Patent Description:
Many green energy sources (e.g., solar or wind power) are highly volatile meaning that the quantity of power they deliver is variable. Without a suitable approach for matching generation and consumption under these difficult boundary conditions, it is more likely that unwanted tripping or disconnection of loads, as well as power sources, may occur. Currently, one solution for this problem is to operate only in areas where a proper electrical infrastructure is available to meet the energy demand of such an industry. This solution limits the possibility to utilize the full potential of renewable energy for green production available at many remote locations around the globe where the best conditions for the generation of renewable energy may exist.

Currently, there is a significant unused potential of renewable energy which is not being fed into existing electrical grids. This available power could be leveraged to produce green hydrogen, methanol, ammonia, e-fuels, or equivalent on a large scale which would provide a significant contribution to drive the energy transition forward. <CIT> relates to a dynamic energy demand management system.

In one aspect, a method of operating a microgrid includes operating one of a plurality of power sources to deliver power to the microgrid. The method also includes measuring a quantity of power delivered to the microgrid, drawing power from the microgrid to power one of a plurality of loads, each load including a plurality of separately operable subsystems, and calculating an automation level and a production change capability for each load and subsystem of the plurality of subsystems. The method also includes measuring a quantity of power drawn from the microgrid and reducing the quantity of power drawn from the microgrid in response to a measured quantity of power drawn exceeding a measured quantity of power provided. The reducing step follows a sequence of reductions which includes reducing an operating level of a first load of the plurality of loads, determining that the reduction in operating level was insufficient to reduce the measured quantity of power drawn from the microgrid to a point at or below the measured quantity of power provided, and limiting the power consumption of a first subsystem below the reduced operating level in response to the determining step concluding the reducing step did not sufficiently reduce the quantity of power drawn from the microgrid. The first subsystem is selected based in part on the calculated automation level and the production change capability.

The method may also include determining that the limiting step failed to reduce the measured quantity of power drawn from the microgrid to the point at or below the measured quantity of power provided; and transitioning one of the first subsystem and a second subsystem to a standby mode, the first subsystem and the second subsystem selected based in part on the calculated automation level and the production change capability.

The method may also include additionally determining that the transitioning step failed to reduce the measured quantity of power drawn from the microgrid to the point at or below the measured quantity of power provided; and shutting down operation of one of the first subsystem, the second subsystem, and a third subsystem, the first subsystem, the second subsystem, and the third subsystem selected based in part on the calculated automation level and the production change capability.

The method may also include determining a green coefficient for each power source of the plurality of power sources and increasing a first quantity of power delivered to the microgrid from a first power source, the first power source selected in part based on the green coefficient.

The method may also include operating a first load of the plurality of loads to produce a first product, storing the first product in a first buffer, delivering the first product from the first buffer to a second load of the plurality of loads, operating the second load to produce a second product in response to the receipt of the first product.

The method may also include a microgrid controller operable to control each of the plurality of power sources and the plurality of loads.

The method may also include operating the first load and the second load at a first load point at which a first quantity of the first product produced by the first load equals a second quantity of the first product required by the second load.

The method may also include reducing the power consumed by the first load from the first load point to a second load point while maintaining the power consumed by the second load at the first point, the second load-receiving receiving a portion of the first product from the first load and a second portion of the first product from the first buffer.

The method may operate with systems where the first load is one of a demineralized water plant, an electrolyzer, a direct air capture plant, and a methanol synthesis plant and the second load is one of the electrolyzer, a direct air capture plant, the methanol synthesis plant, and a methanol to gasoline plant.

The method may also operate with systems where the first buffer is one of a demineralized water tank, a steam tank, a hydrogen tank, a CO2 tank and a methanol tank.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings.

Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms "including," "having," and "comprising," as well as derivatives thereof, mean inclusion without limitation. The singular forms "a", "an" and "the" are intended to include the plural forms as well unless the context clearly indicates otherwise. Further, the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "or" is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases "associated with" and "associated therewith," as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

In addition, the term "adjacent to" may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion unless the context clearly indicates otherwise. Further, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise. Terms "about" or "substantially" or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

<FIG> illustrates one possible arrangement of a microgrid <NUM>. Before proceeding, it should be noted that the microgrid <NUM> illustrated in <FIG> includes a number of features that may be omitted in other microgrid arrangements. In addition, other microgrids may include additional features not illustrated in <FIG> or described herein. Additional components could include components such as transformers, switches, electrical conditioning components, sensors, controllers, and other components that may add to the operation and functionality of the system. As such, microgrids should not be limited to the arrangement of the microgrid <NUM> of <FIG>.

With reference to <FIG>, the microgrid <NUM> includes an AC bus <NUM> (alternating current bus), a DC bus <NUM> (direct current bus), and a microgrid controller <NUM>. Some constructions of the microgrid <NUM> may also include a grid connector <NUM> that operates to selectively connect or disconnect the microgrid <NUM> from a transformer <NUM> that ultimately connects to a local energy grid <NUM>, such as a utility grid.

The AC bus <NUM> provides a common connection point for the collection and distribution of alternating current (AC) electrical power. In constructions that include a grid connector <NUM>, the AC bus <NUM> also connects to the local energy grid <NUM> when the grid connector <NUM> is in a closed position to either deliver electrical power to the local energy grid <NUM> or to draw electrical power from the local energy grid <NUM> as may be required. The DC bus <NUM> is similar to the AC bus <NUM> and provides a common connection point for the collection and distribution of direct current (DC) electrical power. It should be noted that one of the AC bus <NUM> or the DC bus <NUM> could be omitted in other microgrid systems.

An AC/DC converter <NUM> is provided to facilitate the transfer of power between the AC bus <NUM> and the DC bus <NUM>. The AC/DC converter <NUM> may include one or more inverters that operate to convert DC power to suitable AC power for addition to the AC bus <NUM>. One or more rectifiers may also be included to convert AC power from the AC bus <NUM> to DC power for delivery to the DC bus <NUM>. In systems that do not include both the AC bus <NUM> and the DC bus <NUM>, one or more AC/DC converters <NUM> could be included to allow the connection of both AC systems and DC systems to the microgrid <NUM>.

Any number of power sources, systems, and components can be connected to the AC bus <NUM> to either deliver power to the AC bus <NUM> or to extract power from the AC bus <NUM>. The microgrid <NUM> of <FIG> includes a wind park <NUM>, a concentrated solar generator <NUM>, and a combustion turbine <NUM> connected to the AC bus <NUM>, with each operable to deliver power to the AC bus <NUM>.

The wind park <NUM> includes one or more separate turbines that operate to generate AC power in response to the wind. The power generated by each wind turbine <NUM> may be AC power or DC power but that power is ultimately delivered to the AC bus <NUM> as AC power. As is well-known in the art, power generated by wind turbines <NUM> can be classified as both a green energy source as well as a variable or volatile energy source as it relies on proper wind conditions to be capable of generating energy, and the amount generated varies with the wind conditions.

The concentrated solar generator <NUM> includes one or more plants that operate to concentrate solar energy to generate steam. The steam in turn powers a conventional steam turbine to generate AC power that can be delivered directly to the AC bus <NUM>. Like the power delivered by the wind park <NUM>, the power delivered by the concentrated solar generator <NUM> can be classified as both a green energy source as well as a variable energy source as it relies on access to sunshine to be capable of generating energy, and the amount generated varies with the level of sunshine.

The combustion turbine <NUM> may include one or more combustion turbines <NUM> that combust a fuel to produce AC power that can be delivered directly to the AC bus <NUM>. Power delivered by the combustion turbines <NUM> can be classified as green or not green depending upon the fuel combusted. For example, a combustion turbine <NUM> that combusts hydrogen or methane from biomass would generally be considered green so long as the source of hydrogen or biomass is green. In addition, other sources of methane can be considered green such that combustion turbines <NUM> that combust green methane could be considered green. Unlike wind turbines <NUM> and concentrated solar generators <NUM>, combustion turbines <NUM> are not considered variable energy sources as they are capable of delivering full power regardless of external conditions, so long as they have a fuel supply.

The wind park <NUM>, the concentrated solar generator <NUM>, and the combustion turbine <NUM> are examples of power sources suitable for use in the microgrid <NUM>. However, other AC electrical generators <NUM> are also suitable for use with the microgrid <NUM> and in particular for connection with the AC bus <NUM>. The additional AC electrical generators <NUM> may be variable and may also be green. For example, additional AC electrical generators <NUM> could include generators powered by hydro, geothermal, nuclear, fossil fuels, tidal, and the like. It is also important to note that many of these power sources are capable of controlling the frequency and voltage of the AC power delivered to the AC bus <NUM>, thereby adding to the stability of the microgrid <NUM>.

In addition to power sources, AC energy storage systems <NUM> or power conditioning systems may also be connected to the AC bus <NUM>. AC energy storage systems <NUM> include systems that use AC power to store energy, typically in another form, when that energy is abundant and then use that stored energy to generate AC power when additional AC power is required by the AC bus <NUM>. One example of an AC energy storage system <NUM> is pumped storage hydro in which water is pumped to a higher elevation when excess energy is available, and the water is passed through a hydro turbine when AC power is required. Another AC energy storage system <NUM> includes a compressed gas storage system that operates to compress a gas with excess energy and then power a turbine or other device using that compressed gas to generate AC power when energy is needed. Power conditioning systems could include synchronous condensers or flywheels that operate to control reactive power and fast frequency response in some cases (e.g., spinning reserve).

Another energy storage system could include a production facility that uses excess energy to produce hydrogen, methane, gasoline, or other compounds that efficiently store energy. With a hydrogen facility, excess electricity is used in an electrolysis process to produce hydrogen. The hydrogen is then pressurized and stored. When additional AC power is required, the stored hydrogen is used as fuel in the combustion turbine <NUM>. Many other AC energy storage systems <NUM> are suitable for use with the AC bus <NUM>. As such, the microgrid <NUM> should not be limited to those examples discussed herein.

Also attached to the AC bus <NUM> are one or more AC loads <NUM>. AC loads <NUM> are loads that do not provide power to the AC bus <NUM> but rather only draw AC power. AC loads <NUM> can include factories, homes, data storage systems, production facilities, and the like.

Like the AC bus <NUM>, any number of systems and components can be connected to the DC bus <NUM> to either deliver power to the DC bus <NUM> or to extract power from the DC bus <NUM>. For example, the microgrid <NUM> of <FIG> includes a PV solar generator <NUM> connected to the DC bus <NUM> to deliver DC power to the DC bus <NUM>. Power delivered by the PV solar generator <NUM> can be classified as both a green energy source as well as a variable energy source as it relies on access to sunshine to be capable of generating energy, and the amount generated varies with the level of sunshine.

Other DC electrical generators <NUM> may also be connected to the DC bus <NUM> to deliver DC power to the DC bus <NUM>. For example, fuel cells could be connected to the DC bus <NUM> to deliver power to the DC bus <NUM>. Many other DC power sources could also be employed such as but not limited to DC generators, alternators, and other variable frequency sources that include a rectifier.

The DC bus <NUM> is well-suited to supporting many energy storage devices including batteries <NUM>, ultracapacitors <NUM>, and other DC energy storage systems <NUM>. Batteries <NUM> and ultracapacitors <NUM> are well-known energy storage devices with virtually any type and arrangement being suitable for use with the microgrid <NUM> of <FIG>. Other DC energy storage systems <NUM> could include flywheels, electrochemical capacitors, thermal storage, and the like.

One or more DC loads <NUM> may be connected to the DC bus <NUM> to draw DC power therefrom. Unlike energy storage devices that can transfer power to and from the DC bus <NUM>, DC loads <NUM> only draw power from the DC bus <NUM>. DC loads <NUM> could include heating systems, data centers, computers, or any other system or component that operates on or consumes DC power.

It should be noted that any AC system including loads, power-producing, systems, and storage systems could be converted to DC systems using one or more rectifiers. Similarly, any DC system could be converted to AC with one or more inverters. As such, the examples provided herein should not be limited to connection to the AC bus <NUM> or the DC bus <NUM> as described herein.

The microgrid controller <NUM> is typically a microprocessor-based controller that includes a microprocessor, memory, a memory storage device, input devices, and some form of output such as a display that allows for user interaction. Of course, other controllers or arrangements of controllers could be employed. It is also important to note that while <FIG> illustrates a single microgrid controller <NUM>, multiple components or systems could be distributed throughout the microgrid <NUM> and could cooperate with one another to perform the functions of the microgrid controller <NUM>.

The microgrid controller <NUM> communicates with the various components of the microgrid <NUM> to monitor and/or control their operation. The microgrid controller <NUM> may include sensors that monitor temperatures, pressures, power flow, valve positions, switch and relay positions, voltage, frequency, and the like to operate the microgrid <NUM>. The microgrid controller <NUM> also communicates with the AC/DC converter <NUM> and can operate to control the quantity of power flow and the direction of power flow between the AC bus <NUM> and the DC bus <NUM>.

The microgrid controller <NUM> may also operate to control the dispatching of power to select the desired power sources to achieve a goal. For example, the microgrid controller <NUM> could operate to maximize the use of power from green energy sources when it is available to power the AC loads <NUM> and the DC loads <NUM> while also storing any excess power. When green power is not available, the microgrid controller <NUM> could operate to use stored energy before initiating operation of non-green power sources.

In operation, the microgrid controller <NUM> determines the total load required by the AC loads <NUM> and the DC loads <NUM> and selects the power generation sources to provide at least that load. Specifically, the microgrid controller <NUM> may operate to first dispatch the green power sources, whether AC or DC to provide the necessary power to the AC loads <NUM> and the DC loads <NUM>. If there is excess green power available, the microgrid controller <NUM> may initiate operation of one or more of the various energy storage systems to store that power. If the green power is not sufficient to support the AC loads <NUM> and the DC loads <NUM> the microgrid controller <NUM> determines which power source or sources to use to deliver the additional power. The microgrid controller <NUM> may initiate additional non-green power generators such as the combustion turbines <NUM>, may utilize energy stored in one of the AC energy storage systems <NUM>, the batteries <NUM>, the ultracapacitors <NUM>, and/or the DC energy storage systems <NUM>.

Under some conditions, the power generation capacity of the microgrid <NUM> may exceed the AC loads <NUM>, the DC loads <NUM>, and the energy storage capacity of the microgrid <NUM>. In these situations, energy production can be reduced.

Before proceeding, it should be noted that terms such as systems, loads, subsystems, and the like are interchangeable. Typically, a subsystem is part of a system or a load, however, subsystems can themselves be loads or systems as well.

<FIG> schematically illustrates a specific portion of the microgrid <NUM> of <FIG>. The arrangement of <FIG> is intended to utilize only green power sources <NUM> to power a production system <NUM> that operates to produce a final output product <NUM>. The arrangement of <FIG> includes a microgrid controller <NUM> that operates to control the production system <NUM>, the green power sources <NUM>, any AC energy storage systems <NUM>, and any DC energy storage systems <NUM> to operate the production system <NUM> using only green energy such that the final output product <NUM> is deemed "green". As used herein, a "green power source <NUM>" is a power source that operates using only renewable inputs to drive the energy source. Examples of green power sources <NUM> include but are not limited to, wind power, geothermal, hydroelectric, solar power, biomass, fuel cells, gas turbines (combusting green fuels), nuclear power, and the like. Similarly, the term "deemed green" refers to products made from processes that are powered by green power sources <NUM>. In some cases, being deemed green requires that at least <NUM>% of the power used to power the process is generated by green power sources <NUM>, with other designations requiring different percentages.

In some constructions, the microgrid controller <NUM> assigns a green coefficient to each of the power sources and uses that coefficient to dispatch the various power sources. The green coefficient can be as simple as a binary choice such as "is green" and "is not green". However, other arrangements may have more varied choices for green coefficients. For example, a gas turbine that operates on a mixed fuel of green methane or hydrogen and a non-green fuel may have a value between green and not green. For example, a green source may have a value of one, a non-green source may be a zero, while a variable source such as the one just described may have a green coefficient of one-half. Of course, other arrangements or methods may be used to identify power sources as green or not green.

As discussed with regard to <FIG>, the green power sources <NUM>, which are a subset of the AC electrical generators <NUM> and the DC electrical generators <NUM> of <FIG> are connected to the AC bus <NUM> (or the DC bus <NUM>) via a controllable input switch <NUM> to provide useable electricity. Similarly, the AC energy storage systems <NUM> and the DC energy storage systems <NUM> are connected to the AC bus <NUM> (or the DC bus <NUM>) via a controllable input switch <NUM> to provide useable electricity. Power generation communication links <NUM> and power storage communication links <NUM> extend between the green power sources <NUM> and the microgrid controller <NUM> and between the AC energy storage systems <NUM>, DC energy storage systems <NUM>, and the microgrid controller <NUM> to allow the microgrid controller <NUM> to control the operation of the green power sources <NUM>, the AC energy storage systems <NUM>, and the DC energy storage systems <NUM>. The power generation communication links <NUM> and the power storage communication links <NUM> provide two-way communication such that in addition to the aforementioned control signals, sensor signals can be transmitted to the microgrid controller <NUM> to allow for monitoring and control. Thus, during operation, the microgrid controller <NUM> is able to measure a quantity of power delivered to the microgrid from the various energy sources. It should be noted that the power generation communication links <NUM> and the power storage communication links <NUM> can be wired connections, wireless connections, or any combination thereof as may be desired.

The production system <NUM> operates to draw a quantity of power from the microgrid <NUM> to convert input materials into the final output product <NUM>. This quantity of power drawn from the microgrid <NUM> is periodically compared to the quantity of power delivered to the microgrid <NUM> to keep the microgrid <NUM> in balance. If the comparison shows too much power is being drawn by the production system <NUM>, the microgrid controller <NUM> will operate to increase the power delivered to the microgrid <NUM> or will reduce the quantity of power drawn from the microgrid <NUM>. One of the goals of the present system is to produce the product using only green energy or at least a sufficient percentage of green energy to deem the final output product <NUM> as a green product. As will be discussed below, the microgrid controller <NUM> operates to achieve this goal by first selecting only green sources of power (i.e., sources of power with high green coefficients).

The production system <NUM> can be virtually any system capable of producing any product. While <FIG> will be described as a specific system, it should be understood that the example is provided for clarity and the production system <NUM> should not be limited to this arrangement alone. Additionally, while the production system <NUM> is illustrated as producing a final output product <NUM> in the form of gasoline, other products produced as part of the process could be the ultimate final output product <NUM> in other arrangements. Therefore, the production system <NUM> should not be limited to systems that produce a final output product <NUM> in the form of gasoline.

Typically, a production system <NUM> can be divided into a number of loads with each load including subsystems therein. The production system <NUM> includes a first load in the form of a demineralized water plant <NUM>, a second load in the form of an electrolyzer <NUM>, a third load in the form of a methanol synthesis plant <NUM>, a fourth load in the form of a methanol to gasoline plant <NUM>, a fifth load in the form of an electrical steam generator <NUM>, and a sixth load in the form of a direct air capture plant <NUM>. Each of the loads is selectively connected to the AC bus <NUM> via an output switch <NUM>. Each output switch <NUM> is separately controllable to allow the microgrid controller <NUM> to selectively separate one or more of the loads from the AC bus <NUM> as may be required.

An input material in the form of raw water <NUM> is directed to the demineralized water plant <NUM> at the start of the production system <NUM>. As will be discussed in greater detail with regard to <FIG>, the demineralized water plant <NUM> includes a number of subsystems that operate to convert the raw water into demineralized water with many of these subsystems consuming power during operation. In the illustrated arrangement, the demineralized water is delivered to a demineralized water storage tank <NUM> following passage through the demineralized water plant <NUM>. It should be noted that one or more tanks could be employed for the storage of the water. These tanks can be open tanks (i.e., unpressurized), closed pressurized tanks, or a combination thereof. It should also be noted that the term "tank" as used herein refers to a storage device capable of storing the desired medium under the desired conditions, thereby acting as a buffer. In many cases, these will be conventional tanks. However, some media or some storage conditions may better utilize storage containers that, while referred to as tanks, are not necessarily tanks as that word might normally be used.

A portion of the demineralized water is directed to the electrolyzer <NUM> with a second portion of the demineralized water being delivered to the electrical steam generator <NUM>. Each of the electrolyzer <NUM> and the electrical steam generator <NUM> include subsystems that consume electrical power and use the demineralized water to produce an output product. In the case of the electrolyzer <NUM>, the subsystems (discussed in greater detail with regard to <FIG>) operate in response to the receipt of electrical power to produce an output product in the form of hydrogen, with a waste stream of oxygen <NUM> being produced as well. The hydrogen is delivered to a hydrogen tank <NUM> for storage and future use. The hydrogen may be refrigerated and/or pressurized for storage in the hydrogen tank <NUM> as may be desired.

The electrical steam generator <NUM> includes subsystems that operate in response to the receipt of electrical power to heat the demineralized water to produce steam. The electrical steam generator <NUM> electrically heats the water without any combustion, thereby maintaining the green nature of the production system <NUM>. However, other constructions may employ a combustion process that utilizes a green fuel to produce the steam. The produced steam is fed to a steam tank <NUM> or other steam storage or buffering system following production.

A portion of the steam is directed to the direct air capture plant <NUM> which also receives a flow of air <NUM> as well as electrical power and operates to extract carbon dioxide from the air <NUM>. The direct air capture plant <NUM> includes subsystems that operate to produce an output in the form of carbon dioxide. The carbon dioxide is directed to a carbon dioxide tank <NUM> in which the carbon dioxide is stored for future use. Again, the carbon dioxide may be chilled and/or compressed for storage in the carbon dioxide tank <NUM>. As will be discussed, portions of the steam are also directed to the methanol synthesis plant <NUM> and the methanol to gasoline plant <NUM>.

The methanol synthesis plant <NUM> includes subsystems that receive as inputs electrical power from the AC bus <NUM>, hydrogen from the hydrogen tank <NUM>, carbon dioxide from the carbon dioxide tank <NUM>, and steam from the steam tank <NUM>, and use those inputs to produce an output product in the form of methanol. The methanol is directed to a methanol tank <NUM> for storage. In some constructions, the methanol is chilled and/or pressurized for storage in the methanol tank <NUM>.

The methanol to gasoline plant <NUM> receives as inputs, electrical power from the AC bus <NUM>, steam from the steam tank <NUM>, and methanol from the methanol tank <NUM>. The methanol to gasoline plant <NUM> includes subsystems that operate to use the various inputs to produce the final output product <NUM> in the form of gasoline. The gasoline may be directed to a pipeline for distribution and/or to various storage facilities for collection and eventual distribution and use.

Each of the tanks <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, are optional and can be omitted if desired. In addition, while the tanks <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are described as storing product, in some cases the storage period may be very short and essentially zero. For example, if one of the loads requires <NUM>% of the product produced by an upstream load, that production simply passes through the tank as it travels to the downstream load. Nevertheless, the tanks <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be provided to provide a buffer to simply store extra production or fill in for periods of underproduction as will be discussed.

<FIG> is a simplified schematic of the demineralized water plant <NUM> better illustrating some of the possible subsystems. As shown, the raw water <NUM> enters the demineralized water plant <NUM> and is collected in a raw water tank <NUM>. A first pump <NUM> operates in response to the receipt of electrical power <NUM> to deliver raw water <NUM> to a first filter <NUM> where it is filtered. The water is then delivered to a cation bed <NUM> that performs a first treatment on the water. The water may then be delivered to a degasser <NUM> or settling tank before a second pump <NUM> operates in response to the receipt of electrical power <NUM> to pump the water into an anion bed <NUM> for further treatment, through a second filter <NUM> and ultimately into the demineralized water storage tank <NUM>. Each of the first filter <NUM> and the second filter <NUM> may include an air blower <NUM> that operates to blow air or another gas into the respective filters to backwash any filter media within the filters.

Thus, the multiple components of the demineralized water plant <NUM> and in particular, those that include components that receive electrical power <NUM> can be considered subsystems of the demineralized water plant <NUM>. It should be noted that the demineralized water plant <NUM> illustrated in <FIG> is greatly simplified and is provided simply to illustrate some possible subsystems within the demineralized water plant <NUM>. Of course, some of these subsystems could be eliminated and additional subsystems could be included in the demineralized water plant <NUM>.

<FIG> is a simplified schematic of an arrangement of an electrolyzer <NUM> better illustrating some of the possible subsystems. As shown, electrical power is provided from the AC bus <NUM> and may be delivered to an electrolyzer transformer <NUM> to adjust the current and/or voltage of the AC power. A rectifier <NUM> is provided to convert the AC power to a direct current for delivery to one or more electrolyzer units <NUM>. As an alternative, DC power can be delivered directly from the DC bus <NUM>, thereby eliminating the need for the rectifier <NUM>.

The electrolyzer unit <NUM> includes a tank or vessel that is filled with an electrolyte (i.e., saltwater) and contains a cathode <NUM> and an anode <NUM>. During the electrolysis process, electrical power separates the water within the electrolyzer unit <NUM> into hydrogen and oxygen. The hydrogen is collected using a hydrogen compressor <NUM> that operates in response to the receipt of electrical power <NUM> to compress the hydrogen for storage in the hydrogen tank <NUM>. While not illustrated, a hydrogen refrigeration system may also be employed to cool or liquefy the hydrogen for more efficient storage. The oxygen <NUM> may be collected and stored for future use or may simply be discharged into the atmosphere.

The electrolysis process consumes water, thereby requiring a replenishment subsystem. As illustrated in <FIG>, a water pump <NUM> operates in response to the receipt of electrical power <NUM> to pump demineralized water from the demineralized water storage tank <NUM> to a water purifier <NUM>. The water purifier <NUM> may include additional filters, water treatment devices, or salt systems that condition the water for delivery into the electrolyzer unit <NUM>.

Thus, the multiple components of the electrolyzer <NUM> and in particular, those that include components that receive electrical power <NUM> can be considered subsystems of the electrolyzer <NUM>. It should be noted that the electrolyzer <NUM> illustrated in <FIG> is greatly simplified and is provided simply to illustrate some possible subsystems within the electrolyzer <NUM>. Of course, some of these subsystems could be eliminated and additional subsystems could be included in the electrolyzer <NUM>.

<FIG> as well as the descriptions of the demineralized water plant <NUM> and the electrolyzer <NUM> are provided as examples of subsystems within these larger loads or systems. It should be understood that each of the methanol synthesis plant <NUM>, the methanol to gasoline plant <NUM>, the electrical steam generator <NUM>, and the direct air capture plant <NUM> may include subsystems similar to those described with regard to <FIG>. The description of these subsystems has been omitted for the sake of brevity.

As discussed, the microgrid controller <NUM> operates to periodically compare the quantity of power delivered to the microgrid and the quantity of power drawn from the microgrid to maintain a balance therebetween. If the power becomes unbalanced, the microgrid <NUM> may become unstable and the voltage or frequency may vary an unacceptable amount from the desired values. In particular, if the power becomes unbalanced, the frequency of the microgrid <NUM> may vary from the desired value.

Instability is particularly concerning when rapidly varying loads are attached to the microgrid <NUM> or when the electrical generators, and in particular the green power sources <NUM> are volatile or highly variable. For example, wind turbines are susceptible to changes in wind speed such that the power generated, and importantly the maximum power available from the wind turbines varies and is unpredictable. Similarly, solar power is reliant upon sunshine. If the level of sunshine suddenly changes (e.g., a cloud forms), the level of power generated by the PV solar generator <NUM> or the concentrated solar generator <NUM> would drop.

To compensate for this instability, the microgrid <NUM> could include excess generation or could limit the loads attached to the microgrid <NUM>. However, this is inefficient. In addition, less volatile power supplies including non-green sources could be included in the microgrid <NUM>. However, the use of these generators would result in a non-green final output product <NUM>.

An alternative to the aforementioned options is to provide the microgrid controller <NUM> with a plant coordination system that balances the power in the microgrid <NUM> by controlling the quantity of power drawn from the microgrid <NUM> when additional power, and in particular additional green power or power from stored energy sources cannot be used to increase the quantity of power delivered to the microgrid. This is particularly important when it is desired to use only green power in a particular system or arrangement.

The quantity of power drawn from the microgrid <NUM> is controlled by implementing a load shedding process that is implemented following a series of escalation levels. To implement the load shedding process, the microgrid controller <NUM> calculates or stores precalculated values for an automation level and a production change capability for each load and in some cases various subsystems for the loads.

"Automation level" refers to a degree of automation of a load, system, or subsystem. Loads, systems, or subsystems that require operator intervention or a number of manual tasks in order to start, stop or change states would have a low automation level. In contrast, loads, systems, or subsystems that automatically start, stop, or change operation with little to no user intervention would have a high automation level.

"Production change capability" refers to the speed or time required for a load, system, or subsystem to transition between operational setpoints as well as the variation between minimum and maximum set points. For example, a load, system, or subsystem that can change operational setpoints rapidly as compared to other loads, systems, or subsystems (e.g., <NUM>% per minute) would have a high production change capability. In contrast, a load, system, or subsystem that is limited to slow operational changes (e.g., <NUM>% per hour) would have a lower production change capability. Similarly, the range of these operational changes also affects the production change capability. For example, two loads, systems, or subsystems that are both capable of changing setpoints at the same rate may still have different production change capabilities if one load, system, or subsystem can operate in a range from <NUM>% load to <NUM>% while the other load, system, or subsystem only operates from <NUM>% to <NUM>%. The larger range would lead to a higher production change capability.

When the microgrid controller <NUM> determines that a reduction in the quantity of power drawn from the microgrid <NUM> is required (i.e., additional power cannot be added to the microgrid <NUM>), the microgrid controller <NUM> follows a series of steps. First, the microgrid controller <NUM> determines if the power reduction can be achieved by reducing the operational setpoints of one or more of the loads to achieve part-load operation of those loads. In making this selection, the microgrid controller <NUM> balances the load reduction with the output level of the final output product <NUM> to maximize the quantity of the final output product <NUM> produced while still operating one or more loads at part load.

If reducing the operational setpoints is not sufficient to achieve the necessary power consumption reduction, the microgrid controller <NUM> next reduces the setpoints and therefore the electrical consumption of one or more subsystems within the loads.

If the reduction of certain subsystems is also not sufficient to achieve the necessary power consumption reduction, the microgrid controller <NUM> next transitions one or more subsystems into a standby mode and ultimately, if this is unsuccessful the microgrid controller <NUM> will shut down selected loads, systems, or subsystems. For example, operation of the air blowers <NUM> of the demineralized water plant <NUM> could be reduced or stopped to reduce the use of electrical power <NUM> without reducing the output of the demineralized water plant <NUM>.

To make the aforementioned reductions in setpoints of the loads or subsystems, or the transition to standby or ultimate shutdown of loads, systems, or subsystems, the microgrid controller <NUM> relies at least in part on the values of the automation level and the production change capability. For example, when reducing setpoints for loads or subsystems, the microgrid controller <NUM> reduces systems with a high automation level and with a high production change capability. These setpoint changes can be done seamlessly and automatically and because the loads or subsystems have a high production change capability, they are more likely to allow for quick and large setpoint changes without adversely affecting the operation of the system.

Similarly, when transitioning a load or subsystem to standby, or shutting down a load or subsystem, the microgrid controller <NUM> will select those loads and subsystems that have the highest automation level and that have the highest production change capability. The high automation level is particularly important when transitioning to standby or shutting down a load or subsystem as it is indicative of the difficulties involved in completing the shutdown as well as initiating a startup. For example, stopping operation of the water pump <NUM> in the electrolyzer <NUM> does not require any significant operational steps. However, shutting down a methanol synthesis plant <NUM> may require the purging of fuel lines and other components to remove any residual methanol. Therefore, the automation level of the electrolyzer <NUM> would be lower than the automation level of the water pump <NUM>.

In block <NUM>, a method of operating a microgrid <NUM> includes operating one of a plurality of power sources to deliver power to the microgrid. In block <NUM>, the method of operating a microgrid <NUM> includes measuring a quantity of power delivered to the microgrid. In block <NUM>, the method of operating a microgrid <NUM> includes drawing power from the microgrid to power one of a plurality of loads, each load including a plurality of separately operable subsystems. In block <NUM>, the method of operating a microgrid <NUM> calculates an automation level and a production change capability for each load and subsystem of the plurality of subsystems. In block <NUM>, the method of operating a microgrid <NUM> measures a quantity of power drawn from the microgrid. In block <NUM>, the method of operating a microgrid <NUM> reduces the quantity of power drawn from the microgrid in response to a measured quantity of power drawn exceeding a measured quantity of power provided. The reducing step follows a sequence of reductions which includes the following. In block <NUM>, the method of operating a microgrid <NUM> reduces an operating level of a first load of the plurality of loads. In block <NUM>, the method of operating a microgrid <NUM> determines if the reduction in operating level was sufficient to reduce the measured quantity of power drawn from the microgrid to a point at or below the measured quantity of power provided. In block <NUM>, the method of operating a microgrid <NUM> limits the power consumption of a first subsystem below the reduced operating level in response to the determining step concluding the reducing step did not sufficiently reduce the quantity of power drawn from the microgrid, the first subsystem selected based in part on the calculated automation level and the production change capability.

Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

Claim 1:
A method of operating a microgrid (<NUM>, <NUM>), the method comprising:
operating one of a plurality of power sources (<NUM>) to deliver power (<NUM>) to the microgrid (<NUM>, <NUM>), wherein the microgrid comprises a production system (<NUM>) which can be divided into a plurality of load (<NUM>, <NUM>)<NUM>;
measuring a quantity of power (<NUM>) delivered to the microgrid (<NUM>, <NUM>);
drawing power (<NUM>) from the microgrid (<NUM>, <NUM>) to power (<NUM>) one of the plurality of loads (<NUM>, <NUM>), each load (<NUM>, <NUM>) including a plurality of separately operable subsystems;
calculating an automation level and a production change capability for each load (<NUM>, <NUM>) and subsystem of the plurality of subsystems, wherein an automation level refers to a degree of automation of a load or subsystem which is high for a load or a subsystem whose start, stop or change operation requires little or no user intervention<NUM>, wherein a production change capability refers to the speed or time required for a load or a subsystem to transition between operational setpoints, wherein a load or a subsystem that can change operational setpoints rapidly as compared to other load or subsystem in the microgrid have a high production change capability<NUM>;
measuring a quantity of power (<NUM>) drawn from the microgrid (<NUM>, <NUM>); and
reducing the quantity of power (<NUM>) drawn from the microgrid (<NUM>, <NUM>) in response to a measured quantity of power (<NUM>) drawn exceeding a measured quantity of power (<NUM>) provided, the reducing step following a sequence of reductions which includes:
reducing an operating level of a first load of the plurality of loads (<NUM>, <NUM>);
determining that the reduction in operating level was insufficient to reduce the measured quantity of power (<NUM>) drawn from the microgrid (<NUM>, <NUM>) to a point at or below the measured quantity of power (<NUM>) provided; and
limiting the power consumption of a first subsystem below the reduced operating level in response to the determining step concluding the reducing step did not sufficiently reduce the quantity of power (<NUM>) drawn from the microgrid (<NUM>, <NUM>),
wherein the first subsystem is selected based in part on the calculated automation level and the production change capability.