the first steam exhaust from the high pressure steam turbine and storing in the steam storage system, the steam storage system having an output with a pressure relief valve for discharging a second steam exhaust to the low pressure turbine.

A method of controlling a thermal power plant for electricity generation, said power plant comprising at least one heat source to supply thermal energy to a working fluid circulation circuit. The circuit comprises a high pressure turbine mechanically connected to an electricity generator, a high pressure regulating valve controlling the steam supply to said high pressure turbine from a high pressure superheater associated with a high pressure storage tank. The fluid supply to said high pressure storage tank from a high pressure steam generator is controlled by a high pressure supply valve, and, in response to a need for additional electrical power, the opening of the high pressure regulating valve is increased the opening of the high pressure supply valve is reduced.

A method of controlling a thermal power plant for electricity generation, said power plant comprising at least one heat source to supply thermal energy to a working fluid circulation circuit. The circuit comprises a high pressure turbine mechanically connected to an electricity generator, a high pressure regulating valve controlling the steam supply to said high pressure turbine from a high pressure superheater associated with a high pressure storage tank. The fluid supply to said high pressure storage tank from a high pressure steam generator is controlled by a high pressure supply valve, and, in response to a need for additional electrical power, the opening of the high pressure regulating valve is increased the opening of the high pressure supply valve is reduced.