Abstract: Method and Apparatus for Combining a Heat Pump Cycle With A Power Cycle. The working fluid for the heat pump cycle will be different than that for the power cycle.

Abstract: The present invention includes systems and methods to recover heat from a lower quality heat source and convert that heat represented by its temperature differential range into a different form of extractable energy. In various illustrative examples, the system may include a heat recovery heat exchanger, a conventional counter-flow vortex tube, a power producing turbine, a condenser heat exchanger, and a liquid circulating pump. The system further comprises a condenser heat exchanger that is adapted to receive the turbine exhaust vapor, wherein the temperature of the exhaust vapor is reduced via heat transfer rejecting the waste heat to the surrounding atmosphere at atmospheric temperatures; wherein the compressible working vapor is converted to a saturated liquid and returned to the first heat exchanger by pumping means for further cycling.

Abstract: There is provided a Rankine cycle system which generates electricity by using heat as an energy source, in which a conventional pump for carrying a working fluid is not used, thereby reducing the cost of manufacturing the Rankine cycle system, saving the electric power consumed to operate the pump and therefore obtaining a greater output of power, and in which a control system is used to automatically operate the Rankine cycle system, thereby enabling to stably operate the Rankine cycle system even though a heat source is intermittently supplied.

Abstract: The invention relates to a thermodynamic machine having a circulation system in which a working fluid, in particular a low-boiling working fluid, circulates alternately in a gaseous and a liquid phase, a heat exchanger, an expansion machine, a condenser, and a fluid pump. The invention also relates to a method for operating the thermodynamic machine. According to certain embodiments of the invention, in the flow line of the fluid pump, a partial pressure increasing the system pressure is applied to the liquid working fluid by adding a non-condensing auxiliary gas. Compact ORC machines can be implemented, preventing cavitation in the liquid working fluid.

Abstract: A regenerative thermal energy system includes a heat exchange reactor that includes a top entry portion, a lower entry portion, and a bottom discharge portion. The system also includes at least one fluid source coupled in flow communication with the at least one heat exchange reactor at the lower entry portion. The system also includes at least one cold particle storage source coupled in flow communication with the at least one heat exchange reactor at the top entry portion. The system further includes at least one thermal energy storage (TES) vessel coupled in flow communication with the heat exchange reactor at each of the bottom discharge portion and the top entry portion. The heat exchange reactor is configured to facilitate direct contact and counter-flow heat exchange between solid particles and a fluid.

Abstract: Systems and methods are provided for the use of systems that recover mechanical power from waste heat energy using multiple working expanders with a common working fluid. The system accepts waste heat energy at different temperatures and utilizes a single closed-loop circuit of organic refrigerant flowing through all expanders in the system where the distribution of heat energy to each of the expanders allocated to permit utilization of up to all available heat energy. In some embodiments, the system maximizes the output of the waste heat energy recovery process. The expanders can be operatively coupled to one or more generators that convert the mechanical energy of the expansion process into electrical energy.

Abstract: Systems, methods, and apparatuses for pressure recovery and power generation may include a pressure recovery generator configured to receive a high-pressure fluid and generate current based on expansion of the high-pressure fluid. The current may be directed to a power electronics module that is configured to receive current from the pressure recovery generator and provide current to a closed-loop thermal cycle, such as an ORC. The current can be used to start components of the closed-loop thermal cycle, such as the pump and/or to black start the turbine generator. In some instances, the current can be combined with current generated by the closed-loop thermal cycle and directed to a utility grid or to external loads. The high-pressure fluid may be directed to heat exchanger components of the closed-loop cycle. For example, high-pressure, high-temperature fluid can be directed to an evaporator, while high-pressure, low-temperature fluid can be directed to a condenser.

Abstract: The present invention is directed generally to a system and method which employ a compressed gas-driven device with a passive thermodynamic composition. Certain embodiments provide a compressed gas-driven (e.g., CO2-driven) device implementation that includes a passive thermodynamic composition which allows for extended use of the device without freezing and without requiring a persistently-maintained, active (e.g., electrically-powered) heating. Further, certain embodiments provide a compressed gas-driven (e.g., CO2-driven) device implementation that includes a passive thermodynamic composition which allows for extended use of the device without freezing and without requiring an ignition heat source (e.g., electrically-powered or pyrotechnic as generator) for heating the device.

Abstract: The invention relates to a method and an apparatus for generating current from hydrogen sulphide-containing exhaust gases, particularly from the natural gas industry. The method according to the invention is characterized in that the hydrogen sulphide-containing exhaust gases are delivered to a current generation device and are burnt there, preferably with air being supplied, the energy released during combustion being employed at least partially for current generation. The apparatus according to the invention is characterized by a current generation device in which supplied hydrogen sulphide-containing exhaust gases are burnt, preferably with air being supplied, the energy released during combustion being employed at least partially for current generation.

Abstract: An object of the present invention is to provide a solar heat steam cycle system capable of operating efficiently and stably in keeping with the status of collected or stored heat, and a control method for use with the system. The system includes a heat collector (1) which collects solar thermal energy, a thermal storage device (2) which stores the solar thermal energy collected by the heat collector, a feed water heater (3) which heats feed water, an evaporator (4) which evaporates the feed water supplied from the feed water heater, and a steam turbine (6) driven by steam generated by the evaporator. The system includes a control valve (31) which controls allocations of heating medium supplied from the thermal storage device to the evaporator and the feed water heater.

Abstract: There is provided a coal-fired power generating system that, in addition to recovering latent heat of condensation and the like from a dry exhaust gas of a drying device, which is for predrying coal, precludes a large variation, from a design value, of the amount of steam flowing at a final stage of a steam turbine. The coal-fired power generating system includes an indirect-heating dryer 1 including a heating medium passage inside its casing, a coal-fired boiler 3 for combusting coal to generate steam, and a steam turbine 6 for generating power with the steam from the boiler 3. The dryer dries the coal fed into the casing by performing indirect heating with steam fed to the heating medium passage. The coal-fired power generating system heats boiler supply water for the coal-fired boiler 3 with extracted steam extracted from the steam turbine 6.

Abstract: A method and a device for conversion of energy are proposed, in which a hydrocarbon-containing energy source is burned in a combustion space (12) in an oxygen-enriched atmosphere and the generated heat is transmitted to a steam power plant circuit (60). Flue gas (104), which is formed in the combustion of the hydrocarbon-containing energy source, is cooled in a direct-contact cooler (20) in direct contact with a water-containing coolant flow (138).

Abstract: A waste heat recovery system is provided. The waste heat recovery system includes a Rankine cycle system for circulating a working fluid. The Rankine cycle system includes at least one first waste heat recovery boiler configured to transfer heat from a heat source to the working fluid. The Rankine cycle system also includes a first expander configured to receive the heated working fluid from the at least one first waste heat recovery boiler. Further, the Rankine cycle system includes a second expander and a third expander coupled to at least one electric generator. The waste heat recovery system also includes a condenser configured to receive the working fluid at low pressure from the first expander, the second expander and the third expander for cooling and a pump connected to the condenser for receiving a cooled and condensed flow of the working fluid from the condenser.

Abstract: Various thermodynamic power-generating cycles are disclosed. A turbopump arranged in the cycles is started and ramped-up using a starter pump arranged in parallel with the main pump of the turbopump. Once the turbopump is able to self-sustain, a series of valves may be manipulated to deactivate the starter pump and direct additional working fluid to a power turbine for generating electrical power.

Abstract: A transient liquid pressure power generation system and associated devices and methods is disclosed. The system can include a liquid source and a transient pressure drive device fluidly coupled to the liquid source to receive liquid from the liquid source. The transient pressure drive device can include a drive component, and a transient wave or pressure producing element to cause a high pressure transient wave in the liquid traveling toward the liquid source to operate the drive component. Additionally, the system can include a heat source fluidly coupled to the transient pressure drive device and the liquid source to receive liquid from the transient pressure drive device and heat liquid returning to the liquid source.

Abstract: Various thermodynamic power-generating cycles employ a mass management system to regulate the pressure and amount of working fluid circulating throughout the working fluid circuits. The mass management systems may have a mass control tank fluidly coupled to the working fluid circuit at one or more strategically-located tie-in points. A heat exchanger coil may be used in conjunction with the mass control tank to regulate the temperature of the fluid within the mass control tank, and thereby determine whether working fluid is either extracted from or injected into the working fluid circuit. Regulating the pressure and amount of working fluid in the working fluid circuit helps selectively increase or decrease the suction pressure of the pump, which can increase system efficiency.

Abstract: A supercritical fluid comprises carbon dioxide and at least one disorder-inducing species. The proportion of carbon dioxide to the at least one disorder-inducing species in the supercritical fluid may be sufficient to induce disorder in the fluid. Power generation systems and thermal energy storage systems configured to use the supercritical fluid are described.

Abstract: In a waste heat utilization arrangement for an internal combustion engine of a motor vehicle including a waste heat utilization circuit in which a working medium is circulated, a pumping device for pressurizing the working medium, an evaporator for vaporizing the working medium by waste heat of the internal combustion engine, an expansion machine for expanding the working medium while extracting mechanical energy therefrom and a condenser for condensing the working medium in a resting state, the waste heat utilization circuit is in communication with a pressure store capable of maintaining a pressure for setting and ensuring a predetermined adjustable minimum pressure of the working medium in the waste heat utilization circuit.

Abstract: A power plant (1) that includes at least one of a gas turbine (GT), a steam turbine (ST) with a water-steam cycle, and a heat recovery steam generator (B) operatively connected to a heat generating member such as solar energy system (Ssolar) by means of a primary circuit (10a, 10b, 10c) and a secondary circuit system (20a). The primary heat transfer circuit (10a, 10b) includes solar heating system (Ssolar) configured to heat a primary fluid (10), and the secondary circuit (20a) comprises a flow line (20A) for a secondary flow (20) and a main heat exchanger (23) to exchange heat between the secondary water flow and a gas turbine inlet air flow (2). A first line (10B) in the primary circuit (10b) leads to a first heat exchanger (12) to heat the water flow in the secondary circuit (20a).

Abstract: A closed-cycle system and method of electrical power generation uses steam to transport charge carriers through an MHD generator. Water droplets, fine particles or mixtures thereof are used as the charge carriers. The fine particles are sufficiently small to allow the particles to pass through pumps and other equipment in the flow path with little or no damage, thereby eliminating the need to remove and re-inject a seed material, or treat it prior to discharge to the environment. The high operating temperatures of prior art MHD generators are avoided, thereby allowing more economical and readily available materials to be used. The system and method also allows the MHD generator to be used as the bottoming cycle in a single-loop power generation system, with a conventional steam turbine-generator used as the topping cycle, resulting in an increased heat rate with reduced emissions of greenhouse gases and other pollutants, and with reduced heat rejection to the environment per unit of electricity produced.

Abstract: A method and system for converting a feedstock using thermal plasma or other gassifier, into a feedwater or make up water energy transfer system. Feedstock is any organic material or fossil fuel. The energy transferred in the feedwater or make N up water is used in any Rankine or other steam process, or any process that requires heat. Heat is extracted from a gas product issued by a gassifier and is delivered to a power plant via its feedwater system or make up water system. Preferably, the gassifier is a plasma gassifier and the gas product is syngas that is combusted in an afterburner. A heated air flow and/or EGR flow is provided the afterburner at a variable flow rate that is responsive an operating characteristic of the afterburner.

Abstract: Work is produced from heat in a continuous cycle. The cycle involves communicating a first flow of a first working fluid to a low pressure boiler. The low pressure boiler forms a first flow of first working fluid vapor by using a low temperature thermal source. A second flow of the first working fluid is provided to a high pressure boiler to produce a second flow of first working fluid vapor at a pressure higher than the low pressure boiler. A second working fluid in vaporous form is compressed, after which a third working fluid is formed by mixing the first flow of first working fluid vapor, the second flow of second working fluid vapor, and the second working fluid. Thermal energy is transferred directly between one or more of the working fluids in the mixing chamber exclusive of any intervening structure.

Abstract: Ocean Thermal Energy Conversion (OTEC) systems and methods utilizing the systems are disclosed for producing a useable form of energy utilizing warm surface seawater and cold seawater from depths up to 2 miles below the surface and utilizing a multi-component working fluid. The systems and methods are designed to maximize energy conversion per unit of cold seawater, the limited resource, achieving relative net outputs compared to a Rankine cycle using a single component fluid by at least 20% and even as high as about 55%.

Abstract: A steam power plant is suggested having, parallel to the low-pressure passage (VW1 to VW2), a heat reservoir (A) which is loaded with preheated condensate in weak-load times. This preheated condensate is taken from the heat reservoir (A) for generating peak-load and inserted downstream of the low-pressure preheater passage (VW1 to VW2) into the condensate line (19.2) resp. the feed water container (8). Thus it is possible to quickly control the power generation of the power plant in a wide range without significantly having to change the heating output of the boiler of the steam generator (1). A steam power plant equipped according to the invention can thus be operated with bigger load modifications and also provide more control energy.

Abstract: A power system based on a binary power cycle and utilizing a multi-component working fluid is disclosed. The working fluid is partially vaporized and a split recirculation approach is used to control the enthalpy-temperature profiles to match the heat source. A portion of the unvaporized working fluid is sprayed into the condenser.

Abstract: An electric energy delivery device using waste energy sources such as steam, hot water, hot gases etc., a turbine being inserted into a circuit where a fluid suitable to change state (gas and liquid) at low temperature, comprising at least a heat exchanger where the fluid is made gaseous, a condenser where the fluid is made liquid and a recirculation pump, the turbine being fed with said gaseous fluid.

Abstract: A steam engine receives steam from a boiler which is heated by hot gas produced by a burner. The flue gas from the boiler is used to heat the body of the steam engine. The body of the steam engine has a plurality of passages which are shaped and dimensioned to receive and pass the flue gas, so that the flue gas heats the body, and thereby increases the power and efficiency of the steam engine.

Abstract: A thermal power station system has at least one heat engine connected to at least one work receiver. The heat engine is arranged to be able to utilize a working fluid alternating between liquid and gas phase. In the heat engine is arranged at least one heat exchanger in thermal contact with at least one expansion chamber. A method is for energy supply to a building or a vessel.

Abstract: A method for the production of alcohol and other bioproducts from power boiler woody biomass extract containing hemicelluloses, with or without combining extract from wood prior to Kraft cooking. The process is integrated with the host Kraft pulp mill plant process to minimize the heat loss from extracting hemicelluloses and the energy used in the process.

Abstract: An energy recovery arrangement is disclosed for use with an engine. The energy recovery arrangement may include a closed circuit containing a high-pressure working fluid, a first boiler configured to receive waste heat from a first source on the engine, and a second boiler disposed upstream of the first boiler and configured to receive waste heat from a second source on the engine. The energy recovery arrangement may also include an energy extractor disposed at a location downstream of the first and second boilers, a condenser disposed at a location downstream of the energy extractor, and a pump disposed at a location downstream of the condenser and upstream of the first and second boilers. The energy recovery arrangement may further include a recuperator disposed in parallel with the second boiler and configured to transfer heat from working fluid exiting the extractor to working fluid exiting the pump.

Abstract: An arrangement and a method for converting thermal energy to mechanical energy includes a circulation unit (4) a refrigerant in the a circuit (3), an evaporator (6) for the refrigerant, a turbine (9) driven by vaporised refrigerant, a condenser (12) cooling the refrigerant to condense, and an accumulator tank (14) for storage of the refrigerant is not being circulated in the line circuit (3). A control device estimates the degree of filling of the line circuit (3) with refrigerant at which the turbine (9) achieves a substantially optimum effect, and controls the flow of refrigerant between the line circuit (3) and the accumulator tank (14) to achieve the estimated degree of filling the line circuit (3) with refrigerant.

Abstract: The technology combines a secondarily-fueled boiler with a primary-fueled Rankine steam cycle combustion system in a hybrid process. Outputs from a secondarily-fueled combustion system are fed into the feedwater heater(s), deaerators, feedwater heating lines, and/or reheat lines of a primary-fueled Rankine system. The integrated steam flow eliminates or reduces one or more extractions from the steam turbine generator, thereby allowing it to generate more electrical power using the same Rankine system input energy or generate equivalent electrical power using energy inputs from multiple fuel sources. The technology can be utilized in any type and/or configuration of secondary fuel or secondarily-fueled combustion technology and/or can utilize any type of primary-fueled steam source.

Abstract: Ocean Thermal Energy Conversion (OTEC) systems and methods utilizing the systems are disclosed for producing a useable form of energy utilizing warm surface seawater and cold seawater from depths up to 2 miles below the surface and utilizing a multi-component working fluid. The systems and methods are designed to maximize energy conversion per unit of cold seawater, the limited resource, achieving relative net outputs compared to a Rankine cycle using a single component fluid by at least 20% and even as high as about 55%.

Abstract: A combined cycle power plant with a gas turbine, steam turbine, and first HRSG comprises a CO2 capture plant for the at least partial capture of CO2 from the exhaust gases from the gas turbine. It comprises in particular a second HRSG or boiler arranged to receive a portion of the exhaust gases and transfer its heat to steam and feedwater. Steam generated in the second HRSG or boiler is used for the operation of the CO2 capture plant and/or to operate a steam turbine that drives a generator and optionally a CO2 compressor. The power plant according to the invention allows for greater flexibility in power plant part load control and power plant efficiency. A method to operate the power plant is also claimed.

Abstract: A method of retrofitting a power generation system includes modifying a pre-existing power generation system that includes a combustor and a steam-based cycle to include a super-critical carbon dioxide-based Brayton cycle that is directly coupled through the combustor. The steam-based cycle is converted into a steam-based Rankine cycle that is in thermal-receiving communication with the super-critical carbon dioxide-based Brayton cycle.

Abstract: A method of utilizing waste heat to create a pressurized working fluid is disclosed. The method includes providing a vessel containing a sorbent system, introducing a feed of waste heat to a heat exchanger external to the vessel to heat a feed of working fluid, introducing the heated working fluid from the heat exchanger to the vessel to obtain pressurized working fluid, and directing the pressurized working fluid from the vessel to a work component. The method is particularly suited to make use of waste heat an industrial process, (e.g., a chemical processing or petrochemical refining operation) in which low grade heat source(s) are used to drive the sorption system.

Abstract: Embodiments of the invention relate to a method for operating a steam cycle process performed in an apparatus having an evaporator or steam generator for the evaporation of a liquid working medium and an expander, which is lubricated by a lubricant, for the performance of mechanical work. The method comprises a) supplying the liquid working medium to the evaporator, in which it evaporates and is fed to the expander in the form of steam; b) supplying an ionic liquid, which at room temperature forms two liquid phases with the liquid working medium, to the expander as a lubricant; and c) separating the ionic liquid forming the lubricant for the expander from the working medium upstream of the evaporator.

Abstract: Methods and/or systems using magnetically assisted pressurization of a gas for the generation of useful power from heat transfer using heat sources at lower temperatures in a manner that does not require the emission of CO2.

Abstract: The invention relates to a method and system for recovering power from the gaseous stream produced by a paraxylene-air oxidation reaction. Specifically, the invention is based on heating the gaseous stream from the oxidation reaction to a temperature of at least 600° C., recovering energy through an expander, heating the expander vent stream and recovering heat from the vent stream. The recovered heat is used to maintain the oxidation process, purification process, start-up the process, or re-start the process after an interruption.

Abstract: An integrated process for the partial oxidation of whole crude oil mixed with a low cost finely divided solid ash-producing material in a membrane wall gasification reactor produces a syngas and, optionally, a more hydrogen-rich product stream by subjecting the syngas to a water-gas shift reaction. Process steam and electricity are produced by recovering the sensible heat values from the hot syngas.

Abstract: Disclosed herein is a system comprising a compressor in mechanical communication with a turbine; the compressor being operative to produce compressed air; a premixer; the premixer being operative to mix a fuel with the compressed air; a carbonator being located downstream of the premixer; the carbonator being operative to receive a mixture of carbon dioxide and syngas and to convert a metal oxide into a metal carbonate by reacting it with the carbon dioxide; a calciner; the calciner being operative to receive the metal carbonate from the carbonator; and to dissociate carbon dioxide from the metal carbonate; and a combustor; the combustor being located downstream of the carbonator; where the combustor is operative to combust syngas received from the carbonator.

Abstract: A method and apparatus for implementing the Rankine Cycle with improved efficiency through the use of thermal exchange between the working fluid and a brine liquid. In one embodiment, the brine liquid is further processed through a multistage flash distillation unit to produce distilled water or other minerals. Geothermal or exhaust waste heat may be used to further improve the Rankine Cycle efficiency, with remaining thermal energy improving the distillation process.

Abstract: Disclosed is a process for improving the efficiency of a combined-cycle power generation plant and desalination unit. The process includes supplying exhaust gases from a gas turbine set used to generate electrical power to a heat recovery steam generator (HRSG) and then directing the steam from the HRSG to a steam turbine set. Salinous water is supplied into an effect of the desalination unit. Steam exhausted from the steam turbine set is utilized in the effect of the desalination unit to produce a distillate vapor and brine from the effect by heat exchange. Additionally, steam is introduced steam from at least one additional heat source from the combined-cycle power generation plant to the effect to increase the mass flow rate of steam into the effect. In one embodiment, the additional heat source is an intercooler heat exchanger. Heated water from the intercooler heat exchanger is provided to a reduced atmosphere flash tank, and the steam flashed in the flash tank is provided to the effect.

Abstract: A solar thermal power plant is provided. The plant includes a steam-electric power plant associated with a steam generation system operationally connected thereto for providing heat to drive its operation, a solar collection system designed to heat thermal fluid and is in communication with the steam-electric power plant to provide heat thereto for driving its operation, and a non-solar power plant including a power generation unit and a waste heat recovery unit. The solar thermal power plant further includes a controller configured to selectively operationally connect the solar collection system and the waste heat recovery unit to the steam-electric power plant to provide heat thereto.

Abstract: Systems, methods, and apparatuses may involve a burner configured to burn gas to produce burned gas and output radiant heat. A gas valve controlled by the system can regulate the flow of gas to the burner. A heat exchanger associated with a thermal cycle can be used to heat a working fluid of the thermal cycle. The heat exchanger positioned out of a convective heat flow from the burner. A heat valve between the burner and the heat exchanger can be selectively adjustable to adjust heat transfer to the heat exchanger.

Abstract: A method and system for integrating a power plant and a post combustion carbon capture plant such as a solvent based absorption-regeneration process plant. Electricity is produced by a boiler feeding steam to one or more turbines. The flue gas from the boiler is fed to a waste heat recovery unit which captures heat and provides it to the post combustion capture plant where it can be used in a stripper interstage heater as a supplemental heat for solvent regeneration. Additionally recovered heat can be also integrated with the power generation plant by transferring it to the boiler feed water heating system. Part of the electricity that is generated is also fed to the post combustion capture plant where it will be used to power unit operations therein.

Abstract: A power generation system that includes a heat source loop, a heat engine loop, and a heat reclaiming loop. The heat can be waste heat from a steam turbine, industrial process or refrigeration or air-conditioning system, solar heat collectors or geothermal sources. The heat source loop may also include a heat storage medium to allow continuous operation even when the source of heat is intermittent. Heat from the heat source loop is introduced into the heat reclaiming loop or turbine loop. In the turbine loop a working fluid is boiled, injected into the turbine, recovered condensed and recycled. The power generation system further includes a heat reclaiming loop having a fluid that extracts heat from the turbine loop. The fluid of the heat reclaiming loop is then raised to a higher temperature and then placed in heat exchange relationship with the working fluid of the turbine loop. The power generating system is capable of using low temperature waste heat is approximately of 150 degrees F. or less.

Abstract: A thermo-acoustic engine and/or cooler is provided and includes an elongated tubular body, multiple regenerators disposed within the body, multiple heat exchangers disposed within the body, where at least one heat exchanger is disposed adjacent to each of the multiple regenerators, multiple transducers axially disposed at each end of the body, and an acoustic wave source generating acoustic waves. At least one of the acoustic waves is amplified by one of the regenerators and at least another acoustic wave is amplified by a second one of regenerators.

Abstract: A Steam power plant comprising a steam turbine (3) and a condenser (5), wherein the condenser (5) is disclosed, comprising a first heat sink being a ground heat exchanger (29) is connected to the condenser during times when ground temperature is lower than air temperature; and a second heat sink being an above-ground heat exchanger is connected to the condenser during times when ground temperature is not lower than air temperature.

Abstract: Embodiments of the invention provide methods and apparatus for using a controllable heat source to generate electricity. One embodiment provides an energy generation module comprising a controllable heat source, one or more jackets of thermoelectric devices, and heat conducting fluids surrounding or otherwise thermally coupled to the jackets. The energy generation module can be used to convert heat from a heat source such as a gas combustion chamber into electricity. Embodiments of the invention are particularly useful for generating electricity when electrical power is not existent, cost prohibitive or otherwise in short supply. The generated electricity can be used by the user, stored in an electrical storage battery or sold to a local or remote power grid.