U.S. patent application number 15/882128 was filed with the patent office on 2019-02-07 for method and system for scheduling the discharge of distributed power storage devices and for levelizing dispatch participation.
The applicant listed for this patent is GridPoint. Invention is credited to Zachary AXELROD, Michaela BARNES, Sarah CARTWRIGHT, Alexei COWETT, Brian GOLDEN, David HAKIM, Steven HUGG, David HYAMS, Nicholas JHIRAD, R. Carl LEWIS, Edward SHNEKENDORF, Louis SZABLYA.
Application Number | 20190041886 15/882128 |
Document ID | / |
Family ID | 39970367 |
Filed Date | 2019-02-07 |
View All Diagrams
United States Patent
Application |
20190041886 |
Kind Code |
A1 |
HAKIM; David ; et
al. |
February 7, 2019 |
METHOD AND SYSTEM FOR SCHEDULING THE DISCHARGE OF DISTRIBUTED POWER
STORAGE DEVICES AND FOR LEVELIZING DISPATCH PARTICIPATION
Abstract
Disclosed is a computerized method for dispatching energy from
distributed resources in a discharge event so that the energy
stored in individual devices is ilevelized, or so that an operator
request is met. Evaluation of event parameters may be deferred. The
method may be utilized to dispatch energy from plug-in electric
vehicles. Systems and methods to account for electricity dispatched
to or from electric vehicles are disclosed. Systems and methods for
incentivizing consumers to participate in a dispatch event or
curtail energy use are disclosed.
Inventors: |
HAKIM; David; (Silver
Spring, MD) ; HUGG; Steven; (Bethesda, MD) ;
SHNEKENDORF; Edward; (Falls Church, VA) ; CARTWRIGHT;
Sarah; (Washington, DC) ; AXELROD; Zachary;
(Washington, DC) ; JHIRAD; Nicholas; (Washington,
DC) ; SZABLYA; Louis; (Houston, TX) ; LEWIS;
R. Carl; (Great Falls, VA) ; GOLDEN; Brian;
(Great Falls, VA) ; BARNES; Michaela; (Bethesda,
MD) ; COWETT; Alexei; (Arlington, VA) ; HYAMS;
David; (Mclean, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GridPoint |
Reston |
VA |
US |
|
|
Family ID: |
39970367 |
Appl. No.: |
15/882128 |
Filed: |
January 29, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14502292 |
Sep 30, 2014 |
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15882128 |
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12118644 |
May 9, 2008 |
8849687 |
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14502292 |
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60916861 |
May 9, 2007 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L 53/63 20190201;
B60L 53/64 20190201; Y02T 90/14 20130101; G06Q 10/06315 20130101;
Y02T 10/7072 20130101; Y02T 90/169 20130101; B60L 2200/26 20130101;
H02J 3/008 20130101; B60L 53/65 20190201; H02J 3/381 20130101; Y02T
90/16 20130101; Y04S 30/14 20130101; Y02T 90/12 20130101; B60L
2240/72 20130101; B60L 53/305 20190201; H02J 3/383 20130101; G05B
15/02 20130101; H02J 3/46 20130101; Y04S 10/126 20130101; G05F 1/66
20130101; Y02T 90/167 20130101; Y02T 10/70 20130101; G06N 5/048
20130101; H02J 2300/24 20200101; B60L 53/665 20190201; B60L 55/00
20190201; Y04S 50/10 20130101; Y02E 60/00 20130101; Y02T 10/72
20130101; Y02E 10/56 20130101 |
International
Class: |
G05F 1/66 20060101
G05F001/66; G06N 5/04 20060101 G06N005/04; B60L 11/18 20060101
B60L011/18; H02J 3/00 20060101 H02J003/00; G06Q 10/06 20060101
G06Q010/06; G05B 15/02 20060101 G05B015/02; H02J 3/38 20060101
H02J003/38; H02J 3/46 20060101 H02J003/46 |
Claims
1. A method for dispatching energy from a plurality of distributed
storage resources in a discharge event so that the energy stored in
each of the plurality of distributed resources is levelized,
comprising: receiving, in a computer, a dispatch request comprising
an amount of power required during a dispatch event and a duration
of the discharge event; determining, in the computer,
accomplishability of the dispatch request by: determining an
aggregate rate of discharge for the plurality of distributed energy
resources based on the rates of discharge at which each of the
individual resources of the plurality of distributed resources are
capable of producing; determining if the determined aggregate rate
of discharge is sufficient to meet the amount of power required to
satisfy the dispatch request; determining if the determined
aggregate rate of discharge can be maintained at all times during
the dispatch event, and if so, identifying the dispatch request as
accomplishable: causing, if the dispatch request is determined to
be accomplishable, the computer to determine the amount of energy
to be discharged from each of the plurality of distributed
resources during the dispatch event so as to reduce the variance
among the stored energy levels of the plurality of distributed
energy resources; scheduling the dispatch of each of the plurality
of distributed resources to participate in the dispatch event by:
implementing a bin packing algorithm to select the start and stop
times of the discharge of each of the plurality of distributed
resources during the dispatch event; and tilting the dispatch
schedule by adding a fractional time offset to intervals in each
bin used by the bin packing algorithm; sending dispatch
instructions to each of the plurality of distributed resources to
participate in the scheduled dispatch event.
2. The method of claim 1, wherein the step of scheduling the
dispatch of each of the plurality of distributed resources further
comprises: adding a ramp up time and a ramp down time to each
distributed resource participating in the dispatch event, ensuring
that all ramp up and ramp down transitions of the plurality of
distributed resources occur in pairs.
3. The method of claim 1, wherein the step of scheduling the
dispatch of each of the plurality of distributed resources further
comprises: prioritizing the participation of each of the plurality
of distributed resources in order of their respective potential
discharge duration potential.
4. The method of claim 1, wherein the rates of discharge at which
each of the plurality of resources are capable of discharging
energy are approximately the same.
5. The method of claim 1, wherein the rates of discharge at which
each of the plurality of resources are capable of discharging
energy are not all the same.
6. The method of claim 1, wherein the variance among the stored
energy levels of each of the plurality of distributed energy
resources is maximally brought to a state where each resource has a
fraction of the total remaining energy of each of the plurality of
distributed energy resources proportional to its discharge
rate.
7. The method of claim 1, wherein the amount of energy each of the
plurality of distributed energy resource is capable of storing is
approximately the same, and the sending dispatch instructions to
each of the plurality of distributed resources to participate in
the scheduled dispatch event.
2. The method of claim 1, wherein the step of scheduling the
dispatch of each of the plurality of distributed resources further
comprises: adding a ramp up time and a ramp down time to each
distributed resource participating in the dispatch event, ensuring
that all ramp up and ramp down transitions of the plurality of
distributed resources occur in pairs.
3. The method of claim 1, wherein the step of scheduling the
dispatch of each of the plurality of distributed resources further
comprises: prioritizing the participation of each of the plurality
of distributed resources in order of their respective potential
discharge duration potential.
4. The method of claim 1, wherein the rates of discharge at which
each of the plurality of resources are capable of discharging
energy are approximately the same.
5. The method of claim 1, wherein the rates of discharge at which
each of the plurality of resources are capable of discharging
energy are not all the same.
6. The method of claim 1, wherein the variance among the stored
energy levels of each of the plurality of distributed energy
resources is maximally brought to a state where each resource has a
fraction of the total remaining energy of each of the plurality of
distributed energy resources proportional to its discharge
rate.
7. The method of claim 1, wherein the amount of energy each of the
plurality of distributed energy sources is capable of storing is
approximately the same, and the accomplishable is now
unaccomplishable, providing an operator making the request a
notification that the dispatch request is no longer
accomplishable.
12. The method of claim 1, wherein the plurality of distributed
resources are mobile energy resources and the step of determining
accomplishability further comprises: receiving historical arrival
and departure times at a location of each of the plurality of
distributed resources; and determining the probability that a
dispatch request can be satisfied using plurality of distributed
mobile resources based on the historical arrival and departure
times of the plurality of distributed resources.
13. The method of claim 12, wherein the probability determination
is performed for regular time steps of the duration of the dispatch
event to ensure that a sufficient number of distributed mobile
resources will be available to satisfy the dispatch request during
the duration of the dispatch event.
14. The method of claim 13, further comprising: determining
accomplishability using the historical data of the amount of stored
energy available upon arrival at a location from each of the
plurality of mobile distributed resources.
15. The method of claim 14, further comprising: weighting a
distribution of a predicted arrivals at that location with the
historical amount of stored energy available upon arrival of a
mobile resource at a location; and, combining the weighted
distribution with the energy available in distributed mobile
resources that are actually available at a given time in order to
compute accomplishability.
16. The method of claim 13, further comprising: selecting the
length of the time step length so as to minimize the number of
distributed mobile resources that are removed from participation in
the dispatch event while also minimizing the number of calculations
resulting from the number of potential distributed mobile resources
used to calculate the accomplishability.
17. A method for dispatching energy from a plurality of distributed
mobile storage resources in a discharge event so that the energy
stored in each of the plurality of distributed mobile storage
resources is levelized, comprising: causing a computer to receive a
dispatch request comprising an amount of power required during a
dispatch event and a duration of the dispatch event; receiving the
historical arrival times, departure times, and stored energy
available, of each of the plurality of distributed mobile storage
resources at a location; predicting the number of arrivals,
departures, and the amount of stored energy available for the
plurality of distributed mobile storage resources during the
dispatch event, the prediction being based, in part, on the
historical arrival times, departure times, and the stored energy
available for each distributed mobile storage resource; weighting a
distribution of the predicted arrival times of mobile resources
with the predicted amount of stored energy available for the
plurality of distributed mobile storage resources and combining the
weighted distribution with the number of mobile resources actually
available; computing the accomplishability of the dispatch request
by aggregating the combined weighted distribution at multiple time
steps during the predicted dispatch and determining if the
aggregate rate of discharge capability of each of the plurality of
mobile resources is sufficient to meet the amount of power required
to satisfy the dispatch request at each time step in the dispatch
event, and if so, identifying the dispatch event as accomplishable;
causing, if the dispatch event is determined to be accomplishable
the computer to determine the amount of energy to be discharged
from each of the plurality of distributed mobile resources during
the dispatch event so as to maximally reduce the variance among the
stored energy levels of the plurality of distributed energy
resources; p1 scheduling the dispatch of each distributed mobile
storage resource of the plurality of distributed mobile storage
resources to participate in the dispatch event using a bin packing
algorithm to select the start and stop times of the discharge of
each of the plurality of distributed mobile storage resources;
tilting the dispatch schedule by adding a fractional time offset to
intervals in each bin used in the bin packing algorithm; sending
the discharge instructions to the plurality of distributed
resources according to the dispatch schedule; adding a ramp up time
and a ramp down time to each distributed mobile storage resource
participating in the dispatch event, ensuring that all ramp up and
ramp down transitions of the plurality of distributed mobile
storage resources occur in pairs; and, repeating the
accomplishability step each time a new dispatch request is created
or cancelled, and if a dispatch request that was previously
determined not to be accomplishable is now determined to be
accomplishable, providing an operator making the request a
notification that the dispatch request is now accomplishable, and
if a dispatch request that was previously determined to be
accomplishable is now unaccomplishable, providing a utility
operator making the request a notification that the dispatch
request is no longer accomplishable.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/118,644 filed May 9, 2008, which claims the
benefit of U.S. Provisional Application No. 60/916,861, entitled
Method and System for Scheduling The Discharge Of Distributed Power
Storage Devices And For Levelizing Dispatch Paticipation, filed May
9, 2007, which are herein incorporated by reference in their
entirety.
[0002] This application includes material which is subject to
copyright protection. The copyright owner has no objection to the
facsimile reproduction by anyone of the patent disclosure, as it
appears in the Patent and Trademark Office files or records, but
otherwise reserves all copyright rights whatsoever.
FIELD OF THE INVENTION
[0003] The present invention relates in general to the field of
electric power distribution systems, and in particular to methods
and systems for the discharge of stored energy from distributed
energy resources.
BACKGROUND OF THE INVENTION
[0004] Work scheduling of centralized electricity generation, such
as from electricity power plants, is known. Such work scheduling
includes, e.g., scheduling of discharge and curtailment events.
However, known solutions are poorly applicable for determining
optimal schedules for distributed energy resources, such as
distributed consumer electrical power generation devices and
distributed power storage devices such as batteries in consumer
power control appliances. Such distributed energy resources are
described in U.S. patent application Ser. No. 11/968,941 entitled
"Utility Console for Controlling Aggregated Energy Resources" filed
Jan. 3, 2008, which is incorporated herein by reference in its
entirety. Known solutions for scheduling discharge and curtailment
events are particularly inapplicable to distributed energy
resources where the quantity of such resources is relatively large
and where the discharge capability varies for each unit.
[0005] One distributed energy resource is plug-in electric vehicles
("PEVs"). A PEV is any vehicle such as a car, truck, bus,
motorcycle, etc that draws electricity from a power distribution
network ("grid"), stores the electricity through some means, and
uses electricity to power the vehicle. A PEV may come in a variety
of forms, including hybridized drivetrain and electric-only
drivetrain vehicles.
[0006] Hybridized drivetrain vehicles use a combination of
electricity drawn from the grid and on-board motive force that may
be used to both drive the vehicle and/or as a generation source to
extend the range of the vehicle by augmenting the on-board
electricity storage. The on-board motive force/generation source
can include a variety of power plants including gasoline, diesel,
bio-fuel combustion engines driving a generator. Or the on-board
electricity generation may come from more advanced means such as
fuel cells that use hydrogen, or other fuels to generate a flow of
electricity. In the future, it is possible that some part of the
electricity generation will come from photo-voltaic generation,
kinetic energy capture, or advanced technology means. In general,
most hybridized drivetrains generate additional electricity for
on-board storage through regeneration by using the motor as a
generator during coasting and braking operations.
[0007] Electric-only drivetrain vehicles use only an electric
motor(s) to provide motive force coupled with sufficient
electricity storage to provide suitable driving characteristics and
range. As with the hybridized drivetrain, the energy storage may be
in a variety of forms: chemical batteries, electrostatic capacitive
storage, or a combination of the two. Other forms of energy storage
may include electro-kinetic such as fly wheels, or thermal methods
that rely upon the energy captured and released during phase-change
operations. The electric-only drivetrain may use regeneration (see
above) to capture electricity for storage to extend the range of
the vehicle. In addition, there is the potential to use
extra-vehicular means to generate or transfer electricity into the
car for direct motive force or to supplement the energy storage.
Examples of this include magneto-coupling built into roadways,
linear generators embedded into roadways, or other means not yet
contemplated that involve interaction between the vehicle and its
environment.
[0008] The amount of electricity storage on the vehicle varies as
to whether it is a hybridized or an all-electric configuration.
Current development efforts by the automotive community indicate
that a hybridized drivetrain requires 12-16 kWh of on-board energy
storage and that all electric vehicles will require 50-60 kWh of
energy storage, depending upon desired range and performance
characteristics. The primary limiting factors of the storage
capacity remain both physical size, weight, and cost of the storage
medium. The secondary limiting factors will be crashworthiness,
replenishment times, and electrical infrastructure within the home
or at commercial charging stations. As new materials and methods
come to market, the on-board storage capacity will increase over
time with the significant possibility that an all-electric
drivetrain will be prevalent in the daily transportation vehicles
on the road.
[0009] While the PEV has tremendous consumer and societal benefits,
it potentially has a significant negative impact on electric grid
operations. This is due to the charging requirements of the vehicle
and innate consumer behavior. For example, a PEV that has 16 kWh of
energy storage that is depleted 80% every day will require 12.8 kWh
of replenishment before use again the next day. A typical 110V wall
outlet of 20 amp capacity--with many only at 15 amps--limits the
current draw to roughly 2000 watts. Charge management algorithms
for chemical batteries are non-linear with a decrease in current
flow into the batteries when they are both near empty and near
full. As such, the charge time is extended beyond the six hours
normally expected in this case if the charging cycle was linear.
The amount of "stretch" required for optimal charge management
varies by battery type and manufacturer.
[0010] The combination of the high draw rate (2000 watts), the time
required (6-8 hours) to replenish the stored energy, and the timing
of the consumer places a significant burden on the electric power
delivery system when millions of PEVs are on the road. Once the
energy storage device is in "bulk charge" mode--neither almost
empty nor almost full--it is drawing current at a 100% duty cycle.
This is unlike any other major consumption item within most
households except lighting, which generally accounts for a
relatively small percentage of electricity consumption.
[0011] Consumer driving habits factor into the problem as well.
Assuming that PEVs are used as commuter vehicles, then the typical
driving pattern is to unplug in the morning, drive 30-50 miles per
day round trip, and then come home between 6 pm and 7 pm to plug
the vehicle back into the grid for replenishment. When compared to
the average peak draw of a household over the period of one hour,
the PEV at 110V/20 A current flow effectively doubles the
consumption of the house during a typical evening peak demand
period. This level of consumption is not planned for in the
generation or distribution capacity of electric service providers.
With as little as a few hundred PEVs on a distribution feeder,
there can be significant delivery issues for the electric utility.
With as little as a few thousand within a service territory
charging at peak, there can be significant issues related to
generation capacity.
[0012] Electric only drivetrains with 50-60 kWh of storage
exacerbate this problem further. Normal daily driving habits will
probably not drain the stored energy beyond that expected by the
hybridized drivetrain. However, a longer daily use pattern, or long
trips will require up to three times the replenishment time at
110V/20 A, which results in up to 18 hours of charge time, which is
not practical for most applications. While the circuits to support
replenishment can be upgraded to 220V at high current limits, the
energy storage characteristics will determine how much current can
be flowed into the device without damage. However, the larger the
current draw, the larger the problem for effective grid
management.
SUMMARY OF THE INVENTION
[0013] In an embodiment, the invention provides a computerized
method for dispatching energy from distributed resources in a
discharge event so that the energy stored in individual devices is
levelized. A dispatch request including an amount of power required
during a dispatch event and a duration of the event is received,
and accomplishability of the dispatch request is determined.
Individual resource participation in the dispatch event is
determined utilizing rules that set the amount of energy to be
discharged from each participating resource so as to keep the level
of energy stored in each individual resource equal relative to the
energy level of other participating resources. Individual resource
dispatches are then scheduled, and the resources are commanded to
dispatch energy at their appointed time.
[0014] In another embodiment, the invention provides a computerized
method for dispatching energy from distributed resources to meet an
operator request. A dispatch request including an amount of power
required during a dispatch event and a duration of the event is
received, and accomplishability of the dispatch request is
determined. Individual resource participation in a planned dispatch
event is then determined, and individual resource dispatches are
scheduled at a future time. At that time, the individual resources
are commanded to dispatch energy.
[0015] In another embodiment, the invention provides a computerized
method for dispatching energy from distributed resources that
defers evaluation of event parameters. A dispatch request is
received, and a determination is made of the accomplishability of
the dispatch request. Individual resource participation in a
planned dispatch event is then determined. Individual resource
dispatches are scheduled at a future time. Accomplishability of the
dispatch request is redetermined prior to said future time, and
individual resources are commanded to dispatch energy based upon
such redetermination of accomplishability.
[0016] In another embodiment, the invention provides a computerized
method for dispatching energy from plug-in electric vehicles. A
dispatch request is received, and accomplishability of the dispatch
request is determined. A data network is used to determine
availability of individual PEVs at a requested future time for a
dispatch event. Resource participation in a planned dispatch event
is determined based upon such availability. Individual PEV
dispatches are scheduled at the future time. Individual resources
are commanded to dispatch energy at such time.
[0017] In another embodiment, the invention provides a method of
receiving and transmitting data to account for electricity flowing
through a charging receptacle to or from a storage device in an
electric vehicle. A clearinghouse receives a request for
authorization that has been generated in response to connection of
an electric vehicle to a charging receptacle, the request for
authorization including identification data sufficient to identify
a first account of a first utility company supplying electricity to
said charging receptacle and to identify an electricity billing
account associated with an account holder at a second utility
company. A determination is made that the account holder is
authorized to charge said account for electricity drawn from the
charging receptacle. Data is transmitted to enable the flow of
electricity at the charging receptacle. Data indicating the amount
of electricity drawn from the charging receptacle to charge the
storage device in said electric vehicle is received by the
clearinghouse. The data is used to cause the account associated
with the first utility company to be credited and the utility
company account to be charged.
[0018] In other embodiments, the invention provides systems and
methods for incentivizing consumers to participate in a dispatch
event or curtail energy use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The foregoing and other objects, features, and advantages of
the invention will be apparent from the following more particular
description of preferred embodiments as illustrated in the
accompanying drawings, in which reference characters refer to the
same parts throughout the various views. The drawings are not
necessarily to scale, emphasis instead being placed upon
illustrating principles of the invention.
[0020] FIG. 1 illustrates one embodiment of a system which is
capable of supporting the dispatch of energy from distributed
energy resources;
[0021] FIG. 2 shows a block flow diagram illustrating the steps of
levelizing and scheduling the dispatch of distributed energy
resources;
[0022] FIG. 3A illustrates the dispatch of hypothetical distributed
resources;
[0023] FIG. 3B shows a representation of hypothetical dispatch
requests for distributed resources;
[0024] FIG. 3C illustrates a levelized dispatch of distributed
resources;
[0025] FIG. 4 shows a block flow diagram of a method of scheduling
the dispatch of distributed resources;
[0026] FIG. 5 illustrates a method of scheduling the dispatch of
distributed resources;
[0027] FIG. 6 shows another method of scheduling the dispatch of
distributed resources;
[0028] FIG. 7 illustrates a system capable of supporting the
dispatch of energy from mobile distributed energy resources;
[0029] FIG. 8 shows a block flow diagram of a method of accounting
for a transaction involving the dispatch of energy from distributed
energy resources;
[0030] FIG. 9 shows one example of a user interface; and
[0031] FIG. 19 shows another example of a user interface.
DETAILED DESCRIPTION
[0032] The present invention is described below with reference to
figures, block diagrams and operational illustrations of methods
and devices to manage power generation, consumption, and storage.
It is understood that each block of the block diagrams or
operational illustrations, and combinations of blocks in the block
diagrams or operational illustrations, can be implemented by means
of analog or hardware and computer program instructions. These
computer program instructions can be provided to a processor of a
general purpose computer, special purpose computer, ASIC, or other
programmable data processing apparatus, such that the instructions,
which execute via the processor of the computer or other
programmable data processing apparatus, implements the
function/acts specified in the block diagrams or operational block
or blocks. In some alternate implementations, the functions or acts
noted in the blocks can occur out of the order noted in the
operational illustrations. For example, two blocks shown in
succession can in fact be executed substantially concurrently or
the blocks can sometimes be executed in the reverse order,
depending upon the functionality or acts involved.
[0033] The operator of a utility control system, if given a request
to dispatch or curtail some aggregate total amount of energy (or
power) at some point in the future, may attempt to meet this
request by commanding a distributed set of energy resources to
individually produce or curtail at such future point a certain
amount of energy (or power). Examples of energy resources may
include various types of batteries. Energy resources may also
include devices or systems for generating electricity. Other
examples of energy resources may include power consuming devices,
such as appliances, which if turned off or removed from the grid
reduce the amount of demand for power from the grid, thus freeing
up grid capacity. These may all be referred to as "distributed
resources" as well.
[0034] FIG. 1 illustrates one embodiment of a system and network
which is capable of supporting the dispatch of energy from
distributed energy resources. An electrical utility has an
operations control center 105. Within the control center 105, one
or more servers 110 host applications software which implement
various applications including a utility console. The servers 110
provide information to a display device 115 capable of supporting a
user interface. The servers 110 are additionally connected to one
or more storage devices 120 which may provide for storage of one or
more actively used databases or which may provide backup or
archiving of data collected by the servers. An example of
applications software described above is disclosed in U.S. patent
application Ser. No. 11/968,941 entitled "Utility Console for
Controlling Aggregated Energy Resources" filed Jan. 3,2008, which
is incorporated herein by reference in its entirety.
[0035] The servers are connected to the local network 125 of the
operations control center. The local network 125 is connected to
the Internet 350 though conventional routers and/or firewalls 130.
The local network 125 may also be connected to a common carrier
wireless network or a private network 300. The local network 125 is
also connected to a wide area network 200 which is connected to one
or more power generation points 210.
[0036] Power consumers 400 in the service territory of the utility
have one or more power control appliances 410. Power control
appliances 410 may include one or more energy storage units, such
as batteries (not shown). Power is transmitted to the consumer 400
over transmission lines 220 which form part of the local power
grid. Power drawn by a consumer from the grid may be supplied, in
part, by one or more power generation points 210, or may originate
in remote locations (not shown). Power enters the consumer premises
at a meter 420 and is routed to the power control appliance 410,
which may comprise an onboard computer, energy storage, and an
inverter/charger.
[0037] Power transmission lines 220 can additionally support
transmission of data between the power generation point 210 and
power consumer 400. The power generation point 210 is connected to
the operations control center 105 through the wide area network
(WAN) 200 and is connected to consumers 400 though power
transmission lines 220. Thus, the servers 110 may receive data from
or transmit data or commands to distributed energy management
controllers 410 using the Internet 350, the wireless network 300,
or the WAN 200.
[0038] The power control appliance 410 may be configured to control
one or more electrical circuits which supply power to one or more
power consuming devices 430, such as household appliances. Power
control appliance 410 may also be configured to supply electricity
to, or to draw electricity from, a mobile device capable of energy
storage, such as a plug-in electric vehicle (PEV) 460. In one
embodiment, the system uses a number of load controllers with
integrated measurement and/or a communicating thermostat (not
shown). Load controllers with integrated measurement can be
installed by placing them inline with the circuit to be measured
and controlled, and may be installed near the main load panel
(though there is no requirement to do so). Any number of load
controllers with integrated measurement may be installed at a site.
The power control appliance 410 may additionally have control
connections to the power consuming devices 430 which allow the
power control appliance 410 to control the operation of the power
consuming devices 430.
[0039] The power control appliance 410 may be further connected to
one or more power generation devices 440, such as solar panels,
which are capable of generating power. Power generated by the power
generation devices 440 may is routed to the power control appliance
410 for use by the consumer. Under the control of the power control
appliance 410 power generated by the power generation devices 440
may also be routed, in whole or in part, to the power grid 220. It
may also be stored in storage batteries, or in the storage capacity
of a PEV.
[0040] The power control appliance 410 may be controlled at least
in part by the consumer using a user interface displayed on a
display device 450. Display device 450 may be a mobile device
capable of supporting a user interface. Device 450 may connect
directly to the Internet 350, the wireless network 300, or the WAN
200, or it may connect through power appliance 410. Power control
appliance 410 may be further controlled remotely by the utility
control center 105, for example, over the Internet 350, or over a
common carrier wireless network 300. In one embodiment, the servers
110 at the utility control center 105 may receive and transmit data
and commands to the power appliance using the Internet 350, the
wireless network 300, or the WAN 200.
[0041] Further examples of power control appliances which may be
used in embodiments of the system illustrated in FIG. 1 are
described in U.S. Pat. No. 7,274,975, entitled "Optimized Energy
Management System."
[0042] In order to match electricity supply and demand, a utility
control system operator may desire to curtail load or dispatch
energy from distributed energy resources. One method of meeting a
request to dispatch or curtail energy is to command individual
distributed energy resources differently, based on the state of
each energy resource at the time the command is executed, while at
the same time attempting to ensure that the sum of all the
individual actions meets the requirements of the overall request.
In addition, it is desirable to dispatch stored energy in such a
way so as to preserve as much as possible the ability to meet
subsequent dispatch requests.
[0043] FIG. 2 shows a block flow diagram illustrating the steps of
levelizing and scheduling the dispatch of distributed energy
resources 500. Using information provided to the utility control
center 105 by distributed energy resources, such as, for example,
current stored capacity and rate of discharge, a utility creates a
dispatch event 510 using a control system such as that described
above in, for example, the utility control center 105.
Specifications for the dispatch event include the amount of power
desired during the event and the duration of the dispatch event.
Next, the accomplishability of the requested dispatch event is
determined 520. Next, if the dispatch request is accomplishable,
the amount of energy to be discharged from each participating unit
is determined 530. Then, the energy dispatch of individual units is
scheduled and the instructions for each distributed resource are
determined 540. These steps are further described below. It should
be understood that distributed energy resources can mean any device
capable of storing and discharging electricity and communicating
with a system such as shown in FIG. 1. Distributed energy resources
include the energy storage batteries of power control appliance
410, consumer power generation devices such as solar panels or
generators, and the mobile energy storage capabilities of PEV 460
or any other mobile energy storage device.
[0044] Given the specifications for a dispatch event, the
accomplishability of the requested dispatch event is determined in
step 520. One example of determining the accomplishability of a
dispatch event is discussed below.
[0045] For example, with reference to FIG. 3A, consider three
energy storage devices 610, 620, and 630. Devices 620 and 630
contain 1.8 kWh of stored energy, and device 610 contains 10.8 kWh
of stored energy. Each device is capable of releasing (dispatching)
its stored energy at 3.6 kW. A request for a constant 10.8 kW
dispatch over a 1 hour period may at first seem accomplishable
because there is sufficient stored energy to meet the dispatch
request.
[0046] However, in fact the dispatch is not accomplishable because
all three units would be required to dispatch at 3.6 kW (their
maximum rate), and at that rate devices 620 and 630 would run out
of energy in half an hour. This is shown by the inequality
10.8 = K > i n min ( Y , E ( i ) d ) = 1.8 + 1.8 + 3.6 = 7.2
##EQU00001##
where the rate is given by K and the duration given by d, for n
distributed energy storage devices capable of releasing stored
energy at a constant rate Y, where the amount of energy stored in
the i 'th device (fuel) is given by E(i). In other words, if the
conditions expressed in the inequality are met, a dispatch request
is accomplishable.
[0047] If the energy level in every device were equal, then the
above formula would become
K .ltoreq. i n min ( Y , E d ) = min ( n Y , i n E d ) .
##EQU00002##
[0048] This result has several implications. First, when the energy
levels in storage devices are kept equal, the rate at which energy
can be dispatched over a fixed duration is maximized. Second, when
the energy stored in each individual device is levelized (i.e. kept
equal relative to the energy level of other available resources), a
set of distributed generation or stored energy resources may be
treated as a single large aggregate energy storage device, with a
maximum dispatch rate equal to the sum of all the individual
dispatch rates, and the stored energy equal to the sum of all the
stored energies. Third, over multiple dispatch events where energy
is dispatched from different sub-groups of energy storage devices,
minimizing the variance in energy storage levels maximizes the
ability to meet future dispatch requests.
[0049] In step 530, if a dispatch request is accomplishable, the
amount of energy to be discharged from each participating unit is
determined. For example, with reference to FIG. 3B, consider a
hypothetical situation where two dispatch requests are made for
three distributed resources, A, B, and C, each capable of
dispatching energy at 3.6 kW and all initially filled with 10.8 kWh
of energy. The first request is for 7.2 kW for 3 hours starting at
time t, and the second request is for 10.8 kW, lasting for 1 hour,
to begin at t+3 hours.
[0050] Whether the second dispatch is accomplishable depends on how
the first dispatch is performed. The first dispatch could be
performed by instructing devices A and B to dispatch at their
maximum rate for the full three hour period, as shown in FIG. 3B.
However, in that case the second dispatch is not accomplishable
because units A and B have been drained of all their stored energy,
and unit C is only capable of dispatching at a rate of 3.6 kW. If,
however, the first dispatch levelized the stored energy of each of
the three units, one example of which is shown in FIG. 3C, then the
second dispatch would be accomplishable.
[0051] One example of an algorithm for determining participation
information for an accomplishable dispatch that maximally reduces
variance among the stored energy in the distributed resources is
provided. Other equivalent embodiments of this specific method
should be readily apparent to one of ordinary skill in the art
without departing from the scope of the method disclosed here.
[0052] n=number of units that can be considered, Y=the rate in kW
that an individual unit can dispatch, and E(i)=a function returning
the initial energy in each unit. The specification for a dispatch
request (assumed to be accomplishable) include the number of kW
requested (K) and the duration of the dispatch, (d).
[0053] M:=S:={}
[0054] U:=All available units
[0055] c:=0
[0056] D[i]:=0
[0057] let R(i)=E(i)-D[i]
[0058] while(c<dK) [0059] if(|S|=0) [0060] I={i
U:R(i)=max(R(i))}; S=I; U=U-I [0061] r:=R(i):i S [0062]
e:=min((dK-c)/|S|,dY-max(D[i]):i S,r-max(R(i)):i U) [0063]
c:=c+e|S| [0064] .A-inverted.i S:D[i]=D[i]+e [0065] if (c<dK)
[0066] l:={i S:D[i]=dY}:=M.orgate.I:S:=S-I [0067] r:=R(i):i S
[0068] I:={i U:R(i)=r}:S:=S.orgate.I:U:=U-I
[0069] Once completed, every unit for which i M .orgate. S will be
scheduled to dispatch for
D [ i ] Y ##EQU00003##
hours in order to meet the dispatch request.
[0070] Next, in step 540, when participation information has been
determined for distributed resources in an accomplishable discharge
event, the energy dispatch of individual units is scheduled and the
instructions for each distributed resources are determined. One
example of a method of scheduling the dispatch is provided. Other
equivalent embodiments of this specific method should be readily
apparent to one of ordinary skill in the art without departing from
the scope of the method disclosed here.
[0071] Let ScheduleDispatch(i,t.sub.start, t.sub.end) be a function
which commands unit i to dispatch between the times t.sub.start and
t.sub.end
TABLE-US-00001 t := t.sub.0 foreach (i .di-elect cons. I) if ( t -
t 0 + D [ i ] Y < d ) ##EQU00004## ScheduleDispatch ( i , t , t
+ D [ i ] Y ) ##EQU00005## t := t + D [ i ] Y ##EQU00006## else
ScheduleDispatch (i, t, t.sub.0 + d) ScheduleDispatch ( i , t 0 , t
+ D [ i ] Y - d ) ##EQU00007## t := t + D [ i ] Y - d .
##EQU00008##
[0072] However, the method described above does not take into
account any minimum dispatch time which a given resource may have
(e.g., because of the physical constraints of the storage unit). It
also does not address the "splitting" of the dispatch of units from
the end of the dispatch back to the beginning, as shown occurring
with unit B in FIG. 3C, which shows unit B scheduled for discharge
from time t to time t+1, and again from time t+2 to t+3. A method
of scheduling accomplishable discharges which addresses these
issues is provided below. Other equivalent embodiments of this
specific method should be readily apparent to one of ordinary skill
in the art without departing from the scope of the method disclosed
here.
[0073] FIG. 4 shows a block flow diagram of a method 700 of
scheduling the dispatch of distributed resources. First, resources
are allocated for the discharge event 710. Next, in step 720 the
start and stop times of the allocated resources are redistributed
to minimize any coincidental starting or stopping of the discharge
of resources. This is done to minimize the "ripple" (i.e.,
fluctuation in power) on the electrical grid which may be caused by
multiple resources starting or stopping simultaneously. Finally,
the start time of each resource is further changed by the addition
of a factor, to further minimize ripple. Each step is further
described below.
[0074] In step 710, resources are allocated for the discharge
event. One way to schedule resources over time is by use of a
"bin-packing" method. Resources are selected to fulfill the power
and duration requirements of the dispatch request. referring to
FIG. 5, in one embodiment, discharge intervals I(i) are scheduled
for the number of participating storage devices (N) using a
bin-packing algorithm where T is the maximum length of a bin. In
FIG. 5, a filled bin is shown at reference number 810. Many known
bin-packing algorithms may be applied to step 710, such as the
first-fit-first-descending algorithm.
[0075] The purpose of step 710 is to create full bins, since
intervals in a full bin will not require splitting. I(i) must be
equal to or less than T, and both quantities must be specified as
positive non-zero integers. Each storage unit is assumed to have
constant and identical discharge rates, and thus the only parameter
needed for each device is the duration of discharge. Units should
be chosen such that the time quantum is also the minimum allowable
discharge time of any unit.
[0076] Discharge intervals I(i) are redistributed in step 720. Full
intervals (F) are reordered to remove even ordering which may be
imposed by the allocation in step 710. In one embodiment, a hash
function may be applied to each interval to sort the intervals, for
example, by the vector (hash(bin), hash(interval+bin)). This
effectively randomizes the start and stop times of each distributed
resource to minimize "ripple" in the rate of discharge.
[0077] Next in step 730, a bin index B(i) and a starting offset
time S(i) are assigned to each interval in F. Intervals for
non-full bins (G) are scheduled by stacking them end-to-end, and
letting them wrap around the time window T shown in FIG. 5.
[0078] Let b=max(B)+1
[0079] Let p=0
[0080] For each G: [0081] if p>=T: [0082] p:=p-T [0083] b:=b+1
[0084] B(i):=b [0085] S(i):=p [0086] p:=p+1(i)
[0087] NumBins:=b+1
[0088] If S(i)+I(i)>T, the event is split across the time window
such that two discharge events are created with start time and
duration: (S(i), T-S(i)) and (0, S(i)+I(i)-T). Otherwise the
discharge event is simply (S(i), I(i)).
[0089] At the end of this step, discharge events can be created
from all intervals such that the total dispatch at any time does
not vary more than a ratio of (1/NumBins) across the time interval
T.
[0090] Next, the start and stop times are further redistributed
730. Since the intervals are of discrete size, their boundaries
will tend to line up at discrete time intervals. Multiple
simultaneous discharge start or stop events may create undesirable
"ripple" on the grid. This can be smoothed by "tilting" the
schedule. Each interval has been assigned a start time S(i) and a
bin index B(i). The tilt is defined by adding a fractional part
F(i) to each interval:
F(i)=B(i)/NumBins
[0091] The final start time for an interval is defined as:
S(i)+F(i). This will add a ramp-up and ramp-down period for all
discharging resources. The ramp-up and ramp-down time lasts exactly
one time unit, and the total dispatch power will approach a linear
curve. By adding this offset, the number of device transitions over
each time quantum is no more than (NumBins*2). Also, by adding this
offset, there will be more than two device transitions that are
less than (1/NumBins) time units apart (device transitions will
always occur in pairs).
[0092] FIG. 5 shows a graphical view illustrating scheduling of the
dispatch of multiple resources over time, where over 25% of
intervals were required to split, such as interval 820. FIG. 6
shows a graphical view illustrating scheduling of the dispatch of
multiple resources over time, where interval lengths are uniformly
distributed. Note that no intervals were required to split.
[0093] the discharge scheduling method disclosed above can include
several variations from that described. The method of
redistributing intervals after the bin-packing step can be varied.
Also, the "tilt" step may be omitted, eliminating the ramp-up and
ramp-down time at the expense of uneven state transitions.
[0094] The examples above assume that distributed resources have
constant and identical dispatch rates. However, the method may be
adapted to distributed energy resources with varying discharge
rates. For example, a slightly modified definition of
accomplishability may be used in step 520. Similarly, in the step
of determining participation information 530, distributed resources
may be levelized on the basis of their potential discharge
duration. In addition, the step of scheduling 540 may be modified
to account for variable discharge rates.
[0095] In one embodiment, slightly modifying the step of
determining accomplishability 520,
K .ltoreq. i min ( E i d , Y i ) ##EQU00009##
permits a comparison of each distributed resources' individual
dispatch rate Y.
[0096] Similarly, in one embodiment, in the step of determining
individual resource participation 530, to levelize distributed
resources with varying dispatch rates, the stored energy in every
resource should be brought to a state where each resource has a
fraction of the total remaining energy of all available resources
proportional to its dispatch rate:
E i = Y i i Y i E total ##EQU00010##
Participation information for each available resource may thus be
determined by prioritizing resources based on each unit's potential
discharge duration, such that the longer a resource may discharge
its stored energy, the greater its level of participation.
[0097] In addition, in one embodiment, in the step of scheduling
the dispatch of individual resources 540, resources may be grouped
by individual rate of dispatch and "bin-packed" by group in
accordance with the method described above. This may result in a
difference between the amount of energy requested in the dispatch
request and the amount actually delivered in the dispatch event;
however, the difference in the dispatch duration and dispatch rate
decreases as the number of participating resources increases.
Specifically, the maximum %-error is:
% error = Y max K ##EQU00011##
where Y is the maximum output rate of any unit and K is the total
dispatch rate. For example, if 100 resources are scheduled for
dispatch of a total dispatch of 330 kW and the maximum discharge
rate is 6.6 kW, then the percentage error is only 2%. It will be
evident that as the number of participating resources increases,
the margin of error will decrease.
[0098] Dispatch events may be requested in advance of the time of
the desired dispatch. However, the longer the interval of time, the
greater the chance that the condition of at least some distributed
resources may change. For example, distributed resources may have
become disabled, or in the case of mobile energy storage, the
distributed resources may be remove from the grid.
[0099] It is therefore desirable to re-evaluate the
accomplishability of a utility-commanded dispatch event repeatedly
between the time the dispatch request is initially made and the
start of the dispatch event. Such re-evaluation provides the
utility control system operator lead time to act on a notification
that a previously accomplishable event is now no longer
accomplishable because of a change in circumstances. Conversely,
repeated evaluation of accomplishability may also show that an
event that was unaccomplishable when scheduled has become
accomplishable without any further interaction by the operator. For
example, distributed resources may have been charged, or additional
mobile energy storage may have become available for dispatch.
[0100] It is also desirable to perform an accomplishability check
when a new dispatch event is created or canceled. When a new event
is created, it may affect the accomplishability of subsequent
dispatch events. For example, creating a new dispatch event before
other dispatch events may cause the later dispatch events to become
unaccomplishable (for example, due to a lack of available energy).
On the other hand, the cancellation of a dispatch event may make
later dispatch events accomplishable.
[0101] Instructions for dispatching energy from distributed
resources may be computed based upon the state of each distributed
energy resource at a specified point in time. The determination and
generation of these instructions may be referred to as processing
the event. The generation of instructions for individual resources
may be deferred until as near to the desired start time of the
event as possible, and then evaluated for accomplishability up to
the time of event execution.
[0102] Reevaluation of accomplishability allows use of the best
possible data as an input (e.g. the data closest to the start time
of the event). Reevaluation also facilitates the implementation of
event cancellation, out of order event scheduling (i.e. the ability
to submit events in an order other than the one in which they will
be executed); and maximum lead-time notification that an event has
become unaccomplishable. The latest possible moment that a
background task can process an event and still expect that all the
resources will be able to download and execute the corresponding
instructions successfully is a function of how frequently the
control system communicates with the distributed resources. If
individual resource instructions are determined too late, then
there may not be enough time for the participating resources to
receive instructions prior to the dispatch event start time, and
the event will fail to fully execute.
[0103] In an embodiment, in order to both defer event evaluation
and repeatedly evaluate the accomplishability of events, a process,
such as a software process (co-located with the control system in
utility control center 105 in one embodiment) may perform event
evaluation. Instructions for individual distributed resources are
determined no later than the sum of the following durations prior
to the start of the event; (a) the frequency at which the
background task runs (evaluation frequency); (b) the duration it
takes for the background task to complete; (c) the communication
frequency of participating resources; (d) the time it takes for the
instruction transmission to complete; and (e) other
implementation-specific delays. Since some of these intervals may
vary, implementation-specific maximum values should be chosen.
[0104] Deferred evaluation and re-evaluation of accomplishability
allows the cancellation of events that have been submitted to the
control system, but for which individual resource instructions have
not yet been determined and transmitted to distributed resources.
Re-evaluation of accomplishability also permits the scheduling of
events that are currently unaccomplishable, but which the operator
knows will become accomplishable by the desired execution time,
increasing the operator's flexibility in scheduling events.
[0105] It is important for a control system operator to know what
upcoming events are not currently deemed accomplishable and thus
require remediation. In order to confirm a cancellation of an
event, a confirmation dialog may be presented, for example, that
identifies the event and displays the event's duration, start time,
and end time. An operator may similarly be notified of a successful
or an unsuccessful cancellation of an event. For example,
notifications can be displayed to the system operator on display
115, for example, in a list that is always visible. Notification
may also be done, for example, on a schedule or dashboard view,
which quickly conveys information to an operator about events
scheduled to take place in a given time period. Notifications may
also be presented through visible cues on the schedule that
indicate unaccomplishable events in the time period of interest.
Notification may also be performed via messaging, such as by email,
fax, pager, instant messaging, or automated voice mail. In an
embodiment, unaccomplishable events are distinguished from
accomplishable ones by color, highlighting at-risk events to a
system operator.
[0106] The systems and methods heretofore described may be applied
to mobile distributed resources, such as PEVs. However, the
mobility of such resources creates issues not posed by non-mobile
resources.
[0107] Individual owners of PEVs may use the storage capability of
the PEV as part of an electricity use management system, such as
that shown in FIG. 1. Mobile energy storage may be charged during
non-peak hours, thus reducing the total cost of electricity, and
electricity can be sold back to the grid during favorable
conductions. An example of a system which permits the rescheduling
of deferrable electrical consumption to off-peak hours is described
in U.S. patent application Ser. No. 11/144,834, entitled "Optimized
Energy Management System," filed on Jun. 6, 2005.
[0108] Individual owners of mobile energy storage systems may also
permit utilities to control when the systems are charged or
discharged. Mobile energy storage may be connected to a system such
as that illustrated in FIG. 1. In addition, mobile energy storage
may be connected to a system such as that illustrated in FIG. 7.
Mobile energy storage may thus become another distributed energy
resource on the electric grid.
[0109] However, the integration of mobile energy storage into the
system introduces additional issues of availability of the
resources and accomplishability of a utility-commanded dispatch
event. By its very nature, mobile energy storage is connected and
disconnected from the electrical grid. A dispatch might be
accomplishable with the mobile energy resources that are connected
at one point in time, but may cease to be accomplishable if enough
resources are removed from the grid without offsetting arrivals.
Minor modifications to the steps of method 500 address these
issues.
[0110] To levelize and schedule the dispatch of mobile energy
resources, for example, use of a statistical method in step 520,
supplemented by information regarding the historical arrival and
departure of mobile energy resources from a specific location,
permits the determination of the probability that a
utility-commanded event utilizing mobile energy storage is
accomplishable. Such a statistical method may be used to determine
the availability of energy from mobile resources at a given
location. In an embodiment, a statistical method may use data such
as the number of mobile resources which historically enter and
leave a location during a given time period, the price of
electricity (which may be a price offered by a utility, as further
described below), and weather conditions (such as rain or snow) or
seasons (such as whether is it summer or winter) which may affect
mobile resource availability. A statistical method may also account
for the day of the week and the time of day, which may affect
availability of mobile resources, for example, at a shopping mall
or at a commuter mass transit station parking lot. A statistical
method may also account for holidays and for other events which may
affect the availability of mobile resources at given locations.
[0111] In an embodiment, a statistical method may use a historical
distribution for a given time period, to determine the available
resources for intervals of time within the duration of a requested
dispatch (each interval being a "timestep"), then to compute the
accomplishability of a requested dispatch by determining
accomplishability at each timestep.
[0112] In another embodiment, the number of arrivals may be modeled
as a Poisson distribution, and the number of departures may be
modeled as a set of Bernoulli trials, to provide a prediction of
the number of arrivals and departures of mobile resources at a
given location. Historical arrival data, for example, for the
distribution of resources, and the amount of stored energy
available, may then be used to weight the distribution of the
predicted arrivals and combine their distribution with the number
of mobile resources actually available at a given time. The
predicted distribution is then used to compute accomplishability
for each timestep. In an embodiment, a Markov Chain Monte Carlo
simulator is used to rapidly compute accomplishability.
[0113] In another embodiment, the techniques described above may be
combined, so that the result of the calculations is a weighted
average of the results. Relatively small timesteps may be used in
the determination of participation information and the scheduling
of dispatch events to minimize the probability that distributed
resources may become unavailable.
[0114] In an embodiment, a dispatch event using mobile distributed
resources is created in utility control center 105, including
specifications as discussed above. Next, the accomplishability of
the dispatch request is determined using a statistical method to
determine the availability of mobile distributed resources. Next,
if the dispatch request is accomplishable, the amount of energy to
be discharged from each participating unit is determined, and then
the energy dispatch of individual units is scheduled and the
instructions for each distributed resource are determined. The
length of the timesteps should be selected to minimize as much as
possible the number of resources which may be removed from the
electrical grid during a dispatch event, and yet reasonably
minimize the computation time required. The precise length of the
timesteps can be determined, for example, with reference to
historical data about the arrival and departure of resources from a
location. In an embodiment, the accomplishability of a dispatch
event may be increased by the inclusion in the calculations of a
"reserve" of mobile resources, to provide a buffer of redundancy in
the determination of accomplishability.
[0115] To account for transactions in which utilities buy stored
energy from or sell energy to PEV consumers, a method is required
for settling an account with an owner of mobile energy storage for
electricity charged or discharged or discharged at any
location.
[0116] With reference to FIG. 8, when a transaction is requested
1010, first the PEV owner is authenticated 1020. Next, the
transaction is authorized 1030. Finally, the accounting for the
transaction is performed 1030. These steps are further described
below.
[0117] For example, a PEV owner may drive to work and park in an
office parking lot, as may be represented by the grouping of PEVs
910 shown in FIG. 7. The PEV owner may plug in his vehicle and
identify himself to the charger. This could be accomplished, for
example, by use of a charging receptacle 920, enabled with a device
permitting the owner of the mobile storage unit to use, for example
an account number or other unique identifier, or swipe a credit
card, for identification. Similarly, the mobile resource itself may
provide identifying information to the charging receptacle. The
mobile resource may communicate with the charging receptacle using
a wired connection, or using a wireless protocol such as WiFi,
Bluetooth, or ZigBee. In an embodiment, a unique identifier is
associated with the mobile energy resource. Examples of unique
identifiers include an IP address (such as using IETF RFC 2460); a
vehicle identification number or VIN (such as using ISO standard
3779); a credit card number; and a personal identification code.
The unique identifier may be associated with the electricity
billing account of the PEV owner's home. Or, it might be associated
with an account established expressly for the purposes of the
mobile energy resource. The unique identifier is also associated
with the record of electricity consumption or dispatch, which may
include the amount of electricity consumed or dispatched, the
location, the time, and the applicable rate or rates for the
electricity.
[0118] Receptacle 920 may be any type of location configured to
charge or discharge energy from a mobile energy resource, and can
be, for example, at a commuter train station, or a shopping mall,
or a public performance venue, or an athletic stadium, or any other
similar location. Receptacle 920 may be in any location capable of
accommodating mobile energy resources, and the exemplary use of a
municipal or public parking location is in now way intended to be
limiting.
[0119] In step 1030, a transaction is authorized. For example, if
the mobile resource is plugged in to recharge outside of its home
service territory, the utility providing the electricity may use
the unique identifier to confirm with the consumer's billing entity
that a transaction should be permitted. A variety of levels of
permission may be granted. For example, the home billing utility
might approve a transaction, but only up to a certain amount; or,
the transaction could receive blanket approval; or, authorization
could be denied, for example if the consumer is delinquent in bill
payment, or if the consumer's billing utility does not have an
arrangement with the utility requested to sell or purchase
electricity. Similarly, mobile devices reported stolen may appear
on a blacklist, and can be denied authorization to charge or
dispatch. Ideally authorization should occur in real or nearly
real-time.
[0120] A transaction may also be authorized if a utility requests
the dispatch of energy from the mobile resource. In that case,
information about the mobile resource and the owner's account
information is verified, to permit a credit to be made to the
mobile resource owner's account if energy is purchased and
discharged from the mobile resource.
[0121] In step 1040, accounting for the transaction is performed.
If the mobile resource is physically within the service territory
of the utility associated with the billing account, a record of the
unique identifier and electricity exchange may be readily attached
to the resource owner's billing account. However, the location of
charging receptacle may be in the service territory of a different
electrical utility company, and settlement of a transaction in
another service territory may be handled directly between utility
companies. Alternatively, multiple electrical utilities may provide
and receive information from a central clearing house 930, which
may receive, store, and provide unique identifier and transaction
information to the relevant utilities. Information relevant to the
transaction may be provided to the central clearing house over the
Internet 350. Central clearing house 930 may, for example, have a
database of unique identifiers matched to billing electrical
utilities. The central clearing house may sort records
appropriately, and on a batch or real-time basis distribute them to
the correct electrical billing company for billing to the consumer.
A consumer's bill could thus contain roaming records from multiple
companies combined by the home company and presented to the
consumer. Utilities may charge different electricity rates for
residential or commercial customers. In an embodiment, a separate
rate may be applied for "roaming" charges.
[0122] Similarly, a credit maybe applied to the mobile resource
owner's account if energy is purchased by a utility and discharged
from the mobile resource. In an embodiment, a mobile resource owner
parks her vehicle at a parking lot in an office building in a
parking space enabled with a charging receptacle as described
above. The owner swipes her credit card on the charging receptacle
to identify herself. The mobile resource then establishes a
wireless connection to the charging receptacle and provides
information about itself. The energy stored in the mobile resource
is now available for discharge. Later that day, the utility in
whose service area the mobile resource is parked initiates a
dispatch request to the owner's mobile resource. Using the
information earlier provided, the transaction is authorized and
energy is dispatched from the mobile resource. A credit is applied
to the mobile resource owner's account for the amount of energy
dispatched. The system may take into consideration multiple charge
or discharge conditions. For example, the owner may have indicated
to the system, through an interface on the mobile resource, or
through user interface an interface such as on display device 450,
that she wishes to fully charge the mobile resource. Alternatively,
the mobile resource owner may have granted access to the mobile
resource such that the utility, in order to prepare for a discharge
event, the utility may charge the mobile resource. The systems and
methods described above may account for multiple charge and
discharge events, and thus multiple transactions.
[0123] The pre-existing onboard systems of the vehicle may be
leveraged to provide roam charging capabilities such that a single
invoice can be presented to the customer independent of where they
recharge their vehicle. An automobile's on-board telemetry system
for navigation and safety monitoring, an example of which is the GM
OnStar system, can be utilized in this respect. These systems have
cellular telephone-based communications systems combined with
on-board diagnostics that can convey the health and status of the
vehicle along with "black box" data such as speed and g-force load
sensor information prior to an airbag deployment. For smart
charging and roam charging applications of PEVs, these on-board
telemetry systems combined with an on-board user interface such as
the navigation system, can be used to have the PEV interact with
the grid.
[0124] Such systems may be configured to operate as follows. When a
user turns off the car, a pop up menu within the navigation screen
asks the user if they will be plugging the vehicle in for
re-charging at home or at another location. If the user responds in
the affirmative, then the system further asks if the user is going
to "smart charge" the vehicle. If the response is again
affirmative, the vehicle communicates with the network operations
center for the on-board telemetry system to request the charging
parameters for that particular instance. The network operations
center interfaces with a private service provider's network
operations center (NOC), which in turn interfaces with the
integrated resource planning system of a utility company to
determine the optimum charging routine for the vehicle based upon
least cost algorithms across the fleet of PEVs within the service
territory of the utility.
[0125] Once the vehicle receives the charge timing parameters, and
the user has plugged the vehicle into the electrical outlet, the
vehicle will not draw power from the outlet until the start time is
achieved. Using the on-board clock of the vehicle, it begins
charging according to the set parameters through direct control of
the power electronics onboard the vehicle. If the user selects not
to use the smart charging, then the onboard display within the
vehicle may notify the use that they may be paying a premium rate
to charge the vehicle, with appropriate acknowledgement, specific
to the utility-defined program.
[0126] If the user has chosen to roam charge the vehicle at a
location other than their billing address, then the onboard system
may ask the user to verify their location as determined by the GPS
system. User verification of address is then captured, transmitted
to the vehicle system NOC, and on to the service provider's NOC for
capture of a billing event data set. This information is then sent
on to the utility's billing system to debit the account of the user
while crediting the account of the customer where the vehicle is
being charged. This solution can be applied within residential,
commercial or municipal parking areas.
[0127] The onboard menu system may also allow the combination of
roam charge management with smart charge parameters to delay the
start of vehicle charging to match the tariff schedule of the user
as defined by the utility program.
[0128] Within this approach, there is required modified software on
the on-board vehicle system, a NOC to NOC interface between the
vehicle systems operations center and the service-provider's
operations center and a systems integration with the utility
operational environment. In this manner, no end point hardware is
required.
[0129] The systems and methods described above further permit
numerous additional applications. For example, utility operators
may command distributes mobile energy resources as they might other
resources on a network, to reduce load or to add capacity to the
electrical grid. One benefit of integrating mobile energy storage
in such a manner is that mobile energy storage can be used to
provide additional stability to the electrical grid.
[0130] However, owners of mobile storage must choose to make their
mobile energy storage available to utility operators. Market
applications of the system and method are therefore not only
possible but highly desirable. Moreover, incentives may be offered
not only to individual consumers but also to entities controlling
more than one mobile resource, such as municipalites, car rental
companies, taxi companies, or any owner of a fleet of PEVs. The
systems and methods disclosed herein may thereby provide incentives
related to fleet management. The examples described below may
therefore be applicable to consumers and to entities, and the use
of one in an example is not intended to exclude any applications or
use with the other.
[0131] For example, with reference to FIG. 7, a parking lot, such
as a municipal parking lot at a mass transit station, can be
enabled with charging facilities 920 for mobile storage, such as
PEVs 910. Further, the charging facilities (such as a "smart
charger" device) may be enabled to identify the consumer or the
specific resource, as described above. By identifying themselves to
the charging facility, consumers may choose to make the storage
capacity of their mobile storage available for command as a
distributed energy resource. A plurality of PEVs able to be
commanded by a utility operator may serve as a significant source
of stored electricity available for dispatch, and can be dispatched
using the systems and methods described above. Indeed, a number of
commandable PEVs may collectively serve a utility as a "virtual
power plant," providing a significant amount of energy available
for dispatch.
[0132] The utility has a clear motivation to incentivize consumers
to participate, because the amount of energy made available to the
utility for dispatch is potentially substantial. The utility may
reap financial benefit from the arrangement, for example, because
it may avoid bringing additional generation capacity online to
provide needed electricity. The additional capacity made available
by numerous available distributed mobile resources may also aid in
stabilizing the electrical grid through the availability of the
stored capacity. The use of the methods of levelizing and
scheduling the requested dispatches conserves the capacity of
multiple distributed mobile resources, as well as minimizing
"ripple" across the grid which may occur as a result of closely
occurring dispatch starts or stops.
[0133] A variety of incentives may be offered. For example, a
municipality may offer discounted mass transit tickets or other
discounts to consumers who park their PEVs at municipal parking
lots and take public transportation. Such discounts or coupons can
be offered at particular times of day. The discounts or coupons can
also be offered seasonally, or at any time when the need for the
availability of additional electricity exists. For example, hot
summer weather may create demand for additional electricity to meet
the needs of numerous HVAC units in operation. Consumer incentives
may be offered to draw PEV owners to make their mobile energy
capacity available, for example, at a municipal parking lot. The
utility stands to gain by purchasing the PEV stored capacity at a
fraction of the cost of bringing additional generating capacity
online.
[0134] the owners of private parking facilities may also provide
incentives to consumers to make their mobile storage capacity
available. For example, the owner of a parking lot at a shopping
mall may offer consumers a discount at a store or stores within the
shopping mall to PEV owners who park their vehicle at the shopping
mall lot and make their mobile storage capacity available for
dispatch. In an embodiment, a consumer receives a message on user
interface 1100 offering a discount at a particular store in a
shopping mall in exchange for making the storage capacity of his
mobile device available for dispatch, for example, on Saturday
between 10:00 AM and 2:00 PM. The consumer uses the user interface
1100 to accept the offer, which causes data indicating such
acceptance to be transmitted back to the utility company or a third
party service provider. The consumer then drives to and parks at
the shopping mall at a charging facility at the appointed time,
provides identification information to the charging facility, and
makes his mobile resource available for dispatch, as described
above. The shopping discount may be applied in any number of ways.
For example, the consumer's identifying information may be provided
electronically to the store so that if the consumer makes a
purchase, the discount is immediately applied to the transaction.
The consumer may be required to make his mobile resource available
for a minimum amount of time in order to receive the discount.
[0135] The available energy may be used in any number of ways. For
example, the energy made available may be used to power a store, or
a building. The mobile energy resources available in an office
building parking lot, for example, may be used to power the office
building at peak prices times, or to at least decrease the load on
the grid created by the building. Private parking facilities may
require retrofitting of existing parking, or the provision of new
parking, equipped with charging receptacles and the means to
identify consumers, as described above. However, the incentive of a
utility to enter into economic arrangements with private parking
lot owners is high, and a utility may subsidize or pay entirely for
the creation of new parking or the retrofitting of old parking to
accommodate PEVs as described herein.
[0136] Utilities and other entities may therefore use consumer
incentives to draw mobile energy resources to specific locations or
at specific times. Specific locations and times may be determined
on the basis of historical or predicted need, or on predicted
availability of mobile energy resources, using the method described
above. Furthermore, incentives may be offered to PEV owners to
discourage driving.
[0137] Incentives may be built around considerations such as
environmental factors. For example, if a weather report indicates
that a particular day is going to be smoggy, utilities may offer
incentives to PEV owners to park at municipal lots and ride public
transportation. Similarly, a utility or other entity may offer an
incentive to consumers not to drive at all on such a day. Such
incentives may be offered, for example, on the same day at
different price points. For example, on a day of heavy smog,
consumers may be offered a lower incentive for parking at a
municipal lot and using public transportation, and a higher
incentive for staying home and not driving at all. It may be that
consumers capable of telecommuting may benefit more than other
consumers. This may in turn create pressure on employers to permit
greater telecommuting, which may have an additional and
incrementally greater environmental benefit. Similarly, the
emissions of a PEV may depend on the state of health of the
battery, or on its level of charge. By taking environmental
variables into account, the systems and methods may be used to
provide behavioral incentives which tend to control auto
emissions.
[0138] With reference to FIGS. 9 and 10, in an embodiment, the
utility sends a message to participating consumers in its service
area. Such message may appear, for example, on user interface 1100
in FIG. 9, which displays messages 1110 to a user. A consumer may
choose to participate by making a selection in user interface 1200.
Similarly, a consumer may choose to participate by making her
mobile resource available at a parking location as described
above.
[0139] One way to permit incentives to be included in the systems
and methods described herein is to include a cost value in the step
of determining participation information. Cost values may be
assigned by a utility, or by the owner of a mobile resource. Cost
values may also be determined algorithmically. For example, an
electrical utility may determine a value for the energy discharged
from, or used to charge, a mobile energy resource. As shown in FIG.
10, a utility may, for example, offer a lower cost value for
electricity discharged from a mobile resource at a downtown office
location, a higher cost value for electricity discharged from a
mobile resource at a mass transit parking lot, and a yet-higher
cost value for electricity discharged from a mobile resource at the
owner's home (1220). The variable pricing thus provides an
incentive for the mobile resource owner to reduce driving (by only
driving from home to a public transportation lot) or to eliminate
it (by not driving). Additional incentives are possible. For
example, a utility may enter into an agreement with a municipality,
and may offer additional incentives to ride public transportation,
such as discounted mass transit tickets, or discounted parking at a
mass transit station. A utility may thereby create incentives for
mobile resource owners to make their mobile resources available at
particular locations and at particular times.
[0140] A utility may also enter into arrangements with other
commercial entities, or with municipalities or other governmental
organizations, and provide incentives to such larger entities. For
example, a utility may offer an incentive, such as discounted
electricity, or favorable billing rates, to a municipality to make
its vehicle fleet of mobile energy resources available at a
particular location or at a particular time. The utility make
provide levels of incentives, for example, in accordance with the
greatest need for electricity at on a particular day, or at a
particular time. The utility may thus use incentives to align the
needs of a private or public entity with the needs of the utility
to match energy supply to energy demand.
[0141] Utilities and other entities may apply other incentive
schemes to motivate consumer behavior. For example, a utility may
offer a sweepstakes style incentive, wherein, for example, the
first five thousand consumers who "enter"--by making the mobile
energy capacity available for discharge--eligible for a prize of
monetary value, or of some other value. A message 1110 may be sent
to consumers, who may elect to participate, for example, by making
a selection in a user interface 1220. Similarly, utilities seeking
to motivate consumers to participate in a dispatch event may offer
incentives in increasing steps until the desired amount of
participation capacity is met. For example, a utility seeking to
dispatch the amount of energy that may be stored in, for example,
one thousand PEVs, may offer to pay one price for energy, which may
draw four hundred participants. The utility may later offer a
higher price, for which an additional three hundred participants
may join. The utility may offer a yet higher price for stored
energy at a later point in time, at which price the remaining three
hundred participants are motivated to make available their mobile
stored energy capacity. A Dutch auction method may also be employed
to determine the lowest clearing price of energy desired by a
utility. For example, a utility may send a message, to be displayed
in user interface 1100, stating its desired to purchase 5 MW of
energy. Consumers may enter a value for their stored energy and
place bids 1230 through user interface 1100. The utility may then
purchase the desired 5 MW of energy at the lowest price at which
the entire 5 MW is purchasable from the consumers who have placed
bids.
[0142] Where owners of mobile energy resources are permitted to
indicate a cost value for their stored energy, utilities may
respond to owner-indicated values, and an electronic marketplace
for stored energy may thus be enabled by the systems and methods
herein described. For example, an owner may place a value at which
the owner is willing to sell energy to a utility and make it
available for discharge. The owner may indicate a value through a
user interface on the mobile resource, or through user interface
1200. A utility seeking to dispatch energy from mobile resources
may, for example, order the available resources in its service
territory by the average price of energy per resource, then select
resources for participation in a dispatch event from among the
lowest price set of resources for participation in a dispatch event
from among the lowest price set of resources with a high
probability of accomplishability. A utility may also discharge
smaller amounts of energy from resources with higher priced energy
and larger amounts of energy from higher priced energy. A utility
may respond to owner-set prices by increasing or decreasing the
price it is willing to pay to purchase stored energy from mobile
resource owners, for example by increasing the price it is willing
to pay in order to gain access to a larger number of resources, or
decreasing the price it is willing to pay if a surplus of lower
cost mobile storage is available. Mobile resource owners may
similarly vary the cost values which they assign to their stored
energy.
[0143] Cost values may be determined for other criteria as well.
For example, a value may be assigned based on the source of energy
used to generate the stored electricity, such as a from a coal
power plant, or from a nuclear power plant, or from a renewable
energy source such as wind or solar. The distribution of types of
energy stored may be presented 1120, and mobile resource owners and
utilities may, for example, select preferences for energy generated
using cleaner forms of generation. For example, a utility may offer
to purchase at a higher price stored energy generated from
renewable sources, such as energy generated from solar panels on a
resource owner's home. Similarly, a resource owner may, for
example, offer to purchase from the utility energy generated from
renewable sources at a higher price, creating an incentive for the
utility to use renewable energy over non-renewable sources.
[0144] A cost value for energy may also be determined
algorithmically by the system. The cost value may take many
variables into account, including time-of-day pricing, the price of
gasoline, and the usage of gasoline in charging the battery. A
value may also be assigned or determined based on the carbon
emissions associated with the energy stored. Similarly, carbon
credits may also be assigned a value, or the system may be
configured to account for carbon credits independent of an assigned
value.
[0145] Utilities may thus provide incentives to reduce emissions,
by providing an incentive to consumers to curtail driving. A
utility may similarly use incentives offered to larger entities,
such as companies, parking lot owners, and municipalities, for
similar aims. In addition, a municipality may employ incentives in
a similar fashion. For example, a municipality wishing to decrease
smog during a particular summer week may offer an incentive to
consumers to curtail driving, or to the utility to similarly
incentivize consumers. For example, a municipality may make its
vehicle fleet available to the utility for dispatch in exchange for
the utility offering incentives to consumers to curtail driving, in
order to drive down emissions.
[0146] The interface of FIGS. 9 and 10 may also be used to allow a
utility to borrow stored energy in PEVs when they are plugged into
the grid with a promise to return the energy at a later time with
no consequence to either the driving pattern or cost to the
consumer. The interfaces can allow the consumer to define their
parameters for participation along with appropriate economic
incentives and verification procedures. For instance, the consumer
might define that they always want enough energy to get home under
all electric power and that they live 15 miles away from work and
leave work at 6 pm. The boundary condition defined by the consumer
provides a window of opportunity for the utility, and when
multiplied by hundreds of thousands of available PEVs can amount to
significant peak energy availability.
[0147] In addition to providing an interface to the incentive
functions discussed above, a user interface such as that shown in
FIGS. 9 and 10 can also be used to allow the owners of mobile
energy resources such as PEVs to define their driving requirements
such as typical morning departure time, typical return time and
their tolerance for peak vs. off peak pricing. A variation of this
definition can include environmental requirements such that a
consumer can specify the source of electricity used to replenish
the stored energy in the PEV. Through software algorithms, the
utility can match their resource planning needs to the needs of the
consumer. It is possible to predict the daily load duration
requirements of the PEV by measuring the actual energy consumed by
the device and normalizing to day of week or other patterns of
usage. This information can then be aggregated within the control
system to load level a fleet of PEVs through staggered charge
management routines. A more-advanced version of this scenario
includes getting information directly from the energy storage
device to state the need to the control system at that point in
time, again with a staggered approach to the fleet of PEVs to load
level the system. From a utility's perspective, the load leveling
may be highly locational in nature to deal with distribution
capacity and congestion issues. Therefore, the PEV must be
provisioned within the control system in such a way that localized
capacity can be managed properly.
[0148] The timing of when the PEV replenishes its energy storage
may be controlled based upon a combination of time-of-use (TOU)
pricing schedules and the integrated resource plan (IRP) of the
electric utility. A schedule may be set for controlling the charge
on or off state that matches the TOU schedule or the goals of the
IRP. Separately, due to the seasonal nature of available capacity
in many areas, direct price signals may also be used alone or in
conjunction with TOU pricing schedules to control when a PEV is
re-charged. This would allow a utility to provide unfettered
re-charging during most of the year but utility-controlled during
peak seasons. No human interaction or interface required.
[0149] While the TOU schedule is simple and effective, it may not
be adequate for incentivizing consumers to participate in a smart
charging program. Peak price schemas along with corresponding
pricing signals broadcast to the network of participating devices
may be required. Another method includes using value-based pricing
in which the PEV is separately metered and has a unique tariff
apart from the other devices within the home. This reduced tariff
for the PEV (for example, $0.05 rather than the nominal $0.12) can
provide a strong incentive to participate in a smart charging
program while also optimizing the cost-benefit to the utility.
[0150] The gasoline tax is a major source of revenue for federal,
state and local taxing authorities. Typically funds collected
through the gas tax are applied (at least in part) toward
maintaining roadways and other vehicle infrastructure. However, the
increase adoption of PEVs will result in decreased use of gasoline,
and thus a decrease in the associated tax revenues. To offset the
loss of the ability to collect funds to maintain the roadway
infrastructure, a method is required to tax the electricity used in
powering PEVs.
[0151] The overall size of the tax may be determined by taking into
account the funds required to maintain infrastructure, spread over
the expected electricity required to power the extant PEV fleet. In
the event that a carbon tax is also imposed, the pollution
component of PEV use may be included in the marginal cost of
energy.
[0152] However, simply levying a tax on electricity used to charge
PEVs is unfeasible, because of the PEV's capability of
discharging--and reselling--its stored energy back to the grid.
Systems and methods such as those disclosed herein facilitate the
tracking of the charging and discharging of mobile storage
connected to the power grid. For example, information about the tax
associated with the charging and discharging of electricity from a
PEV'storage capacity may be stored by the PEV owner's electrical
utility, or by a government entity, or at the point of sale of
electricity, or at the point of sale of gasoline for the PEV, or
through a network communication system such as OnStar. Such
information may be transmitted, for example, between the PEV and
the charging receptacle, as described above. Similarly, a gasoline
point of sale ma also have the capability to transmit and receive
information from a PEV, for example, a WiFi, Bluetooth or Zigbee
enabled device or hotspot, and may exchange such information with a
PEV.
[0153] A range of options are available to a taxing authority for
recapturing gasoline consumption tax revenue lost to PEV use. In an
embodiment, the electricity delivered into PEVs is differentiated
from that delivered to other devices. A system such as that
described above may permit the identification of a PEV or its
owner. A utility, or a data clearing house, or a credit card
company, or a government entity, or another entity, may record data
on how much electricity is delivered to a specified PEV. The data
regarding charging may be reconciled against any discharges of
energy to the grid performed by the identified consumer or PEV.
[0154] In an embodiment, a national transportation electricity
accounting system may be provided. All electricity flowing into a
uniquely identifiable PEV may be aggregated into a single account
for the purposes of the transportation tax. This electricity could
be further tagged with the appropriate regional tax information in
the accounting system. The PEV electricity tax is a net tax, as
electricity delivered back to the grid will be substracted from the
account so as to accumulate an amount equal to that which is used
for transportation. The account will be separate from whatever
process is used to pay the utility or utilities delivering the
electricity. At the end of a given period, be it weekly, monthly,
or quarterly, the net electricity used for transportation may be
taxed electronically by the relevant parties.
[0155] In an embodiment, a differentiated tax may be imposed on
gasoline purchased for a PEV owner than for a gasoline-only
vehicle. The differentiated tax may be lower or higher than the tax
imposed for a gasoline-only vehicle.
[0156] In an embodiment, a PEV owner may receive a reduction in his
home electricity bill based on the tax imposed on electricity
purchased for the PEV.
[0157] While the invention has been described in detail and with
reference to specific embodiments thereof, it will be apparent to
those skilled in the art that various changes and modifications can
be made therein without departing from the spirit and scope
thereof. Thus, it is intended that the present invention cover the
modifications and variations of this invention provided they come
within the scope of the appended claims and their equivalents.
* * * * *