Patent Publication Number: US-2017363666-A1

Title: Method and apparatus for energy flow visualization

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. provisional patent application Ser. No. 62/351,060, entitled “Energy Flow Calculations”, and filed Jun. 16, 2016, which is herein incorporated in its entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     Embodiments of the present disclosure relate generally to determining energy flow information and, more particularly, to presenting a visualization of the energy flow information pertaining to a distributed energy resource (DER). 
     Description of the Related Art 
     As the electricity grid continues to modernize, the use of distributed energy resources (DERs) to produce energy from renewable resources and to provide energy storage is rapidly increasing. Energy produced by a DER&#39;s renewable resources may be used by one or more loads, stored for later use, and/or coupled to a larger grid such as a commercial power grid. The combination of the commercial grid, a DER, and a locale (such as a home or business) coupled to a DER provides a variety of both energy sources and energy recipients that varies over time; for example, a solar power system of the DER may provide sufficient energy on sunny days to power a home&#39;s loads and also store additional energy in a battery bank, while during evening hours the loads receive energy from the commercial grid. In order for an operator of the DER (such as a homeowner) to evaluate system operation and efficiencies, it is necessary to understand the various flows of energy between the energy sources and the energy recipients. 
     Therefore, there is a need in the art for providing a visualization of energy flow between energy sources and energy recipients in a readily understandable format. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention generally relate to visualizing energy flows substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims. 
     Various advantages, aspects and novel features of the present disclosure, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
         FIG. 1  is a block diagram of a system for energy generation and consumption in accordance with one or more embodiments of the present invention; 
         FIG. 2  is a block diagram of a power conditioner controller in accordance with one or more embodiments of the present invention; 
         FIG. 3  is a block diagram of a DER controller in accordance with one or more embodiments of the present invention; 
         FIG. 4  is a block diagram of a master controller in accordance with one or more embodiments of the present invention; 
         FIG. 5  is a block diagram depicting energy sources and sinks of the system and corresponding computed energy flows in accordance with one or more embodiments of the present invention; 
         FIG. 6  is a plurality of tables for a rolling time series in accordance with one or more embodiments of the present invention; 
         FIG. 7  is a representation of displays for energy flow visualization for the system  100  in accordance with one or more embodiments of the present invention; and 
         FIG. 8  is a flow diagram of a method for energy flow visualization in accordance with one or more embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of a system  100  for energy generation and consumption in accordance with one or more embodiments of the present invention. This diagram only portrays one variation of the myriad of possible system configurations. The present invention can function in a variety of environments and systems for visualizing energy flow. 
     The system  100  comprises a locale  102 , such as a residential or commercial building, coupled to a distributed energy resource (DER)  118  and a power grid  124  (e.g., a commercial power grid). The DER  118  can both generate alternating current (AC) power as well as store energy for later use, as described in detail below. Although the DER  118  is depicted as situated outside of the locale  102 , in some other embodiments one or more components of the DER  118  may reside within the locale  102 . 
     The locale  102  comprises a load center  112  coupled to the DER  118  via a bus  170 , to the power grid  124 , to one or more loads  114  (e.g., appliances and the like), and to a DER controller  116 . The load center  112  couples the AC power generated by the DER  118  to the loads  114  and/or to the power grid  124 . A meter  190  is coupled between the load center  112  and the power grid  124  for measuring the net energy from the power grid  124 . The measured net energy may then be communicated from the meter  190  to the DER controller  116  (e.g., via power line communication). 
     The DER  118  comprises power conditioners  110 - 1  . . .  110 -N, . . .  110 -N+M (collectively referred to as power conditioners  110 ) coupled in parallel to the bus  170 . Each of the power conditioners  110  comprises a controller  140 , described below with respect to  FIG. 2 , for controlling the corresponding power conditioner  110 . 
     As shown in  FIG. 1 , the power conditioners  110 - 1  . . .  110 -N are coupled to direct current (DC) energy sources  120 - 1  . . .  120 -N, respectively, to form DER generators  182 - 1  . . .  182 -N, respectively. The DC energy sources  120 - 1  . . .  120 -N, collectively referred to as DC sources  120 , are generally renewable energy sources such as wind, solar, hydro, and the like, and provide DC power to the corresponding power conditioners  110 . The power conditioners  110  generate commercial power grid compliant AC power from the received DC power. In certain embodiments, such as the embodiment described with respect to  FIG. 1 , each DC source  120  is a photovoltaic (PV) module, although in other embodiments one or more of the DC sources  120  may be other types of sources of DC energy (e.g., other types of renewable energy sources, a DC generator, or the like). In some alternative embodiments, the power conditioners  110  are AC-AC converters (such as AC-AC matrix converters), and the DC sources  120  are AC sources). In still other alternative embodiments, one or more the DER generators  182  are different types of distributed generators, such as internal-combustion generators fueled by gas, diesel, propane, or the like. 
     The power conditioners  110 -N+1 . . .  110 -N+M are coupled to energy storage devices  122 - 1  . . .  122 -M, respectively, to form AC batteries  180 - 1  . . .  180 -M, respectively. The energy storage devices  122 - 1  . . .  122 -M, collectively referred to as energy storage devices  122 , may be any type of suitable device for storing and subsequently delivering energy, such as batteries, flywheels, compressed air storage, hot water heaters, electric cars, or the like. When storing energy in the energy storage devices  122 , the power conditioners  110 -N+1 . . .  110 -N+M convert AC power from the bus  170  to energy that is stored in the corresponding energy storage device  122 - 1  . . .  122 -M. When energy from the energy storage devices  120  is discharging, the power conditioners  110 -N+1 . . .  110 -N+M convert energy from the corresponding energy storage devices  122 - 1  . . .  122 -M to commercial power grid compliant AC power that is coupled to the bus  170 . 
     Each of the power conditioners  110  measures one or more associated energy levels, such as the amount of energy it is receiving from a corresponding DC source  120  or energy storage device  122 , the amount of energy it is generating from the received DC energy, the amount of energy it is receiving from the bus  170  for charging a corresponding energy storage device  122 , the amount of energy it is coupling to a corresponding energy storage device  122 , and the like. Such energy measurements may be continuously obtained (in near real-time), or periodically obtained. 
     In other embodiments, the DER  118  may have different numbers of DER generators  182  and/or AC batteries  180 , for example only a single DER generator  182  and/or a single AC battery  180 . In some alternative embodiments, multiple DC sources  112  are coupled to a single power conditioner  110  (e.g., a single, centralized power conditioner) rather than in a one-to-one correspondence. In one or more alternative embodiments, the power conditioners  110  are DC-DC converters that generate DC power and couple the generated power to a DC bus (i.e., the bus  170  is a DC bus in such embodiments); in such embodiments, the power conditioners  110 -N+1 through  110 -N+M also receive power from the DC bus and convert the received power to energy that is then stored in the corresponding energy storage device  122 . 
     The DER controller  116  is coupled to the load center  112  for communicating with the power conditioners  110  using power line communications (PLC), although other types of wired and/or wireless techniques may additionally or alternatively be used. The DER controller  116  may provide operative control of the DER  118  (e.g., sending control and command instructions to the power conditioners  110 ) and/or may receive data or information (e.g., measured energy data) from the DER  118 . For example, the DER controller  116  may be a gateway that receives data (e.g., alarms, messages, operating data and the like) from the power conditioners  110  and communicates the data and/or other information to a remote device or system, such as a master controller  128  described below. The DER controller  116  may also send control signals to the power conditioners  110 , such as control signals generated by the DER controller  116  or sent to the DER controller  116  by the master controller  128 . 
     The DER controller  116  is further communicatively coupled to the master controller  128  via a communications network  126  (e.g., the Internet) for sending information to and/or receiving information from the master controller  128 . The DER controller  116  may utilize wired and/or wireless techniques for coupling to the communications network  126 ; in some embodiments, the DER controller  116  may be wirelessly coupled to the communications network  126  via a commercially available router. 
     The system  100  comprises a plurality of energy sources (e.g., the DER generators  182 , the discharging AC batteries  180 , and the power grid  124 ) and a plurality of energy recipients or sinks (e.g., the loads  114 , the charging AC batteries  180 , and the power grid  124  when excess energy generated by the DER  118  is fed back to it) among which energy flows at varying levels over time. For example, energy received by the loads  114  can come from the power grid  124 , from the DER generators  182 , and/or from the AC batteries  180  if they are sufficiently charged. Energy generated by the DC sources  120  can be used by the loads  114  (which may be also be referred to as the home  114 ), to charge the energy storage devices  122  if they are not already fully charged, and/or coupled back to the grid  124 . 
     In accordance with embodiments of the present invention, one or more readily-understandable visualizations of various energy flows between one or more energy sources and one or more energy sinks is provided as described herein. A user may access, for example via a conventional web browser, a website  192  supported by the master controller  128  (or a server having access to the master controller data) to obtain an energy flow display based on the energy flow data. Additionally, a multitude of users may access one or more of such displays via a password protected portal. 
     During operation of the DER  118 , the DER controller  116  periodically reports a plurality of energy flow measurements (which also may be referred to as energy time series information) to the master controller  128 , such as production by the DC sources  120  (which may also be referred to as the “solar production” or “PV production”), total consumption, discharge of the AC batteries  180 , and AC battery charge. In other embodiments, other energy flow measurements may be additionally or alternatively used. Generally, the energy flow measurements have granularity on the order of 5-15 minutes, although in other embodiments other levels of granularity may be used. The energy flow measurements are used to provide one or more visual depictions of various energy flows as described in detail below. For a particular time interval, for example from 15 minutes on up, energy flow information can be presented in a readily understandable format to visualize energy flows between one or more energy sources and one or more energy sinks, such as PV production flow (e.g., how much of the energy produced by the DC sources  120  is going to each of the loads  114 , the energy storage devices  180 , and the grid  124 ) and consumption flow (e.g., how much of the energy consumed by the loads  114  is coming from each of the DC sources  120 , the energy storage devices  180 , and the grid  124 ). 
     In order to provide a visualization of such complex energy flow metrics, a plurality of different energy flow values are computed using the obtained energy measurements and defined energy priority allocation rules as described in detail further below. 
       FIG. 2  is a block diagram of a power conditioner controller  140  in accordance with one or more embodiments of the present invention. The power conditioner controller  140  comprises at least one central processing unit (CPU)  202  coupled to each of a memory  204 , support circuits  206  (i.e., well known circuits used to promote functionality of the CPU  202 , such as a cache, power supplies, clock circuits, buses, input/output (I/O) circuits, and the like), and a transceiver  208  that is communicatively coupled to the DER controller  116 . 
     The CPU  202  may comprise one or more conventionally available microprocessors or microcontrollers. The power conditioner controller  140  may be implemented using a general purpose computer that, when executing particular software, becomes a specific purpose computer for performing various embodiments of the present invention. In one or more embodiments, the CPU  202  may be a microcontroller comprising internal memory for storing controller firmware that, when executed, provides the controller functionality described herein. In some embodiments, the power conditioner controller  140  may additionally or alternatively comprise one or more application specific integrated circuits (ASIC) for performing one or more of the functions described herein. 
     The memory  204  may comprise random access memory, read only memory, removable disk memory, flash memory, and various combinations of these types of memory; the memory  204  is sometimes referred to as main memory and may, in part, be used as cache memory or buffer memory. The memory  204  generally stores an operating system (OS)  210 , such as one of a number of available operating systems for microcontrollers and/or microprocessors (e.g., LINUX, Real-Time Operating System (RTOS), and the like). The memory  204  further stores non-transient processor-executable instructions and/or data that may be executed by and/or used by the CPU  202 . These processor-executable instructions may comprise firmware, software, and the like, or some combination thereof. 
     The memory  204  stores various forms of application software, such as a power conversion control module  212  for controlling power conversion by the power conditioners  110  and a data measurement module  214  for measuring various data associated with the power conditioner  110 , such as energy flows to and/or from the power conditioner  110 . The memory  204  additionally stores a database  216  for storing data related to power conversion and/or the present invention. In various embodiments, the power conversion control module  212  and the database  216 , or portions thereof, may be implemented in software, firmware, hardware, or a combination thereof. 
       FIG. 3  is a block diagram of a DER controller  116  in accordance with one or more embodiments of the present invention. The DER controller  116  comprises a DER transceiver  302 , a master controller transceiver  316 , support circuits  306 , and a memory  308  each coupled to at least one CPU  304 . The CPU  304  may comprise one or more conventionally available microprocessors; additionally or alternatively, the CPU  304  may include one or more application specific integrated circuits (ASICs). In some embodiments, the CPU  304  may be a microcontroller comprising internal memory for storing controller firmware that, when executed, provides the controller functionality herein. The DER controller  116  may be implemented using a general purpose computer that, when executing particular software, becomes a specific purpose computer for performing various embodiments of the present invention. 
     The support circuits  306  are well known circuits used to promote functionality of the CPU  304 . Such circuits include, but are not limited to, a cache, power supplies, clock circuits, buses, network cards, input/output (I/O) circuits, and the like. 
     The DER transceiver  302  is communicatively coupled to the power conditioners  110 , and the master controller transceiver  316  is communicatively coupled to the master controller  128  via the communications network  126 . The transceivers  302  and  316  may utilize wireless (e.g., based on standards such as IEEE 802.11, Zigbee, Z-wave, or the like) and/or wired (e.g., PLC) communication techniques for such communication, for example a WI-FI or WI-MAX modem, 3G modem, cable modem, Digital Subscriber Line (DSL), fiber optic, or similar type of technology. 
     The memory  308  may comprise random access memory, read only memory, removable disk memory, flash memory, and various combinations of these types of memory. The memory  308  is sometimes referred to as main memory and may, in part, be used as cache memory or buffer memory. The memory  308  generally stores an operating system (OS)  310  of the DER controller  116 . The OS  310  may be one of a number of available operating systems for microcontrollers and/or microprocessors. 
     The memory  308  stores various forms of application software, such as a local DER control module  312  for providing operative control of the DER  118  (e.g., providing command instructions to the power conditioners  110  regarding power production levels), and a data module  314  for obtaining various data from the system  100 , such as measured energy flow data from the DER  118  and the meter  190 . The data module  314  may additionally perform processing on received data as necessary, such as performing arithmetic computations. 
     The memory  308  additionally stores a database  318  for storing data, such as data related to the DER  118 , one or more algorithms for operating on data, energy priority allocation rules, and the like. In various embodiments, the local DER control module  312 , the data module  314 , and the database  318 , or portions thereof, may be implemented in software, firmware, hardware, or a combination thereof. 
       FIG. 4  is a block diagram of a master controller  128  in accordance with one or more embodiments of the present invention. The master controller  128  comprises a transceiver  402 , support circuits  406 , and a memory  408  each coupled to at least one central processing unit (CPU)  404 . The CPU  404  may comprise one or more conventionally available microprocessors; additionally or alternatively, the CPU  404  may include one or more application specific integrated circuits (ASICs). In some embodiments, the CPU  404  may be a microcontroller comprising internal memory for storing controller firmware that, when executed, provides the controller functionality herein. The master controller  128  may be implemented using a general purpose computer that, when executing particular software, becomes a specific purpose computer for performing various embodiments of the present invention. 
     The support circuits  406  are well known circuits used to promote functionality of the CPU  404 . Such circuits include, but are not limited to, a cache, power supplies, clock circuits, buses, network cards, input/output (I/O) circuits, and the like. 
     The transceiver  402  is communicatively coupled to the DER controller  116  via the communications network  126 . The transceiver  402  may utilize wireless (e.g., based on standards such as IEEE 802.11, Zigbee, Z-wave, or the like) and/or wired communication techniques for such communication, for example a WI-FI or WI-MAX modem, 3G modem, cable modem, Digital Subscriber Line (DSL), fiber optic, PLC, or similar type of technology. 
     The memory  408  may comprise random access memory, read only memory, removable disk memory, flash memory, and various combinations of these types of memory. The memory  408  is sometimes referred to as main memory and may, in part, be used as cache memory or buffer memory. The memory  408  generally stores an operating system (OS)  410  of the master controller  128 . The OS  410  may be one of a number of available operating systems for microcontrollers and/or microprocessors. 
     The memory  408  stores various forms of application software, such as a DER control module  412  for providing operative control of the DER  118  (e.g., providing command instructions to the DER controller  116  regarding power production levels) and, in some embodiments, additional DERs. The memory  408  further comprises an energy flow visualization module  414  computing various energy flows and generating one or more visualizations of energy flows based on the computed energy flows. Further detail on the functionality provided by the energy flow visualization module  414  is described below with respect to  FIG. 8 . 
     The memory  408  additionally stores a database  416  for storing data, such as data related to the operation of the DER  118 , measured energy flow data, computed energy flow data, energy priority allocation rules, one or more algorithms for determining computed energy flows, and the like. In various embodiments, the DER control module  412 , the energy flow visualization module  414 , and the database  416 , or portions thereof, may be implemented in software, firmware, hardware, or a combination thereof. 
     In one or more alternative embodiments, some or all of the energy flow computations, and/or the energy flow visualization, may additionally or alternatively be done by the DER controller  116 . 
       FIG. 5  is a block diagram depicting energy sources and sinks of the system  100  and corresponding computed energy flows in accordance with one or more embodiments of the present invention. As shown in  FIG. 5 , energy flow metering points  508 ,  502 ,  504  and  506  are depicted that correspond to measured energy flows P=production by the DC sources  120  (which may also be referred to as the PVs  120  for the embodiment described here), T=total consumption, C=charge for the energy storage devices  122  (which may also be referred to as batteries  122  for the embodiment described here), and D=discharge for the batteries  122 , respectively. In some other embodiments, the measured energy flow P may be a measurement of production by the DER generators  110  (for example, the energy generated by the power conditioners  110  from the corresponding DC sources  120 ). The measured energy flow data is used by the DER controller  116  and/or the master controller  128  for determining the computed energy flows for providing the energy flow visualizations. 
     The computed energy flows determined using the measured energy flows are depicted as solar-to-grid (Sg) from the PVs  120  to the grid  124 ; solar-to-batteries (Sb) from the PVs  120  to the batteries  122 ; solar-to-home (Sh) from the PVs  120  to the loads  114  (also referred to as the home  114 ); batteries-to-home (Bh) from the batteries  122  to the home  114 ; battery-to-grid (Bg) from the batteries  122  to the grid  124 ; grid-to-home (Gh) from the grid  124  to the home  114 ; and grid-to-batteries (Gb) from the grid  124  to the batteries  122 . Generally, the computed energy flow Bg is equal to zero, although in certain embodiments it may be non-zero, for example during an emergency when energy from the AC batteries  180  is used to support the grid  124 . 
     In some embodiments, one or more of the metering points  502 ,  504 ,  506  and  508  are physical meters that measure the corresponding energy flows and communicate the measured data by any suitable wired and/or wireless technique to another component for processing (e.g., the master controller  128 ). 
     In other embodiments, one or more of the metering points  502 ,  504 ,  506  and  508  represents a combination of measured energy data obtained within the system  100 . For example, in some embodiments the metering point  508  represents the sum of energy measurements from each of the DER generators  182  over a particular time period; the metering point  506  represents the sum of energy measurements from each of the discharging AC batteries  180  over a particular time period; and the metering point  504  represents the sum of energy measurements from each of the charging AC batteries  180  over a particular time period. The resulting energy flow measurements P, D and C, respectively, may be computed by the DER controller  116  from the individual energy measurements from the DER  118  and sent to the master controller  128 ; alternatively, they may be computed by the master controller  128 . 
     In one or more embodiments, the metering point  502  represents a net energy flow measurement from the grid  124  (Net) over a particular time period, less the PV production P over that same time period. The net energy flow measurement Net may, in some embodiments, be provided by the meter  190 . 
       FIG. 6  is a plurality of tables for a rolling time series in accordance with one or more embodiments of the present invention. Tables  602 ,  604 , and  606  are shown in  FIG. 6 . 
     The table  602  shows a time-series of energy flow measurements that correspond to the four metering points in  FIG. 5 —metering point  508  for the measured energy flow P; metering point  502  for the measured energy flow T; metering point  504  for the measured energy flow C, and metering point  506  for the measured energy flow D. As shown in table  602 , the measurements are provided in a 15-minute time series on a particular day from 3:00 pm-5:30 pm, although in other embodiments measurements may be in different time increments and/or over different times periods. 
     The table  604  shows the values for the computed energy flows Sg, Sb, Sh, Gb, Gh, Bg, and Bh for each of the time intervals of the table  602 . The order of calculations for the computed energy flows, based on the assigned priorities, is shown under the heading “calc order”. The particular computed energy flows are listed under the heading “flow”, and the corresponding computed energy flow sources and sinks are listed under the headings “source” and “sink”, respectively. 
     The table  606  shows the equations used for determining each of the computed energy flows Sg, Sb, Sh, Gb, Gh, Bg, and Bh, where Net may be measured by the meter  190 ). The computed energy flows are used to derive the visual depictions described below with respect to  FIG. 7 . 
     Although the embodiment described with respect to  FIG. 6  is directed to energy flow, in other embodiments the flows computed and the resulting visualizations may pertain to other parameters related to the DER  118  such as power or current. 
       FIG. 7  is a representation of displays  702  and  704  for energy flow visualization for the system  100  in accordance with one or more embodiments of the present invention. In the embodiment shown in  FIG. 7 , the DC energy sources  120  are PV modules and the energy storage devices  122  are batteries, although in other embodiments other types of DC energy sources  120  may be used (such as other types of renewable energy sources) and/or other types of energy storage devices  120  may be used. 
     The display  702  comprises a display image  720  which visually depicts the computed energy flows during a particular time period from the DER generators  182  to each of the grid  124  (i.e., Sg), the AC batteries  182  (i.e., Sb), and the home  114  (i.e., Sh) as shown by display image portions  708 ,  710 , and  706 , respectively. The display image portions  708 ,  710  and  706  may be visually differentiated from one another by any suitable technique or combination of such techniques, such as color, hue, display intensity, cross-hatching, and the like. In some other embodiments, energy flows from other energy sources may additionally or alternatively be depicted, such as diesel generators. In certain embodiments, energy flow to other types of energy sinks may be depicted, and/or the energy flows to various energy sinks may be depicted in more granularity (e.g., energy flow to each of specific loads, energy flow to each AC battery  180 , and the like). 
     The display image  720  is displayed on a display; for example, the display image  720  may be displayed on a user&#39;s computer via a conventional web browser. Although the display image  720  is annularly shaped, in other embodiments other types of displays may be used to provide the energy flow visualizations, such as pie charts, bar charts, and the like. 
     The display  704  comprises a display image  740  which visually depicts the computed energy flows during a particular time period to the loads  114  from each of the DER generators  182  (i.e., Sh), the grid  124  (Gh), and the AC batteries  182  (i.e., Bh) as shown by display image portions  714 ,  716 , and  712 , respectively. The display image portions  714 ,  716 , and  712  may be visually differentiated from one another by any suitable technique or combination of such techniques, such as color, display intensity, cross-hatching, and the like. In some other embodiments, energy flows from other energy sources may additionally or alternatively be depicted, such as diesel generators, and/or the energy flows from various energy sources may be depicted in more granularity (e.g., energy flow from each AC battery  180 , energy flow from each DER generator  182 , and the like). 
     The display image  740  is displayed on a display; for example, the display image  740  may be displayed on a user&#39;s computer via a conventional web browser. Although the display image  740  is annularly shaped, in other embodiments other types of displays may be used to provide the energy flow visualizations, such as pie charts, bar charts, and the like. 
       FIG. 8  is a flow diagram of a method  800  for energy flow visualization in accordance with one or more embodiments of the present invention. The energy flow visualization described below pertains to a system having a distributed energy resource (DER), such as the system  100  comprising the DER  118 . In other embodiments, the energy visualization may pertain to other types of systems having other types of DERs. 
     In one or more embodiments, the method  800  is an implementation of the master controller&#39;s energy flow visualization module  414  described above. In other embodiments, the module of the DER controller  116  may perform the method  800 . In still other embodiments, the method  800  may in part be performed by master controller&#39;s energy flow visualization module  414  and in part by a module of the DER controller  116 . In certain embodiments, a computer readable medium comprises a program that, when executed by a processor, performs the method  800  that is described in detail below. 
     The method  800  begins at step  802  and proceeds to step  804 . At step  804 , a plurality of energy flow measurements are obtained. The energy flow measurements T, C, D and P are obtained with respect to the metering points  502 ,  504 ,  506  and  508 , respectively, described above with respect to  FIG. 5 . The energy flow measurements are periodically obtained, for example on the order of every 5 to 15 minutes. 
     In some embodiments, one or more of the metering points  502 ,  504 ,  506  and  508  are physical meters that measure the corresponding energy flows and communicate the measured data by any suitable wired and/or wireless technique to a central location for processing (e.g., the master controller  128 ). In other embodiments, one or more of the metering points  502 ,  504 ,  506  and  508  represents a combination of measured energy data obtained within the system  100 . For example, in some embodiments, the energy flow measurement T is equal to the net energy flow measurement Net (e.g., obtained from the meter  190 ), less the PV production P; the PV energy production P is equal to the sum of the measured energy from each of the DER generators  182  as measured by the corresponding power conditioner  110 ; the battery charge energy C is equal to the sum of energy consumed to charge each of the energy storage devices  122  as measured by the corresponding power conditioner  110 ; and the battery discharge energy D is equal to the sum of energy discharged by each of the energy storage devices  122  as measured by the corresponding power conditioner  110 . 
     The method  800  proceeds to step  806 . At step  806 , energy priority allocation rules are set. The energy priority allocation rules define the priorities for the various energy sinks to receive generated energy from the DER energy sources and the power grid  124 . In certain embodiments, the energy priority allocation for energy derived from the PV modules  120  is defined as to the home  114  first, followed by the AC batteries  180  and lastly the power grid  124 ; the energy priority allocation for energy output from the AC batteries  180  is defined as to the home  114  first, followed by the grid  124 ; and the energy priority allocation for energy from the power grid  124  is whatever in the system  100  is not addressed by the DER. In other embodiments, the priorities of recipients of energy from the DER energy sources may be defined differently and/or the priorities of recipients of energy from the grid  124  are also defined. 
     The method  800  proceeds to step  808 , where a plurality of energy flows between energy sources and energy sinks in the system  100  is computed. The energy flows Sg, Sb, Sh, Gh, Gb, Bg and Bh are computed using the measured energy flows T, P, C and D and the energy priority allocation rules as shown in the table  606  previously described with respect to  FIG. 6 . The energy flows Sg, Sb, Sh, Gh, Gb, Bg and Bh are computed in the order as shown in the table  604 , also previously described with respect to  FIG. 6 . 
     At step  810 , one or more energy flow visualizations are generated for at least one of the computed energy flows. Various energy flow visualizations may be generated, including visualizations depicting energy distributed from one or more energy sources to one or more energy sinks (e.g., as depicted in the display image  702  previously described with respect to  FIG. 7 ), visualizations depicting energy usage from one or more energy sources (e.g., as depicted in the display image  702  previously described with respect to  FIG. 7 ). In some embodiments, relative amounts of computed energy flows may be depicted; in other embodiments, absolute amounts of computed energy flows may additionally or alternatively be depicted. 
     The energy flow visualizations depicted may be determined by user selections, where a user may select one or more types of visualizations to be displayed as well as a time period over which each visualization applies. Additionally or alternatively, one or more energy flow visualizations may be periodically displayed; for example, an energy flow visualization may be shown every hour depicting the data from the last hour. 
     The method  800  proceeds from step  810  to step  812 , where a decision is made whether to continue. If the result of the decision is yes, the method  800  returns to step  804 . In some embodiments, the method  800  automatically repeats; in one or more of such embodiments, the same energy priority allocation rules are utilized during each execution of the method  800 . 
     If the result of the decision at step  812  is no, the method  800  proceeds to step  814  where it ends. 
     In some alternative embodiments, one or more of the steps of the method  800  may be done in an order different from that described above; for example, the step  806  may be performed before the step  804 . 
     The foregoing description of embodiments of the invention comprises a number of elements, devices, circuits and/or assemblies that perform various functions as described. These elements, devices, circuits, and/or assemblies are exemplary implementations of means for performing their respectively described functions. 
     While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is defined by the claims that follow.