Patent Application
20100222935
1. Field of the Invention
The present invention relates generally to the field of electric power supply and generation systems and, more particularly, to a system and method for estimating and/or providing dispatchable operating reserve energy capacity for an electric utility using active load management so that the reserve capacity may be made available to the utility or to the general power market (e.g., via a national grid).
2. Description of Related Art
Energy demand within a utility's service area varies constantly. Such variation in demand can cause undesired fluctuations in line frequency if not timely met. To meet the varying demand, a utility must adjust its supply or capacity (e.g., increase capacity when demand increases and decrease supply when demand decreases). However, because power cannot be economically stored, a utility must regularly either bring new capacity on-line or take existing capacity off-line in an effort to meet demand and maintain frequency. Bringing new capacity online involves using a utility's reserve power, typically called “operating reserve.” A table illustrating a utility's typical energy capacity is shown in
Normal fluctuations in demand, which do not typically affect line frequency, are responded to or accommodated through certain activities, such as by increasing or decreasing an existing generator's output or by adding new generating capacity. Such accommodation is generally referred to as “economic dispatch.” A type of power referred to as “contingency reserve” is additional generating capacity that is available for use as economic dispatch to meet changing (increasing) demand. Contingency reserve consists of two of the types of operating reserve, namely, spinning reserve and non-spinning reserve. Therefore, operating reserve generally consists of regulating reserve and contingency reserve.
As shown in
Non-spinning reserve (also called supplemental reserve) is additional generating capacity that is not online, but is required to respond within the same time period as spinning reserve. Typically, when additional power is needed for use as economic dispatch, a power utility will make use of its spinning reserve before using its non-spinning reserve because (a) the generation methods used to produce spinning reserve capacity typically tends to be cheaper than the methods, such as one-way traditional demand response, used to produce non-spinning reserve or (b) the consumer impact to produce non-spinning reserve is generally less desirable than the options used to produce spinning reserve due to other considerations, such as environmental concerns. For example, spinning reserve may be produced by increasing the torque of rotors for turbines that are already connected to the utility's power grid or by using fuel cells connected to the utility's power grid; whereas, non-spinning reserve may be produced from simply turning off resistive and inductive loads such as heating/cooling systems attached to consumer locations. However, making use of either spinning reserve or non-spinning reserve results in additional costs to the utility because of the costs of fuel, incentives paid to consumers for traditional demand response, maintenance, and so forth.
If demand changes so abruptly and quantifiably as to cause a substantial fluctuation in line frequency within the utility's electric grid, the utility must respond to and correct for the change in line frequency. To do so, utilities typically employ an Automatic Generation Control (AGC) process or subsystem to control the utility's regulating reserve. To determine whether a substantial change in demand has occurred, each utility monitors its Area Control Error (ACE). A utility's ACE is equal to the difference in the scheduled and actual power flows in the utility grid's tie lines plus the difference in the actual and scheduled frequency of the supplied power multiplied by a constant determined from the utility's frequency bias setting. Thus, ACE can be written generally as follows:
ACE=(NIA−NIS)+(−10B1)(FA−FS), [Equation 1]
In view of the foregoing ACE equation, the amount of loading relative to capacity on the tie lines causes the quantity (NIA−NIS) to be either positive or negative. When demand is greater than supply or capacity (i.e., the utility is under-generating or under-supplying), the quantity (NIA−NIS) is negative, which typically causes ACE to be negative. On the other hand, when demand is less than supply, the quantity (NIA−NIS) is positive (i.e., the utility is over-generating or over-supplying), which typically causes ACE to be positive. The amount of demand (e.g., load) or capacity directly affects the quantity (NIA−NIS); thus, ACE is a measure of generation capacity relative to load. Typically, a utility attempts to maintain its ACE very close zero using AGC processes.
If ACE is not maintained close to zero, line frequency can change and cause problems for power consuming devices attached to the electric utility's grid. Ideally, the total amount of power supplied to the utility tie lines must equal the total amount of power consumed through loads (power consuming devices) and transmission line losses at any instant of time. However, in actual power system operations, the total mechanical power supplied by the utility's generators is seldom exactly equal to the total electric power consumed by the loads plus the transmission line losses. When the power supplied and power consumed are not equal, the system either accelerates (e.g., if there is too much power in to the generators) causing the generators to spin faster and hence to increase the line frequency or decelerates (e.g., if there is not enough power into the generators) causing the line frequency to decrease. Thus, variation in line frequency can occur due to excess supply, as well as due to excess demand.
To respond to fluctuations in line frequency using AGC, a utility typically utilizes “regulating reserve,” which is one type of operating reserve as illustrated in
The Federal Energy Reliability Commission (FERC) and NERC have proposed the concept of Demand Side Management (DSM) as an additional approach to account for changes in demand. DSM is a method in which a power utility carries out actions to reduce demand during peak periods. Examples of DSM include encouraging energy conservation, modifying prices during peak periods, direct load control, and others.
Current approaches for using DSM to respond to increases in demand have included using one way load switches that interrupt loads, as well as statistics to approximate the average amount of projected load removed by DSM. A statistical approach is employed because of the utility's inability to measure the actual load removed from the grid as a result of a DSM load control event. In addition, current DSM approaches have been limited to use of a single power measuring meter among every one hundred (100) or more service points (e.g., residences and/or businesses). Accordingly, current DSM approaches are inadequate because they rely on statistical trends and sampling, rather than on empirical data, to make projections and measure actual load removal events.
More recently, FERC and NERC have introduced the concept of flexible load-shape programs as a component of DSM. These programs allow customers to make their preferences known to the utility concerning timing and reliability of DSM load control events. However, DSM approaches utilizing load-shaping programs do not meet all of the criteria for implementing regulating reserve or spinning reserve, such as being dispatchable within 15 minutes or less. Additionally, in order for a generating source to be considered dispatchable energy, it must be forecasted twenty-four (24) hours prior to being delivered to a utility. Current DSM approaches do not facilitate accurate forecasting twenty-four (24) hours in advance due to their heavy reliance on statistics.
Therefore, there is a need for utilities to be able to create operating reserve, especially regulating and/or spinning reserve, by using accurate forecasting and flexible load shaping techniques. There is a further need to involve the consumer in a two-way approach in which the consumer can make their energy consumption preferences known and the utility can make use of those preferences to respond to increased demand and maintain line frequency regulation.
Before describing in detail exemplary embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of apparatus components and processing steps related to actively monitoring and managing power loading at an individual service point (e.g., on an individual subscriber basis) and throughout a utility's service area, as well as determining available or dispatchable operating reserve power derived from projected power savings resulting from monitoring and management of power loading. Accordingly, the apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
In this document, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terms “comprises,” “comprising,” and any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “plurality of” as used in connection with any object or action means two or more of such object or action. A claim element proceeded by the article “a” or “an” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.
Additionally, the term “ZigBee” refers to any wireless communication protocol adopted by the Institute of Electronics & Electrical Engineers (IEEE) according to standard 802.15.4 or any successor standard(s), and the term “Bluetooth” refers to any short-range communication protocol implementing IEEE standard 802.15.1 or any successor standard(s). The term “High Speed Packet Data Access (HSPA)” refers to any communication protocol adopted by the International Telecommunication Union (ITU) or another mobile telecommunications standards body referring to the evolution of the Global System for Mobile Communications (GSM) standard beyond its third generation Universal Mobile Telecommunications System (UMTS) protocols. The term “Long Term Evolution (LTE)” refers to any communication protocol adopted by the ITU or another mobile telecommunications standards body referring to the evolution of GSM-based networks to voice, video and data standards anticipated to be replacement protocols for HSPA. The term “Code Division Multiple Access (CDMA) Evolution Date-Optimized (EVDO) Revision A (CDMA EVDO Rev. A)” refers to the communication protocol adopted by the ITU under standard number TIA-856 Rev. A.
The terms “utility,” “electric utility,” “power utility,” and “electric power utility” refer to any entity that generates and/or distributes electrical power to its customers, that purchases power from a power-generating entity and distributes the purchased power to its customers, or that supplies electricity created either actually or virtually by alternative energy sources, such as solar power, wind power, load control, or otherwise, to power generation or distribution entities through the FERC electrical grid or otherwise. The terms “energy” and “power” are used interchangeably herein. The terms “operating reserve,” “spinning reserve,” “regulating reserve,” “non-spinning reserve,” “supplemental reserve,” and “contingency reserve” are conventional in the art and their uses and inter-relations are described in Paragraphs [0005]-[0008] and [0012] above. The term “environment” refers to general conditions, such as air temperature, humidity, barometric pressure, wind speed, rainfall quantity, water temperature, etc., at or proximate a service point or associated with a device (e.g., water temperature of water in a hot water heater or a swimming pool). The term “device,” as used herein, means a power-consuming device, and there may generally be two different types of devices within a service point, namely, an environmentally-dependent device and an environmentally-independent device. An environmentally-dependent device is any power consuming device that turns on or off, or modifies its behavior, based on one or more sensors that detect characteristics, such as temperature, humidity, pressure, or various other characteristics, of an environment. An environmentally-dependent device may directly affect and/or be affected by the environment in which it operates. An environmentally-independent device is any power-consuming device that turns on or off, or modifies its behavior, without reliance upon inputs from any environmental sensors. Generally speaking, an environmentally-independent device does not directly affect, and is not typically affected by, the environment in which it operates, although, as one skilled in the art will readily recognize and appreciate, operation of an environmentally-independent device can indirectly affect, or occasionally be affected by, the environment. For example, as those skilled in the art readily understand, a refrigerator or other appliance generates heat during operation, thereby causing some heating of the ambient air proximate the device.
It will be appreciated that embodiments or components of the systems described herein may be comprised of one or more conventional processors and unique stored program instructions that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions for determining an electric utility's available or dispatchable operating (e.g., regulating and spinning) reserve that is derived from projected power savings resulting from monitoring and management of loads in one or more active load management systems as described herein. The non-processor circuits may include, but are not limited to, radio receivers, radio transmitters, antennas, modems, signal drivers, clock circuits, power source circuits, relays, meters, memory, smart breakers, current sensors, and user input devices. As such, these functions may be interpreted as steps of a method to store and distribute information and control signals between devices in a power load management system. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of functions are implemented as custom logic. Of course, a combination of the foregoing approaches could be used. Thus, methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill in the art, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein, will be readily capable of generating such software instructions, programs and integrated circuits (ICs), and appropriately arranging and functionally integrating such non-processor circuits, without undue experimentation.
Generally, the present invention encompasses a system and method for estimating operating reserve (e.g., spinning and/or regulating reserve) for a utility servicing one or more service points. In one embodiment, the utility employs an active load management system (ALMS) to remotely determine, during at least one period of time, power consumed by at least one device located at the one or more service points and receiving power from the utility to produce power consumption data. The power consumption data is regularly stored and updated in a repository. The ALMS or a control component thereof, such as an active load director (ALD), determines an expected, future time period for a control event during which power is to be interrupted or reduced to one or more devices. Prior to commencement of the control event, the ALMS or its control component: (i) estimates power consumption behavior expected of the device(s) during the time period of the control event based at least on the stored power consumption data, (ii) determines projected energy savings resulting from the control event based at least on the estimated power consumption behavior of device(s), and determines operating (e.g., regulating and/or spinning) reserve based on the projected energy savings. The determined operating reserve may be made available to the current power utility or to the power market through the existing (e.g., Federal Energy Regulatory Commission) power grid. In one embodiment, the ALD populates an internal repository (e.g., database, matrix, or other storage medium) with measurement data indicating how individual devices within individual service points consume power or otherwise behave under normal operation and during control events. The power consumption data is updated through regular (e.g., periodic or otherwise) sampling of device operating conditions (e.g., current draw, duty cycle, operating voltage, etc.). When an ALD is first installed in an ALMS for an electric utility power grid, there is little data with which to create regulating and spinning reserve forecasts. However, over time, more and more data samples are used to improve the quality of the data in the repository. This repository is used to project both energy usage and energy savings. These projections can be aggregated for an entire service point, a group of service points, or the entire utility.
In an alternative embodiment, additional data may be used to help differentiate each data sample stored in the repository. The additional data is associated with variability factors, such as, for example, outside air temperature, day of the week, time of day, humidity, sunlight, wind speed, altitude, orientation of windows or doors, barometric pressure, energy efficiency rating of the service point, insulation used at the service point, and others. All of these variability factors can have an influence on the power consumption of a device. Some of the variability factor data may be obtained from public sources, such as local, state or national weather services, calendars, and published specifications. Other variability factor data may be obtained privately from user input and from sensors, such as humidity, altitude, temperature (e.g., a thermostat), and optical or light sensors, installed at or near a service point (e.g., within or at a residence or business).
The present invention can be more readily understood with reference to
The ALMS 10 monitors and manages power distribution via an active load director (ALD) 100 connected between one or more utility control centers (UCCs) 200 (one shown) and one or more active load clients (ALCs) 300 (one shown) installed at one or more service points 20 (one exemplary residential service point shown). The ALD 100 may communicate with the utility control center 200 and each active load client 300 either directly or through a network 80 using the Internet Protocol (IP) or any other (IP or Ethernet) connection-based protocols. For example, the ALD 100 may communicate using RF systems operating via one or more base stations 90 (one shown) using one or more wireless communication protocols, such as GSM, ANSI C12.22, Enhanced Data GSM Environment (EDGE), HSPA, LTE, Time Division Multiple Access (TDMA), or CDMA data standards, including CDMA 2000, CDMA Revision A, CDMA Revision B, and CDMA EVDO Rev. A. Alternatively, or additionally, the ALD 100 may communicate via a digital subscriber line (DSL) capable connection, cable television based IP capable connection, or any combination thereof. In the exemplary embodiment shown in
Each active load client 300 is preferably accessible through a specified address (e.g., IP address) and controls and monitors the state of individual smart breaker modules or intelligent appliances 60 installed at the service point 20 (e.g., in the business or residence) to which the active load client 300 is associated (e.g., connected or supporting). Each active load client 300 is preferably associated with a single residential or commercial customer. In one embodiment, the active load client 300 communicates with a residential load center 400 that contains smart breaker modules, which are able to switch from an “ON” (active) state to an “OFF” (inactive) state, and vice versa, responsive to signaling from the active load client 300. Smart breaker modules may include, for example, smart breaker panels manufactured by Schneider Electric SA under the trademark “Square D” or Eaton Corporation under the trademark “Cutler-Hammer” for installation during new construction. For retro-fitting existing buildings, smart breakers having means for individual identification and control may be used. Typically, each smart breaker controls a single appliance (e.g., a washer/dryer 30, a hot water heater 40, an HVAC unit 50, or a pool pump 70). In an alternative embodiment, IP addressable relays or device controllers that operate in a manner similar to a “smart breaker” may be used in place of smart breakers, but would be installed coincident with the load under control and would measure the startup power, steady state power, power quality, duty cycle and energy load profile of the individual appliance 60, HVAC unit 40, pool pump 70, hot water heater 40, or any other controllable load as determined by the utility or end customer.
Additionally, the active load client 300 may control individual smart appliances directly (e.g., without communicating with the residential load center 400) via one or more of a variety of known communication protocols (e.g., IP, Broadband over PowerLine (BPL) in its various forms, including through specifications promulgated or being developed by the HOMEPLUG Powerline Alliance and the Institute of Electrical and Electronic Engineers (IEEE), Ethernet, Bluetooth, ZigBee, Wi-Fi (IEEE 802.11 protocols), HSPA, EVDO, etc.). Typically, a smart appliance 60 includes a power control module (not shown) having communication abilities. The power control module is installed in-line with the power supply to the appliance, between the actual appliance and the power source (e.g., the power control module is plugged into a power outlet at the home or business and the power cord for the appliance is plugged into the power control module). Thus, when the power control module receives a command to turn off the appliance 60, it disconnects the actual power supplying the appliance 60. Alternatively, the smart appliance 60 may include a power control module integrated directly into the appliance, which may receive commands and control the operation of the appliance directly (e.g., a smart thermostat may perform such functions as raising or lowering the set temperature, switching an HVAC unit on or off, or switching a fan on or off).
The active load client 300 may further be coupled to one or more variability factor sensors 94. Such sensors 94 may be used to monitor a variety of variability factors affecting operation of the devices, such as inside and/or outside temperature, inside and/or outside humidity, time of day, pollen count, amount of rainfall, wind speed, and other factors or parameters.
Referring now to
In one embodiment, a sampling repository is used to facilitate the determination of dispatchable operating reserve power or energy (e.g., spinning and/or regulating reserve) for a utility. An exemplary sampling repository 500 is shown in block diagram form in
As alluded to above, the present invention optionally tracks and takes into account the “drift” of an environmentally-dependent device. Drift occurs when the environmental characteristic(s) (e.g., temperature) monitored by an environmentally-dependent device begins to deviate (e.g., heat up or cool down) from a set point that is to be maintained by the environmentally-dependent device. Such deviation or drift may occur both normally and during control events. Thus, drift is the time it takes for the monitored environmental characteristic to move from a set point to an upper or lower comfort boundary when power, or at least substantial power, is not being consumed by the device. In other words, drift is a rate of change of the monitored environmental characteristic from a set point without use of significant power (e.g., without powering an HVAC unit compressor, but while continuing to power an associated digital thermostat and HVAC unit control system). One of ordinary skill in the art will readily appreciate that devices, such as HVAC units 50, which control one or more environmental characteristics at a service point 20, are also influenced or affected by the environment at the service point 20 because their activation or deactivation is based on one or more sensed environmental characteristics at the service point 20. For example, an HVAC unit 50 in cooling mode that attempts to maintain an inside temperature of 77° F. activates when the inside temperature is some temperature greater than 77° F. and, therefore, is influenced or affected by the environment in which the HVAC unit 50 operates.
The inverse of drift is “power time,” which is the time it takes for the sensed environmental characteristic to move from a comfort boundary to a set point when significant or substantial power is being supplied to the environmentally-dependent device. In other words, “power time” is a rate of change of the monitored environmental characteristic from a comfort boundary to a set point with significant use of power. Alternatively, “drift” may be considered the time required for the monitored environmental characteristic to move to an unacceptable level after power is generally turned off to an environmentally-dependent device. By contrast, “power time” is the time required for the monitored environmental characteristic to move from an unacceptable level to a target level after power has been generally supplied or re-supplied to the environmentally-dependent device.
The power consumption data for an environmentally-dependent device, which may be gathered actively or passively as described above, may be used to empirically determine the drift and power time (rate of change, temperature slope, or other dynamic equation (f{x})) that defines an environmental characteristic's variation at a service point 20, or at least within the operating area of the environmentally-dependent device, so as to permit the determination of a uniquely derived “fingerprint” or power usage/consumption pattern or behavior for the service point 20 or the environmentally-dependent device.
Customers define the upper and lower boundaries of comfort by inputting customer preferences 138 through the web browser interface 114, with the set point optionally being in the middle of those boundaries. During normal operation, an environmentally-dependent device will attempt to keep the applicable environmental characteristic or characteristics near the device's set point or set points. However, all devices, whether environmentally-dependent or environmentally-independent, have a duty cycle that specifies when the device is in operation because many devices are not continuously in operation. For an environmentally-dependent device, the duty cycle ends when the environmental characteristic(s) being controlled reaches the set point (or within a given tolerance or variance of the set point). After the set point has been reached, the environmentally-dependent device is generally turned off and the environmental characteristic is allowed to “drift” (e.g., upward or downward) toward a comfort boundary. Once the environmental characteristic (e.g., temperature) reaches the boundary, the environmentally-dependent device is generally activated or powered on again until the environmental characteristic reaches the set point, which ends the duty cycle and the power time.
Drift may also occur during a control event. A control event is an action that temporarily reduces, terminates, or otherwise interrupts the supply of power to a device. During a control event, the environmental characteristic (e.g., temperature) monitored and/or controlled by an environmentally-dependent device will drift toward a comfort boundary (e.g., upper or lower) until the environmental characteristic reaches that boundary. Once the environmental characteristic reaches the boundary, the ALMS 10 generally returns or increases power to the device to enable the environmental characteristic to reach the set point again.
For example, an HVAC unit 50 may have a set point of 72° F. and minimum and maximum comfort boundary temperatures of 68° F. and 76° F., respectively. On a cold day, a control event may interrupt power to the HVAC unit 50 causing the monitored temperature within the service point 20 to move toward the minimum comfort boundary temperature. Once the monitored temperature inside the service point 20 reaches the minimum comfort boundary temperature, the control event would end, and power would be restored or increased to the HVAC unit 50, thus causing the monitored temperature to rise toward the set point. A similar, but opposite effect, may take place on a warm day. In this example, “drift” is the rate of change with respect to the time it takes the HVAC unit 50 to move from the set point to either the upper or lower comfort bounds. Analogously, “power time” is the rate of change with respect to the time required for the HVAC unit 50 to move the monitored temperature from the upper or lower comfort bounds to the set point. In one embodiment of the present invention, drift and power time are calculated and recorded for each environmentally-dependent or environmentally-independent device or for each service point 20.
In another embodiment, drift and other measurement data available from the ALD database 124 are used to create a power consumption behavior or pattern for each environmentally-dependent or environmentally-independent device or for each service point 20. The other measurement data may include vacancy times, sleep times, times in which control events are permitted, and/or other variability factors.
The environment within an energy-efficient structure will have a tendency to exhibit a lower rate of drift. Therefore, environmentally-dependent devices operating within such structures may be subject to control events for longer periods of time because the amount of time taken for the monitored environmental characteristic to reach a comfort boundary due to drift after being set to a set point is longer than for less efficient structures.
In another embodiment, the ALD 100 may identify service points 20 that have an optimum drift for power savings. The power savings application 120 calculates drift for each service point 20 and/or for each environmentally-dependent device at the service point 20, and saves the drift information in the ALD database 124 as part of power consumption data for the device and/or the service point 20. Thus, power saved as a result of drift during a control event increases overall power saved by the environmentally-dependent device at the service point 20.
According to the logic flow, the active load client 300 polls devices within the service point 20, such as a washer/dryer 30, hot water heater 40, HVAC unit 50, smart appliance 60, pool pump 70, or other devices within the service point 20, and obtains current readings. Upon receiving the current reading data from the active load client 300, the ALC interface 112 sends the data to the ALC manager 108. The ALC manager 108 stores the data to the sampling repository 500, which may be implemented in the ALD database 124 using the operational flow illustrated in
The following information may be provided as parameters to the operational flow of
Initially, the ALD 100 determines (802) whether the device used any, or at least any appreciable amount of, energy. If not, then the logic flow ends. Otherwise, the ALD 100 determines (804) the time duration of the data sample, the time duration when the device was on, and the time duration when the device was off based on the data sample. Next, the ALD 100 determines (806) whether the received data comes from an environmentally-dependent device or an environmentally-independent (e.g., binary state) device. If the received data comes from an environmentally-dependent device, then the ALD 100 determines (808) the energy used per minute for the device, and determines (810) whether the device is drifting or powering. The ALD 100 determines that the device is drifting if the environmental characteristic monitored by the device is changing in a manner opposite the mode of the device (e.g., the room temperature is rising when the device is set in cooling mode or the room temperature is decreasing when the device is set in heating mode). Otherwise, the device is not drifting.
If the device is drifting, then the ALD 100 determines (814) the drift rate (e.g., degrees per minute). On the other hand, if the device is not drifting, then the ALD 100 determines (812) the power time rate. Once either the drift rate or the power time rate has been calculated, the ALD 100 determines (880) whether there is already a record in the sampling repository 500 for the device being measured under the present operating conditions of the device (e.g., set point and other variability factors (e.g., outside temperature)). If there is no existing record, then the ALD 100 creates (882) a new record using, for example, the device's ID, time of record, current set point, current outside temperature, energy used per minute, power time rate, and drift rate (assuming that either a power time rate or a drift rate has been determined). However, if there is an existing record, then the ALD 100 updates (884) the existing record by averaging the new data (including energy usage, drift rate, and power time rate) with the existing data and storing the result in the repository 500.
If the ALD 100 determines (806) that the received data comes from an environmentally-independent device, then the ALD 100 determines (842) the energy used per minute for the device and further determines (844) the energy saved per minute for the device. The ALD 100 then searches the repository 500 (e.g., ALD database (124)) to determine (890) whether there is already a record for the device for the applicable time period. If there is no existing record, then the ALD 100 creates (892) a new record using the device's ID, time of record, current time block, energy used per minute, and energy saved per minute. However, if there is an existing record, then the ALD 100 updates (894) the existing record by averaging the new data (including energy usage and energy savings) for the time block with the existing data for the time block and stores the result in the repository 500. For environmentally-independent devices, energy usage and energy savings are saved with respect to a block or period of time.
The following information may be provided as parameters to the operational flow of
Initially, the ALD 100 (e.g., power savings application 120) determines (902) a future time period based on the start and stop times. The future time period may be set by the utility implementing the load control procedure of the present invention or a second utility that has requested delivery of operating reserve power from the utility implementing the load control procedure of the present invention. After the time period at issue is known, the power savings application 120 begins the procedure for projecting or estimating the amount of power that can be saved as the result of execution of a control event during the future time period. Accordingly, the power savings application 120 analyzes the devices to be controlled during the control event. Thus, the power savings application 120 determines (904) whether the devices include both environmentally-dependent and environmentally-independent (e.g., binary state) devices. For each environmentally-dependent device, the power savings application 120 determines (920) whether the device is in environment controlling (e.g., heating or cooling) mode. Next, the power savings application 120 retrieves (922) the anticipated set points for the device during the future time period of the control event and obtains (924) information regarding the outside environmental characteristic(s) (e.g., the outside temperatures) expected during the control event time period. The power savings application 120 then makes projections (926) about the device's expected power consumption behavior during the future time period. In one embodiment, the projection determination of block 926 is implemented using a best match algorithm, as described in detail below with respect to
However, if the power savings application 120 determines (904) that the proposed control event is to affect an environmentally-independent device, then the power savings application 120 determines (960) whether the device is currently scheduled to be on or off during the proposed time period of the control event. Next, the power savings application 120 creates, obtains, or otherwise determines (962) a list of time blocks for the specified control event time period. The power savings application 120 then makes projections (964) about the device's power consumption behavior during the future, control event time period. In one embodiment, the projection determination of block 964 is implemented using a best match algorithm, as described in detail below with respect to
One or ordinary skill in the art will readily recognize and appreciate that the operational flow of
In one embodiment, the operational flow of
Initially, the ALD 100 determines (1002) whether the requested repository search relates to an environmentally-dependent device or an environmentally-independent device. If the search relates to an environmentally-dependent device, then the ALD 100 attempts to find (1004) power consumption records in the sampling repository 500 that match the device ID, duty mode, environmental characteristic (e.g., temperature) set point, and associated outside environmental characteristic data. Power consumption records include power consumption data, such as power consumed, current drawn, duty cycle, operating voltage, operating impedance, time period of use, set points, ambient and outside temperatures during use (as applicable), and/or various other energy use data. If a record exists that matches all the power consumption search criteria, such record would be considered the record that most closely matches the given environment setting. If no exact match is found (1010), then the ALD 100 begins looking for records that slightly differ from the given environment setting. In one embodiment, the ALD 100 incrementally increases or decreases (1012) the environment-related search criteria (e.g., temperature set point and/or outside/ambient temperature) using the set point delta and the outside temperature/environmental characteristic delta as a guide to look for relevant records. Such incremental/iterative modification of the search criteria continues until either relevant records are found or some applicable limit (e.g., as indicated by the set point delta and/or other parameter deltas) is reached.
If the ALD 100 determines (1002) that the search relates to an environmentally-independent device, then the ALD 100 attempts to find (1040) power consumption records in the sampling repository 500 that match the device ID, duty mode, and time of operation (corresponding to the expected, future time of the control event). If a record is not found that matches all the search criteria (1070), then the ALD 100 modifies its search to look for records that slightly differ from the given environment setting. In one embodiment, the ALD 100 modifies its search by incrementally increasing or decreasing (1072) the time of operation for a given duty mode. The iterative searching continues until either relevant records are found or some applicable limit (e.g., as indicated by the time block delta or other parameter deltas) is reached. Any records that were found as a result of the search are provided (1060) to the requesting program (e.g., the operational flow of
The following information may be provided as parameters to the operational flow of
Another context in which the ALMS 10 may be utilized is in conjunction with other renewable energy sources. A number of renewable energy sources, such as wind power and solar power, are variable in nature. That is, such energy sources do not generate power at a constant rate. For example, wind increases or decreases from moment to moment. Wind turbines can generate a large amount of power due to large winds or can stop generating completely due to lack of any wind. Solar panels may be able to generate a great deal of power on very sunny days, a little power on cloudy days, and virtually no power at night.
As a result, power utilities that make use of renewable energy must compensate for the under-generation or over-generation of power from those sources. When renewable energy sources are under-generating, the ALMS 10 may utilize the processes disclosed above to provide additional operating reserve to compensate for the lack of power generation by the renewable energy source and for the effects resulting therefrom, including output frequency instability. For example, a utility utilizing wind or solar energy sources may further incorporate the ALMS 10 into the utility distribution system to provide regulating reserve during time periods of under-generation.
In the load profile graph of
Normally, when a utility observes energy demand that is near its peak capacity, it will attempt to initiate control events for customers who voluntarily participate in power saving programs (i.e., flexible load-shape programs, as described earlier). Typically, these control events will provide sufficient capacity to prevent the utility from using non-spinning reserve. However, there are situations in which a sufficient number of customers may have manually decided to opt out of power saving programs and, as a result, the utility would be unable to recover enough energy to meet its spinning reserve needs from its remaining customers who voluntarily participate in the program. Such a situation could happen, for instance, on a very hot day when many people are home, such as on a holiday or a day over the weekend. In such a case, the utility would still be in danger of using non-spinning reserve or even running out of reserve capacity altogether. In such a situation, the utility would be in a “critical control” mode. In critical control mode, the utility may override all customer preferences, including both those who voluntarily participate in power saving programs and those who do not. During periods of critical control, the utility may utilize the ALD 100 to adjust settings of environmentally-dependent devices to settings outside of normal comfort preferences (but not life-threatening). Invoking critical control enables a utility to return power demand to acceptable levels.
Use of the ALMS 10 may help a utility mitigate the likelihood of critical control situations. For example, whenever a customer overrides or opts out of a control event, the ALMS 10, using the techniques disclosed herein, finds additional customers who may be the target of a voluntary control event. Analogously, when controlled devices that are participating in a control event are required to exit the control event due to customer preferences (e.g., the amount of time that the customer's devices may participate in a control event), the ALD 100 may release such devices from the control event and replace them with other voluntarily controlled devices. The replacement devices would then preferably supply, through deferment, at least the same amount of reserve power as was being sourced by the devices that were released from the control event. Thus, the system 10 of the present invention increases the likelihood that a utility will be able to spread control events to other customers before invoking critical control.
In a further embodiment, the entire ALMS 10 described in
In an additional embodiment of the present invention, the sampling data stored in the repository 500 using the operational flow of
In another alternative embodiment of the present invention, transmission line loss may be included in the projected energy savings determination of
In a further embodiment of the present invention, the operating reserve (e.g., spinning reserve or regulating reserve) determined by a utility using the techniques disclosed above can be sold to a requesting utility 1306, as illustrated in
In yet another embodiment, the ALD 100 for a utility may determine projected energy savings for each service point 20 served by the utility in accordance with the operational flow of
In a further embodiment, instead of or in addition to using the operational flow of
In yet another embodiment, a requesting utility may utilize a method for acquiring operating reserve power from a sourcing utility. According to this embodiment, the requesting utility requests operating reserve power from the sourcing utility sufficiently in advance of a transfer time at which the operating reserve power will be needed so as to facilitate measurable and verifiable load-controlled generation of the operating reserve power. The load-controlled generation of the operating reserve power results from a determination of operating reserve as detailed above with respect to
In a further embodiment, the operating reserve determination techniques may be utilized by a virtual utility 1302 as disclosed in U.S. Patent Application Publication No. US 2009/0063228 A1. For example, the virtual utility 1302 may be operable to at least offer energy to one or more requesting utilities 1306 for use as operating reserve for the requesting utilities 1306. In such a case, the virtual utility 1302 may include, among other things, a repository 500 and a processor 160 (e.g., within an ALD 100). In this embodiment, the processor 160 is operable to remotely determine, during at least one period of time, power consumed by at least one device to produce power consumption data. The processor 160 is further operable to store the power consumption data in the repository 500 and, at the appropriate time, determine an expected, future time period for a control event during which power is to be reduced to the device or devices. The processor 160 is also operable to estimate, prior to commencement of the control event, power consumption behavior expected of the device or devices during the time period of the control event based at least on the stored power consumption data. The processor 160 is further operable to determine, prior to commencement of the control event, projected energy savings resulting from the control event based at least on the estimated power consumption behavior of the device or devices. Still further, the processor 160 is operable to determine, prior to commencement of the control event, operating reserve based on the projected energy savings. After determination of the operating reserve, the processor 160 is operable to communicate an offer to supply the operating reserve to a requesting utility 1306 or utilities.
As described above, the present invention encompasses a system and method for determining operating reserve capacity using an ALD or comparable device, software, or combination thereof so that the operating reserve capacity may be made available to the power utility that generated the operating reserve through load control or to the power market generally (e.g., via the FERC grid). When a utility requires power beyond its native load, the utility must make use of its operating reserve or acquire the additional power via the FERC grid from other utilities. As discussed above, one type of operating reserve is spinning reserve. Spinning reserve is additional generating capacity that is already connected to the power system and, thus, is almost immediately available. In accordance with one embodiment of the present invention, the ALD makes spinning reserve available to a utility. Thus, through use of the ALD, a utility (power generating utility or a virtual utility) can determine or project spinning reserve or other operating reserve that is available through interruptible power savings at service points. The spinning reserve is measurable and verifiable, and can be projected for a number of days in advance, and such projections can be sold to other utilities on the open market.
As disclosed above, the ALD 100 may be considered to implement a type of flexible load-shape program. However, in contrast to conventional load control programs, the load-shape program implemented by the ALD 100 projects an amount of operating reserve resulting from selective control of devices (loads) based on known, real-time customer preferences. In addition, due to its communication and control mechanisms, the ALD 100 can project power savings, as well as operating reserve (e.g., regulating, spinning and/or non-spinning reserve) that is active, real-time, verifiable, and measurable so as to comply with protocols and treaties established for the determination of carbon credits and offsets, as well as renewable energy credits. The information acquired by the ALD 100 is not simply samples of customer preferences and data, but actual power consumption information.
In the foregoing specification, the present invention has been described with reference to specific embodiments. However, one of ordinary skill in the art will appreciate that various modifications and changes may be made without departing from the spirit and scope of the present invention as set forth in the appended exemplary claims. For example, the passive sampling algorithm of
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments of the present invention. However, the benefits, advantages, solutions to problems, and any element(s) that may cause or result in such benefits, advantages, or solutions to become more pronounced are not to be construed as a critical, required, or essential feature or element of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.
This application is a continuation-in-part of U.S. application Ser. No. 11/895,909 filed on Aug. 28, 2007, now U.S. Pat. No. 7,715,951, which application is incorporated herein by this reference as if fully set forth herein. This application is also a continuation-in-part of co-pending U.S. application Ser. No. 12/001,819 filed on Dec. 13, 2007, which application is incorporated herein by this reference as if fully set forth herein. This application further claims priority under 35 U.S.C. §119(e) upon U.S. Provisional Application Ser. No. 61/215,725 filed on May 8, 2009 solely to the extent of the subject matter disclosed in said provisional application, which application is incorporated herein by this reference as if fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| 61215725 | May 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11895909 | Aug 2007 | US |
| Child | 12775979 | US | |
| Parent | 12001819 | Dec 2007 | US |
| Child | 11895909 | US |
