Thermal energy storage system for simple and combined cycle power generation
AssigneeRondo Energy, Inc.
InventorsJohn Setel O'Donnell, Rahul Terdalkar, Yusef Desjardins Ferhani, Colin Riley
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Abstract
A thermal energy storage (TES) system converts variable renewable electricity (VRE) to continuous heat at over 900° C. Intermittent electrical energy heats a solid medium. Heat from the solid medium is delivered continuously on demand. Heat delivery via flowing gas establishes a thermocline which maintains high outlet temperature throughout discharge. The delivered heat which may be used for processes including power generation and cogeneration. Configurations of simple cycle systems and combined cycle power plants using thermal energy storage units can provide even greater efficiency and responsiveness.
Claims44
A method of enhancing responsiveness of a combined cycle power generation system including at least one gas turbine, at least one heat recovery steam generator (HRSG), a steam turbine, and a thermal energy storage (TES) system, the method including:
- charging the TES system using heat energy generated from electricity from a renewable energy source and/or an electrical grid;
- using heat output from the TES system to generate steam;
- using a portion of the TES-generated steam to maintain a preselected temperature condition in one or more portions of the HRSG while the gas turbine is in an offline condition;
- using a second portion of the TES-generated steam to operate the steam turbine in a spinning state while the gas turbine is in an offline condition;
- and
- selectively placing the gas turbine in an online condition in response to detection of a predefined system condition including at least one of:
- an energy drop from the renewable energy source below an availability threshold, a TES system drop below a heat output threshold level, a real-time or forecast electricity market price increase above a predetermined price threshold level, a command from a system operator, and/or a power demand increase above a demand threshold level.
A power generation system for enhancing responsiveness of a combined cycle power plant, including:
- a gas turbine;
- a heat recovery steam generator (HRSG) thermally coupled to the gas turbine;
- a steam turbine coupled downstream of the HRSG;
- a thermal energy storage (TES) system configured to be charged using heat derived from electricity supplied by a renewable energy source and/or an electrical grid;
- a steam generation subsystem configured to receive thermal energy output from the TES system and generate steam therefrom;
- a first steam delivery pathway configured to route a portion of the steam generated from the TES system to one or more regions of the HRSG;
- a second steam delivery pathway configured to supply another portion of the TES-generated steam to the steam turbine;
- a control system configured to selectively initiate operation of the gas turbine in response to detection of at least one predefined system condition, the system condition including one or more of:
- 1) a reduction in energy output from the renewable energy source below an availability threshold, 2) a drop in heat output from the TES system below a predetermined threshold level, 3) an increase in real-time or forecast electricity market prices above a defined price threshold, 4) a command received from a system operator, or 5) an increase in power demand above a defined demand threshold;
- wherein the control system is configured to modulate the first steam delivery pathway to maintain a predetermined temperature condition in the HRSG while the gas turbine is in an offline condition;
- wherein the control system is configured to regulate the second steam delivery pathway to maintain the turbine in a spinning state while the gas turbine is in an offline condition.
A method for clean-energy operation of a microgrid power generation system including at least one gas turbine, at least one heat recovery steam generator (HRSG), a steam turbine, and a thermal energy storage (TES) system with a steam generation subsystem, the method including:
- charging the TES system using heat energy generated from electricity from a renewable electricity source and/or an electrical grid;
- selectively operating the steam turbine using steam generated from the steam generation subsystem of the TES system to maintain the steam turbine in an operational state while a gas turbine is offline;
- and
- selectively operating the gas turbine so as to maintain a substantially constant power output despite variations in renewable electricity supply and steam availability from the TES system.
A microgrid power generation system for clean-energy operation, including:
- at least one gas turbine;
- at least one heat recovery steam generator (HRSG) thermally coupled to the gas turbine;
- a steam turbine;
- a thermal energy storage (TES) system configured to be charged using heat energy derived from electricity from at least one of a renewable electricity source and an electrical grid;
- a steam generation subsystem configured to generate steam using heat output from the TES system;
- and
- a control system configured to:
- (a) selectively operate the steam turbine using TES-generated steam to maintain the steam turbine in an operational state while the gas turbine is offline, or (b) operate the gas turbine to maintain a substantially constant power output in response to variations in renewable electricity supply and TES system output.
A method of enhancing responsiveness of a combined cycle power generation system including a gas turbine, a heat recovery steam generator (HRSG), a steam turbine, and a thermal energy storage (TES) system, the method including:
- charging the TES system using heat energy generated from electricity from a renewable energy source and/or an electrical grid;
- using heat output from the TES system to generate steam;
- using a first portion of the TES-generated steam to maintain a first preselected temperature condition in one or more portions of the HRSG while the gas turbine is in an offline condition;
- and
- using a second portion of the TES-generated steam to maintain a second preselected temperature condition in one or more portions of the steam turbine while the gas turbine is in the offline condition.
A combined cycle power generation system configured to enhance responsiveness, including:
- a gas turbine;
- a heat recovery steam generator (HRSG) thermally coupled to the gas turbine;
- a steam turbine coupled downstream of the HRSG;
- a thermal energy storage (TES) system configured to be charged using heat energy derived from electricity supplied by at least one of a renewable energy source and an electrical grid;
- a steam generation subsystem configured to generate steam using heat output from the TES system;
- a first steam delivery subsystem configured to direct a first portion of the TES-generated steam to one or more portions of the HRSG to maintain a first preselected temperature condition while the gas turbine is in an offline condition;
- a second steam delivery subsystem configured to direct a second portion of the TES-generated steam to one or more portions of the steam turbine to maintain a second preselected temperature condition while the gas turbine is in the offline condition;
- and
- a control system configured to selectively place the gas turbine in an online condition in response to detection of a predefined system condition.
Dependencies are inferred from the claim text.