Methods and systems for charging electrical devices via an electrical system

Disclosed herein are methods, systems, and devices that may be implemented by an energy aggregator to control, or regulate, the electric load placed on an electric grid by an aggregation of electrical devices, such as electric vehicles. Generally, the disclosed methods, and systems may provide for the modulation of the power draw of each electric vehicle around a first power draw, or scheduled power draw. Further, the disclosed methods and systems provide for the determination of a desirable scheduled power draw for a given electric vehicle. In one example, the scheduled power draw may be determined based on, among other things, the amount of time left in a given charging scenario and the state of charge of the given electric vehicle. In another example, the scheduled power draw may be determined based on, among other considerations, a maximization of the profit derived by the energy aggregator for both providing power to an aggregation of electric vehicles and for providing a regulation function to the electrical grid (at the request, for example, of an electrical-system operator).

BACKGROUND

Today, power is typically generated by a given power-generation source (e.g., a coal-, natural gas-, nuclear-, hydro-, or oil-based power plant, and/or, increasingly, some other renewable energy source, such as wind or solar) and then transmitted and distributed throughout a given geographic region via an electrical grid. Entities that generate, transmit, and/or distribute power may be referred to as utilities, while entities that coordinate, control, and/or monitor electricity transmission throughout the electrical grid may be referred to as electrical-system operators (e.g., a regional transmission organization (RTO) or an independent system operator (ISO)). Grids covering large geographic regions, such as the United States, may consist of a patchwork of utilities and operators.

Individuals increasingly demand inexpensive and more power to support various activities—yet those same individuals, generally, do not desire to have that energy produced near their homes (e.g., by power plants, which may generate, in addition to power, pollution, noise, etc.). To address this problem, utilities and operators attempt to generate and distribute power in a manner that is as efficient and unobtrusive as possible. As a result, advances in efficient approaches to energy management, e.g., efficient approaches to energy generation, transmission, and distribution, are clearly desired.

One recent approach to efficient energy management involves the aggregation of many electrical devices connected to an electrical grid (including those that are relatively small consumers/resources of energy) by an energy aggregator, such that the many electrical devices may be treated as a single, significant entity that is connected to the electrical grid. Thereby, such energy aggregators may enable an electrical-system operator, and other entities associated with the electrical grid more generally, to treat the aggregated electrical devices as a power generation source and/or a storage device. Within this configuration, it may be possible to control the aggregated electrical devices in a unidirectional and/or a bidirectional manner. For instance, in the unidirectional case, the respective power draw of the aggregated electrical devices may be controlled such that those electrical devices are treated as a controllable load. And in the bidirectional case, the energy stored in aggregated electrical devices to be pumped back into the electrical grid.

SUMMARY OF THE INVENTION

Recent advancements in electric vehicles suggest that electric vehicles are poised to become more and more pervasive in coming years. As such, electric vehicles (which, generally, run on power supplied by a battery), may be one type of electrical device well suited for control via an energy-aggregation arrangement. While bidirectional control of electric vehicles has garnered significant interest of energy aggregators, in many ways unidirectional control of electric vehicles may be more desirable and/or practical, at least in the near future.

Bidirectional control of aggregated electric vehicles may be desirable to the extent that it enables an energy aggregator to cause the aggregated vehicles to both consume energy from and provide energy to the electrical grid. However, bidirectional control faces serious challenges for its adoption, especially in the short term. For example, in order to pump energy from electric vehicles back into the electrical grid, such electric vehicles may require special hardware. Further, bidirectional power flow gives rise to the need for anti-islanding protection, as well as the need to address numerous other interconnection issues, resulting in significant infrastructure-related concerns. Further still, bidirectional power flow results in increased cycling wear on batteries and, therefore, decreased lifetimes of batteries. And, not insignificantly, consumers may be resistant to allowing a utility to pull energy from the batteries of their electric vehicles. Such drawbacks of bidirectional control may apply to the aggregation of electrical devices other than electric vehicles.

However, many existing electric vehicles, and electrical devices more generally, can participate in unidirectional energy aggregation without the need for significant modifications to infrastructure, charging stations, or the electrical devices themselves. Thus, the optimization of unidirectional control of aggregated electrical devices, such as electrical vehicles, may have particular benefits. Nonetheless, efforts thus far to develop such optimization techniques have proven inadequate. Accordingly, the disclosure herein is generally directed to the unidirectional control of aggregated electrical devices.

Disclosed herein are methods, systems, and devices that enable the efficient control of respective power draws of various electrical devices in an electrical system. According to the disclosed methods, systems, and devices, an energy aggregator (or some other component) may control the electric load placed on an electric grid by an aggregation of electrical devices, such as electric vehicles. For instance, the energy aggregator may modulate the power draw of each electric vehicle around a first power draw (e.g., a scheduled power draw). Further, the energy aggregator may determine a desirable scheduled power draw for a given electric vehicle. In one example, the scheduled power draw may be determined based on, among other things, the amount of time left in a given charging scenario and the state of charge of the given electric vehicle. In another example, the scheduled power draw may be determined based on a maximization of the profit derived by the energy aggregator for both providing power to an aggregation of electric vehicles and for providing a regulation function to the electrical grid (e.g., at the request of an electrical-system operator).

A first embodiment of the disclosed methods, systems, and devices may take the form of a method that includes (a) determining, based on at least a respective state of charge of each electrical device from a set of electrical devices, a respective first power draw of each electrical device, where each electrical device is coupled to an electrical system, (b) receiving an electrical-system-regulation value from an electrical-system operator that indicates a variation from a scheduled power consumption of the electrical system, (c) determining a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value, and (d) transmitting to the given electrical device a power-draw message indicating the determined second power draw. The respective first power draw may be a respective scheduled power draw of each electrical device. The second power draw may be a respective dispatched power draw of each electrical device.

In an aspect of the first embodiment, determining the respective first power draw of each electrical device may involve maximizing an energy-aggregator profit based on various factors. For example, the energy-aggregator profit may be maximized based on at least the respective first power draw for each electrical device. As another example, the energy-aggregator profit may also be maximized based on at least one of (i) a respective maximum additional power draw for each electrical device, (ii) a respective minimum additional power draw for each electrical device, and (iii) a respective final state of charge for each electrical device. As yet another example, the energy-aggregator profit may be maximized subject to a set of conditions defined by at least (a) one of an income of the energy aggregator and a cost to the energy aggregator, (b) the respective first power draw of each electrical device, and (c) a respective maximum possible power draw of each electrical device. The energy-aggregator profit may be maximized based on other factors as well.

In another aspect of the first embodiment, determining the respective first power draw of each electrical device may involve dividing (i) a difference of a respective maximum charge capacity of each electrical device and a respective current state of charge of each electrical device by (ii) an amount of time remaining in a charging time period. According to such an aspect, the determined first power draw may be subject to at least one condition, such as (a) the first power draw is not greater than a charge remaining to be supplied to the given electrical device, (b) a maximum additional power draw of the given electrical device is the lesser of (i) a difference of a maximum possible power draw of the given electrical device and the first power draw of the given electrical device and (ii) a difference of the charge remaining to be supplied to the given electrical device and the first power draw of the given electrical device, and (c) a minimum additional power draw of the given electrical device is equal to the first power draw of the given electrical device.

In yet another aspect of the first embodiment, determining the second power draw may involve the use of one or more regulation algorithms. Such regulation algorithms may involve an analysis of, for example, the electrical-system-regulation value received from the electrical-system operator, a responsive-reserve-regulation value received from the electrical system operator, and/or the determined first power draw. Other examples are possible as well.

A second embodiment of the disclosed methods, systems, and devices may take the form of a computing device that includes a non-transitory computer readable medium; and program instructions stored on the non-transitory computer readable medium and executable by at least one processor to cause the computing device to: (a) determine, based on at least a respective state of charge of each electrical device from a set of electrical devices, a respective first power draw of each electrical device, where each electrical device is coupled to an electrical system, (b) receive an electrical-system-regulation value from an electrical-system operator that indicates a variation from a scheduled power consumption of the electrical system, (c) determine a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value, and (d) transmit to the given electrical device a power-draw message indicating the determined second power draw.

A third embodiment of the disclosed methods, systems, and devices may take the form of a physical computer-readable medium having computer executable instructions stored thereon, the instructions comprising: (a) instructions for determining, based on at least a respective state of charge of each electrical device from a set of electrical devices, a respective first power draw of each electrical device, where each electrical device is coupled to an electrical system, (b) instructions for receiving an electrical-system-regulation value from an electrical-system operator that indicates a variation from a scheduled power consumption of the electrical system, (c) instructions for determining a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value, and (d) instructions for transmitting to the given electrical device a power-draw message indicating the determined second power draw.

These as well as other aspects and advantages will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings.

DETAILED DESCRIPTION

Further, certain aspects of the disclosure herein refer to the “optimization,” or some variation thereof, of the power draw of a given electrical device. It should be understood that use of such a term (i.e. “optimization,” or some variation thereof) is not mean to imply that the power draw reflects a power draw that is ideal, perfect, or desirable in all situations. Instead, such a term is used for purposes of example and explanation only to describe the example power draws that may be determined according to the various methods described herein. Therefore, use of the term “optimization,” or some variation thereof, should not be taken to be limiting.

I. Example Electrical System

FIG. 1depicts a simplified block diagram of an example electrical system in accordance with some embodiments. It should be understood that this and other arrangements described herein are set forth only as examples. Those skilled in the art will appreciate that other arrangements and elements (e.g., machines, interfaces, functions, orders, and groupings of functions, etc.) can be used instead and that some elements may be omitted altogether. Further, many of the elements described herein are functional entities that may be implemented as discrete or distributed components in conjunction with other components and in any suitable combination and location. Various functions described herein as being performed by one or more entities may be carried out by hardware, firmware, and/or software. For instance, various functions may be carried out by a processor executing instructions stored in memory.

As shown inFIG. 1, example electrical system100includes energy aggregator102, electrical-system operator104A, and electrical utility104B. Electrical system100also includes various electric vehicles such as electric vehicles112A-112C (shown as parked in parking facility112),116, and120, and includes home118, each of which is directly or indirectly coupled to electrical-system operator104A and electrical utility104B. Additional entities could be present as well or instead. For example, there could be additional electric vehicles coupled to electrical-system operator104and/or energy aggregator102; furthermore, there could be additional entities coupled to, or otherwise in communication with electrical-system operator104and/or energy aggregator102, including electrical devices that consume energy other than electric vehicles112A-112C,116, and120. Generally, electrical-system operator104A, electrical utility104B, and/or energy aggregator102may be coupled to one or more electrical grids and thereby may participate in the provisioning of electrical-energy services to electrical devices in electrical system100.

Energy aggregator102may provide electrical energy to parking facility112by way of electrical link108A. In turn, parking facility112may distribute electrical energy provided by energy aggregator102to each of electric vehicles112A-112C by way of electrical interconnects114A-114C, respectively, which may take any suitable form such as a power outlet. As one specific example, an electrical interconnect may take the form of a Society of Automotive Engineers (SAE) J1772 compliant electrical connector. Charging of an electric vehicle that is coupled to energy aggregator102via a SAE compliant electrical connector may be controlled by adjusting a control-pilot signal sent by energy aggregator102to the electric vehicle. It should be understood, however, that a SAE compliant electrical connector is but one example of an electrical interconnect, and that other types of electrical interconnects may be used as well.

Energy aggregator102may provide electrical energy to individual electric vehicle116by way of electrical link110A, which may be accessed by electric vehicle116by way of electrical interconnect116A. Generally, the disclosure herein is directed to the unidirectional provisioning of power, and thus, according to the example shown inFIG. 1, power may flow in a single direction between energy aggregator102to each of parking facility112and electric vehicle116. That is, power may flow from energy aggregator102to each of parking facility112and electric vehicle116. However, it should be understood that the disclosure herein could just as well be applied to, or otherwise carried out with, bidirectional electrical links and therefore, in at least this respect, the examples set forth inFIG. 1should not be taken to be limiting.

Energy aggregator102may also be communicatively coupled to parking facility112and electric vehicle116by way of, for example, communication links108A and110A, respectively. Parking facility112may then indirectly communicatively couple electric vehicles112A-112C with energy aggregator102by way of communication links108C-108E, respectively.

As such, each of energy aggregator102, parking facility112, and electric vehicles112A-112C and116may be arranged to carry out the communication functions described herein and may therefore include a communication interface. The communication interface may include one or more antennas, chipsets, and/or other components for communicating with other entities and/or devices in electrical system100. The communication interface may be wired and/or wireless and may be arranged to communicate according to one or more communication protocols now known (e.g., CDMA, WiMAX, LTE, IDEN, GSM, WIFI, HDSPA) or later developed.

As shown, energy aggregator102may be electrically coupled to electric utility104B by way of electrical link106A. Although electrical link106A is shown as a unidirectional electrical link, it should be understood that electrical link106A may also be implemented as a bidirectional electrical link. Energy aggregator102may also be communicatively coupled to electrical-system operator104A by way of communication link106B. Further, electrical-system operator104A may be communicatively coupled to electrical utility104B by way of communication link104C. As such, energy aggregator102, electrical-system operator104A, and electrical utility104B may be arranged to include respective communication interfaces, such as that described above, so as to enable communications between or among themselves and/or other network entities.

Electrical utility104B may be directly coupled to various other entities in electrical system100, including, ultimately, electrical devices that are consumers of electrical energy. For example, electrical utility104B may be connected to home118by way of electrical link106A. In turn, home118may distribute electrical energy provided by electrical utility104B to other electrical devices, such as electrical vehicle120, by way of electrical interconnect122.

Energy aggregator102may be any entity that carries out the energy-aggregator functions described herein. For example energy aggregator102may be any private or public organization, or combination thereof, that is generally authorized to connect to the electrical grid and therefore participate in electrical system100.

Generally, energy aggregator102may include any necessary electrical system equipment, devices, or other elements necessary to both distribute electrical energy, as needed, and communicate with other entities and/or devices in electrical system100. As an example, energy aggregator102may include a computing device, such as computing device202shown inFIG. 2. As shown, energy-aggregator computing device202may include, without limitation, a communication interface204, processor206, and data storage208, all of which may be communicatively linked together by a system bus, network, and/or other connection mechanism214.

Communication interface204typically functions to communicatively couple energy aggregator102to other devices and/or entities in electrical system100. As such, communication interface204may include a wired (e.g., Ethernet, without limitation) and/or wireless (e.g., CDMA and/or Wi-Fi, without limitation) communication interface, for communicating with other devices and/or entities. Communication interface204may also include multiple interfaces, such as one through which energy-aggregator computing device202sends communication, and one through which energy-aggregator computing device202receives communication. Communication interface204may be arranged to communicate according to one or more types of communication protocols mentioned herein and/or any others now known or later developed.

Processor206may comprise one or more general-purpose processors (such as INTEL processors or the like) and/or one or more special-purpose processors (such as digital-signal processors or application-specific integrated circuits). To the extent processor206includes more than one processor, such processors could work separately or in combination. Further, processor206may be integrated in whole or in part with wireless-communication interface204and/or with other components.

Data storage208, in turn, may comprise one or more volatile and/or non-volatile storage components, such as magnetic, optical, or organic memory components. As shown, data storage208may include program data210and program logic212executable by processor206to carry out various energy-aggregator functions described herein. Although these components are described herein as separate data storage elements, the elements could just as well be physically integrated together or distributed in various other ways. For example, program data210may be maintained in data storage208separate from program logic212, for easy updating and reference by program logic212.

Program data210may include various data used by energy-aggregator computing device202in operation. As an example, program data210may include information pertaining to various other devices and/or entities in electrical system100such as, without limitation, any of electrical system operator104A, electrical utility104B, parking facility112, and/or electric vehicles112A-112C and116. Similarly, program logic212may include any additional program data, code, or instructions necessary to carry out the energy-aggregator functions described herein. For example, program logic212may include instructions executable by processor206for causing computing device202to carry out any of those functions described herein with respect toFIGS. 3-8.

II. Example Functions

FIGS. 3-5are generally directed to an example method for unidirectional control of aggregated electrical devices such as electric vehicles. More specifically,FIG. 3depicts a simplified flow chart of an example energy-optimization method, method300, in accordance with some embodiments. Correspondingly,FIG. 4depicts a simplified regulation-algorithm flowchart in accordance with some embodiments, including embodiments that implement aspects of method300.FIG. 5Adepicts a power-draw chart, andFIG. 5Bdepicts a state-of-charge chart, in accordance with some embodiments, including embodiments that implement aspects of method300.

FIGS. 6-8are generally directed to an additional example method for unidirectional control of aggregated electrical devices such as electric vehicles, which includes the control of utility responsive reserves. More specifically,FIG. 6depicts a simplified flow chart of an additional example energy-optimization method, method600, in accordance with some embodiments. Correspondingly,FIG. 7depicts an additional regulation-algorithm flowchart in accordance with some embodiments, including embodiments that implement aspects of method600.FIG. 8depicts an additional power-draw chart in accordance with some embodiments, including embodiments that implement aspects of method600.

Generally, the methods and functions described herein may be carried out in an electrical system, such as example electrical system100, by an energy aggregator, such as energy aggregator102. Again, however, it should be understood that example electrical system100is set forth for purposes of example and explanation only, and should not be taken to be limiting. The present methods and functions may just as well be carried out in other electrical systems having other arrangements.

As noted above, the methods and systems described herein may enable energy aggregator102to efficiently control respective power draws of various electrical devices in electrical system100. Before turning to a more detailed description of such methods and systems, a brief summary of some of the nomenclature used in the remainder of the disclosure is provided, for convenience.

The variables in the table set forth below may be referred to in the remainder of this disclosure for purposes of explanation of the methods disclosed herein. However, it should be understood that reference to such variables is for purposes of example and explanation only, and that the listing of such variables below is for purposes of convenience only, and therefore neither the variables themselves, nor the listing of the variables below, shall be taken to be limiting.

αPercentage of regulation revenue taken by the energyaggregator.ρPenalty fee that the energy aggregator must pay thecustomer per kWh for failure to meet the desiredminimum-allowable state of charge.Avi(t)Availability of the ED for V2G. 1 if the ED is availableand 0 otherwise.CCost to the energy aggregator.Compi(t)Compensation factor of the ithED to account forunplanned departures.CRiCharge remaining to be supplied to the ithED.Depi(t)Probability that the ithED will depart unexpectedly inhour t.E(PDi(t))Expected value of energy received by ithED.EfiEfficiency of the ithED's battery charger.ExDExpected percentage of regulation down capacitydispatched each hour.ExRExpected percentage of responsive reserve capacitydispatched each hour.ExUExpected percentage of regulation up capacity dispatchedeach hour.EVPer(t)Expected percentage of the EDs remaining to connect togrid at hour t.FPiFinal power draw of the ithED combining the effects ofregulation and responsive reserves.HAmount of time remaining in a charging period.InIncome of the energy aggregator.L(t)System net load (load minus renewables) at time t.MCiMaximum charge capacity of the ithED.MkEnergy-aggregator markup over wholesale energy price.MnAPiMinimum additional power draw of the ithED.MnLMinimum day-ahead forecasted net load.MnPMinimum day-ahead forecasted energy price.MPiMaximum possible power draw of ithED.MxAPiMaximum additional power draw of the ithED.MxLMaximum day-ahead forecasted net load.MxPMaximum day-ahead forecasted energy price.P(t)Energy price at time t.PDiPower draw of the ithED.POPiPreferred (target) operating point of the ithED.PRD(t)Forecasted price of regulation down for time t.PRR(t)Forecasted price of responsive reserves for time t.PRU(t)Forecasted price of regulation up for time t.RDRegulation down capacity of the aggregator.RRResponsive reserve capacity of the energy aggregator.RRSResponsive reserve signal provided to the aggregator.RSElectrical-system-regulation value provided to the energyaggregator.RSRPiReduction in power draw available for spinning reservesof the ithED.RURegulation up capacity of the energy aggregator.SOCiCurrent state of charge of the ithED.SOCmiFinal state of charge of the ithED.SOCmin,iMinimum-allowable state of charge of the ithED.SOCI,iInitial state of charge of the ithED.TripiReduction in SOC that results from the evening commutetrip home on a weekday or the second daily trip on theweekend.Ttrip,iTime that the ithED makes its second trip of the day. Ona weekday this is the commute from work to home. Onthe weekend this is simply the second excursion whichends when the ED returns home.

b. Energy Optimization

With reference toFIG. 3, method300begins at step302when the energy aggregator determines, based on at least a respective state of charge of each electrical device from a set of electrical devices, a respective first power draw of each electrical device, where each electrical device is coupled to an electrical system. At step304, the energy aggregator receives an electrical-system-regulation value from an electrical-system operator that indicates a variation from a scheduled power consumption of the electrical system. At step306, the energy aggregator determines a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value. And at step308, the energy aggregator transmits to the given electrical device a power-draw message indicating the determined second power draw. Each of these steps is discussed further below.

i. Determine First Power Draw of Each Electrical Device

At step302, energy aggregator102determines, based on at least a respective state of charge of each electrical device from a set of electrical devices such as set of electric vehicles112A-112C, a respective first power draw of each electrical device, where each electrical device is coupled to electrical system100.

Generally, the respective first power draw of each electrical device may be a respective scheduled power draw of each electrical device. Such a respective scheduled power draw is commonly referred to as a “Preferred Operating Point (POP)” in energy-aggregation contexts. As such, reference is made herein to Preferred Operating Points, and in particular to variables associated with a Preferred Operating Points, such as POPi. However, it should be understood that such references are for purposes of example and explanation only and should not be taken to be limiting. Further, the terms “first power draw,” “scheduled power draw,” and “preferred operating point” may be used herein, at times, interchangeably.

For purposes of example and explanation, two example techniques for selecting a first power draw (or scheduled power draw) for each electrical device, in accordance with step302, are described below. The first is an example heuristic charging algorithm that is referred to herein, without limitation, as a “smart selection algorithm.” The second is an example optimal charging algorithm that is referred to herein, without limitation, as an “optimal selection algorithm.” As described above, the use of the term “optimal” is for purposes of example and explanation only and should not be taken to be limiting.

According to one example smart selection algorithm, determining, based on at least the respective state of charge of each electrical device from the set of electrical devices, the respective first power draw of each electrical device involves dividing (i) a difference of a respective maximum charge capacity of each electrical device (MC,i) and a respective current state of charge of each electrical device (SOCi) by (ii) an amount of time remaining in a charging time period (H). Such an example smart selection algorithm is represented below by Equation 1.

In accordance with the smart charging algorithm represented by Equation 1, the determined first power draw, or preferred operating point, is constrained by at least one condition. As one such example condition, the first power may not be greater than a charge remaining to be supplied to the given electrical device (CRi). Such an example condition is represented below by Equation 2.
POPi=min(POPi,CRi)  (2)

As another such example condition, a maximum additional power draw of the given electrical device (MxAPi) is the lesser of (i) a difference of a maximum possible power draw of the given electrical device (MPi) and the first power draw of the given electrical device and (ii) a difference of the charge remaining to be supplied to the given electrical device (CRi) and the first power draw of the given electrical device. Such an example condition is represented below by Equation 3.
MxAPi=min(MPi−POPi,CRi−POPi)  (3)

As yet another such example condition, a minimum additional power draw of the given electrical device (MnAPi) is equal to the first power draw of the given electrical device. Such an example condition is represented below by Equation 4.
MnAPi=POPi(4)

The determined first power draw may be subject to (or may otherwise be constrained by or define) each of the conditions represented by Equations 2-4. Together, such conditions may ensure that the given electrical device does not fully charge until the end of a given charging time period (H). They also define the regulation up capacity and regulation down capacity of each electrical device.

According to one example optimal selection algorithm, determining, based on at least the respective state of charge of each electrical device from the set of electrical devices, the respective first power draw of each electrical device may involve maximizing an energy-aggregator profit based on at least the respective first power draw for each electrical device. The energy-aggregator profit may be determined as a function of the income of the energy aggregator (In), cost to the energy aggregator (C), or a difference thereof (In−C).

Maximizing the energy-aggregator profit based on at least the respective first power draw for each electrical device may involve maximizing the energy-aggregator profit based on the respective first power draw for each electrical device and at least one additional consideration. One example of such an additional consideration is a respective maximum additional power draw for each electrical device (MxAPi). Another example of such an additional consideration is a respective minimum additional power draw for each electrical device (MnAPi). Yet another example of such an additional consideration is a respective final state of charge for each electrical device (SOCmi). The energy-aggregator profit may be maximized based on the respective first power draw for each electrical device and one or more of each such additional considerations. Maximization of the energy-aggregator profit according to all such conditions is represented below by Equation 5.
maximizePOPi(t),MxAPi(t),MnAPi(t),SOCmiIn−C(5)

In general, the income of the energy aggregator (In) may be determined based on at least a regulation-service income and an energy-supply-service income. In an example, the income of the energy aggregator (In) may be determined based on the sum of the regulation-service income and the energy-supply-service income. The regulation-service income may be defined by a percentage of regulation revenue taken by the energy aggregator (a) multiplied by the summation of (i) a forecasted price of regulation up for time t (PRU(t)) multiplied by a regulation up capacity of the energy aggregator for time t (RU(t)) and (ii) a forecasted price of regulation down for time t (PRD(t)) multiplied by a regulation down capacity of the energy aggregator for time t (RD(t)), over time. The energy-supply-service income may be defined by a summation of an expected value of the energy received by each electrical device over time (E(PDi(t))) multiplied by an energy-aggregator markup over wholesale energy price (Mk). Such an income of the energy aggregator (In) is represented below by Equation 6.
In=∝Σt(PRU(t)RU(t)+PRD(t)RD(t))+MkΣiΣt(E(PDi(t)))  (6)

The regulation up capacity of the energy aggregator for time t (RU(t)) may be defined as the summation of the respective minimum additional power draw for each electrical device (MnAPi), as represented below by Equation 7.

The regulation down capacity of the energy aggregator for time t (RD(t)) may be defined as the summation of the respective maximum additional power draw for each electrical device (MxAPi), as represented below by Equation 8.

The energy received by each electrical device over time (E(PDi(t))) may be further defined as a respective maximum additional power draw for each electrical device (MxAPi) multiplied by an expected percentage of regulation down capacity dispatched (ExD) plus the first power draw minus a respective minimum additional power draw for each electrical device (MnAPi) multiplied by an expected percentage of regulation up capacity dispatched (ExU). Such an energy received by each electrical device over time (E(PDi(t))) is represented below by Equation 9.
E(PDi(t))=MxAPi(t)ExD+POPi(t)−MnAPi(t)ExU(9)
Where:

In general, the cost of the energy aggregator (C) may be determined based on at least a respective minimum-allowable state of charge of each electrical device, a respective final state of charge of each electrical device, and a respective maximum charge capacity of each electrical device. In an example, the cost of the energy aggregator (C) may be determined based on a penalty fee that the energy aggregator must pay the customer per kilowatt hour (kWh) for failure to meet the desired minimum-allowable state of charge (p), multiplied by a summation of a respective maximum charge capacity of each electrical device (MG) multiplied by a difference of a respective minimum-allowable state of charge for each electrical device (SOCmin,i) and a respective final state of charge for each electrical device (SOCmi). Such a cost of the energy aggregator (C) is represented below by Equation 12.

In general, maximizing the energy-aggregator profit may be subject to any one or more of a number of various conditions. Such conditions may be defined by various combinations (or formulations) of variables relevant to the operation of energy aggregator102. As one example, maximizing the energy-aggregator profit may be subject to a set of conditions defined by at least the respective first power draw of each electrical device and a respective maximum possible power draw of each electrical device (MPi). For instance, an example condition may be that the respective first power draw of each electrical device is less than or equal to a respective maximum possible power draw of each electrical device (MPi). Such an example condition is represented below by Equation 13.
POPi(t)≦MPi(13)

Maximizing the energy-aggregator profit may be subject to any one or more of a number of additional various conditions defined by various combinations (or formulations) of variables relevant to the operation of energy aggregator102. As represented by the equations above and below, for example, such additional considerations may be further defined by at least a bid-regulation up capacity of the energy aggregator (RU), a respective minimum additional power draw of each electrical device (MnAPi), a bid-regulation down capacity of the energy aggregator (RD), a respective maximum additional power draw of each electrical device (MxAPi), a respective expected value of the energy received by each electrical device (E(PDi(t))), a respective final state of charge of each electrical device (SOCmi), a respective initial state of charge of each electrical device (SOCLi), a respective charging efficiency of each electrical device (Efi), and a respective maximum charge capacity of each electrical device (MCi). Further examples of such conditions are represented below by Equations 14-22.
MnAPi(t)≦POPi(t)  (14)
Σt(E(PDi(t)))+SOCi≧SOCmi(15)
Σt(E(PDi(t)))+SOCi≦MCi(16)
(MxAPi(1)+POPi(1))Efi+SOCI,i≦MCi(17)
MxAPi(t)+POPi(t)≦MPi(18)
MxAPi(t)≧0  (19)
MnAPi(t)≧0  (20)
POPi(t)≧0  (21)
SOCmi≧0  (22)

At step304, energy aggregator102receives an electrical-system-regulation value from electrical-system operator104A that indicates a variation from a scheduled power consumption of the electrical system. For example, electrical-system operator104A may provide Electrical-system-regulation value (RS) to energy aggregator102by way of communication link106B.

Electrical-system operator104A may be arranged to monitor the state of electric resources of electrical utility104B and compare the state of such electric resources to a pre-determined schedule of electric resources. In the event that the state of such electric resources varies from the predetermined schedule of electric resources, electrical-system operator102A may indicate as much to energy aggregator102by way of communication link106B.

As one example, in the event that the amount of power consumed by a certain segment of an electrical grid is below that which was scheduled for the electrical grid, electrical-system operator104A may indicate that variation from schedule to energy aggregator102with the expectation that energy aggregator102will provide a regulation-down service (e.g., consume excess energy resources available from electrical utility104B by consuming more energy resources than energy-aggregator102was originally scheduled to consume), if possible. As another example, in the event that the power consumed by a certain segment of an electrical grid is above that which was scheduled for the electrical grid, electrical-system operator104A may indicate that variation from schedule to energy aggregator102with the expectation that energy aggregator102will provide a regulation-up service (e.g., consume less energy resources than energy-aggregator102was originally scheduled to consume), if possible.

iii. Determine Second Power Draw for Given Electrical Device

At step306, energy aggregator102determines a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value.

Generally, the second power draw for the given electrical device may be a dispatched power draw for the given electrical device. That is, energy aggregator102may direct the given electrical device, perhaps via one of communication links108B,110B, or another similar communication link, to operate at the second power draw.

FIG. 4depicts simplified regulation-algorithm flowchart400in accordance with some embodiments. At decision point402energy aggregator102determines whether the electrical-system regulation value (RS) exceeds system-regulation-value threshold402A. Note that, in the example shown inFIG. 4, system-regulation-value threshold402A is shown as being equal to “0.” However, this is for purposes of example and explanation only, and should not be taken to be limiting.

If, at decision point402, energy aggregator102determines that the electrical-system-regulation value (RS) exceeds system-regulation-value threshold402A, then energy aggregator102may proceed to decision point406where energy aggregator102may determine whether first regulation value406A is less than second regulation value406B, where first regulation value406A is a ratio of (i) the system-regulation value (RS) and (ii) a regulation-up capacity of the energy aggregator (RU), multiplied by a minimum additional power draw of the given electrical device (MnAPi), plus the first power draw of the given electrical device, and where second regulation value406B is a ratio of (i) a charge remaining to be supplied to the given electrical device (CRi) and (ii) a charging efficiency of the given electrical device (Efi).

If, at decision point406, energy aggregator102determines that first regulation value406A is less than second regulation value406B, energy aggregator102may proceed to decision point414and determine that the second power draw is equal to first regulation value406A (a ratio of (i) the system-regulation value (RS) and (ii) a regulation-up capacity of the energy aggregator (RU), multiplied by a minimum additional power draw of the given electrical device (MnAPi), plus the first power draw of the given electrical device).

If, at decision point406, energy aggregator102determines that first regulation value406A is greater than second regulation value406B, energy aggregator102may proceed to decision point412and determine that the second power draw is equal to second regulation value406B (a ratio of (i) a charge remaining to be supplied to the given electrical device (CRi) and (ii) a charging efficiency of the given electrical device (Efi)).

If, at decision point402, energy aggregator102determines that the electrical-system-regulation value (RS) does not exceed system-regulation-value threshold402A, then energy aggregator102may proceed to decision point404where energy aggregator102may determine whether first regulation value404A is less than second regulation value404B, where first regulation value404A is a ratio of (i) the electrical-system-regulation value (RS) and (ii) a regulation-down capacity of the energy aggregator (RD), multiplied by a maximum additional power draw of the given electrical device (MxAPi), plus the first power draw of the given electrical device, and where second regulation value404B is a ratio of (i) a charge remaining to be supplied to the given electrical device (CRi) and (ii) a charging efficiency of the given electrical device (Efi).

If, at decision point404, energy aggregator102determines that first regulation value404A is less than second regulation value404B, energy aggregator102may proceed to decision point410and determine that the second power draw is equal to first regulation value404A (a ratio of (i) the electrical-system-regulation value (RS) and (ii) a regulation-down capacity of the energy aggregator (RD), multiplied by a maximum additional power draw of the given electrical device (MxAPi), plus the first power draw of the given electrical device).

If, at decision point404, energy aggregator102determines that first regulation value404A is greater than second regulation value404B, energy aggregator102may proceed to decision point408and determine that the second power draw is equal to first regulation value404B (a ratio of (i) a charge remaining to be supplied to the given electrical device (CRi) and (ii) a charging efficiency of the given electrical device (Efi)).

iv. Transmit Power-Draw Message Indicating Second Power Draw

At step308, energy aggregator102transmits to the given electrical device a power-draw message indicating the determined second power draw. For example, energy aggregator102may transmit the power-draw message to parking facility112via communication link108B, which may be relayed directly or indirectly to one of electric vehicles112A-112C via communication links108C-108E, respectively. As another example, energy aggregator102may transmit the power-draw message to electric vehicle116via communication link110A.

As noted above, the second power draw may be a dispatched power draw, and accordingly, a given electrical device that receives the power-draw message may respond by adjusting the power draw of its battery to correspond (or to equal) the second power draw indicated in the power-draw message. In this way, the power draw of the given electrical device may vary in time, according to the second power draw determined by energy aggregator102for the given electrical device.

For purposes of example and explanation,FIG. 5Adepicts power-draw chart510in accordance with some embodiments.FIG. 5Arepresents an example power draw514(PDi) of a given electrical device. Note that inFIG. 5A, the amount of power draw of the given electrical device is shown as the vertical axis510A and time is shown as the horizontal axis510B.

Additionally, the first power draw (scheduled power draw or preferred operating point)512of the given electrical device is shown as constant in time. Thus, power draw514varies with time around, generally, first power draw512according to the second power draw indicated in the power-draw message provided by energy aggregator102.

Further, power-draw chart510shows the maximum possible power draw of the given electrical device516(MPi). Further still, power-draw chart510shows the maximum additional power draw of the given electrical device518(MxAPi), as well as the minimum additional power-draw of the given electrical device520(MnAPi).

For purposes of example and explanation,FIG. 5Bdepicts state-of-charge chart530in accordance with some embodiments.FIG. 5Brepresents an example state of charge532(SOCi) of a given electrical device. Note that inFIG. 5B, the state of charge of the given electrical device is shown as the vertical axis530A and time is shown as the horizontal axis530B.

Additionally, state-of-charge chart530shows a maximum charge capacity of the given electrical device534(MCi), and a charge remaining to be supplied to the given electrical device536(CRi). The state of charge532is shown as generally increasing with time (although at varying rates, in accordance with the second power draw indicated by the received power-draw message).

c. Energy Optimization with Responsive Reserves

Most electrical systems are arranged such that an electrical-system operator associated with the electrical system has access to responsive reserves—or extra generating capacity that is available in a short interval of time to meet demand in case, for example, a generator goes down or there is another disruption in the electrical supply of the electrical system. Such responsive reserves are commonly divided into spinning reserves (i.e., extra generating capacity that is available by increasing the power output of generators that are already connected to the power system), and supplemental reserves (i.e., extra generating capacity that is not currently connected to the electrical system but can be brought online after a short delay). Generally, such responsive reserves provide a particularly extreme regulation-up service.

Aggregated electrical devices that are under unidirectional control are able to provide a regulation-up service similar to that provided by responsive reserves by decreasing the amount of energy consumed by the aggregated electrical devices. That is, by decreasing the energy consumed by the aggregated electrical devices, the aggregation may decrease the electrical burden of the electrical system and thereby make additional energy resources available to other electrical-system entities. An energy aggregator, such as energy aggregator102, may play a critical role in implementing such a responsive reserve function for an aggregation of electrical devices.

Further, while method300described with respect toFIG. 3, generally involved the optimization of electrical-device power draws over a given period of charging, it may be beneficial to optimize electrical-device power draws over longer periods of time, such as, for example, a day. Such an approach may enable an energy aggregator to more accurately account for the availability of electrical devices throughout the day and therefore maximize energy-aggregator profit to a further extent with the end result that the power draw dispatched to a given electrical device is even more desirable.

Accordingly, method600begins at step602when the energy aggregator determines, based on at least a respective state of charge of each electrical device from a set of electrical devices, a respective first power draw of each electrical device, where each electrical device is coupled to an electrical system. At step604, the energy aggregator receives an electrical-system-regulation value from an electrical-system operator that indicates a variation from a scheduled power consumption of the electrical system. At step606, the energy aggregator determines a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value. At step608, the energy aggregator receives a responsive-reserve-regulation value from an electrical-system operator that indicates a requested-responsive-reserve amount. At step610, the energy aggregator determines a third power draw for the given electrical device from the set of electrical devices based on at least the determined second power draw and the received responsive-reserve-regulation value. At step612, the energy aggregator transmits to the given electrical device a third-power-draw message indicating the determined third power draw.

i. Determine First Power Draw of Each Electrical Device

At step602, energy aggregator102determines, based on at least a respective state of charge of each electrical device from a set of electrical devices, a respective first power draw of each electrical device, where each electrical device is coupled to an electrical system.

Many of the general concepts and principals described above with respect to method300may be applied to method600. Therefore, for conciseness in explanation, an example of the determination of the first power draw in accordance with step602of method600is presented below in the form of a number of equations. However, it should be understood that such equations provide but one example of the determination of the first power draw in accordance with method600and that other ways, methods, or manners of determining the first power draw may be possible as well. For instance, the various variables and conditions described by the equations below may be combined in various alternative ways including ways similar to that in which the various variable and conditions are explained as being combined with respect to method300above.

Generally, determining, based on at least the respective state of charge of each electrical device from the set of electrical devices, the respective first power draw of each electrical device in accordance with step602may involve maximizing an energy-aggregator profit based on at least the respective first power draw for each electrical device. Maximizing the energy-aggregator profit based on at least the respective first power draw for each electrical device may involve maximizing the energy-aggregator profit based on the respective first power draw for each electrical device and at least one additional consideration. Maximization of the energy-aggregator profit according to all such conditions is represented below by Equation 23.
maximizePOPi(t),MxAPi(t),MnAPi(t),SOCmiIn−C(23)

Maximization of energy-aggregator profit throughout the day, including a consideration of the provisioning of responsive reserves, may involve the consideration of a number of additional considerations beyond those explained above with respect to method300. At a minimum, for example, maximization of the energy-aggregator profit may be subject to a set of conditions that includes a consideration of a reduction in power available for spinning reserves of each electrical device (RsRPi). As another example, the set of conditions may include a consideration of a reduction in state of charge that results from the evening commute trip home on a weekday or the second daily trip on the weekend for each electrical device (Tripi). Further additional considerations may be included in the conditions as well.

Thus, one example of maximizing the energy-aggregator profit as defined by Equation 22 involves maximizing Equation 23 subject to the conditions set forth by Equations 24-43 below:

At step604, energy aggregator102receives an electrical-system-regulation value from electrical-system operator104A that indicates a variation from a scheduled power consumption of the electrical system. The electrical-system-regulation value received by energy aggregator102in accordance with step604may be received in a manner similar to that described with respect to step304of method300.

iii. Determine Second Power Draw for Given Electrical Device

At step606, energy aggregator102determines a second power draw for a given electrical device from the set of electrical devices based on at least the determined respective first power draw for each electrical device and the received electrical-system-regulation value. The second power draw may be determined by energy aggregator102in accordance with step606in a manner similar to that described with respect to step306of method300.

At step608, energy aggregator102receives a responsive-reserve-regulation value from an electrical-system operator that indicates a requested-responsive-reserve amount. Generally, the responsive-reserve-regulation value received by energy aggregator102in accordance with step608may be received in a manner similar to that described above with respect to step604of method600and step304of method300.

Electrical-system operator104A may be arranged to monitor the state of electric resources of electrical utility104B and compare the state of such electric resources to a pre-determined schedule of electric resources. In the event that the state of such electric resources varies from the predetermined schedule of electric resources to such an extent that responsive reserves are necessary to regulate the electrical resources of electrical system100, electrical-system operator102A may indicate as much to energy aggregator102by way of communication link106B.

v. Determine Third Power Draw for Given Electrical Device

At step610, energy aggregator102determines a third power draw for the given electrical device from the set of electrical devices based on at least the determined second power draw and the received responsive-reserve-regulation value. Generally, the third power draw for the given electrical device may be a dispatched power draw for the given electrical device. That is, energy aggregator102may direct the given electrical device, perhaps via one of communication links108B,110B, or another similar communication link, to operate at the third power draw.

FIG. 7depicts an additional simplified regulation-algorithm flowchart700in accordance with some embodiments. At decision point702energy aggregator102determines whether the responsive-reserve-regulation-regulation value (RRS) exceeds responsive-reserve-regulation-regulation-value threshold702A. Note that, in the example shown inFIG. 7, responsive-reserve-regulation-regulation-value threshold702A is shown as being equal to “0.” However, this is for purposes of example and explanation only, and should not be taken to be limiting.

If, at decision point702, energy aggregator102determines that the responsive-reserve-regulation-regulation value (RRS) exceeds responsive-reserve-regulation-regulation-value threshold702A, then energy aggregator102may proceed to decision point704where energy aggregator102may determine whether first regulation value704A is less than second regulation value704B, where first regulation value406A is a ratio of (i) responsive-reserve-regulation-regulation value (RRS) and (ii) a responsive-reserve capacity of the energy aggregator (RR), multiplied by a reduction in power draw available for spinning reserves of the given electrical device (RsRPi), plus the power draw of the given electrical device, and where second regulation value704B is a ratio of (i) a charge remaining to be supplied to the given electrical device (CRi) and (ii) a charging efficiency of the given electrical device (Efi).

If, at decision point704, energy aggregator102determines that first regulation value704A is less than second regulation value704B, energy aggregator102may proceed to decision point708and determine that the third power draw is equal to first regulation value704A (a ratio of (i) responsive-reserve-regulation-regulation value (RRS) and (ii) a responsive reserve capacity of the energy aggregator (RR), multiplied by a reduction in power draw available for spinning reserves of the given electrical device (RsRPi), plus the power draw of the given electrical device).

If, at decision point704, energy aggregator102determines that first regulation value704A is greater than second regulation value704B, energy aggregator102may proceed to decision point706and determine that the third power draw is equal to second regulation value704B (a ratio of (i) a charge remaining to be supplied to the given electrical device (CRi) and (ii) a charging efficiency of the given electrical device (Efi)).

vi. Transmit Third-Power-Draw Message Indicating Third Power Draw

At step612, energy aggregator102transmits to the given electrical device a third-power-draw message indicating the determined third power draw. The third-power-draw message may be sent to the given electrical device in accordance with step610in a manner similar to that described with respect to the power-draw message of step308of method300.

As noted above, the third power draw may be a dispatched power draw, and accordingly, a given electrical device that receives the third-power-draw message may respond by adjusting the power draw of its battery to correspond (or to equal) the third power draw indicated in the third-power-draw message. In this way, the power draw of the given electrical device may vary in time, and may additionally be varied for the purposes of providing responsive reserves to electrical system100, according to the third power draw determined by energy aggregator102for the given electrical device.

For purposes of example and explanation,FIG. 8depicts power-draw chart810in accordance with some embodiments.FIG. 8represents an example power draw814(PDi) of a given electrical device. Note that inFIG. 8, the amount of power draw of the given electrical device is shown as the vertical axis810A and time is shown as the horizontal axis810B.

Additionally, the first power draw (scheduled power draw or preferred operating point)812of the given electrical device is shown as constant in time. Thus, power draw814varies in time around, generally, first power draw812according to the second power draw indicated in the power-draw message provided by energy aggregator102.

Further, power-draw chart810shows the maximum possible power draw of the given electrical device816(MPi). Further still, power-draw chart810shows the maximum additional power draw of the given electrical device818(MxAPi), as well as the minimum additional power-draw of the given electrical device826(MnAPi). And power-draw chart810shows the reduction in power draw available for spinning reserves of the given electrical device828(RsRPi).

Further still, in accordance with the provisioning of responsive reserves, power-draw chart810also shows responsive-reserve amount822(which is generally equal to a ratio of (i) responsive-reserve-regulation-regulation value (RRS) and (ii) a responsive-reserve capacity of the energy aggregator (RR), multiplied by a reduction in power draw available for spinning reserves of the given electrical device (RsRPi)). As shown by third power draw824, power draw814(PDi) may be modified according to the responsive-requirements of electrical system100. That is, in the example shown by power chart810electrical system100may have experienced an unexpected spike in energy consumed by electrical system100, and therefore energy aggregator102provided a regulation-up service to electrical-system operator104A by directing the given electrical device to temporary reduce its dispatched power draw (as reflected by third power draw824).

CONCLUSION