Patent Publication Number: US-RE46093-E

Title: Energy reduction

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No. 12/328,703, entitled “ENERGY SAVINGS AGGREGATION,” filed on even date herewith, which is incorporated by reference in its entirety for all purposes. 
     BACKGROUND 
     In electric power grids, demand response refers to the management of demand from customers in response to supply conditions, for example, having electricity customers reduce their consumption at critical times or in response to market prices. In demand response, customers may cut or reduce loads, called load shedding, in response to a request by a utility or market price conditions. An alternative to load shedding is on-site generation of electricity to supplement the power grid. Under conditions of tight electricity supply, demand response can significantly improve system reliability, reduce the peak price and, in general, reduce electricity price volatility. Since electrical systems are generally sized to correspond to peak demand (plus margin for error and unforeseen events), lowering peak demand reduces overall plant and capital cost requirements. Depending on the configuration of power generation facilities, demand response may also be used to increase demand (load) at times of high production and low demand. As the proportion of intermittent power sources such as wind power in a system grows, demand response may become increasingly important to effective management of the electric grid. 
     Demand response is generally used to refer to mechanisms used to encourage consumers to reduce demand, thereby reducing the peak demand for electricity. Energy consumers usually need some incentive to respond to a request from a demand response provider. For example, the utility might create a tariff-based incentive by passing along short-term increases in the price of electricity. The utility could impose mandatory cutbacks during a heat wave for selected high-volume users, who are compensated for their participation. High volume energy users may receive a rebate or other incentive based on firm commitments to reduce power during periods of high demand 
     SUMMARY 
     An exemplary power reduction system in accordance with the disclosure includes a power reduction system including: an input configured to receive power from a power source; outputs configured to provide output power to loads; switches coupled to the input and the outputs; a network interface configured to receive a power status message from a network; a controller coupled to the switches and the network interface and configured to control the switches to selectively couple/decouple the input to/from the outputs in response to the power status message; and an energy consumption module coupled to the input and configured to determine an energy consumption measure of energy provided by the input to the outputs that are coupled to the input, where the network interface is coupled to the energy consumption module and is further configured to transmit the energy consumption measure toward a remote device connected to the network. 
     Embodiments of such power reduction systems may include one or more of the following features. The energy consumption measure is a reduced energy consumption measure based on (1) energy provided by the input during a time period during which the controller decouples the input from at least one of the outputs and (2) a baseline energy consumption estimate for the time period. The energy consumption module is configured to determine the baseline energy consumption estimate based on energy provided by the input during a time period during which none of the outputs are decoupled from the input by the controller, and store the baseline energy consumption estimate in memory. The energy consumption module is configured to determine an average baseline consumption estimate for multiple time periods based on the stored baseline energy consumption estimate, where the average baseline consumption estimate time periods comprise at least one of hours, days, weeks, months and years. The received power status message may include information indicating to cancel an action induced by a previously received power status message. The power status message may include information regarding at least one of instructions regarding a type of device to decouple from the input, instructions regarding a specific output to decouple from the input, instructions regarding an amount of energy reduction to induce, or a level of compensation that will be received for a level of energy reduction induced. Systems may include a backup power source, where the controller is further configured to couple the backup power source to at least one of the outputs. The backup power source may include an uninterruptible power supply. The energy consumption measure is a reduced energy consumption measure based on (1) energy provided to the outputs during a time period during which the controller decouples the input from at least one of the outputs and (2) baseline energy consumption estimates for the time period, and where the energy consumption module is further configured to determine baseline energy consumption estimates based on energy provided to each of the outputs. The energy consumption measure comprises a first energy consumption measure based on energy provided by the input while none of the outputs are de-coupled from the input by the controller in response to any power status message and a second energy consumption measure based on energy provided by the input while at least one of the outputs is decoupled from the input by the controller in response to the power status message. 
     An exemplary method of power reduction includes: receiving power from a power source; providing power received from the power source to outputs coupled to loads; receiving a power status message from a network; controlling switches coupled to the power source and the outputs to selectively couple/decouple the power source to/from the outputs in response to receiving the power status message; determining an energy consumption measure of energy provided by the input to the outputs that are coupled to the input, and transmitting the energy consumption measure toward a remote device connected to the network. 
     Embodiments of such a method may include one or more of the following features. The energy consumption measure is a reduced energy consumption measure based on (1) energy provided by the power source during a time period during which the power source is selectively decoupled from at least one of the outputs in response to the power status message and (2) a baseline energy consumption estimate for the time period. Controlling at least one of the switches to couple at least one of the outputs to a backup power source. The backup power source may include an uninterruptible power supply. Determining the baseline energy consumption measure based on the energy consumed by the loads during a time period while none of the outputs is controlled to be decoupled from the power source in response to the power status message, and storing the baseline energy consumption measure in memory. The method includes transmitting the reduced energy consumption measure to the network toward a remote device. The method may include controlling at least one of the switches to couple at least one of the outputs to a backup power source. The backup power source is an uninterruptible power supply. The energy consumption measure is a reduced energy consumption measure based on (1) energy provided to the outputs during a time period during which the power source is selectively decoupled from at least one of the outputs and (2) baseline energy consumption estimates for the time period, the method further comprising determining the baseline energy consumption estimates based on energy provided to each of the outputs. The energy consumption measure is a first energy consumption measure based on energy provided by the input while none of the outputs are de-coupled from the input by the controller in response to any power status message and a second energy consumption measure based on energy provided by the input while at least one of the outputs is decoupled from the input by the controller in response to the power status message. 
     An exemplary embodiment includes a computer readable medium having stored thereon sequences of instruction including instructions that will cause a processor to: receive a power status message from a network; control switches, the switches being coupled to a power source and outputs, where the outputs are coupled to loads, to selectively couple/decouple the power source to/from the output in response to receiving the power status message; determine an energy consumption measure of energy provided by the input to the outputs that are coupled to the input, and cause a transmitter to transmit the energy consumption measure toward a remote device connected to the network. 
     Embodiments of the disclosure may provide one or more of the following capabilities. Multiple retail electric energy users (from single homeowner to a multi-family residence, or a small office building) may participate in selling saved power back to the utility during shortages. Energy consumption can be reduced voluntarily and/or automatically and with little inconvenience. Energy savings by small individual users can be measured, aggregated, verified, controlled and rewarded. The peak power demand of a power grid may be reduced, e.g., avoiding power failures such as brownouts, blackouts, etc. Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an embodiment of a power reduction aggregation system for reducing peak power supplied to customers connected to a power grid. 
         FIG. 2  is a block diagram of an embodiment of a power reduction system for selectively controlling power supplied to loads connected to the power grid of  FIG. 1 . 
         FIG. 3  is a schematic of an embodiment of the power reduction system shown in  FIG. 2 . 
         FIG. 4  is a block diagram of an embodiment of a central server of the power reduction aggregation system for reducing peak power shown in  FIG. 1 . 
         FIG. 5  is a flowchart of an embodiment of a process performed by a power reduction system of  FIG. 2 . 
         FIG. 6  is a flowchart of an embodiment of a process performed by a central server of  FIG. 4 . 
         FIG. 7  is a flowchart of another embodiment of a process performed by the power reduction system of  FIG. 2 . 
         FIG. 8  is a flowchart of another embodiment of a process performed by the central server of  FIG. 4 . 
     
    
    
     In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. 
     DETAILED DESCRIPTION 
     The disclosure provided herein describes, among other things, techniques, embodied in methods and/or apparatus, for controlling power supplied to customers connected to a power grid in order to manage the peak power demand. For example, a central server is provided for aggregating the energy savings of a large number of small electric energy users in such a way to meet the peak power reduction needs of electric utilities, while providing incentives and payments to the small energy users in proportion to the amount of energy saved. The central server transmits power status messages via a communication network to customers connected to a power grid in order to reduce the demand on the power grid. The power status messages contain instructions directing power reduction systems associated with the customers to selectively control power supplied by the power grid to loads connected to the power reduction system. 
     Power status messages are transmitted to programmable power reduction devices connected to the power grid to selectively control the power supplied to various customer loads. When a power reduction device receives a power status message indicating that power reduction is requested, the power reduction device determines from which loads to cut or reduce power. The programmable power reduction device can be programmed to cut power to different loads based on various priorities. The power reduction device communicates information indicative of the amount of energy reduction or the amount of energy consumed back to the central server for aggregation purposes. Further, the power reduction device can also couple the loads to a backup power supply, such as an uninterruptible power supply. Other embodiments, e.g., of both the central server and the power reduction device, are within the scope of the description and the claims. 
       FIG. 1  is a diagram of an embodiment of a power reduction use system  10  for reducing peak power supplied to customers connected to a power grid  16 . The system  10  includes a power reduction aggregation system including a central server  12  and multiple power reduction systems  20 - 1  to  20 -n. Multiple customer homes and/or small businesses  18 - 1  to  18 -n each include a respective power reduction system  20 - 1  to  20 -n. The system  10  further includes a power utility  14  that provides power to the power grid  16 . The homes  18  are tied to the power grid  16 . The power reduction systems  20  are coupled to the power grid  16  and to the loads of the homes  18  with which each power reduction system  20  is associated. 
     The power reduction systems  20  are communicatively connected to the central server  12  via a network  13 . The network  13  can include one or more wired or wireless networks. Wired networks can include telephone networks (e.g., plain old telephone system or POTS), cable networks, computer networks such as LAN, MAN, WAN, power line communications, etc. Wireless networks can include cellular telephone networks, WiFi networks, satellite networks, etc. The network  13  provides for bi-directional communication between the power reduction systems  20  and the central server  12 . The central server  12  transmits power status messages to the power reduction systems  20  and receives information regarding energy reduction and/or energy consumption from the power reduction systems  20  via the network  13 . 
     In the system  10 , the central server  12  is communicatively connected, here, through the network  13  to the power utility  14  that supplies power to the power grid  16 . In other embodiments, the central server could be co-located at the power utility. The central server  12  can receive power status instructions and/or information indicative of the status of the power grid  16  from the power utility  14  via the network  13 . 
     The power utility  14  can contact the central server  12  to request energy reduction (e.g., of a specified and/or pre-arranged amount). For example, the power utility  14  may do so in response to determining that it cannot meet the power demand without interruption or bringing expensive standby capacity online, e.g., during a period of peak power use. The central server  12  then acts to reduce the energy use of participating individual users, by communicating power status messages to power reduction systems  20  associated with the individual users, and adds up the aggregate total energy savings. This aggregate energy savings is communicated to the utility and payment can be made to the operator of the central server  12 . In turn, the operator will distribute a portion of this payment to participating individual users, preferably in amounts proportional to the actual energy saved. Changes in the power grid status that may result in power status messages being transmitted can include the power demand level nearing the capacity or a threshold level related to the capacity of the power grid  16 . In other cases some of the capacity of the power grid  16  may be temporarily lowered because of a need to divert power to other power grids or other sections of the power grid  16 . 
     Power status messages are used by the central server  12  to affect the way the individual power reduction systems  20  supply power to the various loads coupled to them. The central server  12  can transmit power status messages to individual power reduction systems  20  or to all the power reduction systems  20 . The central server  12  can determine the individual power reduction systems that are to receive power status messages based on current usage levels associated with the individual systems  20 , and/or based on past usage levels. 
     Power status messages can include various instructions for controlling the operations of the power reduction systems  20 . For example power status messages can include instructions requesting a power reduction, cancelling a previous power reduction, requesting a percentage reduction in power consumption, or requesting an absolute power reduction amount. Further, power status message can include information regarding a level of compensation, e.g., a price rate or savings amount, that is being offered for reduction in power of a certain level. A power status message can include instructions regarding what to decouple. The instructions could include, for example, instructions regarding which loads or at least which type of loads (e.g., air conditioner, heater, television, computer, games, stereo, etc.) to decouple. A power status message can refer to a previous power status message and affect, in various ways, the previous power status message instructions. For example a power status message could contain instructions for cancelling or modifying the previous instructions. The instructions contained in a power status message could be optional and it could be left up to the power controller  27 , based on how it is configured, to determine whether power reduction is desired. The instructions could also be mandatory and the power reduction systems would not have the ability to choose whether or not to follow the instructions. Some power status messages could contain requests for energy usage estimates, current and/or past, or energy reduction estimates (e.g.. the amount that energy usage was reduced below a baseline level in response to being instructed to reduce power). 
     Referring to  FIG. 2 , energy reduction system  20  includes a power reduction controller  24 , and a main electric panel  26 . The system  20  may be fully or partially within the house  18 , or completely external to the house  18 . The power reduction controller  24  is connected via a line  30  to an electric panel  26 . The line  30  may contain multiple electrical lines and may be contained within a single mechanical conduit. The main electric panel  26  is connected via one or more lines  32  to appropriate AC loads within the house  18  and via appropriate lines  33  to the power grid  16 . The power reduction system  20  includes an optional backup power source  22 . The optional backup power source  22  could be an uninterruptible power supply (UPS), a generator or other alternative energy source such as solar power or wind power. for example. The optional backup power source  22  is coupled to a switching module  31  of the power reduction controller  24 . The module  31  can connect the source  22  to the panel  26  such that the backup power source  22  can supply power to one or more of the AC loads. 
     The power reduction controller  24  also includes one or more processors  21  coupled to memory  23 . The processor  21  can include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, micro-controllers, microprocessors, electronic devices, other electronic units, or a combination thereof. 
     The processor  21  is configured to store data received by one or more interfaces and process and store the data on the memory  23 . The memory  23  can be implemented within the processor  21  or external to the processor  21 . The memory may be long term, short term, volatile, nonvolatile, or another type of memory and is not limited to any particular type of memory or number of devices. 
     The processor  21  is also configured to communicate/receive data and/or instructions to/from a network interface  25 , send data/instructions to a controller module  27 , and receive data from an energy consumption module  29 , and the switching module  31 . The network interface  25  is configured to transmit and receive data to/from the network  13 . 
     The switching module  31  contains switches as discussed below with reference to  FIG. 3 . Outputs of the switches are coupled to loads connected to the electric panel  26 . The switches are configured to selectively couple the outputs to an input power source, e.g., the power grid  16  or, if present, the backup power supply  22 . 
     The controller module  27  is coupled to the switching module  31 . The controller module  27  is configured to control the switches in the switching module  31  to selectively couple/decouple power to/from the loads. The controller module  27  can decouple selected loads from the power grid line  33  input in response to receiving a power status message. The controller  27  can selectively couple previously decoupled loads to receive power as conditions change (e.g., in response to receiving a power status message cancelling or modifying a previously received power status message). Details of other functions performed by the controller module  27  are discussed below in reference to  FIGS. 5 and 7 . 
     The energy consumption module  29  is coupled to the switching module  31  and the controller module  27 . The energy consumption module can be coupled to one or more inputs of the switching module  31  and/or one or more of the outputs that are coupled to the loads. The energy consumption module  29  is configured to determine a measure of the energy consumed by the loads. The energy consumption module  29  can determine a measure of the energy consumed separately by each of the loads, e.g., when coupled to the outputs of the switches and/or determine a total energy provided by the input power source(s), e.g., when coupled to the inputs from the power grid. Using information obtained from the controller module  27  about which switches are connected to the power grid and, optionally, which switches are connected to the backup power supply, the energy consumption module  29  can determine which outputs to include in the energy consumption calculations. 
     The energy consumption module  29  can determine a baseline energy measure and, in response to the power reduction controller  24  receiving a power status message from the central server  12 , determine a measure of the reduced energy consumption. The reduced energy consumption measure is the difference between (1) the energy provided to the loads by the input during a time period during which the controller module  27  decouples the input form at least one of the outputs, and (2) the baseline energy consumption measure previously determined. The baseline energy consumption measure is an indicator of an expected energy consumption. The baseline energy consumption measure is preferably based on an historical average of multiple past energy consumption measures for periods of time when no loads are controllably decoupled by the power reduction controller  24 . 
     Preferably, the baseline energy consumption measures are determined for each of the loads independently. In this manner, the baseline energy consumption measures can reflect changes in energy usage for loads which are not correlated to each other. For example, the baseline energy consumption measures of some loads may depend on outside temperatures and/or humidity, e.g., air conditioners and heaters, while others do not. The baseline energy consumption measure for heaters and air conditioners may then be stored as a function of outside temperature and humidity in addition to time of day, week, year, etc. 
     As an alternative to the energy consumption module  29  calculating the baseline energy consumption measures and the reduced energy consumption measure, the energy consumption module  29  can determine energy consumption measures of energy supplied to the loads in the same way for all time periods and communicate these measures to the processor  21 . The processor  21  then communicates these measures over the network  13 , via the network interface  25 , to the central server  12 . In this way, the energy consumption measures determined by the energy consumption module  29  are determined using the same method for all time periods, regardless of whether or not loads are controllably decoupled. The central server  12  periodically transmits a power status message requesting an energy consumption measure to a power reduction system  20 . When an energy consumption measure is requested by the central server  12  during a period of normal power grid conditions, a period when power reduction instructions are not in effect, the central server  12  stores the received energy consumption measure as a baseline energy consumption measure. When an energy consumption measure is requested by the central server  12  during a period when power reduction instructions are in effect, the central server uses the received energy consumption measure to determine the reduced energy consumption measure by subtracting the received energy consumption measure from a previously stored baseline consumption measure corresponding to a similar time period (e.g., time of day, day of the week, day of the year, etc.). 
     Referring to  FIG. 3 , the switching module  31  of the power reduction controller  24  comprises load switches  42 - 45 . The electric panel  26  includes lines  50  and  52  connected to the power grid  16 , lines  62 - 65  connected to AC loads, and circuit breakers  72 - 75 . Outputs of the switches  42 - 45  include fuses  48  and are connected to each of the lines  62 - 65  connected to AC loads. The controller module  27  and energy consumption module  29  are shown as a single block, but are referred to separately. While only four switches  42 - 45  and corresponding fuses  48  and load lines  62 - 65  are shown, other quantities may be used. 
     Each of the switches  42 - 45  can be placed in any of three states, connecting its output load line  62 - 65  to one of the power lines  50 ,  52 , connecting its output load line  62 - 65  to the optional backup power supply  22  via line  82  or line  84 , or connecting its output load line  62 - 65  to a disconnect position/terminal  92 - 95  (e.g., an open circuit, not connected to the backup power supply  22  or either of the power lines  50 ,  52 ). 
     The controller module  27  is coupled to the switches  42 - 45  and selectively couples and decouples the output load lines  62 - 65 , connected to the AC loads, to/from the power grid  16 , the open circuit disconnect terminals  92 - 95 , and the backup power supply  22  via lines  82  and  84 . The energy consumption module  29  is coupled to the output power lines  62 - 65  and monitors the power provided to the AC loads. Using switch state information obtained from the controller module  27 , the energy consumption module  29  can determine whether the output power is being supplied by the power grid or by the backup power supply  22 . Using this information, the energy consumption module can determine whether or not to include the measured output energies in a measure of the total energy being provided by the power grid. 
     As an alternative to being coupled to the output lines  62 - 65 , the energy consumption module  29  can be coupled to the power lines  50  and  52 , or to the input lines of the switches  42 - 45 . The energy measurements determined by the energy consumption module in these cases would be a measure of the energy received from the power grid. Measuring the energy usage at the input lines to the switches  42 - 45  allows for measurement of the energy usage of each of the loads. Computation of the energy provided by the power grid is simplified in these cases because the computations are not affected by the states of the switches  42 - 45 . 
     The controller module  27  is configured to selectively couple and decouple certain loads from the switches  42 - 45  in accordance with one or more methods including, but not limited to, priorities of associated loads, pre-determined or programmable load management settings, and programmable settings as to which loads can be decoupled when they are drawing power (e.g., a user may not want a microwave decoupled when it is drawing power). The controller module  27  can be re-configured by the customer to decouple loads based on several different criteria. The controller module  27  can be configured, for example, to decouple certain types of loads before other types of loads. For example, an air conditioner circuit may be decoupled before a refrigerator circuit is decoupled. 
     Criteria that can be used by the controller module  27  in determining which loads to couple and/or decouple include: the amount of power being drawn by a load compared to amounts being drawn by other loads, the amount of power being drawn by a load in comparison to the requested power reduction amount (e.g., to decouple the highest drawing loads first in order to decouple the fewest loads to meet the requested amount), a user defined priority of importance or criticality of a load compared to other loads drawing power, and/or to provide minimum on-time duty cycles to the loads. The controller module  27  could request user input from a user, via a user interface not shown in  FIG. 3 , to allow the user to determine which loads to decouple. Other criteria can also be used in determining which loads to decouple and/or couple to the power grid  16 . 
     The controller module  27  can be configured to decouple loads based on priorities that depend on the time of day, the day of the week, the time of the year, etc. For example, the controller module  27  for home use is configured not to decouple certain loads during hours when it is expected that people are home and to decouple certain loads during hours when it is expected that people are not home. The controller module  27  is configured to decouple certain loads on weekdays, but not on weekends, and vice-versa. The controller module  27  is also preferably configured to decouple different loads at different times during the year. 
     The controller module  27  is configured to decouple loads in order to meet a requested power reduction, e.g., a percentage, threshold or an absolute power reduction threshold (e.g., so many kw-hours). The prioritizations discussed above are utilized to choose the order in which the loads are decoupled to try to meet the requested power reduction threshold. 
     The controller module  27  can be configured to decouple and the recouple loads to the power input such that the loads are run at a reduced duty cycle. For example, a refrigerator circuit could be decoupled for an amount of time and then recoupled for an amount of time. Further, the controller module  27  can control loads not just to be on/off, but to be part-on or part-off. The reduced duty cycle on/off periods or part-on part-off levels can be varied based on various factors, e.g., time of day, temperature (e.g., for an air conditioner or other climate control load), etc. The controller module  27  can also indirectly couple or decouple loads by adjusting control settings, e.g., thermostat settings, lighting levels, etc. 
     The controller module  27  can be configured to decouple certain loads only if one or more shedding criteria is (are) met, e.g., a threshold amount of savings or payments being offered, e.g., a reduction in cost per kw-hour, or a certain price rate is offered. Preferably, the power status message received from the central server  12  includes a lump sum savings amount or a price rate per kw-hour that is being offered to reduce power consumption by a threshold amount. The savings amount or price rate could depend on a percentage or absolute amount of power reduction that is induced in response to the offer. For example, a power utility may offer a reduction of 10% in rates charged per kw-hour for a power reduction between 1 kw to 5 kw, a reduction of 15% for a power reduction between 5 kw and 10 kw, etc. The controller module  27  is configured to determine which loads to shed and by how much based on prioritizations, shedding criteria, incentives offered/available, how many loads are drawing power, which loads are drawing power (e.g., high priority loads, low priority loads, etc.), the time of day, the day of the week, the season, etc. Again, the prioritization methods discussed above can be utilized in choosing the order in which the loads are decoupled in order to meet the threshold levels. 
     Referring to  FIG. 4 , the central server  12  includes a processor  102  coupled to memory  104 . The processor  102  can include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, micro-controllers, microprocessors, electronic devices, other electronic units, or a combination thereof. 
     The processor  102  is configured to process and/or store data received from a network interface  106  on the memory  104 . The memory  104  can be implemented within the processor  102  or external to the processor  102 . The memory  104  may be long term, short term, volatile, nonvolatile, or another memory and is not limited to any particular type of memory or number of devices. 
     The processor  102  is also configured to communicate data and/or instructions to and/or from the network interface  106 , a power grid status module  108 , a power savings computation module  110 , and a power reduction module  112 . 
     The network interface  106  is configured to transmit and receive data over the network  13 . The network interface  106  can transmit the power status messages to the power reduction systems  20 . In addition, the network interface  106  can transmit and receive information to and from the power utility  14 . For example, the network interface  106  can receive indications from the power utility  14  that power reductions are to be initiated or can be canceled. Further, the network interface  106  can transmit power reduction estimates toward the power utility  14  over the network  13 . 
     The power grid status module  108  is coupled to the network interface  106  and is configured to transmit power status messages to the network  13 , via the network interface  106 , toward the power reduction controllers  24 . The determination of when to transmit a power status message can be made independently by the power grid status module  108 , or the power grid status module  108  can receive direction from an external source, e.g., the power utility  14 , via the network interface  106 . The power status messages can request a power reduction, request cancelling a previous power reduction, request a percentage reduction in power consumption, or request an absolute power reduction amount. The power status message can include information regarding one or more incentives, e.g., a level(s) of compensation such as price rates or savings amounts, that are being offered for reductions in power of corresponding amounts. The requested amounts can be the same for all the power reduction controllers  24  on the grid, or the requested amounts can be determined based on criteria such as the current energy consumption level, historical baseline energy consumption levels, etc. 
     Some of the functions of the power controller module  27  discussed above can be included in the power grid status module  108 , or another module, of the central server  12 . For example, the power grid status module  108  could be configured to transmit a power status message including instructions regarding what to decouple. The instructions could include, for example, instructions regarding which loads or at least which type of loads (e.g., air conditioner, heater, television, computer, games, stereo, etc.) to decouple, instructions regarding an amount (percentage or absolute amount) of power to decouple, etc. 
     The power savings compensation module  110  is configured to determine an aggregate compensation earned for providing an aggregate energy reduction induced by the power reduction devices in response to receiving the power status messages transmitted by the power grid status module  108 . In addition, the power savings compensation module  108  is configured to determine individual portions of the aggregate compensation associated with each of the power reduction devices that received the power status messages. The power savings compensation module  110  receives, from the power reduction module  112 , individual power reduction estimates corresponding to the power reduction controllers  24 . The individual power reduction estimates are combined by the power reduction module  112 , to determine an aggregate power reduction estimate. The power savings compensation module  110  receives the aggregate power reduction estimate from the power reduction module. As discussed above, the individual energy reduction estimates can be determined by the individual energy consumption modules  29  of the individual power reduction controllers  24 , or by the power reduction module  112  of the central server  12 . In cases where the individual energy reduction estimates are determined by the power reduction controllers  24 , the power savings compensation module  110  preferably confirms and/or verifies the energy reduction estimates, e.g., using utility company records, to prevent fraudulent energy reduction claims. 
     Based on what the power utility agreed to pay for power reduction, the power savings compensation module  110  determines the amount of aggregate compensation earned for the aggregate power reduction estimate. The power savings compensation module  110  can then determine the individual portions of the aggregate compensation associated with each of the power reduction devices. The central server  12  subtracts a portion of the aggregate compensation before determining the individual portions in order to cover expenses and in some cases make a profit. The power savings compensation module  110  can then determine the individual portions of the reduced aggregate compensation proportionally, or some other agreed upon compensation structure, (e.g., after subtracting the expenses and/or profit) based on the ratios of the individual power reduction estimates to the aggregate power reduction estimate. 
     The individual compensation portions can also be affected by the amount of power reductions that were induced by the individual power reduction devices. For example, a higher price rate could have been offered for higher levels of power reduction, as discussed above. In theses cases, the power savings module  110  can include the various price rates in determining the individual compensation portions. Other methods of determining the individual compensation portions are within scope of the methods describe herein. 
     The power reduction module  112  is coupled to the network interface  106  and the power savings module  110 . The power reduction module  112  is configured to receive indicia, via the network interface  106 , of a reduction in energy consumption of loads associated with each of the power reduction devices that induced power reductions in response to a power status message. The power reduction module  112  estimates the aggregate power reduction by adding the individual energy reduction estimates. The individual and aggregate energy reduction estimates are provided to the power savings compensation module  110 , e.g., by storing them in the memory  104 , in order for the power savings compensation module  110  to perform its functions as discussed above. 
     The indicia of the reduction in energy received by the power reduction module  112  can be individual estimated energy reductions that were computed by the individual energy consumption modules  29  of the individual power reduction controllers  24 . The power reduction module  112  computes the aggregate energy reduction estimate by combining these individual energy reduction estimates. 
     Instead of the energy reduction indicia being energy reduction estimates computed by the energy consumption modules  29 , the indicia of the reduction in energy received by the power reduction module  112  can be periodic energy consumption measures. The power reduction module  112  determines the energy reduction estimate based on the energy consumption measures communicated periodically from the power reduction devices to the central server  12 . The power reduction module  112  can use methods similar to those discussed above, e.g., computing baseline energy consumption measures, to calculate the reduction in energy estimates. The power reduction module  112  keeps track of when each power reduction device is in a normal state for calculating the baseline measures, and when each power reduction device is in a reducing state for calculating the energy reduction estimates. More details of determining the power reduction estimates are discussed below in reference to  FIGS. 5-8 . 
     Referring to  FIG. 5  with reference to  FIGS. 1-3 , a process  210  performed by the power reduction system  20  of  FIG. 2  includes the stages shown. The process  210  is performed by the various modules of the power reduction controller  24 . In this example, the energy consumption module  29  is configured to determine the reduced energy consumption measures including calculating baseline energy consumption measures. At stage  212 , an input of the switching module  31  receives power from a power source, e.g., the power grid  33 . 
     At stage  214 , the power received from the power source at stage  212  is provided to outputs of the switching module  31  which are connected to the various loads of the house  18  associated with the power reduction controller  24  performing the process  210 . Depending on whether the current state of the power grid  33  is normal or abnormal (e.g., a power reduction state), some or all of the switches  42 - 45  are in a state that couples the outputs and corresponding loads to the power grid  16 . 
     At stage  215 , the energy consumption module  29  determines baseline energy consumption estimates for the outputs/loads. The baseline consumption estimates are determined for each of the output lines  62 - 65  attached to the AC loads. The baseline energy consumption estimates can be made periodically, e.g., every 15 minutes, every half-hour, every hour (or other periodic or aperiodic intervals), in order to develop a robust baseline usage database for each of the loads. The baseline energy consumption estimates can be stored in memory and cross-referenced to the time of day, week, year. The baseline energy consumption estimates can also be cross-referenced to other parameters, such as, for example, outside temperature and humidity, e.g., for loads including air conditioners, heaters, fans, or other devices affected by the weather. 
     At stage  216 , the network interface  25  receives a power status message via the network  13  from the central server  12 . The power status message contains a request/instruction regarding power consumption, to reduce power consumption and/or cancel or modify a previous power reduction request/instruction. 
     Based on the information contained in the power status message received at the stage  216 , the power controller  27  determines, at stage  218 , whether or not to change which loads are connected to receive power. The determination made at stage  218  depends on the power reduction request contained in the power status message received at stage  216 . The instructions in a power status message can include required actions or optional actions. If the power reduction request is unchanged from a previous message, the power controller  27  determines that no change is necessary. If the power status message contains a new power reduction request, the power controller determines that changes should be made if the requested power reduction criteria is not currently being met. For example, if the power reduction request is for a percentage reduction of the baseline power consumption, the power controller  27  compares a current power reduction measure to the requested reduction level in making the determination. If the power reduction request is for decoupling specific loads, such as air conditioners, televisions, etc., the power controller  27  determines that changes are required if the requested loads are not decoupled. 
     The determination at stage  218  could utilize priority and shedding criteria or rules, pre-determined or programmable load management settings, and/or programmable settings as to which loads can be decoupled when they are drawing power. Priority criteria could include a hierarchical list of loads in order of importance. If any loads below a threshold level of importance are drawing power, the power controller determines that changes are desired. Shedding criteria considered at stage  218  can include rules as to the time of day, week or year that certain loads can be decoupled, rules regarding minimum reimbursement levels that certain loads will be decoupled, rules regarding the current power consumption level, etc. 
     If it is determined at stage  218  that coupling and decoupling of loads are not to be enacted, the process  210  continues back to stage  216 . If a predetermined amount of time passes with no new power status message received, the process  210  moves from stage  216  to stage  218 . In this way, the process  210  determines if conditions have changed such that at stage  218  it is determined to alter the power connection states of one or more of the loads. 
     If it is determined at stage  218  that power reductions are to be enacted, the process  210  continues to stage  220  where the power controller  27  controls one or more of the switches  42 - 45  to selectively couple and/or decouple the input power received from the grid  16  to the outputs of the switching module  31 . Determining which loads to couple or decouple can include criteria such as the amount of power being drawn by one load compared to amounts being drawn by other loads, the amount of power being drawn by a load in comparison to the requested power reduction amount, a user defined shedding criteria such as a priority of importance or criticality of a load compared to other loads drawing power, and providing a minimum on-time duty cycle to certain loads. The controller module  27  could request user input from a user, via a user interface not shown in  FIG. 3 , to allow the user to determine which loads to decouple. Other criteria can also be used in determining which loads to decouple and/or couple to the power grid  16 . 
     At stage  222 , the energy consumption module  29  determines a reduced energy consumption measure. The reduced energy consumption measure is determined based on (1) the energy provided by the input power source during the time period during which one or more of the switches is controlled to decouple one or more of the outputs from the input power source, and (2) a baseline energy consumption estimate for the same time period. 
     The energy consumption module  29  determines, at stage  215 , the baseline energy consumption estimates based on the energy provided by the input power source during time periods during which none of the outputs are decoupled from the input power by the power controller module  27 . The baseline power estimates can be calculated for each of the AC loads connected to the output lines  62 - 65 . The baseline estimates are stored in the memory  23 . The baseline energy consumption estimates are determined and stored to memory periodically in order to build a baseline energy consumption database. The baseline energy consumption measures are categorized into time periods including fractions of hours or hours of the day, days of the week, weeks or months of the year, etc. By storing a large time history of baseline energy consumption measures that spans an entire year, the baseline energy measures reflect how energy usage is affected by climate, seasonal activities, personal behavior characteristics of the customers, etc. Past baseline energy consumption measures that are stored in memory can be combined (e.g., averaged, time averaged, weight averaged, etc.) with newly determined baseline measures corresponding to similar time periods. In this way, the baseline energy consumption measures can be closer to a statistical mean. 
     At stage  224 , the network interface  25  transmits the reduced energy consumption measure toward a remote device over the network  13 . The remote device is determined by the operator of the power aggregation system  10 , and in some embodiments, is the central server  12  from which the power status message originated. The process  210  then loops back to stage  216 . Stages  216  to  224  continue to be performed as discussed above. 
     In an alternative to the process  210  of  FIG. 5 , stage  218  could be omitted. In this alternative, the power status messages received at stage  216  include specific instructions as to which loads to couple or decouple. For example, a customer could have an agreement with the operator of the central server  12  that enables control of the power reduction controller  24  by the central server  12 . At stage  220 , the power controller  27  uses the instructions received from the central server in controlling the switches  42 - 45  to couple and/or decouple the input power received from the grid  16  to the outputs of the switching module  31 . 
     Referring to  FIG. 6 , with reference to  FIGS. 1-4 , a process  310  performed by the central server  12  of  FIG. 3  includes the stages shown. The process  310  is utilized by the central server  12  for controlling power reduction controllers  24  that perform the process  210  of  FIG. 5 . In the process  210 , the power reduction controllers  24  determine the reduced energy consumption measures, at the stage  222 , and communicate these to the central server  12  at the stage  224 . 
     The process  310  starts at stage  312  where the power grid status module  108  determines if a status of the power grid  16  has change such that a power status message should be sent to any of the power reduction systems  20  connected to the power grid  16 . The power grid status module  108  can receive, via the network interface  106  and the network  13 , indications of power grid status from the power utility  14 . The power grid status module  108  can also be coupled to the equipment of the power grid and be able to determine on its own the status of the power grid. 
     Changes in the power grid status that may result in a positive determination at the stage  312  include the power demand level nearing the capacity, or the power demand level nearing a threshold level related to the capacity of the power grid  16 . The capacity level used at the stage  312  can vary. For example, the capacity level of the power grid  16  could be temporarily lowered because of a need to divert power to other power grids or other sections of the power grid  16 . 
     Other changes that can result in a positive determination at the stage  312  include expected increases in demand such as, for example, expected demand peaks and valleys that consistently occur day to day because of work schedules, for example. The changes that are identified at the stage  312  can result in increases, decreases or cancellation of previous power reduction requests. The power grid status module could also monitor the voltage and frequency characteristics of the grid and use these measurements in determining whether the power grid status is changing. 
     If, at the stage  312 , it is determined that the power grid status has changed and warrants power reduction (or a previous power reduction state could be cancelled or modified in some way), the process  310  continues to stage  313  where the power grid status module  108  determines whether power reduction is desired or warranted due to the power grid status changes. The determination at stage  313  can include determining a cost (e.g., marginal cost or total cost) for acquiring extra power capacity for an anticipated future increase in power. As power grid capacity nears a current capacity limit, additional power generation systems can be brought online. The additional power generation systems can be generators which can be very expensive to operate compared to normal power plants such as coal, natural gas, etc. 
     Another method of increasing power supply, which can also be expensive, is to purchase power from other power utilities and transfer the purchased power to the power grid. The purchase price can get very expensive due to supply and demand factors. As demand increases, e.g., due to other power grids also demanding more power, the cost increases. If the cost for supplying the anticipated increase is high enough and the expected savings for reducing power exceeds cost incentives offered to the customers to reduce power, then a positive determination at stage  313  could result, and the process  310  proceeds to stage  314 . In some embodiments, where a profit is desired, the power savings should be high enough to exceed the cost of the incentives as well as a profit that is desired in order for a positive determination to result at stage  313 . If a negative determination is made at stage  312 , the process  310  repeats stage  312  until the power grid status changes. 
     If a positive determination results at stage  313 , the process  310  continues to stage  314  where the power grid status module  108  transmits, via the network interface  106 , a power status message to a plurality of power reduction devices such as power reduction controllers  24  associated with power reduction systems  20 . The power status messages transmitted at the stage  314  can include various instructions for controlling the operations of the power reduction systems  20 . For example power status messages can include instructions requesting a power reduction, cancelling a previous power reduction, requesting a percentage reduction in power consumption, or requesting an absolute power reduction amount. Further, power status messages transmitted at the stage  314  can include information regarding a level of compensation, e.g., a price rate or savings amount, that is being offered for reduction in power of a certain levels. A power status message can include instructions regarding what to decouple. The instructions could include, for example, instructions regarding which loads or at least which type of loads (e.g., air conditioner, heater, television, computer, games, stereo, etc.) to decouple. A power status message can refer to a previous power status message and affect, in various ways, the previous power status message instructions. The instructions contained in a power status message could be optional and it could be left up to the power controller  27 , based on how it is configured, to determine whether power reduction is desired. The instructions could also be mandatory and the power reduction systems would not have the ability to choose whether or not to follow the instructions. Some power status messages transmitted at the stage  314  could contain requests for energy usage estimates, current and/or past, or energy reduction estimates (e.g., the amount that energy usage was reduced below a baseline level in response to being instructed to reduce power). 
     At the stage  316 , the network interface  106  receives indicia of a reduction in energy consumption of loads associated with each of the multiple power reduction devices to which power status messages were transmitted at the stage  314 . The energy reduction indicia received at the stage  316  is a energy reduction estimate determined by the power reduction systems  20  such as discussed above in reference to the process  210  shown in  FIG. 5 . The energy reduction indicia can be received periodically from the power reduction systems  20  during time periods when the power grid  16  is in a power reduction state. The energy reduction indicia can also be received in response to the central server transmitting a power status message at the stage  314  requesting an energy reduction estimate. The central server  12  requests an energy reduction estimate when the power grid status changes and/or when another power status message is determined to be needed at the stage  312 . 
     The indicia received at the stage  316  are forwarded to the power reduction module  112 . At stage  318 , the power reduction module  112  estimates the aggregate energy reduction by adding the individual energy reduction indicia that were received at the stage  316 . The aggregate energy reduction estimate and the individual energy reduction indicia are stored to the memory  104  for use by the power savings computation module  110  in calculating the aggregate and individual compensations earned by the energy reduction that was induced by the power reduction systems  20  in response to receiving the power reduction requests. 
     At stage  320 , the power savings module  110  determines the aggregate compensation earned for providing the aggregate energy reduction induced in response to the power reduction devices receiving the power status message that was transmitted at the stage  314 . Preferably, agreed upon contracts between the operator of the central server  12  (in cases where the power utility  14  running the power grid  16  is not providing the central server  12 ) and the power utility  14  have been executed such that predefined compensation rates have been defined. The compensation rates can vary as a function of the amount of the power reduction. For example, a higher rate of compensation could be afforded for higher reduction amounts. Alternatively, lower compensation rates could be afforded for higher reduction amounts. The power savings module  110  determines the aggregate compensation amount by multiplying the aggregate energy reduction by the appropriate compensation rate. 
     At stage  322 , the power savings compensation module determines the individual portions of the aggregate compensation that were earned by the individual power reduction devices. The power savings compensation module  110  determines the individual portions of the aggregate compensation associated with each of the power reduction devices to which power status messages were transmitted at the stage  314 . The power savings compensation module  110  subtracts a portion of the aggregate compensation before determining the individual portions in order to cover expenses and in some cases make a profit. The power savings compensation module  110  then determines the individual portions of the reduced aggregate compensation proportionally (after subtracting the expenses and/or profit) based on the ratios of the individual energy reduction estimates to the aggregate energy reduction estimate. 
     Upon determining the aggregate and individual compensations at the stages  320  and  322 , the process  310  returns to the stage  312  to determine when to transmit the next power status message when the power grid status changes. 
     Referring to  FIG. 7 , with reference to  FIGS. 1-3 , a process  260  performed by the power reduction system  20  of  FIG. 2  includes the stages shown. The process  260  differs from the process  210  of  FIG. 5  in that the energy reduction estimates are not determined by the power reduction device  24 , utilizing the energy consumption module  29 , but are instead computed by the remote device (e.g., the central server  12 ) to which baseline and reduced energy consumption measures are transmitted. 
     Stages  212 - 214  are unchanged from the same stages in the process  210 . 
     At stage  268  the energy consumption module  29  determines a baseline energy consumption measure or measures. Baseline consumption measures can be determined for each of the AC loads or a single baseline consumption measure can be determined for all the AC loads combined, depending on the embodiment. At stage  270 , the network interface  25  transmits the baseline energy consumption measure toward a remote device, e.g., the central server  12 , that is connected to the network  13 . Stages  268  and  270  can be repeated on a periodic basis during periods when the power grid  16  is in a baseline condition. 
     Stage  216  is unchanged from the same stage in the process  210 . At stage  218 , the power controller  27  determines whether or not to change which loads are connected to receive power and how much. Stage  218  is unchanged from the same stage in the process  210  and the same methods discussed above can be performed by the power controller  27 . 
     If it is determined at the stage  218  that coupling and decoupling of loads are not to be enacted, the process  260  continues back to stage  216  to wait for the next power status message to be received. If a predetermined amount of time passes at stage  216  with no new power status message being received, the process  260  continues from stage  216  to stage  218  to again determine if changes are required or desired. 
     If it is determined at the stage  218  that coupling/decoupling of power to the outputs are to be enacted, the process  260  continues to stage  220  where the power controller  27  controls one or more of the switches  42 - 45  to selectively couple and/or decouple the input power received from the grid  16  to the outputs of the switching module  31 . Stage  220  is unchanged from the same stage in the process  210  and the same methods discussed above can be performed by the power controller  27 . 
     At stage  272 , the energy consumption module  29  determines a reduced energy consumption measure based on the energy provided by the input power source to the loads. The same methods that were used to calculate the baseline energy consumption measures at the stage  268  are used to calculate the reduced energy consumption measure at the stage  272 . At stage  274 , the network interface  25  transmits the reduced energy consumption measure to the remote device, e.g., the central server  12 , that is connected to the network  13 . 
     Subsequent to transmitting the reduced energy consumption measure at the stage  274 , the process  260  continues to stage  276 . At stage  276 , the power controller  27  determines if the power grid status has returned to a baseline condition (e.g., the power status message received at stage  216  indicated that previous power reduction actions were to be canceled). If so, the process  260  returns to stage  268  to compute baseline energy consumption. If it is determined at stage  276  that the power grid is not in a baseline condition, the process  260  returns to stage  216  to receive another power status message. When the power reduction system  20  utilizes the process  260 , the central server  12  computes the energy reduction measures based on the baseline energy consumption measures transmitted at the stage  270  and based on the reduced energy consumption measures transmitted at the stage  274 . Compensations are computed as discussed above in reference to  FIG. 6 , using historical baseline measures corresponding to similar time frames (e.g., similar time of day, week, month and/or year), where the historical baseline measures were previously transmitted to the central server by the same power reduction system  20 . 
     Referring to  FIG. 8  with reference to  FIGS. 1-4 , a process  410  performed by the central server  12  of  FIG. 4  includes the stages shown. In the process  410 , the central server  12  receives periodic indicia of energy consumption from the power reduction devices such as was discussed above in reference to  FIG. 7 . This is in contrast to the process  310  where the central server received indicia of energy reduction estimates that were determined by the individual power reduction systems  20 . 
     At the stage  412 , the network interface  106  receives indicia of baseline energy consumption associated with multiple power reduction devices such as power reduction controllers  24 . The energy consumption measures received at the stage  412  reflect power usage when none of the loads are controlled to be decoupled from the power grid. The baseline energy consumption estimates are received periodically and stored in the memory  104  in order to build a baseline energy consumption database. The baseline energy consumptions are categorized into time periods including fractions of hours or hours of the day, days of the week, weeks or months of the year, etc. By storing a large time history of baseline energy consumptions that span an entire year, the baseline energy usages can reflect how energy consumption measures is affected by climate, seasonal activities, personal behavior characteristics, etc. 
     Past baseline energy consumption measures that are stored in memory can be combined (e.g., by averaging, weighted averaging, time averaging, etc.) with newly received baseline measures corresponding to similar time periods. In this way, the baseline energy reduction measures can be closer to a statistical mean. 
     At stage  414 , the power grid status module  108  determines if the status of the power grid  16  has changed from the baseline state. The same methods discussed above in reference to the stage  312  of the process  310  can be used at the stage  414 . If the power grid status has not changed, the process  410  returns to the stage  412 . If it is determined at the stage  414  that the power grid status has changed, e.g., power consumption nearing capacity, power outages reducing system capacity, etc., the process  410  continues to stage  415 . At stage  415 , the power grid status module determines if the changed power grid status warrants action in the form of requesting power reductions. The same methods discussed above in reference to stage  313  can be used at the stage  415 . If a negative determination results at stage  415 , the process  410  returns to stage  412 . If a positive determination is made at stage  415 , the process  410  continues to stage  416 . 
     At stage  416 , the power grid status module  108  transmits, via the network interface  106 , a power status message to at least two of the power reduction devices. The power status message includes information regarding the amount of power to reduce (percentages and/or absolute amounts), types of devices to decouple, price rates and/or discounts that can be earned based on the amount of energy reduction, or any of the information as discussed above in reference to power status messages. 
     At the stage  418 , the network interface  106  receives indicia of reduced energy consumption associated with each of the multiple power reduction devices to which power status messages were transmitted at the stage  416 . The reduced energy consumption indicia received at the stage  418  are determined by the power reduction systems  20  in the same way as the baseline energy consumption indicia, but the reduced energy consumption indicia will reflect reduced power usage since the power reduction systems  20  are configured to decouple loads in response to the power status message. The energy consumption indicia are received periodically from the power reduction systems  20  or in response to the central server transmitting a message requesting a power reduction estimate. 
     At stage  420 , the power reduction module  112  estimates individual energy reduction measures associated with the power reduction devices based on (1) the reduced energy consumption indicia received at the stage  418  and (2) the historical baseline energy consumption measures received at the stage  412  and stored in the memory  104 . The power reduction module  112  then determines an aggregate energy reduction estimate by adding the individual energy reduction indicia that were received at the stage  418 . The aggregate energy reduction estimate and the individual energy reduction indicia are stored to the memory  104  for use by the power savings computation module  110  in calculating the aggregate and individual compensations earned by the energy reduction. 
     At stages  422  and  424 , the power savings compensation module  110  determines the aggregate and individual compensations earned for providing the energy reduction in response to the power status messages. The power compensation module  110  uses similar methods at the stages  422  and  424  as discussed above in reference to the stages  320  and  322  of the process  310 . 
     At stage  426 , the power grid status module  108  determines if the status of the power grid  16  has changed such that a new power status message is warranted. If it is determined that the power grid status has not changed, the process  410  returns to the stage  418  to receive additional reduced energy consumption measures and proceed through stages  420 - 426  as discussed above. 
     If it is determined, at the stage  426 , that the power grid status has changed, the process  410  continues to stage  428 . At stage  428 , if the new power grid status is determined to be a baseline condition, the process  410  proceeds to stage  430 . At stage  430 , the power grid status module  108  transmits a baseline power grid status message to all the power reduction devices that had been transmitted the non-baseline power status message at the stage  416 . The process  410  then returns to the stage  412  to resume receiving baseline energy consumption indicia. 
     If the new power status is determined, at the stage  428 , not to be a baseline condition, the process  410  returns to the stage  416  where a new power status message containing new power reduction instructions is transmitted to power reduction systems  20 . The new power status message instructions will depend on how the power grid status changed. If the status is a more severe condition, additional power reduction devices can be requested to reduce power, or larger reductions in power can be requested. If the status is a less severe condition, some power reduction devices can be instructed to cancel the power reduction actions, or smaller reductions in power can be requested. Other types of instructions, such as discussed above, can be included in the new power status message transmitted at the stage  416 . The process  410  proceeds through the remaining stages as discussed above. 
     It should be noted that the stages of the processes  210 ,  260 ,  310  and  410  can be combined, rearranged, combined and, in some instances omitted. These processes are examples and other processes are within the scope of the description and claims. 
     Further, more than one invention may be described herein.